Beta-alanine

Beta-alanine is a nonessential amino acid whose availability limits how fast muscle can make carnosine.^{1Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 256.} It’s found in foods such as chicken and does little on its own.^{1Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 256.} Carnosine sits mainly in type II muscle fibers and accounts for up to 40% of muscle’s ability to buffer the hydrogen ions produced during intense anaerobic work.^{1Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 256.} In one study, taking beta-alanine raised muscle carnosine by 58% after four weeks.^{1Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 256.}

Beta-alanine doesn’t seem to improve maximal strength or aerobic power, though it may raise anaerobic threshold.^{1Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 256.} It helps most during work that produces extreme acidity in the muscle, such as repeated high-intensity bouts longer than 60 seconds.^{1Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 256.}

In practice

• Helms and colleagues rate it as conditionally useful, with a small effect in efforts of about 0.5 to 10 minutes.^{2Helms et al., The Muscle & Strength Pyramid: Nutrition, 2nd ed., p. 159.} It’s unlikely to help powerlifting, weightlifting or most bodybuilding unless sets run to 15 to 20 reps or more, or rest intervals are cut short.^{2Helms et al., The Muscle & Strength Pyramid: Nutrition, 2nd ed., p. 159.}
• Studies have used 2.4 to 6.4 g a day, usually split into two to four smaller doses.^{1Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 256.} Helms and colleagues list 3 to 4 g a day.^{3Helms et al., The Muscle & Strength Pyramid: Nutrition, 2nd ed., p. 166.} The International Personal Trainer Academy gives 4 to 6 g a day for 2 to 4 weeks.^{4International Personal Trainer Academy, Certified Personal Trainer Textbook, p. 543.}
• The only reported side effect is paresthesia, a tingling or pricking of the skin after a large single dose, which fades within about an hour.^{1Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 256.} Smaller divided doses reduce it.^{4International Personal Trainer Academy, Certified Personal Trainer Textbook, p. 543.} At usual doses it appears safe for most healthy people, though not for those who are pregnant or breastfeeding.^{4International Personal Trainer Academy, Certified Personal Trainer Textbook, p. 543.}
• Recommending supplements is outside a personal trainer’s scope of practice.^{5Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 134.} Trainers can share the evidence and steer clients to a registered dietitian.^{5Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 134.}