Short answer
There is no human evidence that it does. The worrying headlines come from mouse studies: some found creatine helped tumors spread, others found it helped the immune system fight them. A 2025 review by creatine researchers concluded that standard doses do not raise cancer risk in people, though a 2026 review stressed that direct human data are still missing.
The mouse studies pulling in two directions
A 2021 Cell Metabolism study found creatine promoted colorectal and breast cancer spread and shortened survival in mice. A 2026 Nature Communications study, also in mice, linked creatine to overactive platelets that helped tumors spread, and reported more reactive platelets in healthy volunteers who took it; it did not measure cancer in people. Pointing the other way, a 2019 Journal of Experimental Medicine study found creatine helped T cells fight tumors in several mouse models, and a 2026 iScience study reported similar anti-tumor effects in mice.
What human research shows
Very little, and none of it shows harm. A 2015 trial in The Journal of Physiology tested whether creatine raises cancer-linked compounds called heterocyclic amines in urine: of 576 measurements, only 9 were detectable, 3 on creatine and 6 on placebo, and diet explained them. A 2025 review in the Journal of the International Society of Sports Nutrition concluded that 3 to 5 grams a day does not increase cancer risk. Several of its authors disclose ties to creatine makers, which is worth knowing.
How to read this
A 2026 systematic review in Cureus found only preclinical studies and emphasized the absence of human data. That is the honest summary: the mouse signals are mixed and unconfirmed in people. If you have cancer or are being treated for it, the mouse findings are a fair reason to ask your oncologist before taking creatine. For everyone else, the current human evidence does not point to a cancer risk. Educational content, not medical advice.
Related questions
Did a 2026 study prove creatine spreads cancer?
No. The 2026 Nature Communications study showed tumor spread in mice. In people it only measured platelet activity, not cancer.
Should I stop creatine if I have cancer?
Ask your oncologist. The mouse results are mixed and there are no human trials in people with cancer, so it is a decision for your care team.
Read next
Sources
- Zhang et al., Cell Metabolism, 2021 (mice, metastasis)
- Xie et al., Nature Communications, 2026 (mice and platelets)
- Di Biase et al., J Exp Med, 2019 (mice, anti-tumor T cells)
- Kang et al., iScience, 2026 (mice, dendritic cells)
- Pereira et al., J Physiol, 2015 (human trial, heterocyclic amines)
- Antonio et al., JISSN, 2025 (common questions about creatine, part II)
- Shin et al., Cureus, 2026 (systematic review)
Published 2026-10-04 · Last checked 2026-10-04
Educational content, not medical advice. Made for the United States.