The most relevant effects L-Arginine for weight loss are boosting levels of nitric oxide (NO) and HGH (human growth hormone). In 2008 researchers at AgriLife Research Centre in College Station, Texas A&M University, and scientists from the University of Maryland School of Medicine teamed up to explore arginine supplementation in rats. They found that by regulating the amino acid in the rats they were able to promote muscle gain.

Emerging Evidences

Study showed that Nitric Oxide (NO), which is synthesised from L-arginine by NO synthase in virtually all cell types, regulates the metabolism of fatty acids, glucose and amino acids. In particular, NO inhibits the synthesis of fat, glucose and glycogen, while enhancing lipolysis in adipocytes. The study proved that an inhibition of NO synthesis cause hyperlipidemia and fat accretion in rats, whereas dietary arginine supplementation reduces fat mass in diabetic fatty rats. NO appears to increase blood flow to insulin-sensitive tissues, promoting substrate uptake and product removal via the circulation, this led researchers to suggest that dietary supplementation with L-arginine or L-citrulline may help in the prevention and treatment of the metabolic syndrome in obese humans as well.

In the 2008 study at the University of North Carolina Wilmington, published in Medicine and Science in Sports and Exercise, researchers examined the impact of arginine on body fat mass in two groups of endurance-trained athletes who took L-arginine or a placebo while doing aerobic exercise. Throughout the four-week study, the arginine cluster encountered considerable reduction in body fat proportion and fat accumulation contrasted to the placebo cluster. According to “Amino Action” by Steven Stiefel, the increase in HGH, from arginine supplementation, allows IGF-1 and other related hormones to align with muscle receptors for more muscle building and fat burning, L-arginine helps to increased nutrient delivery, boost energy levels. This helps performing workouts longer and harder in the gym.

Study: L-arginine and Type-2 diabetics

In other 2006 study, published in in the American Journal of Physiology Endocrinology and Metabolism, scientists from the Fondazione Centro San Raffaele del Monte in Italy analysed the results of L-arginine supplementation on Type-2 diabetics who undertook a reduced-calorie diet and workout training for 21 days.

The participants have been taking 8.3 grams of L-arginine or a placebo daily. while. It was discovered that L-arginine cluster dropped a larger quantity of fat mass, particularly in the region of their waist, compared to the placebo cluster.


In his “The Top Ten Supps You Can’t Live Without”, Jim Stoppani PhD recommends to take L-arginine supplements three times daily in order to get the optimum level of both NO and HGH for weight loss. He advises taking 3-5g upon waking, 3-5g before a workout and a final dose before bedtime. The larger dose of 7-10g makes a greater impact on HGH, which has potent fat-burning effects. However, as Dr Siva Arunasalam noted, the dose larger that 10g (taking at once) does not bring any extra benefits. He recommends to keep 4 hours intervals between L-arginine intakes