Probiotics
probiotic capsules and powders. Fish oil & probiotics.
- Verdict
- UnclearThere isn't enough human evidence to say either way.
- How sure
- Rung 2 · LimitedFew, small or conflicting human studies, or only indirect measures such as blood markers.
The rung shows how sure the science is, not how big the effect is. How to read these ratings
Cancers affected
Melanoma, during immunotherapy
What the evidence shows
In a 2021 study (Science) of people with melanoma on immunotherapy, those who ate enough fiber and didn't take probiotic supplements responded best (82% vs 59%). Probiotics alone weren't significantly linked to survival in people, but in mice they weakened the response to immunotherapy.
What to do
If you're on immunotherapy, ask your care team before taking probiotic supplements. Fiber-rich foods look helpful.
Sources
Spotted an error? Tell us and we’ll check it against the sources.
Related
Every supplement we rated, or follow one cancer step by step: breast cancer, colorectal cancer, lung cancer and prostate cancer.