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L-Ornithine HCL Side Effects

author image Catherine Frances
Catherine Frances began writing professionally in 2011. She graduated magna cum laude from Pepperdine University in Malibu, Calif., earning a B.S. in nutritional science. While at university, she competed as a sprinter on Pepperdine’s NCAA Division 1 track team. Frances has worked as a Peer Nutrition Educator and also volunteered in medical-surgical and postpartum departments of a hospital.
L-Ornithine HCL Side Effects
L-Ornithine HCL is commonly used by bodybuilders Photo Credit Jupiterimages/Brand X Pictures/Getty Images

L-Ornithine HCL is a supplement that many athletes and bodybuilders use to gain an athletic edge. Supplement websites say that adding L-Ornithine HCL powders to any workout routine increases tissue growth and leads to more lean muscle mass. However, scientific studies have not shown this to be true. Furthermore, there can be side effects to taking L-Ornithine HCL. As with any supplement, talk to your doctor before using L-Ornithine HCL.

Side Effects

PureBulk, a supplier of this amino acid, describes the supplement's potential side effects, including gastric upset, restlessness and insomnia. This supplier says that the product is more effective when taken while fasting; however, fasting can make the side effects more severe. Individuals taking MAOIs, blood pressure or erectile dysfunction medications should not take this supplement because of possible drug interactions.

Dangers of Large Doses

According to the Material Safety Data Sheet,or MSDS, for L-Ornithine HCL, the acute oral toxicity level is 10,270 milligrams per kilogram of body weight; a kilogram is about 2.2 pounds. A rat study was used to determine the toxicity level, but it demonstrates that toxicity to humans is probably only likely at very large doses. However, this supplement is toxic if it comes into contact with your lungs and mucous membranes. If large doses of L-Ornithine HCL come into contact with the skin, the skin can become irritated. Contact with the eyes also can be dangerous.

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Scientific Studies

The study “Ornithine Supplementation and Insulin Release in Bodybuilders,” published in the "International Journal of Sports Nutrition," tested bodybuilders to see if ornithine resulted in the release of more insulin, which is an anabolic hormone; this study did not find ornithine to release more insulin during workouts. Another study entitled “Use of Amino Acids as Growth Hormone-Releasing Agents by Athletes” in the publication "Nutrition" found that it did not increase growth hormone release with exercise; increased growth hormone would have increased lean muscle mass and strength.

L-Ornithine HCL

The side effects of this supplement tend to be mild, and there are no known long-term effects. However, anyone who is pregnant, lactating or taking medications that may react with this amino acid should not consume it. As with any supplement or medication, you should consult a doctor before adding it to your diet. Although the side effects typically are only diarrhea and stomach upset, there does not appear to be an athletic benefit to adding this supplement to your diet.

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