Why You Can Keep Trusting Your Creatine

A day or two ago, my phone started lighting up with the same link, sent to me by different people, all within the same day. A headline claiming a new study had linked creatine to cancer. My first reaction was somewhere between a sigh and a laugh, because if you've been in this industry as long as we have, this story feels less like news and more like déjà vu.

If you were around sports nutrition in the 1990s and early 2000s, you'll remember the headlines about creatine. It was going to destroy your kidneys. It would dehydrate you. It caused muscle cramps. It raised your risk of heat stroke. It wasn't safe for athletes. And, of course, the big one: it was basically a steroid.

Not one of those claims was ever backed by real evidence. But they didn't need to be, because fear travels faster than fact, and headlines don't wait for nuance. For years, that noise shaped how everyday people felt about one of the safest, most useful supplements available to them. It took over two decades and hundreds of human studies for creatine to shed that reputation and finally earn the mainstream attention it deserved, not just from the hardcore strength training crowd, but from everyday people using it to support their health, their energy, and their ageing bodies.

So when I saw this new headline circulating, I understood immediately why people were worried. What I didn't do, and what I want to walk you through instead of just repeating "don't worry," is skip past what the study actually found.

What the Study Actually Says

Here's the thing about headlines like this: they're built to be shared, not to be read. So let's actually read it.

The researchers did not show that creatine causes cancer in humans. That's not what this study set out to do, and it's not what it found. The core of the research was conducted in mice, using a forced metastasis model, meaning cancer cells were deliberately injected to spread, rather than observing how cancer naturally develops and progresses in a living body. The proposed mechanism is specific: creatine appears to activate a signalling pathway in platelets (via megakaryocytes) that helps circulating tumour cells survive their journey through the bloodstream. That's a narrower claim than "creatine causes cancer”, it's a claim about one cell type's role in helping an already-existing, already-spreading tumour cell survive transit, not about creatine initiating cancer in the first place.

The human portion of the study involved 11 healthy volunteers. None of them had cancer. They followed a high-dose loading protocol of 20 grams of creatine monohydrate per day for 14 days, well above what most people supplement with for everyday use. What researchers measured in these volunteers were platelet activation biomarkers… not tumour growth, not metastasis, not any cancer outcome, because there was no cancer to measure in the first place. We want to be straight with you about what that does and doesn't mean: it's not evidence of harm in humans, since no cancer outcome was measured. But it's also not nothing. Finding the same platelet activation signal in people that the mouse model proposed as the mechanism is a legitimate, if very early, translational data point… the kind of finding that's supposed to make a mechanistic hypothesis worth continuing to watch, not the kind you wave away.

This Isn't the First Time Creatine and Cancer Biology Have Crossed Paths

This new study doesn't sit in isolation, and we'd rather tell you that than let you find it out from someone else. There's an existing body of research, some of it going back over a decade, published in journals including Cell Metabolism and Nature Metabolism, showing creatine promoting invasion and metastasis across several cancer types, including pancreatic, colorectal, and breast cancer, through mechanisms distinct from the one in this new paper. Researchers in this field have described creatine's relationship to cancer biology as having literally "two sides," and they mean it: this is an acknowledged, ongoing scientific question, not a single outlier finding.

At the same time, there's an equally established body of research showing the opposite relationship. Creatine taken up through the SLC6A8 transporter has been shown, across multiple independent labs, to support CD8+ T cell and macrophage antitumor immunity… In some mouse models, creatine supplementation suppressed tumour growth and even worked synergistically with checkpoint-inhibitor immunotherapy.

Put together, the honest scientific picture isn't "creatine is linked to cancer" or "creatine fights cancer." It's that creatine's effect in cancer biology appears to depend heavily on which cell type is using it… platelets potentially assisting circulating tumour cells on one hand, immune cells attacking tumours more effectively on the other. That's a more complicated story than either headline, and it's also the more accurate one.

It's worth being precise about what this back-and-forth in the mouse literature does and doesn't tell us: neither side of it has been tested against actual human cancer outcomes. The real-world evidence base on creatine safety in humans (built over decades, at the doses people actually take day to day) hasn't shifted because of these mechanistic mouse findings, in either direction. That's the distinction that matters most for you, the person deciding whether to keep your daily scoop.

Why Mice Aren't the Whole Story

Human and mouse biology differ in plenty of ways relevant to how a supplement behaves in the body, and that's part of why findings in animal models don't always translate cleanly to people.

It's also why this is still very much an emerging area of research… some of the newer studies in this space are starting to incorporate human cells alongside animal models, which is progress. But progress in research doesn't always arrive with a tidy conclusion attached. Sometimes the honest answer is "we don't know yet, and here's what we're watching."

Why This Keeps Happening

I don't think the people creating this content are necessarily acting in bad faith. Many have good intentions. But they're also creating for platforms that reward alarm over accuracy, and a calm, accurate headline simply doesn't perform the way a frightening one does. The unfortunate result is that most people never make it past the thumbnail. They don't click through to the actual study. They don't see the caveats about mice, about dosage, about sample size, or the fact that this sits inside a much longer, two-sided research conversation. They just absorb the fear, and that fear is what gets repeated at the dinner table, in group chats, and in the comments section.

That's how myths get built. Not through malice, usually, but through repetition of something incomplete.

What I'd Ask You to Take With You

We are, at our core, an industry built on science, and I take that seriously. This is one mechanistic finding in a research conversation that's been running for over a decade, sitting alongside an equally real body of evidence pointing the other way. It should open a conversation, and it should keep us watching, not overwrite decades of human safety research and reassurance. If new findings emerge that seriously change the picture, we'll talk about them honestly, caveats and all. That's what we've always done.

For now, what we have is an honestly mixed, still-developing mechanistic literature and a small, short-term human sub-study that didn't measure cancer outcomes.

So take a breath, keep supplementing with your creatine as you always have, and know that we'll keep watching the research closely so you don't have to untangle it alone.

We all rise together,

Rachael Jennings | Co-Founder + CBO, Jenerise

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