Arginine, ornithine and lysine all have the ability to influence fat metabolism and stimulate growth hormone. While the evidence so far isn’t strong enough to show they’re powerful fat burners, they may help you lose weight, especially if you take arginine together with ornithine or lysine. Stay safe and talk to your doctor before taking supplements. Arginine interacts with some medications and may not be safe if you're pregnant, have low blood pressure, liver disease or kidney disease.
Impact of Arginine
Arginine’s potential impact on weight loss comes from its potential to increase the breakdown of fats, according to a report in Frontiers in Bioscience in June 2012. The report cited studies showing that lab rats and pigs lost white adipose tissue -- the type of fat associated with excess pounds -- after consuming arginine supplements.
Researchers need to complete more studies to determine whether arginine supports weight loss in people, but a study published in the American Journal of Physiology in 2006 shows some promise. In this study, a group diagnosed with type-2 diabetes followed a low-calorie diet, but only half of them took arginine. After 21 days, the arginine group lost more fat than the group taking a placebo.
Support From Ornithine
When healthy volunteers took ornithine supplements and then rode on stationary cycles, they reported having more energy and less fatigue. The researchers concluded that this occurred as ornithine promoted fat metabolism and increased elimination of toxic ammonia, according to Nutrition Research in November 2008.
Studies published so far haven’t tested ornithine’s ability to improve weight loss in people. But when supplemental ornithine was given to lab rats, they lost a significant amount of weight, according to a study published in the February 2015 issue of the Brain Research Bulletin.
Lysine's Role in Fat Metabolism
Lysine must be available for the body to synthesize another amino acid called carnitine. Because carnitine is essential for converting fats into energy, lysine is indirectly involved in fat metabolism.
Whether lysine’s role in fat metabolism can help you lose weight hasn't been determined; only more research with people will tell. But when rats with nonalcoholic fatty liver disease consume supplemental lysine, they lost weight, and their blood levels of triglycerides went down, reported Biomed Research International in May 2014.
Combinations of Arginine, Ornithine and Lysine
All three amino acids promote the secretion of human growth hormone, but taking them individually doesn’t have the same impact as combining arginine with ornithine or lysine, according to Kimberly Pryor and Dr. Ward Dean, writing for Vitamin Research Products.
Growth hormone stimulates fat cells to break down the fat in storage and to stop storing more fat. Taking growth hormone helps people lose weight when they're deficient in the hormone and sometimes supports weight loss in people with normal hormone levels, according to a 2013 review in Endocrine. Amino acids that boost growth hormone may also help with weight loss, but more studies are needed to verify their effectiveness.