title: β-Alanine dose for maintaining moderately elevated muscle carnosine levels.
abstract: BACKGROUND
  Chronic β-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 investigated 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 3.2 g (4 × 800 mg) BA per day for 46 d (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 six more weeks (maintenance phase). The participants were matched and redivided into three groups receiving 0.4, 0.8, and 1.2 g·d(-1) BA, respectively. Muscle carnosine content was measured in the soleus and gastrocnemius muscles using proton magnetic resonance spectroscopy.
  
  
  RESULTS
  Body mass and sex had only minimal effect on the absolute increase in muscle carnosine. Given the lower baseline values in women, the relative increase for women was higher, indicating that women required 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·d(-1) BA was the most effective in keeping muscle carnosine content elevated at the postsupplementation level.
  
  
  CONCLUSIONS
  Sex and body mass did not markedly affect the absolute increase during muscle carnosine loading, although they are determinants for the relative increase. In addition, we established for the first time an effective maintenance dose of ∼1.2 g·d(-1) BA to keep muscle carnosine content elevated at 30%-50% above baseline for a prolonged period.
authors.affiliation: 1Department of Movement and Sports Sciences, Ghent University, Ghent, BELGIUM; 2Laboratory of Pharmaceutical Technology, Ghent University, Ghent, BELGIUM; and 3Department of Radiology, Ghent Institute for Functional and Metabolic Imaging, Ghent University, Ghent, BELGIUM.
authors.forename: Sanne
authors.initials: S
authors.lastname: Stegen
authors.forename: Tine
authors.initials: T
authors.lastname: Bex
authors.forename: Chris
authors.initials: C
authors.lastname: Vervaet
authors.forename: Lander
authors.initials: L
authors.lastname: Vanhee
authors.forename: Eric
authors.initials: E
authors.lastname: Achten
authors.forename: Wim
authors.initials: W
authors.lastname: Derave
mesh_terms: D000328:Adult; D054874:Athletic Performance / Q000502:physiology; D050218:Body Fat Distribution; D015992:Body Mass Index; D002336:Carnosine / Q000378:metabolism*; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D012737:Sex Factors; D055815:Young Adult; D015091:beta-Alanine / Q000008:administration & dosage*
chemical_list: D015091:beta-Alanine; D002336:Carnosine