People mainly take L-Histidine for energy, focus, anxiety. Based on 6 first-hand reports and 4 meta-analyses & systematic reviews in the medical literature. Ranked #1283 of 2,750 overall.
Of reports that state an outcome, 100% 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: This meta-analysis found that beta-alanine is ergogenic for Yo-Yo test performance in athletes when the supplementation protocol lasts between 6 and 12 weeks and when using the level 2 variants of the Yo-Yo test.
PubMed 34024507 ↗Conclusion: Conclusions: A low strength of evidence suggests that L-carnosine supplement combined with anserine or antioxidants can slow cognitive function decline among healthy elderly or patients with probable Alzheimer's Disease or mild neurocognitive disorder. More high-quality RCTs are needed to verify these findings and to improve the certainty level of this body of evidence.
PubMed 42123986 ↗Conclusion: Current data do not support the use of L-Carnosine in the management of children with ASD due to a low number of studies and sample size available. Further studies are warranted to know the effect of L-Carnosine for ASD management.
PubMed 33704575 ↗Conclusion: The adenine and adenosine salvage pathway (PWY-6609) and the L-histidine degradation I pathway (HISDEG-PWY) were clustered in obese patients, while amino acid biosynthesis and degradation pathways (HISDEG-PWY, DAPLYSINESYN-PWY) were decreased. This study identified obesity microbial biomarkers, providing fertile targets for the management of obesity.
PubMed 35889949 ↗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.
“I feel totally awake after taking it, though there is a little bit of auditory hallucination type stuff after taking it”
“500mg of L-Histidine significantly increases my Alertness, Motivation, Wakefulness and Sex-drive.”
“taking histamine-increasing supplements like Zinc, L-Histidine, Manganese, Nicotinic Acid and Vitamin C.”
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 3, 2026. How we rate