What is the recommended dose of L-Ornithine?

- **Look for:** L-ornithine HCl; dose ≥2g per serving for exercise; LOLA form for liver applications - **Avoid:** Low-dose capsules (<500mg); D-ornithine; products marketed as "HGH boosters" (GH in...

Is L-Ornithine safe to take daily?

L-Ornithine is rated "Generally Safe" based on clinical evidence. Always consult your healthcare provider before starting any supplement.

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Ingredient Research

Graded against 173,636 supplements + 177 published clinical interactions, sourced from PubMed, FDA CAERS, openFDA, NIH DSLD

L-Ornithine

MODERATE EVIDENCEAmino AcidLast updated

AVELOR SUMMARY

L-ornithine is a non-proteinogenic amino acid (not incorporated into proteins) that plays a central role in the urea cycle — the body's primary system for removing ammonia. Our research shows the primary supplemental benefit is ammonia detoxification during prolonged exercise and in liver disease. A 2010 RCT found L-ornithine supplementation reduced fatigue by 52% in a cycling test and lowered blood ammonia by 28%. L-ornithine also stimulates growth hormone (GH) release during sleep, but the magnitude is too small to produce meaningful body composition changes. The most evidence-backed application is hepatic encephalopathy treatment (L-ornithine-L-aspartate, or LOLA).

WHAT IT DOES

L-ornithine is a key intermediate in the urea cycle — the metabolic pathway that converts toxic ammonia (NH₃) to urea for excretion. During intense or prolonged exercise, ammonia accumulates from amino acid catabolism and AMP deamination, contributing to central and peripheral fatigue. Supplemental ornithine provides additional substrate for the urea cycle, accelerating ammonia clearance. For GH release, ornithine stimulates the anterior pituitary via inhibition of somatostatin. The sleep improvement mechanism involves cortisol reduction — ornithine accelerates ammonia clearance, reducing hypothalamic stress signaling.

OPTIMAL DOSAGE

Look for: L-ornithine HCl; dose ≥2g per serving for exercise; LOLA form for liver applications
Avoid: Low-dose capsules (<500mg); D-ornithine; products marketed as "HGH boosters" (GH increase is real but clinically meaningless for body composition)
Minimum effective dose: 2g for exercise fatigue; 400mg for sleep
Third-party tested brands: NOW Foods, Jarrow Formulas, bulk powder (transparent)

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SAFETY PROFILE

Critical Interactions (Do Not Combine Without Medical Supervision)

No critical interactions identified.

Moderate Interactions (Monitor Closely)

Theoretical/Low-Risk Interactions

WHO SHOULD BE CAREFUL

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BCAAs / EAAs

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Independently graded against 173,636 indexed supplements with 177 published clinical interactions, sourced from PubMed, FDA CAERS, openFDA, and NIH DSLD | Last updated:

Not medical advice. Based on published clinical research and systematic reviews.

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