Do Muscle Building Supplements Really Cause Cancer?

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A recent study investigating muscle-building supplements and testicular cancer has been trending online and in the media because the authors reported that using muscle-building supplements was associated with a 65% increased risk for testicular germ cell cancer (TGCC). Moreover, they claim that the study results suggest taking multiple supplements for a longer period of time increases the risk even more.


This sounds pretty alarming, especially to me, since on any given day I’m typically eating about 20-40g of some kind of protein powder like goat whey or a vegan protein, downing about 5g of creatine, and depending on the time of year (and my plans for the night, heh), using colostrum for my immune system or a testosterone boosting herbal blend for drive. But just like anything, it’s also important to break down the methods used in the study to determine how the researchers arrived at this conclusion.

I relied heavily upon my friends over at Examine Research Digest to dig into the details of many of the studies and information you’ll find below. So let’s dive in and take a look, shall we?


The Study

The authors of the study recruited male hospital residents that had been diagnosed with TGCC (remember, that's the cancer I mentioned earlier) and gave them a questionnaire investigating their supplementation habits. The researchers recruited a control group from the same hospitals, using the same demographic criteria, except that the control group participants had not been diagnosed with TGCC.

Seems simple enough.

And the results of this study were deduced from the answers participants gave in the questionnaire.


The Ambiguity

However, there were a few glaring issues with this study, including one major ambiguity: researchers did not disclose how they selected the supplements that qualify as muscle-building supplements. Instead, they reported that there were 30 total supplements asked about on the questionnaire. They only specifically named creatine, whey protein powder, and androstenedione (which in my opinion, is a pretty powerful steroidal precursor far different than something like creatine or whey, and also something I personally stay far away from for those reasons).

Since the researchers did not disclose all of the supplements they investigated, it is completely impossible to know how many of the supplements contained androgens, how many have been shown to be safe, and how many were just plain old protein powder. It’s also of course completely impossible to know whether participants were using NSF-certified supplements vs. some supplement they purchased from an overseas pharmacy, a bottle of pills they grabbed out of the bargain bin at their local drugstore, or something their buddy at the gym handed them in the locker room.

Despite the ambiguity and big differences in the investigated supplements, the researchers applied their conclusion to muscle-building supplements as a whole. This doesn’t make sense when you consider just how different creatine, whey protein powder, and androstenedione are, not to mention the 27 other “mystery” supplements.


Previous Research On Cancer and Muscle-Building Supplements

Though the above study is flawed, it is still important because there is not very much existing research investigating the link between ergogenic supplements and cancer. There is no amount of research that can conclusively “prove” a supplement is not linked to cancer, but there is a lot of existing evidence for the effects of the three supplements investigated in this study. Let’s check out that evidence, shall we?


I personally use 5g of creatine daily for its nootropic and strength/power building effects. Creatine has never been conclusively linked to cancer. Early studies suggested a metabolite of creatine (formaldehyde) indicated that formaldehyde could contribute to cancer growth, but follow-up studies showed that the amount was too small to have an effect. Some studies actually suggest creatine can protect against DNA damage caused by oxidative stress when it is supplemented in conjunction with exercise, which provides further evidence that creatine does not cause cancer.

Protein powder

Protein has often been associated with cancer risk in the media, due to a number of studies, including the infamous flawed “China Study” (my fellow blogger Denise Minger has pretty thoroughly ripped that study to shred) which was also the title of a follow-up book filled with hyperbole. Since then, multiple studies have investigated the link between protein powder and cancer, but there is zero evidence to suggest a relationship exists. The only exception is heavy metal contamination, which is rare, but results in a lot of media attention when it occurs, leading people to believe it is a common problem. That’s really only the case if you’re using cheap protein powders full of other fillers, artificial sweeteners and nasty additives.


Androgens in general are associated with health risks, since they are testosterone boosters that actually work, which can increase the risk of androgen-responsive cancers, including testicular and prostate cancer. Just because a supplement is sold over the counter doesn’t mean it’s safe, particularly in the United States, where supplement regulation is more likely to be reactive than proactive. This is the one thing mentioned in the study that I’d be particularly concerned about, and I think it would have been interesting to isolate this particular muscle-building supplements effect on cancer, rather than lumping it in with all the rest.

Other supplements

Other popular pre-workout supplements, like l-carnitine, beta-alanine, and caffeine have been researched for decades and zero cancer risk has been identified in actual research that doesn’t rely upon some mysterious questionnaires from a group of male nurses.


More Research Is Needed

Though the methods used in this study are flawed, the results do provide useful evidence because they have revealed a potential relationship between cancer and muscle-building supplements. However, that doesn’t mean muscle-building supplements cause cancer or increase the risk of it. Obviously this article only scratches the surface of the issue, but ultimately:

A) much more thorough, high-quality research is needed to confirm any relationship between muscle-building supplements and cancer and;

B) as I’ve said before on podcasts, shoving oodles of protein powder into your gaping maw and including a host of other anabolic supplements (including pure and simple caloric excess) with no cycling, off-days, or less anabolic periods of time could certainly lead to undifferentiated cell growth (AKA cancer). However, moderation in pro-growth dietary supplements, moderation in calories, intermittent fasting, and a smart cycle of growth, repair and recovery is the most intelligent and safe strategy.

Furthermore, studies could continue investigating the broad category of muscle-building supplements to break them down into specific groups. That would make it much easier to determine which muscle-building supplements are harmful and which are not.

Follow-up studies could also delve much deeper into the actual ingredients included in these supplements. Though the authors mention in their conclusion that muscle-building supplements sometimes contain steroids that are not listed on the label, they also disclose that they did not do any compound analysis during the study whatsoever. That means that if the label claimed a supplement contained certain ingredients, it was taken at face value. And we know from many other studies that this simply isn’t true.



Ultimately, the results of this study cannot be used to prove a relationship between muscle-building supplements and cancer, and the methods the researchers used leave a lot to be desired. I don’t plan on throwing away my supplements just yet. But I also don’t plan on sucking down three protein smoothies a day, oodles of creatine, and some steroids thrown in for good measure anytime soon, even if my biceps may suffer slightly.

After all, it’s all about finding the ideal balance between health, performance, longevity – even if your goal is to get swole, have killer guns, and be 70’s big, right?

For more information about muscle-building supplements and testicular cancer, and an even more detailed breakdown of this latest study, stay tuned for the next issue of the Examine Research Digest, which is one of my go-to sources for the latest research and findings in exercise science and supplementation, and in the meantime, leave your questions, comments and feedback below.

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5 thoughts on “Do Muscle Building Supplements Really Cause Cancer?

  1. Dan says:

    Thank you

  2. Hi Ben, this is as always very helpful for me, thank you!
    I think that our body always needs small supplements or vitamins to work better. Especially if you are engaged in physical activity and the body often spends a lot of energy, you just need to take supplements to grow

  3. Marc says:

    Hi Ben,

    Very much enjoyed the Rich Roll podcast.

    It seems like Rich and others that I consider highly intelligent still hold on to that dang China Study.

    Any thoughts on that? It’s just a disconnect for me in regards to Rich and others I respect.

    Thanks for all you do,


    1. I went into the China Study in this podcast –… check it out. You can also take a look at this –

    2. Stephen says:

      Hi I only want to know if taking muscle blast supplement and smoking also, what is the side effects? Does it cause cancer. Plz reply me tanks
      Stephen from Nigeria

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