Related Terms

• (+)-(S)-2,5-Diaminopentanoic acid, (+)-(S)-2,5-diaminovaleric acid, amino acid, guanidinium, L-arginine, L-norvaline, L-ornithine, L-ornithine-L-aspartate, ornithine (VAN), ornithine hydrochloride, ornithinum (Latin), putrescine, (S)-ornithine, urea.

Background

• Ornithine is an amino acid found in the human body. It is made when the body disposes of excess nitrogen in the urine.

• Ornithine has been shown to stimulate energy and growth hormone, which makes it of interest to bodybuilders. It has been used to improve performance during exercise. However, studies have shown mixed results when using ornithine hydrochloride to improve exercise performance.

• Ornithine is combined with a compound called amino acid aspartate to improve liver health. Although research supports the use of ornithine for liver problems, more evidence is needed before further conclusions can be made.

Scientific Evidence

Tradition/Theory

The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious and should be evaluated by a qualified health care professional.

• Diabetes, immune function, muscle mass / body mass (anabolic effects), organ transplantation (kidney), weight loss, wound healing.

Dosing

The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.

Adults (18 years and older)

• To improve exercise performance, 1,000 milligrams of ornithine has been taken by mouth daily for seven days, followed by 3,000 milligrams after breakfast and lunch on the exercise test day. A dose of 0.1 grams of L-ornithine hydrochloride per kilogram of body mass has been taken by mouth after 30 seconds of exercise and before engaging in anaerobic cycle ergometer exercise, as well as by mouth as a one-time dose before physical activity.

• To treat ornithine deficiency, one gram of ornithine has been taken by mouth daily as a food supplement.

• To reduce blood ammonia levels, doses above five grams of ornithine have been taken by mouth.

Children (under 18 years old)

• There is no proven safe or effective dose for ornithine in children.

Safety

The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergies

• Avoid in people who are allergic or sensitive to ornithine.

Side Effects and Warnings

• Ornithine is likely safe when used in levels that are commonly found in the diet.

• Ornithine may cause blindness, muscle weakness, and upset stomach.

• Ornithine may affect blood sugar levels. Caution is advised in people with diabetes or hypoglycemia, and in those taking drugs, herbs, or supplements that affect blood sugar, such as insulin. Blood glucose levels may need to be monitored by a qualified healthcare professional, including a pharmacist. Medication adjustments may be necessary.

• Use cautiously in people who have heart disorders or in those taking agents to treat heart disorders.

• Use cautiously in people who may experience side effects due to higher protein intake than that commonly found in the diet.

• Use cautiously in people who take anabolics (agents that may increase muscle strength), growth hormones, or hormonal agents.

• Avoid in children and in pregnant or breastfeeding women, due to a lack of safety information.

• Avoid levels over 10 grams daily.

• Avoid in people who are allergic or sensitive to ornithine.

Pregnancy and Breastfeeding

• There is currently a lack of scientific evidence on the use of ornithine during pregnancy or breastfeeding.

• Avoid in pregnant or breastfeeding women due to the risk of low birthweight. Ornithine may remain in the breast milk and may increase blood levels of ornithine in infants. An animal study showed that taking ornithine during pregnancy may raise levels of plasma growth hormone and placental lactogen.

Interactions

Most herbs and supplements have not been thoroughly tested for interactions with other herbs, supplements, drugs, or foods. The interactions listed below are based on reports in scientific publications, laboratory experiments, or traditional use. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy.

Interactions with Drugs

• Ornithine may affect blood sugar levels. Caution is advised when using medications that may also affect blood sugar. People taking insulin or drugs for diabetes by mouth should be monitored closely by a qualified healthcare professional, including a pharmacist. Medication adjustments may be necessary.

• Ornithine may also interact with agents that may affect the immune system, agents used for the liver, agents that may enhance exercise performance, agents that may regulate heart rate, anabolics (agents that may increase muscle strength), blood vessel widening agents, cholesterol-lowering agents, corticosteroids, dexamethasone, dexfenfluramine, growth hormones, hormonal agents, isoniazid, methohexital, weight loss agents, and wound-healing agents.

Interactions with Herbs and Dietary Supplements

• Ornithine may affect blood sugar levels. Caution is advised when using herbs or supplements that may also affect blood sugar. Blood glucose levels may require monitoring, and doses may need adjustment.

• Ornithine may also react with amino acids, anabolics (herbs and supplements that may increase muscle strength), arginine, beta-carotene, beta-hydroxy-beta-methylburate, blood vessel widening agents, butyrate, cholesterol-lowering herbs and supplements, citrulline, dipeptide glycyl-tyrosine, fatty acids, fish oil, glutamate, glutamine, herbs and supplements used for the liver, herbs and supplements that may affect the immune system, herbs and supplements that may enhance exercise performance, herbs and supplements that may regulate heart rate, hormonal agents, lysine, nucleotides, selenium, vitamin B6, vitamin C, vitamin E, weight loss herbs and supplements, wound-healing herbs and supplements, and zinc.

Author Information

• This information is based on a systematic review of scientific literature edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

References

Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to www.naturalstandard.com. Selected references are listed below.

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