People mainly take Vitamin B3 for mood, sleep. Based on 10 first-hand reports and 11 meta-analyses & systematic reviews in the medical literature. Ranked #1431 of 1,974 overall.
Of reports that state an outcome, 0% are positive.
Of the people who reported each effect, the share who said it got better.
Systematic reviews and meta-analyses from PubMed, with their published conclusions.
3+ meta-analyses or systematic reviews and 10+ randomized controlled trials in humans. The grade measures how much human research exists — read the conclusions below for what it found.
Conclusion: The present meta-analysis shows, by pooling immunocompetent and immunosuppressed patients, that there is insufficient evidence that oral nicotinamide therapy significantly reduces the number of keratinocyte cancers.
PubMed 38201930 ↗Conclusion: Acupuncture, acupressure and topical capsaicin have the largest body of evidence for efficacy in the treatment of UP. Larger and higher quality RCTs are required to examine the efficacy and safety of promising CAM.
PubMed 33197658 ↗Conclusion: In a meta-analysis of seven trials of secondary prevention, niacin was associated with a significant reduction in cardiovascular events and possible small but non-significant decreases in coronary and cardiovascular mortality.
PubMed 20208032 ↗Conclusion: The results showed that vitamins A, C, and E had no significant effect on male and female sexual function. The conduction of trials with long-term interventions is recommended to reach a more definitive conclusion about the effect of vitamins on sexual function.
PubMed 33779240 ↗As stated by users — not a recommendation. Follow the label or your doctor.
How often each side effect came up across all reports.
Verbatim quotes, shortened only — each links to the original discussion.
“You also want to combine resveratrol (500mg+) with vitamin B3(500mg).”
“Vit B3”
“He actually suggested I add Blackmores Insolar high dose B3 for my skin.”
“take anti inflammatory supplements like Vitamin B3, Magnesium, NAC and CBD (sometimes THC)”
“Vitamin B9 needs Coenzyme B3 and coenzyme B2 to make MTHF”
User data from public discussions; research from PubMed. Information only, not medical advice — talk to a doctor before starting, stopping or combining anything. Data updated October 2, 2026. How we rate