What does it look like?
- ß-alanine supplements include instant release powders and capsules as well as sustained release preparations.
- Although the sustained and rapid release formulations result in similar increases in muscle carnosine when matched for the amount of ß-alanine ingested12,13, sustained release ß-alanine would be advisable given that a larger single dose can be ingested with improved whole body retention and sensory side-effects that are not discernible from consuming a placebo.13,14 As such, a greater daily intake of sustained release ß-alanine could be tolerated given that paraesthesia symptoms would be mitigated using this formula.
- Efficacy of ß-alanine supplementation is not dependant on baseline muscle carnosine levels or sex and there does not appear to be any nonresponders, although the increase in muscle carnosine content between individuals can vary.
- Muscle carnosine increases are most pronounced during the initial weeks of ß-alanine supplementation, whereby the increase in muscle carnosine content is greater during the first compared to subsequent 12 days of supplementation7, and the first 4 weeks compared to the remaining 20 weeks of supplementation.6
- The initial review conducted by Stellingwerff et al.15 detailing the ß-alanine prescriptive application to augment muscle carnosine highlighted a linear relationship between the total amount of ß-alanine ingested and the subsequent relative increase in muscle carnosine (%) and suggested that for a desired ~50% increase in muscle carnosine, a total of ~230 g of ß-alanine must be taken (within a daily consumption range of 1.6–6.4 g·day-1). However, a more recent review16 has indicated that the muscle carnosine increase in response to ß-alanine supplementation is nonlinear, and that the greatest increases occur in the earlier stages of supplementation. One long term supplementation study (24 weeks) did demonstrate substantial further increases in muscle carnosine in the final 4 weeks of supplementation but there was no clear evidence of further improvements in high-intensity cycling capacity.17
- Once muscle carnosine is augmented, the washout is very slow (~2%·wk-1).15
- The efficiency of carnosine loading is significantly higher when ß-alanine is co-ingested with a meal (+64%) compared with in between meals (+41%), suggesting that insulin stimulates muscle carnosine loading.12
- Carnosine loading is more pronounced in the trained vs. untrained muscles of athletes, whereby the increase in carnosine is greater in arm (deltoid) vs. leg (soleus + gastrocnemius) muscles in kayakers, whereas the reverse pattern is observed in cyclists. Swimmers observe significantly higher increases in carnosine in both deltoid and gastrocnemius muscle compared with nonathletes. These findings suggest that training status and/or exercise training itself is a possible determinant of carnosine loading, but it remains to be determined whether these effects are due to the acute exercise effects and/or to chronic adaptations of training.