Probiotics vs Creatine

for mood

Stronger evidence: tie

Stronger effect: tie

Safety: No notable interactions recorded for either.

For mood, the two are evidence-matched; the difference is in effect and safety.

Probiotics

grade C low certainty

small effects on mood/anxiety in some "psychobiotic" trials; strain-specific, heterogeneous

strain-dependent, adults

Creatine

grade C low certainty

emerging evidence as an adjunct for depressive symptoms; trials small

3–5 g/day, adults with depression
sources: PMID:42221774 · PMID:42180567