The Dark Side of Metformin (Plus Natural, Safe & Healthy Methods I Use To Regulate My Blood Sugar).

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Update from Ben: please go listen to my podcast with Jay Campbell, in which we discuss updates on the information provided below, particularly:

The fear of lactic acidosis happening was based on a study from the 1940s in a massively compromised patient cohort. These patients were in end-stage renal failure and also obese and diabetic. We must be mindful that correlation does not equate to causation. While metformin has been contraindicated in moderate and severe renal impairment, the reported incidence of lactic acidosis in clinical practice has proved to be very low (fewer than 10 cases per 100,000 patients).

The studies on metformin and cardiovascular risk were also performed on a thoroughly compromised patient population group of morbidly obese diabetics who were using anywhere from 6-9 grams of metformin per day – three to five times the recommended and commonly used dose. Other studies show it’s actually the opposite: that metformin may actually reverse mitochondrial dysfunction!

Regarding B12: both B12 and folate are incredibly simple compounds to supplement with, and can easily be stacked with a metformin protocol to avoid these deficiency issues.

There have also been studies out of Taiwan showing that metformin taken by diabetics for long periods of time (12 years or longer) can nearly double the risk of Alzheimer’s and Parkinson’s, but – similar to the studies on lactic acidosis – this study involved heavy use for extended periods of time.

Regarding liver toxicity, it turns out that these issues with metformin occur in people who already have a compromised liver.

Next comes the potential impact that metformin may have on exercise performance. In the study “Impact of metformin on peak aerobic capacity”, it was shown that metformin can significantly decrease VO2 max (–2.7%), peak heart rate (–2.0%), peak ventilation (–6.2%), peak resting energy expenditure (–3.0%), and actual exercise duration (–4.1%). While these reductions were certainly slight, and potentially non-significant for the average exercise enthusiasts, they do suggest that for a professional athlete (especially a professional endurance athlete), the use of metformin may spell the difference between a 1st place finish and not even making the podium! An even newer study, recently reported in the New York Times here, highlights that metformin has also, compared to a placebo, been shown to hamper endurance and limit mitochondrial proliferation in response to an exercise protocol! And as for muscle – the bad news is that large doses of metformin negatively impact the response to strength training in healthy older individuals.

Finally, there’s the concern that metformin causes GI upset. But this seems to happen only in people with bacterial imbalances and, based on recent studies, may occur because metformin is working directly to favorably alter the microbiota. Research has shown that metformin can indeed alter the gut composition in a favorable manner by increasing levels of several different short-chain fatty acid (SFCA) bacteria and by decreasing inflammation in the gut in a manner that actually increases insulin sensitivity and lowers blood glucose! However, one newer study from September 2018 does suggest that metformin causes an “increase in abundance of opportunistic pathogens and further triggers the occurrence of side effects associated with the observed dysbiosis”. 

I’ll sum it up here: don’t use metformin if you have liver and kidney issues, and definitely don’t overdose with metformin. If you get gut discomfort while using metformin, consider waiting it out to see if your gut flora becomes balanced and your symptoms subside, which typically takes 8 to 12 weeks, and proceed with caution if you have any prexisting gut issues due to potential for bacterial imbalances in the gut flora. If you use metformin, supplement with vitamin B12 and, if you’re a woman, monitor your folate levels and consider supplementation with a good multivitamin that contains a natural form of folate like methyltetrahydrofolate (MTHF). Finally, if you’re a professional athlete or aerobic performance is very high on the totem pole for you, I’d avoid metformin.

In the recent Wired magazine article “Forget The Blood Of Teens. This Pill Promises To Extend Life For A Nickel A Pop,” it is reported how Tim Ferriss, in his recent book Tools of Titans, estimates that at least a dozen of the billionaires, icons, and world-class performers in the book take metformin.

Robert Hariri, a member of the anti-aging panel at the Vatican and co-founder and president of genetic sequencing pioneer Craig Venter’s Human Longevity Cellular Therapeutics and Ray Kurzweil, of Singularity fame, along with Ned David, co-founder of Silicon Valley startup Unity Biotechnology (which is developing its own anti-aging drugs) all also take metformin.

In fact, metformin (along with rapamycin, which I will write an article on in the near future) is now considered to be one of the new darlings of the anti-aging industry and is widely used among CEOs, Silicon Valley, many of my friends in the anti-aging industry and beyond.

So what’s my beef with this supposed wonder-drug?

It turns out that there are all kinds of potential problems with metformin. In recent years, evidence has accumulated that metformin may not be all its cracked up to be. Or at least, even if it does what it claims to do, it has a number of adverse side effects. But up until now, pharmaceutical companies have somewhat sugar-coated the drug’s effects.

In this article, I'll briefly highlight why I don't personally take metformin. I'll also introduce you to natural compounds that I personally use to regulate my blood sugar. 

Is Metformin Healthy?

Metformin falls into a category of a biguanide molecule. Biguanides are derivatives of guanidine, a naturally occurring substance found in vegetables such as turnips and cereals. They exert a blood glucose-lowering effect in type 2 (non-insulin dependent) diabetes mellitus, and since they do not increase plasma insulin concentrations and do not cause hypoglycemia (unless, as noted below, combined with exercise), they are generally regarded as antihyperglycemic (rather than hypoglycemic) agents.

But one of the problems with these type of molecules is that they can increase the generation of lactate, which then enters the circulation and produces lactic acidosis.

The study “Fatty acids revert the inhibition of respiration caused by the antidiabetic drug metformin to facilitate their mitochondrial β-oxidation” describes quite clearly this metformin effect on lactate production. But before getting into that, a quick note on phenformin. Phenformin is another member of the biguanide family and was a popular medication for diabetes starting in the 1950s. It was withdrawn from clinical use in the 1970s once it was discovered that it caused severe lactic acidosis. Although phenformin is associated with a 10- to 20-fold greater incidence of lactic acidosis than its relative metformin, metformin’s effects on acidosis are still significant enough in my opinion not to be ignored (especially if you're an athlete who is already flirting regularly with acidosis – although admittedly I've seen little performance data on metformin's effect on lactic acid formation during exercise).

Furthermore, despite being the most commonly prescribed drug for the treatment of type II diabetes for more than five decades, the bioenergetic mechanisms underlying metformin activity remain largely unknown. This ignorance of the inner workings of the drug has triggered many endeavors to uncover how exactly it works – but the results are often contradictory. The study “Cardiovascular and metabolic effects of metformin in patients with type 1 diabetes: a double-blind, randomized, placebo-controlled trial” found that while metformin may play a very wide role in managing cardiovascular risks, it doesn’t necessarily improve glycemia, and it had no average effect on insulin requirement. In fact, while there were two deaths in the placebo group, there were five among the patients allocated to metformin.

But cardiovascular risk management also falls under scrutiny under certain conditions. True, metformin may be beneficial when used on its own. But, according to the study “Reappraisal of Metformin Efficacy in the Treatment of Type 2 Diabetes,” when combined with sulphonylurea (another common antidiabetic medication), metformin can actually result in an increased risk of cardiovascular complications and all-cause mortality. Studies are inconclusive at the time being, but the drug has been shown to have no proven efficacy against microvascular complications. Indeed, the possibility that metformin is not effective at all shouldn’t be dismissed out of hand. After all, the first molecule of this type, phenformin, did induce cardiovascular risk, and, pharmacologically speaking, there’s little difference between phenformin and metformin.

All that to say, the specific efficacy of metformin to prevent death or cardiovascular disease has not been proven beyond reasonable doubt by current studies. So metformin may not be the best comparator for evaluating hypoglycemic drugs – and that’s not even the end of the story.

Metformin can also cause a deficiency of vitamin B12 levels. The study “Long term treatment with metformin in patients with type 2 diabetes and risk of vitamin B-12 deficiency” observed this effect. While the drug did cause reported improvements in cardiovascular morbidity and mortality (but, as you’ve seen, that’s already been called into question), it stimulated vitamin B12 malabsorption.

Decreased B-12 concentrations can cause increased homocysteine concentrations, which is, surprise, an independent risk factor for cardiovascular disease, particularly among individuals with type 2 diabetes. During the 52 months of the study, the placebo group experienced an increase in vitamin B-12 concentrations, while the metformin group experienced an average 19% decrease in B12 concentrations, a decrease which continues to grow over time. While the lower B12 concentrations were not a novel idea, the progressive nature was – they can result in macrocytic anemia, neuropathy, and mental changes, potentially making metformin a dangerous treatment to use.

Another study, “Metformin and Exercise in Type 2 Diabetes,” determined the effects of metformin on the metabolic response to submaximal exercise, the effect of exercise (relevant to activity patterns of type 2 diabetics) on plasma metformin concentrations, and the interaction between metformin and exercise on the response to a standardized meal. There is evidence that suggests that the benefits of exercise and metformin aren’t cumulative. In a study whose results were noted in this one, the reductions in diabetic risk were similar in a lifestyle that combined metformin and lifestyle modifications to the metformin or lifestyle alone groups.

In fact, the two adjustments may have contradictory effects on diabetes. First, metformin reduces blood glucose levels. But exercise tends to increase levels of glucagon, the hormone that deals with low blood sugar. When the two are combined, glucagon concentrations become significantly higher as the body tries to compensate for the effect of metformin. Second, by increasing the heart rate, metformin has the potential to lower some patients’ selected exercise intensity, which means it could lead to the prescription of lower exercise workloads than are commonly recommended.

So, the combination of exercise and metformin, both common prescriptions for diabetics, is likely less effective at lowering the glycemic response to a meal than metformin alone. There have also been studies out of Taiwan showing that metformin taken by diabetics for long periods of time (12 years or longer) can nearly double the risk of Alzheimer’s and Parkinson’s.

There have even been a handful of reports of metformin-induced hepatotoxicity (toxicity in the liver). In a case of nonalcoholic liver disease, metformin was pegged as the cause of jaundice, nausea, fatigue, and unintentional weight loss, two weeks after initiating treatment, due to abnormalities in liver enzymes caused by the drug. Another case involved a 73-year old Japanese woman who experienced fatigue, jaundice, nausea, vomiting, anorexia, and abdominal pain due to severe hepatotoxicity that resulted from metformin.

I recently asked Dr. Dallas Clouatre, a well-established author and consultant in the alternative and complementary medicine and nutrition field and my guest on the podcast episode How Low-Fat Diets Make You Fat, about his thoughts on metformin, and here’s what he had to say:

“My thoughts on metformin are that it is interesting but over-hyped. Keep in mind that it works primarily on the liver (30% of glucose clearance from meals) and not on the peripheral tissues (70% of glucose clearance). It likely does promote a longer ‘health span’ given that lowering insulin and IGF-1 along with mTOR, typical of caloric restriction and of those who naturally live to extreme old age, is usually a good thing. Of course, any item that keeps insulin levels low along with keeping blood glucose in the low-normal range will lower mTOR. Downsides of metformin include reduced efficacy with advancing age, reduced efficacy with prolonged use, and GI-tract issues in some individuals. Given that rehabilitation of the mitochondrial electron transport Complex I is a normal function of a good night’s sleep, for me, it is difficult to suggest the chronic intake of a drug that works by gumming up a natural process of the body.”

So Where Does This All Leave Metformin?

Despite the 20 years of positive clinical observations on metformin, these recent studies and the information above, in my opinion, have called its efficacy and overall health benefits into question.

Perhaps it’s time to broaden the horizons and look to natural alternatives that can have very similar antidiabetic, blood sugar stabilizing and longevity-enhancing effects, including many of the natural strategies and compounds I discuss in my articles “How To Biohack Your Blood Sugar Levels” and  “5 Simple Steps You Can Take To Live Longer, Banish Blood Sugar Swings & Massively Enhance Energy Levels.“, including:

So that you can equip your cupboard with compounds that can safely and naturally support your blood sugar levels, I'd like to expound on that last category of plants, herbs and spices.

Let’s begin with Ceylon cinnamon. Cinnamon has a long history both as a spice and as a medicine, and it’s unique healing abilities come from the essential oils found in its bark, which contain three active components called cinnamaldehydecinnamyl acetate, and cinnamyl alcohol. The cinnamaldehyde in cinnamon helps prevent unwanted clumping of blood platelets, which makes cinnamon anti-inflammatory.

In one study, the antioxidant effects of a cinnamon extract in people with prediabetes decreased a marker of oxidative stress by fourteen percent. Participants took 250 mg of cinnamon extract, twice per day, for twelve weeks. This is significant considering that chronic inflammation and oxidative stress plays a role in nearly every chronic disease, including diabetes.

Cinnamon also mimics the effects of insulin, which increases insulin sensitivity, making insulin more efficient at shuttling glucose into cells.  Five grams of cinnamon is all you need to do this while also reducing total plasma glucose response. Effects last twelve hours. Cinnamon also reduces fasting blood glucose, total cholesterol, and triglycerides, and it increases HDL cholesterol. And the best type of cinnamon to use? Approximately the equivalent of 2 teaspoons of organic Ceylon cinnamon per day will suffice (it is important that the cinnamon is indeed of the Ceylon variety). I like to buy it in bulk.

Gymnema Sylvestre is another potent herbal tactic for controlling glycemic variability. It has been used in traditional Ayurvedic medicine for thousands of years and has promising research around its ability to control blood sugar levels. Its blood sugar lowering effects are possibly due to it causing an increase in insulin secretion, which partially explains its ability to increase glucose utilization, with this also being due to it increasing the activities of enzymes responsible for utilization of glucose by insulin-dependant pathways. The increase in insulin secretion may be explained by Gymnema supplementation regenerating pancreatic islet beta cells, the cells responsible for sensing sugar in the blood and telling the pancreas to release the proper amount of insulin to maintain normal blood sugar levels. Gymnema also inhibits glucose absorption from the intestines and has been shown to lower serum cholesterol and triglycerides.

Gymnema Sylvestre extract administered to non-insulin-dependant type 2 diabetics at 400 mg per day for 18 months significantly reduced blood sugar, hemoglobin A1c and glycosylated plasma protein levels, with many participants lowering their diabetes medication and five participants ending with controlling blood sugar using Gymnema Sylvestre extract alone. The same reductions have occurred in people with type 1 diabetes, with Gymnema also allowing for a decrease in insulin requirements. The easiest way to use Gymnema Sylvestre is by taking one 400-600 mg capsule, standardized to contain 25 percent gymnemic acid, ten minutes before a carbohydrate containing meal.

Berberine, a compound derived from a variety of herbs including goldenseal and Oregon grape root, shows a variety of distinct benefits. It increases glucose uptake by the cells and improves insulin utilization by increasing glucose uptake pathways GLUT-4 and GLUT-1. Berberine also activates AMP-activated protein kinase (AMPK), with increased activation allowing for a reduction in fat storage, increased insulin sensitivity, reduction in cholesterol/triglyceride production, and suppression of chronic inflammation.

Berberine has also been shown to significantly reduce free fatty acids, high levels of which damage the pancreas and insulin production In one study, berberine significantly lowered fasting blood glucose, hemoglobin A(1c), triglyceride, and insulin levels in type 2 diabetics by increasing insulin receptor expression. It also improved liver function. Another study found that 500 mg of berberine taken twice per day by patients with type 2 diabetes lowered blood glucose, fasting insulin, and blood lipid levels and it was as effective at lowering blood glucose as metformin.

There’s a ton more research you can read here on berberine on everything from metabolic syndrome, PCOS, osteoporosis and much more. The standard dose of berberine HCL is 900-2,000mg a day, divided into three to four doses, taken with a meal.

What I Personally Use Daily To Regulate Blood Sugar

Since beginning to test my blood glucose continuously using a Dexcom G6 implanted in my abdomen (as I describe in detail in my last post on how to track ketones and glucose), I’ve experimented with taking THREE servings of Kion Lean each day. I’m taking two capsules before every meal, three times per day.

I realize six capsules a day is a lot, but I may actually continue this as a staple in my life extension and weight management protocol, and I’d highly recommend you try it, especially if you want to support your blood sugar levels. 

You can get it here and read up on the ingredients, but I'm going to elucidate below.

Bitter melon has only positives, as far as I am concerned. It’s fresh on my mind, because like I mentioned, when I was in New York City, I had the pleasure of spending quite a bit of time with Chef David Bouley, a world-famous Japanese cuisine expert who frequently travels to Asia to study specific food consumption and dietary habits that allow locales such as Okinawa, Japan to be such longevity hotspots. And one of the large bags of tea he brought back with him and gave to me was comprised of the same compound they ate in copious quantities before nearly every meal – you guessed it – bitter melon extract.

But I already knew of bitter melon because I’ve personally been using it in the form of a potent tiny capsule I'll fill you in on shortly, and I've been using it to manage my postprandial blood glucose levels with potent efficacy for the three years.

Taxonomically known as Momordica charantia, bitter melon may be effective in controlling blood sugar levels and regulating blood pressure. Although the precise mechanism by which it works (whether it’s through regulation of insulin release or altered glucose metabolism and its insulin-like effect) is not known, bitter melon naturally contains antidiabetic compounds like charantin, vicine, and polypeptide-p, plus some other health-boosting components like antioxidants.

Bitter melon is a popular treatment for diabetes and similar conditions among the indigenous people of Asia, South America, India, and East Africa. As noted earlier, it’s known particularly well in Okinawa, Japan. Okinawa, like the Bama County, is one of the world’s “blue zones”, an area where the average lifespan is unusually long, and it’s also where some of the longest-lived people on the planet live.

In places like Okinawa, almost every part of the bitter melon has been used in traditional medicine, including the fruit, leaves, vines, seeds, and roots. It’s used to treat everything from microbial infections to digestive issues, stimulate menstruation, heal wounds, reduce inflammation and fevers, deal with hypertension, and it’s even been used as a laxative and emetic. It also activates cellular machinery to regulate energy production (particularly AMP-activated protein kinase) and the way fats are processed by the liver.

Centuries of oral consumption have demonstrated that bitter melon is both safe and effective. And on top of all those other conditions, according to a number of animal studies, it can even reduce insulin resistance and protect against diet-induced hyperglycemia and hyperinsulinemia. It should be noted, though, that commercially-sold varietals are not nearly as effective as wild bitter melon. One study observed the effects of bitter melon on diabetic rats. Specifically, they used an aqueous extract powder of fresh, unripe melons, and found that a dose of 20 mg per kilogram of body weight reduced fasting blood glucose levels by 48%.

Part of the reason bitter melon is so darn effective is likely its effect on GLP-1 secretion. GLP-1 is glucagon-like peptide-1, a peptide released from what are called L-cells, which increase in density along the length of the intestines. It helps to raise insulin levels as a part of the incretin effect, a hormonal response that effects insulin secretion following oral glucose ingestion. A study was done to examine the role of bitter melon extract in this process, and found that through bitter taste receptors and/or a PLC β 2-signaling pathway, the melon stimulated GLP-1 release, which contributes, at least in part, to the antidiabetic activity of bitter melon through the incretin effect.

Now, before you think that by supplementing your diet with bitter melon, your insulin levels will get too high, it’s important to note that insulin levels that are regulated by GLP-1 are either reduced or, in some cases, completely absent in people suffering from diabetes. Considering that, and the fact that GLP-1 has an extremely short half-life due to rapid inactivation, it’s not likely that your insulin levels will become abnormally high by using the melon. In all likeliness, your insulin count will rise and settle at a relatively normal level. However, further studies will need to be performed to confirm this.

And there’s more.

Bitter melon, specifically a wild species called Momordica charantia Linn varabbreviata ser., can also regulate inflammation due to various diseases. Wild bitter melon and bitter melon extracts were used in a study to inhibit macrophage activity, which is a part of your natural immunological response to stress, disease, and tears in body tissues. The lipopolysaccharide (LPS)-stimulated macrophages that were targeted responded to both extracts, but especially to the wild variety of the melon, resulting in much-reduced inflammation.

As you may already know, insulin resistance is closely related to chronic inflammation induced by things like tumor necrosis factor-α (TNF- α), a compound that seeks out and destroys cancerous cells. But before jumping into the importance of TNF- α, you should memorize this chemical: triterpene 5β, 19-epoxy-25-methoxy-cucurbita-6.23-diene-3β, 19-diol – or, for short, EMCD. It’s purified from a wild species of bitter melon that was thought to activate AMP-activated protein kinase (AMPK), which itself is thought to repress TNF- α-induced inflammation.

When it was tested alongside a compound extracted from green tea that’s also reported to be anti-inflammatory, EMCD showed more obvious anti-inflammatory activity, but not by activating AMPK. It actually inhibited the activation of the IkB kinase, an important aspect of pro-inflammatory signaling, and thus, the melon extract mitigated inflammation tied to diabetes. Since inflammation is connected to shorter life spans and greater risk of conditions like cardiovascular diseases, you should definitely look into adding wild bitter melon to your diet or supplement cabinet as an anti-inflammatory strategy too.

Want more interesting reading on bitter melon extract? Check out these links:

So how does wild bitter melon promote fat burning, liver health (and of course, anti-aging)? The answer involves caloric restriction and insulin.

Wild bitter melon is health-promoting. For example, it has been found that extracts of the wild bitter melon activate cellular machinery to regulate energy production (technically AMPK-activated protein kinase) and the way that fats are handled by the liver. Activation of this metabolic pathway is important to aging. It is sometimes referred to as “exercise in a bottle” because activation of AMPK is an aspect of the benefits derived from exercise. The effect of an extract from the wild genotype of bitter melon has proved to be more powerful than others on the market and much more consistent in producing positive results.


So in summary, I'm not a huge fan of metformin, but I am a huge fan of strength training and physical activity to manage blood sugar levels for both health and longevity. For regulating my blood sugar levels, I personally consider bitter melon extract to be at the top of my list.

For me personally and based on my own continuous blood glucose testing levels I discuss in my article “The Best Way To Test For Ketosis & Track Your Blood Glucose”, bitter melon works like gang-busters to regulate blood sugar levels after my evening carbohydrate-laden meal – and with more frequent dosing at three times per day is keeping my daily average blood sugar levels in the 70-89 range consistently. All my clients already pop two capsules of Kion Lean prior to any carbohydrate-rich meal, and I do too, for the past four years. It just works.

Do you have questions, thoughts or feedback for me about metformin or managing blood sugar? Leave your comments below and I will reply!

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62 thoughts on “The Dark Side of Metformin (Plus Natural, Safe & Healthy Methods I Use To Regulate My Blood Sugar).

  1. Tina says:

    I am pre-diabetic. I have tried metformin and other blood sugar supplements at various points. I have noticed when I first take metformin at 1000-1500/day I get a surge of symptom improvements- my thinking clears up, my inflammation drops, and I have more energy and feel more lively. About 2 months into it I feel tired. and not so great anymore and I usually stop. Any ideas on why this feels so good in the beginning and then stops feeling good?

  2. Tony says:

    Metformin’s method of action is varied and it’s potential longevity impact is suspected to go beyond blood sugar management.

  3. Walter says:


    I was type 2 diabetic and I use herbs to help with managing my glucose levels.,As a herbs lover, I have learned the benefits of using herbs to help with my diabetes. One of the most beneficial herbs that I use and works great is Worldherbsclinic Diabetes herbs formula. My doctor is still surprised at how well I have been able to reverse my diabetes and High blood pressure. Sugar level normal, blood pressure normal. All thanks to Worldherbsclinic.

  4. Joshua says:

    Is Rock lotus the same as Blue lotus? I dont see the ingredient in the product and would be interested to know the species name. Cheers.

  5. Darragh close says:

    My mother is diabetic type 2 and aged 70
    She is prescribed 3 Metformin tablets per day with a strength of 850mg.
    Most days she only remembers to take one (as she has so much other medications and insulin injections to remember and she’s 70…)
    After reading this, how important is it to stress that she takes all 3 everyday.

  6. Lori says:

    I’m a clinical pharmacy specialist working in a diabetes clinic. Thank you for this interesting article.
    Hoping to obtain a reference for the information regarding metformin and tolerance/intolerance secondary to its impact on the microbiome.
    Thanks, Lori

  7. jack says:

    Hi Ben

    Interesting article

    So one of the questions I have as a endurance athlete is that it appears Berberine and Metformin act in very similar fashions. Ie ampk activation that is a consequence of mitochondrial inhibition. I have been taking Berberine as a lipid supplement primarily. Does it make sense to stop as it impacts me aerobically or does it ?


    1. Jay Campbell says:

      Hi Jack!

      This is a great question. The only honest answer is that each of us is biochemically unique and N-of-1 in our individual responses to drugs and supplements.

      If you believe Metformin impacts you aerobically then there is also the very realistic possibility Berberine will too.

      Myself, I’m using Metformin for these reasons (Berberine would not be as good but close).

      Because its the anti-sclerotic, neuro-protective, insulin suppressing, blood sugar regulating, body fat crushing, microbiome cleansing wonder drug that absolutely enhances and extends life.

      1. Brian says:

        This!!! Don’t let big Pharma funded research dissuade you. I have been on Metformin for 5 years… my health and every marker known has improved. I was fat and tired – I am now lean and full of energy. Jay C. has copious information to back up what he says.

  8. Lerry says:

    I didn’t hear anything about taking goats rue (herb) which is what metformin is derived from. Any thoughts.

  9. Jack M says:

    Why are people with normal blood sugar levels taking a medication made for people with Type II diabetes? It seems senseless despite what claims are being made. I’m a Type II, BTW, and exercise is what burns off excess blood glucose. It seems like a lot of bad decisions are being made here.

    1. Kristi says:

      Jack M, thank you for demonstrating that there are still people with common sense out there! This is clearly the most important question to be asking. One might also ask, why eat a carbohydrate-laden meal and then take a supplement to counteract it? Of course, if you can’t exercise self control on a routine basis, and I understand that given the food options in contemporary America, I guess the supplement is better than routine high blood sugar.

    2. Steven Marshall says:

      Because of impressive data linking metformin to increases in healthy life span and reduction in cancers (eg, pancreatic)!

    3. Richard Wheeler says:

      Jack, most of the top scientists ( Dr. Peter Sinclair ), and groundbreaking geneticists George Church, MD, both from the Harvard University’s aging and genetic reprogramming laboratories at Harvard University, Peter Attia MD., from John Hopkins School of Medicine and now his nationwide Institute of Longevity research, or Mark Hyman, MD Director of the Cleveland Longevity programs, along with at least 100 other respected doctors are taking it themselves because so many longevity researchers have found the 1) longest living people in history eat it in its natural form ( the French Lily – a plant) and all their double-blind studies on mammals show extremely longer lives. Any higher than 70-89 ml/d glucose level is associated with early death, via cardio and other problems. Ben is absolutely correct on the facts that athletes don’t need it (lowers workout energy -VO max.) Go to youtube and search and check it out. It’s everywhere……

      1. Matt G says:

        For what it’s worth, Peter Attia no longer takes metformin

        I think we are further from resolving this question—Is metformin a drug healthy people should take to live longer?—than I would have guessed a year or two ago. So it goes with science. I stopped taking metformin this year (after doing so for 9 years) based on entirely different data and rationale. Perhaps I will resume at some point, pending more information.

  10. Monica says:


    Is it ok to take Kion Lean, even if I am not a hard core athlete? I am looking to loose weight.

    Background: I do exercise, like an average person, gym 3 times a week (15 min of heavy weights, slow until failure, 20 min of cardio and 15 min of sauna), and keep carbs and sugars at minimum. But I am in a plateau. I also fast 24 hours from dinner to dinner every two weeks, only water. I still have some stubburn belly fat I cannot get rid of.

    1. You don't need to be an athlete for blood glucose control to have benefits. It is recommended to take it either directly before or after your most carb-dense meal.

  11. Bernadino Castilleja says:

    Why does David Sinclair take it everyday then?

    1. Sinclair’s comments on an interview is what prompted me to ask my doc about it and get a prescription. My fasting glucose was (and is) around 95-98 but I’m more motivated by the notion that metformin seems to reduce cancer.

  12. Pheobe says:

    For those of you who think Ben is off base just beware if you decide to take Metformin. Also, believing that the FDA has your back regarding safety is pretty naive. My personal experience is that it came very close to killing me and it did that at a low dosage and in the short span of about 6 days. If you have never experienced acidosis and the resulting Kussmaul’s breathing it is SCARY. Metformin has life threatening potential side effects that in my opinion and based on my research have been under reported and even suppressed. I certainly would not consider it a longevity drug by any means and I truly appreciate that Ben is one of the few people out there suggesting some caution about jumping on the Metformin bandwagon.

  13. Delisha Ragnatt says:

    Hi Ben,

    I have polycystic ovary syndrome, I’m not diabetic, but my doctor had

    me on 500mg of metformin 2x a day. I don’t want to end up with all the crazy side effects of this drug. I have tried a few natural drugs that I’ve like and I’m also from South America and we eat Kerala( bitter melon ) at least once a week I love it. Is that safe?

    1. Hi! Unfortunately, I can't diagnose or give medical advice especially given your particular issues, it is really best to discuss these matters with a health advocate you trust.
      Here are a few directories that may help you find a good functional medicine or naturopathic practitioner in your area:

      • – Find a Practitioner, including MDs, DC, ND, etc.

      • – to find an integrative health practitioner

      • – chiroprator – Use their "Find a Doctor" tool to use their directory

      • – Use their "Find a Doctor" tool to use their directory

      • – Dr. Davis is developing his own directory of practitioners




  14. Brett from WI says:

    I find it disconcerting the you can so easily say despite 20 years of positive clinical experience and then launch into some wild idea that the strange combinations of roots and everything else – which by some unexplained action is still supposedly safer and more reliable while still manageable for average people across-the-board. I find articles like this border on the edge of malpractice..except that you have no medical background with which to base a claim of malpractice against.

    And therein lies the truth. You have no clinical basis to make these claims…and anyone who follows this is foolish.

    1. Richard Wheeler says:

      WI, my thoughts, exactly. Thanks for the comment.

    2. TK says:

      If a clinical basis is a prerequisite for credibility then why are you wasting time reading independent health articles Brett? Go back to your doctor and keep your own foolish opinions to yourself.

  15. Louis lerma says:

    In 2016 I had a1c of 14* started 850 metformin once A day lower it 6.2 then to 5.0 My Doc took me off of metformin notice that nerophethy when t away when I stoped taking metformin started taking b1know I take 2000 Mg of cinnamon complex with biotin and chromium per day the problem with metformin is it only masks the underlying problem dose not cure it .I don’t think doctors know any better, but if you want to beat typ 2 diebetes eAt raw veggies three times a day stay on metformin exercise you can eat some f ish and some frozen veggies you Wil start losing Weight and your liver wi
    ‘ll detoxify and your a 1c will come Down once you get your a1c in control reverse ing your diebetes is the best thing you can do for your health more and more drugs is not the answer

  16. Carmen Cairns says:

    I agree with the “A” Team, after all Ben is a cutting edge BIOHACKER. He has to do things out of the ordinary whether people agree or not. “B” team put your anger aside and appreciate what he is doing and what he has done for science, education and the world in terms of bringing all of this awesome information to you. He takes risks that most of wouldn’t take and he educates us through his excellent written and verbal communication “For Free”, doesn’t get much better than that. Thank you Ben Greenfield for all you have done, you’re amazing.

    1. Jennifer Smith says:

      Very much agree.

  17. Lallie says:

    Reading the posts on Dark side of Metformin
    Quite scary.

    I have been on 500 n 850 n I now have neuropathy.
    My meds have now been changed .
    The answer is definitely exercise.
    Complications like fatty liver also comes along.

  18. Dorothy says:

    My doctor put me on 4000 mg of metformin a day. Now I’m in stage 5 kidney failure. So I don’t believe that form and it’s a wonder drug it’s killing me.

    1. Savanna says:

      I’m on 850 mg, I can see a doctor putting anyone on 4000mg a day. I’m sorry, it seems so extreme

      1. Savanna says:

        Sorry meant can not see

    2. CJ says:

      Bulldust, Dorothy. The max dose is 2500mg……if you seriously have a Dr prescribing 4000mg – sue them for malpractice. And the pharmacist for dispensing it.

  19. Doug says:

    Hi Ben, did you also test the other items noted above (i.e. not Kion Lean) while using the DEXCON? In addition, I’m interested in your thoughts on stacking them. Thanks for your work! Cheers, Doug

    1. I'm working on adding many of these to A NEW Kion Lean formulation and testing…stay tuned. ;)

  20. Pat V says:

    Your article presented a lot of new info giving me alot to think about and delve into. How do PCPs handle the use of these ingredients v metformin?

  21. Dave says:

    Thanks Ben for continuing to write and think about this. Ben’s recent Rogan interview, Sinclair’s Rogan interview, and Attia’s interview with Nir Barzilai have all been great resources of information on this topic. Here’s my synthesis of those sources of information and something to consider or to push me back on. This is from the viewpoint of longevity. 1. Metformin is a refined herbal medicine dervied from French lilac / Galega officinalis / Goat’s Rue. So, it has some basis in natural remedies. In fact, I think one can get French Lilac as a supplement, but I’ll leave that out of this discussion. 2. I can’t speak to Ben’s supplement line, but in general the downside of berberine, bitter melon, etc. is that as supplements they are not regulated, whereas FDA has tight regulation of metformin, which is a good for quality. 3. Metformin’s method of action is varied and it’s potential longevity impact is suspected to go beyond blood sugar management. Perhaps related, my understanding from Attia is that it is a much stronger AMPK activator than these other alternatives. Therefore, I think there is grounds for suspecting that metformin is the strongest longevity compound out of those being discussed here. Admitedly, this is somewhat at odds with the argument that exercise and metformin are not additive and Dr. Clouatre’s comments. 4. It sounds like Ben is settling on a consistent dosage of rock lotus and bitter melon, probably based on his Dexcom results. The reduced efficacy of longterm usage of that combo is not clear to me. My observation is that there is a large buffet of varied compounds such as ACV, berberine, ceylon cinnamon, bitter melon, metformin, lotus rock, gymnema sylvestre, etc. This buffet allows for a varied/rotating and (if desired) a conservative, as-meal-needed approach. I am speculating a bit here, but the strengths of such an approach would be to minimize unknown risks, minimize possible dependence / reduced efficacy, and to gain varied activation of longevity pathways. I would suspect such an approach would include further minimizing the (arguably low-already) performance, lactate, and b-12 issues of metformin. Further, half-life of metformin is around 6 hours, so rotating usage of it would allow it time to clear out of your system. I feel clearing the system would be a long-term efficacy benefit and I am not convinced of the argument that the acute-efficacy would be approaching zero with intermittent metformin usage. 5. Metformin can also be less expensive than most supplements. 6. Putting all these points together, this varied/rotating and (if desired) as-meal-needed usage model is a potential way to employ some of the benefits of metformin while minimizing its downsides. Further, by utilizing the other compounds, the ratio of usage could be customized for an individual’s parameters and daily fit (such as fasting, exercise, etc). In other words, just treat metformin like another tool in the toolbox. For all tools, none are probably perfect so, if possible, minimize their downsides and leverage their upsides.

    1. This is a very good thought pattern. I'm also going to be interviewing a physician soon who uses metformin to pick their brain about best use/best practices to avoid some of the issues I discuss in this article.

      1. Debbie Owens says:

        I am interested in finding out more about possibly reducing amount of metformin and utilizing your regimen. I currently take a 1,000 mg Metformin bid and Trulicity 0.75mg/0.5ml once weekly. My A1C is always in the pre-diabetic range. I also am inactive and overweight.


        1. Hi Debbie. I am not a doctor nor do I give medical advice. Please seek advice from a physician and be sure you have the appropriate labs taken. You can also book a consult with me for in-depth coaching:!

  22. Chris says:

    Hi Ben, great article, what about chromium picolinate?

    1. That's a good one too.

  23. Karina says:

    I got so exited reading this I new it all! :)

    Ben what do you think about NAD+?

    1. Here’s a great podcast that takes a deep dive into NAD:…

      1. Yes, this is what I was looking for :) Thanks :)

  24. Chris says:

    Ben, your out of touch on this one.

  25. Deb Gaskin says:

    I’d like TO see Ben address MG’s. The production in the belly fat apparently causes the cell sensitivity to insulin.

  26. No Sugar for Me says:

    I guess I am missing the point of this discussion. Metformin is a drug, chemically produced and available (legally) only by prescription. The only time you should ever take a chemical drug like this is when nothing natural works anymore, which means you are past wellness and fitness optimization and into the ‘sick’ category. That said, Ben presents the ‘natural approach’ to insulin regulation and here is where I have an issue. You don’t need to regulate your insulin if you are not insulin resistant for have a metabolic issue. It is relatively easy to determine this with a $15 blood glucose meter and a starter pack of strips (that they typically come with). Alternatively, your physician can run glucose sensitivity on you if they suspect diabetes. If you are anywhere close to diabetic, then you are sick and need to take action.

    Frankly, I am of the camp that says ‘sugar is the new tobacco’ and the first thing anyone at all concerned with their health does is cut out the sugar, which, BTW, is in almost everything processed. The latter is your clue to eat natural. I cut sugar years ago and am always amazed when I eat something that I probably shouldn’t at how sweet it is. I am a sugar detector now. Likewise salt, but that is a different discussion. Do I never eat a Twinkie? No, I do, probably twice a year I get the crave and when I eat them it’s like a shot of heroin (just guessing what a shot of heroin is like 😜).

    So if you are healthy you really don’t need to fuss with supplements or drugs to regulate blood sugar–exercise will do it for you.

    1. Jay says:

      I would agree with you on most points however the discussion of Metformin vs natural products such as Bitter Melon and Rock Lotus goes beyond medical treatment or even wellness discussions. The main issue at hand is anti-aging and cell longevity. Those are very different discussions when it comes to the use of these items since glycemic variability is just one of the many metabolic issues with the aging human and while avoiding sugar and processed food as you surmise does address this to some degree, Metformin and the others likely have cellular effects on many other aging pathways that for those of us not just interested in living well now but living far beyond the average lifespan of humans, these are interesting and necessary discussions. It really depends on your goals, we all have different ones.

  27. Anthony Llabres says:

    My personal opinion is that you’re simply on the wrong side of this argument regarding metformin. When one sells supplements, it can tend to skew one’s view in the endgame. Time will tell..!

    1. Chrtis says:

      Exactly, If r. Sinclair takes Metformin based on his work in the lab I do too.

  28. Jay Montgomery says:


    I am a long time listener of your podcast and reader of your articles. I currently use Kion Lean every day. My question for you as a nondiabetic health, wellness, and anti-aging enthusiast, is why does your research differ and contradict that of fellow anti-aging guru Dr Sandra Kaufmann? I would love to hear a conversation between you and her on anti-aging concepts and in particular the varying opinion and studies surrounding Metformin. As you likely know, in her book “The Kaufmann Protocol” she is quite supportive of the use of Metformin as an anti-aging supplement. When can we get a podcast with you and Dr Kaufmann discussing these ideas?

    1. HA! Her book is on my bedside to read. Should finish it in next week. Stay tuned.

      1. Jay says:

        Great!! Thank you! I read it and have customized the protocol for myself using the app. I have gone back and forth with Metformin the last few years for all the reasons you mention above. Would LOVE to hear your take on her protocol as well as a podcast soon!

      2. Chris says:

        Listen to Dr. Sinclair podcast on Joe Rogan

    2. I'm actually reading her book right now and plan to get her and another guest on the show to discuss this topic and many others. Stay tuned!

  29. Alan says:

    I’d love for you to do a podcast on dealing successfully with Diabetes II. Not everyone can afford to go to a Functional and Integrated Health Physician. Most of the doctors I’ve seen see this drug and diet as the biggest helps. I certainly know that exercise and diet are HUGE, but long term it’s been a struggle to keep the old A1C in range. A comprehensive chat about Diabetes would be helpful. I know that allot of what you speak about it geared toward folks who want to maintain glucose for health reasons and are not always faced with managing higher blood sugar levels on a regular basis. Thanks for all you do and for sharing so much great stuff!

  30. Brian says:

    Wouldn’t Metformin bee good to use while trying to lose body fat? It decreases insulin (fat storage) and increases glucagon (fat burning)

    1. In my opinion there are many other safer more natural ways to accomplish this… Fasting for instance

  31. Rob Jacks says:

    Having fatigue issues really bad. I have so many ideas and periods of clarity and excitement then get hit super hard out of the blue with fatigue. It is killing my creativity and ideals. Need to figure this fatigue issue out. Thanks Ben!

    1. I'd recommend booking a consult so we can take a deeper, more individualized approach … Here's a good resource to get started:

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