Tabula Rasa

Creatine is moving out of the muscle-and-brain box and into cancer immunology

The textbook role of creatine is a phosphate buffer. Creatine kinase keeps a reserve of phosphocreatine on hand, and when a cell burns ATP faster than its mitochondria can replace it, that reserve donates a phosphate to regenerate ATP almost instantly. Muscle relies on this during hard contractions. The same buffering chemistry exists in any cell with sharp, bursty energy demand, and a tumor-infiltrating immune cell is one of the most energy-stressed cells in the body. It has to proliferate, migrate, and execute effector functions inside a microenvironment that is hypoxic and stripped of glucose by the tumor itself.

Di Biase and colleagues at UCLA built the first direct evidence in 2019. Tumor-infiltrating T cells sharply upregulate SLC6A8, the surface transporter that pulls creatine into a cell. Knocking that transporter out in mice severely impaired the antitumor T cell response, and supplementing creatine suppressed tumor growth across several mouse tumor models. They described creatine as a molecular battery that conserves bioenergy to power T cell activity. The result that drew the most attention was a combination effect: creatine plus PD-1/PD-L1 checkpoint blockade suppressed tumors more than either alone. Checkpoint inhibitors are already frontline immunotherapy, so a cheap metabolite that amplifies them is a real translational hook.

The 2026 study from the same lab moved the mechanism one step upstream, and that is what makes it interesting rather than repetitive. T cells do not act on their own. Dendritic cells are the antigen-presenting scouts that capture tumor proteins and activate T cells in the first place, and they were not part of the original story. Kang and colleagues found that intratumoral dendritic cells also upregulate the creatine transporter and depend on creatine uptake to function. Transporter-deficient dendritic cells failed to activate and could not prime an effective CD8 T cell response. Creatine supplementation restored their activation and suppressed tumor growth in a syngeneic melanoma model. Mechanistically, creatine preserved the intracellular ATP these cells need to drive energy-dependent inflammatory signaling, which is the same molecular-battery logic operating in a different cell type. The same activation boost showed up in human monocyte-derived dendritic cells in culture, which is the first signal the biology might carry across species.

Two cautions belong on this directly. The evidence base is preclinical. It is built on mouse tumor models with in vitro human cell confirmation, and no human cancer trial has tested creatine as an immunotherapy adjunct. The senior author also holds UCLA patents on the approach, which is worth knowing when reading the framing of any single paper. Neither caveat is disqualifying, and both are standard for an early translational program, but they set the ceiling on what can honestly be claimed today.

What the two papers together establish is a coherent energetic model: creatine feeds an ATP buffer that both the dendritic cell and the T cell draw on to do metabolically expensive immune work inside a hostile tumor. That reframes a compound most people file under athletic performance as a candidate metabolic adjunct to immunotherapy, and it gives a concrete, testable rationale for the human trials that would have to come before any of this reaches a clinic.

References: Di Biase et al., Journal of Experimental Medicine, 2019 Kazak and Cohen, Nature Reviews Endocrinology, 2020 Kang et al., iScience, 2026