Summary. Muscle carnosine synthesis is limited by the availability of
b-alanine. Thirteen male subjects were supplemented with b-alanine
(CarnoSynTM) for 4 wks, 8 of these for 10 wks. A biopsy of the vastus
lateralis was obtained from 6 of the 8 at 0, 4 and 10 wks. Subjects
undertook a cycle capacity test to determine total work done (TWD) at
110% (CCT110%) of their maximum power (Wmax). Twelve matched subjects
received a placebo. Eleven of these completed the CCT110% at 0 and
4 wks, and 8, 10 wks. Muscle biopsies were obtained from 5 of the 8 and
one additional subject. Muscle carnosine was significantly increased by
þ58.8% and þ80.1% after 4 and 10 wks b-alanine supplementation.
Carnosine, initially 1.71 times higher in type IIa fibres, increased equally
in both type I and IIa fibres. No increase was seen in control subjects.
Taurine was unchanged by 10 wks of supplementation. 4 wks b-alanine
supplementation resulted in a significant increase in TWD (þ13.0%); with
a further þ3.2% increase at 10 wks. TWD was unchanged at 4 and 10 wks
in the control subjects. The increase in TWD with supplementation followed
the increase in muscle carnosine.