Your Gym Supplement May Also Be a Secret Weapon Against Cancer

A Familiar Supplement, a Surprising New Role

Creatine is typically associated with bodybuilding as a supplement to help people build muscle, improve performance, and aid recovery after exercise. But a new study from UCLA researchers is turning heads in the oncology world, suggesting this over-the-counter powder might do something far more profound — help the immune system fight cancer.

The study, published in iScience, found that creatine boosts the activity of dendritic cells, specialized immune cells that detect tumors and activate the killer T cells responsible for destroying cancer. The findings suggest that creatine, which is best known for supporting muscle performance and exercise recovery, may also help immune cells meet the intense energy demands involved in detecting and fighting tumors.

The Immune System's Scouts Need Energy Too

Dendritic cells function as scouts within the immune system. They identify potential threats, collect pieces of abnormal or foreign cells, and present those materials to T cells — a process that allows T cells to recognize a specific target and mount a focused immune attack. When dendritic cells are weakened or unable to function properly, the body may have greater difficulty generating an effective response against cancer.

Using metabolomics analyses, researchers found that creatine supplementation raised intracellular ATP levels in dendritic cells — ATP being the energy currency cells use to power virtually every function — and sustained the key inflammatory signaling pathways needed for activation. The researchers compared creatine's role to that of a rechargeable battery, allowing dendritic cells to store and release energy as needed, even while competing with rapidly growing tumor cells for limited nutrients.

When creatine-deficient dendritic cells were grown alongside T cells in a lab dish, those T cells divided less and produced fewer of the signaling molecules needed to fight cancer. Then the team flipped the experiment. Giving daily creatine injections to mouse models of melanoma significantly slowed tumor growth and boosted both the abundance and the activation of tumor-infiltrating dendritic cells. Creatine-treated dendritic cells also produced higher levels of chemical signals that draw additional immune cells into the tumor.

Why This Matters for Modern Cancer Treatment

Many modern cancer immunotherapies work by activating killer T cells — immune cells that can identify and destroy cancer. However, only about 20 to 40 percent of patients experience major benefits from these treatments. That stubborn gap is exactly what makes this research so compelling. As Lili Yang, senior author of the study and a professor of microbiology, immunology, and molecular genetics at UCLA, explained: "What this study shows is that creatine doesn't just help the T cells fighting cancer — it also energizes the entire infrastructure that supports and guides them."

Creatine treatment enhanced the activation of human monocyte-derived dendritic cells, which are often used in dendritic cell cancer vaccines, and improved their ability to stimulate human T cells against a cancer-associated target. The findings suggest that incorporating creatine during the manufacturing of dendritic cell vaccines may boost their therapeutic potency.

Promising, But Not a Green Light — Yet

The science is far from routine treatment. The work was preclinical, done in mice and human cells, not in cancer patients. An estimated 2.1 million people will be diagnosed with cancer in the U.S. in 2026, according to the National Cancer Institute, including more than 100,000 expected cases of melanoma, the most serious form of skin cancer — making the urgency to develop better immunotherapy tools very real.

The new study extends a line of research the UCLA lab began in 2019, when it showed that creatine uptake was critical to CD8 T-cell anti-tumor activity. In that earlier mouse work, creatine supplementation improved suppression of skin and colon cancer tumors, using a dose the team described as comparable to what athletes and bodybuilders safely take. With each study, the picture grows clearer: creatine's role in the body may be far bigger than the gym. Human clinical trials will be the next critical step in determining whether this widely available supplement can genuinely change outcomes for cancer patients.