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We all know that familiar uncomfortable feeling of fatigue and intense heat building in the muscles when we exercise hard at high intensities, such as during the final sprint of a race or during an interval training session.
One of the main contributors to this feeling of fire in the muscles is the increase in acidity that occurs when the lactic acid produced disassociates to lactate and H+ ions during high-intensity exercise.
Fortunately, the body has an inbuilt buffering system to deal with this change in pH, which includes intracellular carnosine (inside the cell) and extracellular bicarbonate (outside the cell). Muscle buffering describes your body's ability to neutralise the H+ ions that build up in your muscles during hard exercise.
What if the buffering capacity of the muscles could be improved, delaying muscle fatigue and bringing the potential to improve exercise performance?
Bicarbonate supplementation has been extensively researched and used for many years in sport to assist buffering, but for some can have unwelcome gut side effects, which can limit its use.
However, increasing carnosine levels in the muscles through supplementation with beta alanine is another option, and has a good evidence base with limited side effects. Carnosine helps to delay the accumulation of H+ ions during intense exercise.
Carnosine accounts for ~ 8%1 of the muscles' ability to buffer the acidity (H+ ions) produced by high-intensity exercise, but this could reach 15% if enhanced via beta-alanine supplementation.
Beta-alanine is believed to be the limiting factor in carnosine production and is an amino acid which, when combined with L-histidine, produces the dipeptide carnosine (beta-alanyl-L-histidine).
Beta-alanine is found in dietary sources such as meat, poultry and fish, and so vegetarians have a lower muscle carnosine level than meat eaters.
Significantly increasing carnosine levels through dietary sources of beta-alanine is difficult, and so supplementation is the most effective strategy.
Beta-alanine supplementation is generally used for short periods of time, with most studies looking at durations between 4-12 weeks.
Research has demonstrated that supplementing with beta-alanine over time can increase muscle carnosine levels and therefore enhance intramuscular H+ buffering.
Supplementation may improve performance by 0.2-3% of both continuous and intermittent exercise lasting 30s to 10 minutes2, 3 that includes repeated bouts of high-intensity work (sprints, lifts), which cause an exercise-limiting increase in H+ ions over time. There may also be a modest benefit for exercise lasting up to 25 minutes.
It may also enhance training adaptations, by allowing appropriate intervals to be conducted at a higher intensity.
Supplementation may increase total work done and power output, and decrease feelings of fatigue and perceived exertion.
If beta-alanine is supplemented at levels of 4-6g/day (~ 65mg/kg), muscle carnosine has been found to increase by 64% after 4 weeks and by 80% after 10 weeks.4 Most research protocols range from 4-12 weeks in duration, with just one study of 24 weeks showing a further increase, although this varied between individuals.5
It is unclear how long supplementation needs to be continued to maximise muscle carnosine levels, and no upper limit for muscle carnosine levels have yet been established. There may also be a variation in the response to supplementation, and so some people may have a more marked increase in muscle carnosine levels than others. This may be partly related to baseline muscle carnosine content and muscle fibre composition.
Once supplementation is stopped, it may take 6 weeks in low responders for carnosine levels to fall to baseline, and 15 weeks in high responders.2
For a 75kg athlete taking part in an event lasting 30s-10m, a 5g dose (~65mg/kg) could be taken for 4-12 weeks leading into competition. Supplementation should be taken with a carbohydrate-containing food or drink to enhance muscle uptake, and the dose split throughout the day and taken every 3-4 hours. For example, for a total 5g dose a split of 2x 1.5g plus 2x 1g every 3-4 hours would be appropriate.
The main side effect described is paraesthesia, which is a prickling or 'pins and needles' sensation, which lasts for about 60-90 minutes and occurs approximately 10-20 minutes after a dose of beta-alanine is taken. It typically occurs in the face, neck and back of hands.
It is thought that beta-alanine activates specific receptors in the skin to cause this effect, but to date there is no evidence that this is harmful.4 It is advisable to take beta-alanine in split doses throughout the day to help limit this side effect. Taking it with carbohydrate foods can also help limit side effects as well as enhancing muscle uptake.
To date no studies have evaluated the effects of long-term beta-alanine supplementation (more than 1 year) or whether there may be interference with adaptation if used long term. For this reason, it seems sensible not to use it continuously but to focus its use for short blocks of 4-12 weeks at key points in the year leading into competition or for specific training periods.
This article is written by nutrition professionals, and is aimed at nutritionists and athletes. It is not intended to replace advice from your own doctor or nutritionist. Please consult a professional before trying supplements.
1Hill, C. A., Harris, R. C., Kim, H. J., Harris, B. D., Sale, C., Boobis, L. H., Kim, C. K., & Wise, J. A. (2007). Influence of beta-alanine supplementation on skeletal muscle carnosine concentrations and high intensity cycling capacity, Amino Acids 32(2), 225–233
2Maughan, R., J et al (2018). IOC consensus statement: dietary supplements and the high-performance athlete, British Journal of Sports Medicine 52, 439-455
3Saunders B, Elliott-Sale K, Artioli GG, et al (2017). β-alanine supplementation to improve exercise capacity and performance: a systematic review and meta-analysis, British Journal of Sports Medicine 51:658-669
4Trexler, E.T., Smith-Ryan, A.E., Stout, J.R. et al (2015). International society of sports nutrition position stand: Beta-Alanine, Journal of the International Society of Sports Nutrition 12, 30
5Saunders, B., DE Salles Painelli, V., DE Oliveira, L. F., DA Eira Silva, V., DA Silva, R. P., Riani, L., Franchi, M., Gonçalves, L. S., Harris, R. C., Roschel, H., Artioli, G. G., Sale, C., & Gualano, B (2017). Twenty-four Weeks of β-Alanine Supplementation on Carnosine Content, Related Genes, and Exercise, Medicine and science in sports and exercise 49(5), 896–906
Peeling, P., Binnie, M., Goods, P., S., R., Sim, M., Burke, L (2018). Evidence-based supplements for the enhancement of athletic performance, International Journal of Sport Nutrition and Exercise Metabolism 28, 178-187
Stellingwerff, T., Bovim, I. M., & Whitfield, J (2019). Contemporary Nutrition Interventions to Optimize Performance in Middle-Distance Runners, International journal of sport nutrition and exercise metabolism 29(2), 106–116