The absorption of orally supplied β-alanine and its effect on muscle carnosine synthesis in human vastus lateralis

beta- Alanine in blood- plasma when administered as A) histidine dipeptides ( equivalent to 40mg center dot kg (-1) bwt of beta- alanine) in chicken broth, or B) 10, C) 20 and D) 40mg center dot kg (-1) bwt beta- alanine ( CarnoSyn (TM), NAI, USA), peaked at 428 +/- SE 66, 47 +/- 13, 374 +/- 68 and 833 +/- 43 mu M. Concentrations regained baseline at 2 h. Carnosine was not detected in plasma with A) although traces of this and anserine were found in urine. Loss of b- alanine in urine with B) to D) was < 5%. Plasma taurine was increased by b- alanine ingestion but this did not result in any increased loss via urine. Pharmacodynamics were further investigated with 3 x B) per day given for 15 d. Dietary supplementation with I) 3.2 and II) 6.4 g center dot d (-1) beta- alanine ( as multiple doses of 400 or 800mg) or III) L- carnosine ( isomolar to II) for 4w resulted in significant increases in muscle carnosine estimated at 42.1, 64.2 and 65.8%.