Beta-alanine plays many roles in the body. It is an antioxidant scavenging up those free radicals, an indirect producer of nitric oxide in the body as well as a component of pantothenic acid, otherwise known as vitamin B5. In terms of exercise enhancement, beta-alanine is a component of a very important compound known as carnosine. Carnosine is a fairly simple compound known as a dipeptide as it is made of two amino acids links together, histidine and beta-alanine, as seen here:
As we all know and have felt, high-intensity exercise causes fatigue. This fatigue can be attributed to the depletion of substrates (e.g. ATP) and the accumulation of metabolites (e.g. lactic acid) in the skeletal muscle. Carnosine is thought to play a vital role in intracellular pH buffering mechanisms, reducing the effects of that lactic acid buildup and in the end, resulting in an overall reduction of muscle fatigue.
As previously stated, carnosine is made up of the amino acid histidine as well, so one would think that supplementation of histidine is as important as beta alanine. This however is not the case. Histidine is found in relatively high concentrations in the muscle while beta alanine is found in relatively low concentrations. Multiple studies have shown that the availability of beta alanine is the limiting step in the synthesis of carnosine in our muscle. Intake of beta-alanine, either through our diet or supplementation alone, is thought to increase carnosine muscle concentrations much more profoundly than the intake of histidine.
If carnosine is so important, why not just supplement with carnosine instead of beta-alanine? Multiple studies have shown that supplementing with carnosine is not as effective as supplementing with beta-alanine. This is because carnosine, when taken by mouth, is simply broken down during digestion to its components, histidine and beta-alanine. This results in only about 40% of the total dose being available as beta-alanine. Histidine as discussed before, does not need to be supplemented to increase carnosine levels. It just makes more sense to supplement with beta-alanine alone as this will increase the levels of concentrations of carnosine in the muscle.
Positive Evidence for beta-alanine supplementation
As with any supplement out there, there are generally multiple forms available. Think of creatine for example. You have creatine monohydrate, creatine phosphate, creatine citrate, buffered creatine etc. The list goes on and on. Beta-alanine is similar in the fact that there really is no standardized version. In the studies I reviewed, the most evidence lies with a patented form of beta-alanine known as Carnosyn by a company known as Natural Alternatives International. Carnosyn is available in products by almost every major supplement company including Optimum Nutrition, Gaspari, Dymatize and more. If you plan on supplementing with beta-alanine, I recommend looking for a product with Carnosyn on the label. It simply has the most evidence.
As a pharmacist and health care professional, I am always on the lookout of for positive evidence based results for sports supplements and medicine. While it can sometimes be difficult to use this method for many supplements, beta-alanine has multiple studies in which positive effects were shown.
First off, there is no doubt that supplementing beta-alanine by mouth increases carnosine concentration in the muscle. One study showed that after supplementing with beta-alanine increased levels of carnosine in the muscle by 58.8% and by 80.1% at week 4 and week 10 of supplementation respectively. Another study showed (showed similar results during a 4 week trial period with subjects supplementing with 6.4 grams of Carnosyn daily. It can certainly be seen that beta-alanine availability is the primary factor that contributes to carnosine concentration in the muscles.
Increased carnosine concentration in the muscle is all well and good, but does it have an effect on exercise performance? There has been conflicting evidence but in general, it does appear that beta-alanine supplementation does have positive benefits. One study performed in sprinters showed an 11.4% peak power output increase during a 30 second sprint. Another study performed in college football players showed that there was a statistically significant increase in repetitions performed during a bench press exercise as well as an overall lower fatigue rate in those taking beta-alanine vs. a placebo. Finally, one study including only women showed that beta-alanine supplementation significantly increased the following: Fatigue threshold ventilatory threshold (i.e. the point at which breathing becomes labored and you feel you can't bring in as much air as you want to), oxygen consumption and time to exhaustion. Ideally, I would like to see studies with more subjects, better descriptions of randomization and the like, but all in all, for a supplement, there is a good body of evidence for beta-alanine increasing exercise performance.
A positive finding in all these studies regarding beta-alanine is a relative absence of side effects. It was very well tolerated in all studies. In fact, one of the only reported side effects is known as paresthesia, a sensation of prickling, tickling or slight burning. This side effect is not serious however. Various sources suggest that the paresthesia is caused by beta-alanine binding to nerve receptors. It typically resolves on its own after about 1-2 hours and typically subsides all together after a few weeks of dosing. Taking beta-alanine with carbohydrates may eliminate parestheia from happening at all.
The optimal dosing for beta-alanine can be seen from the clinical trials. Many trials used increasing dosages for 8 weeks (2 grams daily for the first two weeks and increasing by 1 additional gram every two weeks. The maximum dose in the clinical trials was 6.4 grams daily with that dosage producing desirable results. There doesn't appear to be a need to cycle the dosage on and off and there also doesn't appear to be any negative feedback in the body. Many of the studies did start at a lower dosage of beta-alanine and slowly increasing weekly. This may have been done to reduce the possibility of paresthesia.
It's important to note that it may take a few weeks of continuous dosing to notice the effects of beta-alanine supplementation. According to one study, while beta-alanine is absorbed fairly quickly (maximum concentrations in the blood were seen in just under an hour), carnosine wasn't detected in the blood. After 15 days of continuous supplementation however, carnosine in the muscle significantly increased.
Beta alanine supplementation has a lot going for it. Not only does it have a strong body of positive scientific evidence, it is generally recognized as safe (GRAS) by the FDA. Supplementations has been shown to increase exercise performance by increasing time to exhaustion, peak power output, decreased muscle fatigue and a total increase in physical working capacity. It's one of the few supplements know to be both safe and effective and is certainly worth being part of your workout supplementation regimen.