L-Ornithine Hydrochloride

Recovery & relaxation

Function & benefits

A non-protein amino acid at the heart of the urea cycle in the liver; it helps convert ammonia from protein metabolism and muscle effort into urea that leaves the body in urine, and a clinical study suggests it eases fatigue and supports sleep quality.

Dosage & how to use

Recommended dose	2–3 g daily (up to 4 g)
Best time to take	An hour before bed on an empty stomach, or after hard training
Frequency	Once daily

Best forms to choose

Pure L-ornithine hydrochloride, sometimes combined with L-arginine.

Important warnings

Large single doses (more than 7 g) can cause abdominal cramps and diarrhoea

Not for people with the rare inherited ornithine aminotransferase deficiency

Avoid during pregnancy and breastfeeding

Drug interactions

Safe with most medicines; take it two hours apart from epilepsy medication.

View in the supplements guide

Related supplements

Scientific references

Miyake M et al. Nutr J 2014 — PMID: 24889392

📚 Published sources and research: European Food Safety Authority (EFSA) • National Institutes of Health (NIH - ODS) • PubMed / Cochrane databases

Content last updated: 17 October 2026 · Based on published sources and research (EFSA / NIH / PubMed)

⚖️ Medical disclaimer: The information and data provided here are for health education and nutritional guidance only. They are not a medical diagnosis and never replace a direct consultation with your doctor or pharmacist. Always consult your doctor before starting any supplement, especially during pregnancy or breastfeeding or when taking long-term medication.