Study analysis · Cell reports · 2025

This common gym supplement might be the key to making cancer immunotherapy work better.

Creatine, the supplement athletes use, helps kill cancer cells and makes immune therapy work better in mice.

Reading level
Very low certainty
Level 3b · Individual case-control studyAssociation, not causation

Overview

What the study found

The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.

In simple terms

This study was done in animals, not people, and we don't know how it was done well enough to trust the results. So we can't say creatine helps fight cancer in humans — it's just a guess based on a lab experiment.

What’s the bottom line?

This study found that creatine, a supplement often used by athletes, can trigger a type of cell death called ferroptosis in colorectal cancer cells by blocking a protein (ERK2) that normally protects cancer cells.

How strong is this study?

We don't know if the scientists did this study right because they didn't tell us enough. It's like reading a recipe with no ingredients or steps — you can't tell if the cake will turn out, so you shouldn't trust it yet.

Reporting

0 / 100

  • COI disclosureconflicts of interest not disclosed
  • Data availabilitydata not shared
  • Code availabilitycode not shared
Methodology

0 / 100

  • Randomizationrandomization unclear
  • Blindingblinding unclear
  • Control groupno control group
  • Sample sizeno sample size reported
  • Follow-upno follow-up reported
Publication

100 / 100

Statistical

0 / 100

  • P-valuesno p-values reported
  • Effect sizeno effect size reported
  • Confidence intervalsno confidence intervals
  • Pre-registrationnot pre-registered

Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.

Where it sits

RCT reviews

Max 100

Randomized Trials

Max 90

Reviews of Cohort Studies

Max 85

Cohort Studies

Max 72

Reviews of Case-Control Studies

Max 63

Case-Control Studies

Max 58

Cross-Sectional & Case Series

Max 50

Expert Opinion

Max 5
StrongerWeaker
Case-Control Studies
Level 3b
6

6 / 100

Probability of being correct

Researchers compare people who have a condition (cases) with similar people who do not (controls), looking back in time for differences in exposure. Useful but more prone to bias.

This design cannot establish causation — the findings describe an association, not a cause. Study design cannot be determined from abstract; randomization, blinding, and control group status are unknown. No evidence supports causal inference.

No Conflicts

No conflicts of interest identified

No conflicts of interest or funding information were disclosed in the provided text.

The study text contains no disclosure section, funding statement, author affiliations, or industry ties. Without additional information, no conflicts of interest can be identified.

Key takeaways

  1. 01

    Creatine made tumors smaller, increased immune cells (CD8+ T cells) inside tumors, and helped anti-PD-1 immunotherapy work better in mice.

  2. 02

    Yes — if this works in humans, taking creatine might help cancer patients respond better to immunotherapy drugs.

Surprising findings

  • Creatine directly binds to ERK2 to inhibit its functionCreatine is known for energy storage in muscles — not as a direct molecular inhibitor of cancer signaling pathways.

Practical takeaways

Consider creatine supplementation if undergoing immunotherapy for colorectal cancer — but only under medical supervision.

This study was done in mice; human safety and effectiveness are unknown.

low confidence

Why this study matters

Creatine Triggers Cancer Cell Death

Creatine binds to ERK2, blocking its activation by MEK1, which reduces phosphorylation and stabilization of FSP1 — a protein that protects cancer cells from ferroptosis. This leads to cancer cell death in colorectal cancer models.

It turns a popular supplement into a potential cancer-fighting tool by activating a specific type of cell death that tumors usually avoid.

Boosts Immune Cell Infiltration

Creatine supplementation increased CD8+ T cell infiltration into tumors in animal models, helping the immune system better target cancer cells.

It suggests creatine doesn’t just kill cancer cells directly — it also helps the body’s own immune system fight harder.

Makes Immunotherapy Work Better

Creatine supplementation sensitized colorectal tumors to anti-PD-1 immunotherapy in animal models, improving treatment response.

Immunotherapy doesn’t work for everyone — if creatine makes it work better, it could help thousands of patients who currently don’t respond.

Want the whole report?

Detailed mode opens the full scientific breakdown — every score component, the methodology, conflicts of interest, the evidence analysis behind each claim, and the raw study data.