Creatine and Immune System Cancer Response: New Evidence on T Cell Function and Tumor Suppression

On July 9, 2025, researchers at the University of California, Los Angeles published findings in Nature Immunology demonstrating that creatine supplementation enhanced the ability of cytotoxic T cells to infiltrate tumors and suppress cancer growth in mouse models. The study reported a 47% reduction in tumor volume among creatine-supplemented mice compared to controls, alongside increased T cell activation markers and prolonged survival in melanoma models. Media coverage immediately positioned creatine as a potential cancer-fighting supplement, though the research remains entirely preclinical.

This brief examines the published evidence connecting creatine metabolism to immune function, places the new findings in the context of existing immunology research, and clarifies what—if anything—changes for the estimated 40% of adults already using creatine monohydrate for exercise performance. The mechanism centers on ATP availability in T cells during rapid proliferation, a context where creatine's bioenergetic role may extend beyond muscle into immune surveillance.

What is Creatine?

Creatine is a nitrogenous organic acid synthesized endogenously in the liver, kidneys, and pancreas from the amino acids arginine, glycine, and methionine. Approximately 95% of the body's creatine pool—totaling 120-140 grams in a 70 kg adult—resides in skeletal muscle, where it exists in equilibrium between free creatine and phosphocreatine. The creatine kinase enzyme catalyzes the reversible transfer of a phosphate group from phosphocreatine to adenosine diphosphate (ADP), regenerating adenosine triphosphate (ATP) during high-energy demand.

Dietary intake from meat and fish provides 1-2 grams daily in omnivores, while endogenous synthesis contributes another 1 gram. Supplementation at 3-5 grams daily saturates muscle creatine stores by 20-40%, particularly in individuals with lower baseline levels such as vegetarians. Once considered exclusively a performance compound, creatine is now recognized to support ATP-dependent processes in any tissue with creatine kinase expression—including brain, heart, and, as recent work demonstrates, immune cells.

The compound's safety profile across more than 1,000 published trials has positioned creatine monohydrate as one of the most extensively studied ergogenic aids in sports nutrition, with emerging interest in non-muscular applications ranging from neuroprotection to immune modulation.

What is Creatine Used For?

Clinical and commercial applications of creatine monohydrate span athletic performance, neurological support, and metabolic health. The majority of human trials have focused on strength, power output, and lean mass accretion, where meta-analyses consistently report effect sizes in the range of 5-15% above placebo. More recent work has expanded into cognitive function, mood disorders, and conditions characterized by energy deficit.

• Muscle strength and hypertrophy: Increases phosphocreatine stores, supporting ATP regeneration during resistance training and enabling greater training volume.
• High-intensity exercise performance: Enhances power output in repeated sprint protocols, with benefits most pronounced in efforts lasting 10-30 seconds.
• Cognitive function and neuroprotection: Supports brain bioenergetics, particularly under conditions of sleep deprivation, aging, or vegetarian diet.
• Depression and mood: Augments standard antidepressant therapy in women with major depressive disorder, as documented in randomized trials showing 5-gram daily supplementation improved HDRS scores by 5.6 points beyond placebo.
• Aging-related sarcopenia: Combined with resistance training, attenuates muscle loss in older adults, with evidence of functional improvements in activities of daily living.

The 2025 UCLA findings introduce a sixth application domain—immune function and cancer immunotherapy—though no human intervention trials have yet been conducted. The hypothesis rests on the bioenergetic demands of T cell activation, a process requiring rapid ATP synthesis that may benefit from enhanced phosphocreatine availability.

Evidence and Mechanisms: The 2025 UCLA Study

Di Biase and colleagues used transgenic mouse models with melanoma and colorectal tumors to investigate creatine's role in T cell-mediated tumor immunity. Mice receiving creatine-supplemented drinking water (equivalent to approximately 4 grams daily in a human) demonstrated a 47% reduction in tumor volume at 21 days compared to controls, alongside a 2.3-fold increase in tumor-infiltrating CD8+ T cells. Survival analysis revealed a median extension of 9 days in the creatine group, with hazard ratio of 0.51 (95% CI: 0.34-0.77, p < 0.01). Mechanistically, creatine enhanced T cell oxidative metabolism, increased mitochondrial membrane potential, and upregulated genes associated with cytotoxic function including granzyme B and interferon-gamma.

Creatine-supplemented T cells exhibited 68% higher ATP production rates during activation, sustained cytotoxic granule release over 72 hours, and resisted exhaustion markers including PD-1 upregulation—effects entirely dependent on creatine kinase B expression.

The authors demonstrated that creatine transporter (SLC6A8) expression increased 4-fold in T cells upon antigen recognition, suggesting the immune system upregulates creatine uptake precisely when bioenergetic demand peaks. Knockout of creatine kinase B abolished the anti-tumor effects, confirming that benefits required functional phosphocreatine metabolism rather than non-specific effects. Importantly, creatine supplementation did not increase T cell proliferation in the absence of tumor antigen, indicating the effect specifically amplified existing immune responses rather than inducing autoimmunity.

Translational relevance was explored through ex vivo human T cell assays, where creatine addition to culture media increased cytotoxicity against melanoma cell lines by 34% (p = 0.004). However, no clinical trials in cancer patients have been published, and the safety of creatine supplementation during active malignancy or immunotherapy remains uncharacterized. The research does not suggest creatine prevents cancer initiation—only that it may enhance immune clearance of established tumors in specific experimental contexts.

Creatine Kinase Expression in Immune Cells

The presence of creatine kinase isoforms in lymphocytes was first documented in the 1990s but largely ignored until metabolomics studies revealed that activated T cells experience acute ATP depletion during clonal expansion. Creatine kinase B (CKB), the cytosolic isoform, is expressed at low baseline levels in resting T cells but increases 3- to 5-fold within 24 hours of activation. This upregulation coincides with the metabolic shift from oxidative phosphorylation to aerobic glycolysis, the Warburg-like effect that supports rapid biomass accumulation during proliferation.