The beta-alanine dose for maintaining moderately elevated muscle carnosine levels

INTRODUCTION: Chronic beta-alanine (BA) supplementation is an increasingly popular nutritional strategy, because it can elevate muscle carnosine content and thereby enhance high-intensity exercise performance. The current study investigates 1) whether sex and body mass are determinants of BA induced muscle carnosine loading, and 2) the optimal maintenance dose for ensuring constantly elevated muscle carnosine stores. METHODS: During the loading phase, 34 participants (men and women) were supplemented with 3.2g (4×800 mg) BA/day for 46 days (slightly different loading strategies were applied concerning the effect of meal-timing and supplementation form). Thereafter, 19 participants (men and women) continued taking free-powder BA for 6 more weeks (maintenance phase). The participants were matched and re-divided into three groups respectively receiving 0.4g BA/day, 0.8g BA/day and 1.2g BA/day. Muscle carnosine content was measured in m. soleus and m. gastrocnemius using H-MRS. RESULTS: Body mass and sex had only minimal effect on the absolute increase in muscle carnosine. Given the lower baseline values of women, the relative increase for women was higher, indicating that women require less BA for the same relative increase. In addition, a significant negative correlation was observed between body mass and the relative increase in muscle carnosine (r=-0.45, p=0.007). A maintenance dose of ∼1.2 g BA/day, was most effective to keep muscle carnosine content elevated at post-supplementation level. CONCLUSION: Sex and body mass do not markedly affect the absolute increase during muscle carnosine loading, although they are determinants for the relative increase. Additionally, we established for the first time an effective maintenance dose of ∼1.2g BA/day to keep muscle carnosine content elevated at 30-50% above baseline for a prolonged period