Supplement
Ornithine
The urea-cycle amino acid with small sleep trials.
Ornithine is an amino acid involved in the urea cycle and ammonia clearance. We grade Ornithine C- on evidence and C for worth-it at about $10-15 per month.
Evidence
Worth it
Typical cost: $10-15/month
What it does
Ornithine is an amino acid involved in the urea cycle and ammonia clearance. Small Japanese trials suggest it may improve subjective sleep quality and reduce morning fatigue.
What the research says
May improve subjective sleep quality
Evidence: emerging. Small Japanese RCTs; replication is limited.
DRAFT: a handful of small trials, no large replication.
Is it worth it?
DRAFT: inexpensive, but the effect size in the small trials was modest.
Typical cost
$10-15/month
Common form, not a brand recommendation
Dosage contextemerging
400-800 mg studied in the Japanese sleep trials.
Safety notes
Generally safe at studied doses; GI discomfort reported at high doses. Talk to your doctor. This page is information, not medical advice.
Longevity Lab Report
Ornithine news, graded when it happens.
New studies, dose debates, and expert shifts on ornithine, in one email a week. Free.
Changelog
Last updated 2026-10-15
- 2026-10-15|Batch 3 entry, DRAFT. Grades provisional; expert positions unsourced unless noted.