The Dope Sheet: NO Boosters

One of the relatively new kids on the block, but one that has made a lot of money, in the world of exercise supplementation have been NO Boosters.  These come in a few different forms from just straight l-arginine to glycine-arginine-alpha-ketoisocaproic acid (GAKIC).  To most trainees the claims make sense.  Increased vasodilation brings more blood to muscles which makes you stronger in the gym and increases muscle protein sysnthesis (muscle building) afterwards.  And when products like NO Xplode and SuperPump 250 literally claim you will get “roadmap vascularity and muscle tearing pumps” and have professional body builders saying they swear by the stuff there will probably be a line of trainees out the door waiting to buy.  Sounds great, where do I sign up?

What It Does

Arginine is the major player when it comes to nitric oxide (NO) production.  Arginine is a conditionally essential amino acid and has a host of other health benefits not related to training (mostly in postoperative wound healing).  Arginine is oxidated to NO via nictric oxide synthase (NOS).  The NO is then thought to work its bioactive magic on the muscles and vascular system.  It does this by dilating (makes bigger) the blood vessels.  The reasoning is that the bigger the blood vessels the more volume of blood that can get to and help the muscle perform.  There have also been claims that arginine supplements increase the growth hormone response.

But Does It Actually Work?

Yes and no.  Arginine containing supplements will dilate the blood vessels, that much is true.  And when taken in conjunction with caffeine it can give you a boost of energy.  But, NO has been shown to improve exercise performance in UNTRAINED trainees only.  Anytime a study has been done with trained individuals the benefits have disappeared, even with higher doses.

Even when a study has shown a benefit it is usually short lived.  In a study on young males a NO group and a placebo group performed ten 10s sprints with a one minute rest period between sprints.  The NO group showed an increased mean power for the SECOND SPRINT ONLY.  For all the other sprint trials there was no statistically significant improvement in performance.  Also note that this same protocol was performed with trained cyclists and the NO group showed zero increased performance over the control group.

The increased growth hormone response is also very misleading.  When studies have been conducted at rest there has been shown to be an increase in growth hormone secretion with both high and low doses.  When studies have been conducted looking at growth hormone response to NO boosters in conjunction with exercise, the growth hormone response is actually LOWER than it would have been with exercise alone.

If you are brand spanking new to training NO boosters may give you some performance enhancement in the short term.  BUT, it may actually hinder progress by limiting your natural growth hormone response.  Trust me; you’d rather have a higher growth hormone output than a bit of a buzz doing your 95 lb. bench press.

Should I Take It?

No.

Is It Safe?

If you shouldn’t take it, it doesn’t matter if it is safe.  Buuuut if you’re not going to listen to me and take it for psychological reasons then yes, it’s safe to take.  Even at high doses no real negative side effects have been shown.

Summary

In conclusion, my recommendation is to save your money.  If you want a bit of a kick pre-workout there are much cheaper and equally effective means of obtaining it, like coffee for instance.  Save your money, lift heavy, and spend that money on food that will actually help you build muscle.  Not some broscience supplement that only gives you false hopes.

Getting jacked, bro.

Sources

The effect of nitric-oxide-related supplements on human performance.  Bescós R, Sureda A, Tur JA, Pons A.  Sports Med. 2012 Feb 1;42(2):99-117.

Effects of 7 days of arginine-alpha-ketoglutarate supplementation on blood flow, plasma L-arginine, nitric oxide metabolites, and asymmetric dimethyl arginine after resistance exercise.  Willoughby DS, Boucher T, Reid J, Skelton G, Clark M.  Int J Sport Nutr Exerc Metab. 2011 Aug;21(4):291-9.

Effects of citrulline supplementation on fatigue and exercise performance in mice.  Takeda K, Machida M, Kohara A, Omi N, Takemasa T.  J Nutr Sci Vitaminol (Tokyo). 2011;57(3):246-50.

The acute effects of a low and high dose of oral L-arginine supplementation in young active males at rest.  Forbes SC, Bell GJ.  Appl Physiol Nutr Metab. 2011 Jun;36(3):405-11. Epub 2011 May 16.

Failure of glycine-arginine-α-ketoisocaproic acid to improve high-intensity exercise performance in trained cyclists.  Beis L, Mohammad Y, Easton C, Pitsiladis YP.  Int J Sport Nutr Exerc Metab. 2011 Feb;21(1):33-9.

Glycine-arginine-alpha-ketoisocaproic acid improves performance of repeated cycling sprints.  Buford BN, Koch AJ.  Med Sci Sports Exerc. 2004 Apr;36(4):583-7.

Growth hormone, arginine and exercise.  Kanaley JA.  Curr Opin Clin Nutr Metab Care. 2008 Jan;11(1):50-4.

Bolus arginine supplementation affects neither muscle blood flow nor muscle protein synthesis in young men at rest or after resistance exercise.  Tang JE, Lysecki PJ, Manolakos JJ, MacDonald MJ, Tarnopolsky MA, Phillips SM.  J Nutr. 2011 Feb;141(2):195-200. Epub 2010 Dec 29.