L-Ornithine

A non-essential amino acid that plays a key role in the urea cycle and ammonia detoxification.

Also known as: Ornithine

other Names
Ornithine
primary Benefits
Supports ammonia detoxification, reduces fatigue, and may enhance athletic performance.
common Dose
2-6 grams per day.
best Form
L-Ornithine or L-Ornithine HCL
timing
Can be taken before exercise or before bed.
safety Rating
Generally Safe

Overview

L-Ornithine is a non-essential amino acid, meaning the body can produce it on its own. It plays a central role in the urea cycle, a metabolic process that converts toxic ammonia into urea, which is then excreted in the urine. This detoxification process is crucial for preventing the buildup of ammonia in the body, which can be harmful to the brain and nervous system. Ornithine works in conjunction with arginine and citrulline to facilitate this process. Beyond its role in the urea cycle, L-ornithine is also involved in the synthesis of other amino acids and polyamines, which are important for cell growth and proliferation. It is often used as a supplement to support athletic performance, reduce fatigue, and promote wound healing.

Key Benefits

Reduces Fatigue

By promoting the excretion of ammonia, L-ornithine may help reduce fatigue during exercise.

Supports Athletic Performance

Some studies suggest that L-ornithine supplementation can improve measures of athletic performance such as speed and power.

Promotes Wound Healing

Ornithine is a precursor to proline, an amino acid that is essential for collagen synthesis and wound healing.

Dosage & How to Take

Dosage can vary depending on the intended use. It is often taken in divided doses throughout the day.

PurposeDoseNotes
Athletic Performance2-6 grams per dayTaken before exercise.
Ammonia Reduction3-6 grams per dayTaken in divided doses.

Best Time to Take

For athletic performance, take 30-60 minutes before exercise. For general health, it can be taken at any time.

With or Without Food

Optional

Forms & Bioavailability

FormAbsorptionBest ForNotes
L-OrnithineHighGeneral supplementation.The free-form amino acid.
L-Ornithine HCLHighImproved stability and solubility.A salt form of L-ornithine.

Side Effects & Safety

Common

  • Nausea
  • Stomach upset
  • Diarrhea

Rare

  • Insomnia
  • Headaches

Contraindications

  • Individuals with ornithine transcarbamylase deficiency should not take ornithine supplements.

Interactions

None knownNone

No significant interactions have been reported.

Scientific Research

2008PubMed

L-ornithine supplementation attenuates physical fatigue in healthy volunteers by modulating lipid and amino acid metabolism

L-ornithine has an antifatigue effect by increasing the efficiency of energy consumption and promoting the excretion of ammonia.

2002PubMed

Effects of L-ornithine supplementation on growth hormone and insulin-like growth factor-1 in humans

L-ornithine supplementation can increase growth hormone levels.

Food Sources

Meat
Fish
Eggs
Dairy products

Products With L-Ornithine

1 product in our database contains this ingredient

Frequently Asked Questions

Medical Disclaimer

This content is for educational and informational purposes only and is not intended as medical advice. Always consult with a qualified healthcare professional before starting any supplement regimen, especially if you have pre-existing health conditions or are taking medications. The statements on this page have not been evaluated by the Food and Drug Administration.