d-aspartic acid

Ph.D. Candidate Weiliang Chung estimates 75% of top Olympic-level swimmers have experimented with beta-alanine supplementation. This may come to a surprise to you, as many of you probably haven’t even heard of beta-alanine. Nonetheless, beta-alanine is a prolific supplement which may help performance. Now, before you rush off to the store and start taking excessive doses, it is quinessential to understand the possible benefits of beta-alanine.

There are a few proposed mechanisms on how beta-alanine supplementation works. Briefly, beta-alanine supplementation results in increased carnosine content in the muscle. Carnosine has been proposed to be a pH buffer, anti-oxidant and can improve muscle contractile function. The main role that many researchers believe that carnosine loading (via beta-alanine supplementation) is the increased ability to buffer the protons produced from prolonged, high intensity exercise.

Carnosine and Muscle

Carnosine is a dipeptide synthesized from the precursors L-histidine and beta-alanine (BA) by carnosine synthase. It is stored in high concentrations in the humanskeletal muscle (~5 mmol/kg wet muscle). Supplementing beta-alanine (BA) has been shown to increase muscle carnosine by 40 – 80%.

To understand the effects of carnosine in the muscle, carnosine was measured in two muscles of the upper arm, the triceps and deltoid. Seventeen physically active students (M=15, F=2) underwent muscle carnosine testing. Next, thirty-five men (10 nonathletes, 10 road cyclists, 10 swimmers, and 5 flat-water kayakers) supplemented for 23 days with 6.4 g slow-release beta-alanine (SR-BA) (4 times per day two tablets of 800 mg, Carnosyn, Natural Alternatives International).

For the nonathletes, there was a significant increase in carnosine concentration in both arm (deltoid) and leg muscles (soleus gastrocnemius) after supplementation, but the absolute and relative increase in carnosine in the arm vs. leg muscles showed no significant difference.

Bex (2014) looked at carnosine levels in an upper extremity and lower extremity muscle in different athletes. In gastrocnemius muscle, the absolute increase in carnosine (expressed as arbitrary units) was significantly higher in the cyclists  and the swimmers, compared with the nonathletes  and the kayakers. The swimmers had a higher absolute increase in the deltoid muscle compared with cyclists and the nonathletes. There were no differences between the groups in the soleus. For mean muscle carnosine in the legs (soleus and gastrocnemius), the cyclists and swimmers had a higher absolute increase than the nonathletes. We found no significant correlations between training volume or years of training and increases in carnosine concentration with BA supplementation within or across athlete groups. In the kayakers, their deltoid muscle carnosine had a higher absolute increase than their leg muscles (soleus gastrocnemius). An opposite pattern was observed with the cyclists where the leg muscles showed a tendency to a higher absolute increase than the deltoid muscle.

A possible explanation for the acute effect of exercise training is the increased blood flow in contracting muscles, which results in better BA delivery to the muscle cells.

Want to Try Beta-Alanine?

It seems wise to supplement BA during a period of substantial training volume, rather than in a rest or recovery period, in order to optimize beta-alanine benefits throughout a training season. In addition, the physiological carnosine loading mechanism is probably more effective in trained vs. untrained individuals. This is opposite to some other ergogenic supplements, where biological activity and effectiveness is often less pronounced in a trained population.

Depending on the type of beta-alanine supplement (pure or sustained-release) are available on your shelves, you could have a slow loading protocol leading into competition or a faster loading protocol prior to a high-intensity training block or competition.

As for side effects, ingesting more than 1.6 g of pure beta-alanine in a single dose has resulted in significant numbness and tingling. This uncomfortable “pins and needles” sensation is possibly consequential from sensitization of neuropathic pain specific neurons in the skin. The documented side effects from supplementation usually fade away after a few hours. Therefore, I would recommend ingesting no more than 1.6 g of beta-alanine (preferably sustained-release) per single dose and more than 3 hours in between doses.


  1. Bex T, Chung W, Baguet A, Stegen S, Stautemas J, Achten E, Derave W. Muscle carnosine loading by beta-alanine supplementation is more pronounced in trainedvs. untrained muscles. J Appl Physiol (1985). 2014 Jan 15;116(2):204-9. doi: 10.1152/japplphysiol.01033.2013. Epub 2013 Nov 27.