Effects of Twenty-Eight Days of Beta-Alanine and Creatine Monohydrate Supplementation on the Physical Working Capacity at Neuromuscular Fatigue Threshold

J Strength Cond Res. 2006 Nov;20(4):928-31. doi: 10.1519/R-19655.1.


The purpose of this study was to examine the effects of 28 days of beta-alanine (b-Ala) and creatine monohydrate (CrM) supplementation on the onset of neuromuscular fatigue by using the physical working capacity at neuromuscular fatigue threshold (PWC(FT)) test in untrained men. Fifty-one men (mean age +/- SD = 24.5 +/- 5.3 years) volunteered to participate in this 28-day, double-blind, placebo-controlled study and were randomly assigned to 1 of 4 groups: placebo (PLA; 34 g dextrose; n = 13), CrM (5.25 g CrM plus 34 g dextrose; n = 12), b-Ala (1.6 g b-Ala plus 34 g of dextrose; n = 12), or b-Ala plus CrM (CrBA; 5.25 g CrM plus 1.6 g b-Ala plus 34 g dextrose; n = 14). The supplement was ingested 4 times per day for 6 consecutive days, then twice per day for 22 days before posttesting. Before and after the supplementation, subjects performed a continuous incremental cycle ergometry test while a surface electromyographic signal was recorded from the vastus lateralis muscle to determine PWC(FT). The adjusted mean posttest PWC(FT) values (covaried for pretest PWC(FT) values) for the b-Ala and CrBA groups were greater than those for the PLA group (p < or = 0.05). However, there were no differences between the CrM vs. PLA, CrBA vs. b-Ala, CrM vs. b-Ala, or CrM vs. CrBA groups (p > 0.05). These findings suggested that b-Ala supplementation may delay the onset of neuromuscular fatigue. Furthermore, there appeared to be no additive or unique effects of CrM vs. b-Ala alone on PWC(FT).

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Analysis of Variance
  • Creatine / administration & dosage*
  • Creatine / pharmacology
  • Dietary Supplements*
  • Double-Blind Method
  • Electromyography
  • Glucose / administration & dosage
  • Humans
  • Least-Squares Analysis
  • Male
  • Muscle Fatigue / drug effects*
  • Muscle Fatigue / physiology
  • Physical Endurance / drug effects*
  • Physical Endurance / physiology
  • beta-Alanine / administration & dosage*
  • beta-Alanine / pharmacology


  • beta-Alanine
  • Glucose
  • Creatine