Supplements for immune function

Compared by effect and evidence certainty. Cost is not currently assessed, and nothing here is sold to you.

Probioticsgrade Bmoderate certainty— Cochrane systematic review of RCTs: probiotics reduced the number of people experiencing acute upper respiratory tract infections and shortened illness duration versus placebo, though the evidence was of low-to-moderate quality and heterogeneous.

Safety: no modeled interaction found; coverage unknown, not proven safe. Cost: not assessed. Evidence gaps: no major structured gap flagged; review the claim limitations.

Zincgrade Clow certainty— supplementation helps mainly when intake is deficient

Safety: no modeled interaction found; coverage unknown, not proven safe. Cost: not assessed. Evidence gaps: studied dose not reported; population bounds not reported; certainty or evidence strength remains limited.

Vitamin Dgrade Clow certainty— modest reduction in acute respiratory infection risk, concentrated in deficient people

Safety: minor — Magnesium is a cofactor in vitamin D metabolism; the two are complementary.. Cost: not assessed. Evidence gaps: certainty or evidence strength remains limited.

Ashwagandhagrade Dvery-low certainty— Review: ashwagandha shows immunomodulatory effects in mechanistic and early studies, but clinical evidence that it meaningfully improves immune outcomes in people is preliminary.

Safety: moderate — Ashwagandha with an SSRI may carry additive sedative/serotonergic risk; evidence is limited.. Cost: not assessed. Evidence gaps: certainty or evidence strength remains limited.