L-arginine: proven supplement for preventing and treating diabetes

L-arginine: proven supplement for preventing and treating diabetes

L-arginine is an amino acid found in virtually all protein-containing foods. Amino acids are simply protein components, so l-arginine is a completely natural substance that you eat every day.

L-arginine is a proven supplement for type 2 diabetics and prediabetics.

In prediabetics, 6.4 grams of l-arginine per day for 18 months reduced insulin resistance and restored normal blood sugar in more patients than placebo. After an additional 12 months without l-arginine supplementation, fewer people had developed type 2 diabetes in the former l-arginine group, and they still had lower insulin resistance, better insulin secretion and lower HbA1c, versus the placebo group.1

In another study on prediabetics, 6.6 grams per day of l-arginine for 14 days significantly improved insulin sensitivity (+78%) and reduced body fat, compared to placebo. 2

In insulin resistant patients with abdominal obesity, 9 grams per day of l-arginine for 3 months reduced insulin resistance compared to placebo. 3

In non-diabetics with heart disease, 6.4 grams of l-arginine per day for 6 months reduced insulin resistance and inflammation compared to placebo.4

In severely obese type 2 diabetics, 8.3 grams per day of l-arginine for 21 days, combined with exercise and a low calorie diet, lowered insulin resistance compared to placebo in place of l-arginine.5

Another study found that 9 grams per day of l-arginine for 1 month reduced insulin resistance compared to placebo in lean type 2 diabetics.6

Do not buy d-arginine, as it doesn’t reduce insulin resistance the way l-arginine does.7

L-arginine is typically well-tolerated with few side effects,1, 4, 5  but always consult your doctor before taking any supplements.

Dose: Six to nine grams per day seems appropriate based on human studies. It’s best taken in 2-3 divided doses per day.



  1. Monti LD, Setola E, Lucotti PC, et al. Effect of a long-term oral l-arginine supplementation on glucose metabolism: a randomized, double-blind, placebo-controlled trial. Diabetes Obes Metab. Oct;14(10):893-900.
  2. Monti LD, Casiraghi MC, Setola E, et al. l-Arginine enriched biscuits improve endothelial function and glucose metabolism: A pilot study in healthy subjects and a cross-over study in subjects with impaired glucose tolerance and metabolic syndrome. Metabolism. Oct 3.
  3. Bogdanski P, Suliburska J, Grabanska K, et al. Effect of 3-month L-arginine supplementation on insulin resistance and tumor necrosis factor activity in patients with visceral obesity. Eur Rev Med Pharmacol Sci. Jun;16(6):816-823.
  4. Lucotti P, Monti L, Setola E, et al. Oral L-arginine supplementation improves endothelial function and ameliorates insulin sensitivity and inflammation in cardiopathic nondiabetic patients after an aortocoronary bypass. Metabolism. Sep 2009;58(9):1270-1276.
  5. Lucotti P, Setola E, Monti LD, et al. Beneficial effects of a long-term oral L-arginine treatment added to a hypocaloric diet and exercise training program in obese, insulin-resistant type 2 diabetic patients. Am J Physiol Endocrinol Metab. Nov 2006;291(5):E906-912.
  6. Piatti PM, Monti LD, Valsecchi G, et al. Long-term oral L-arginine administration improves peripheral and hepatic insulin sensitivity in type 2 diabetic patients. Diabetes Care. May 2001;24(5):875-880.
  7. Paolisso G, Tagliamonte MR, Marfella R, Verrazzo G, D’Onofrio F, Giugliano D. L-arginine but not D-arginine stimulates insulin-mediated glucose uptake. Metabolism. Sep 1997;46(9):1068-1073.