The use of beta-alanine to produce muscle carnosine offers a way to increase anaerobic exercise potential and is likely to add to the effects of creatine in some exercise settings. First discovered in the early 1990s, beta-alanine and histidine are the two components of carnosine. Histidine is already present in large quantity within skeletal muscles, so it is beta-alanine that acts as the rate-limiting factor in carnosine conversion.
A buildup of metabolic waste limits muscle contraction, with hydrogen ions being the worst. This is primarily true of our fast fibers, which are most sensitive to hydrogen ions and extremely susceptible to fatigue. If the hydrogen ions can be buffered, muscle strength can be maintained for a longer time before fatigue sets in. Anyone, including bodybuilders, involved in exercise where lactic acid buildup is the limiting factor stands to benefit from beta-alanine. In the gym, this benefit may translate into more reps with a given weight.
Carnosine is very effective at buffering the hydrogen ions responsible for producing the lactic acid burn. Studies have shown that increasing muscle carnosine by supplementing beta-alanine may delay fatigue and improve the muscular aspects of athletic performance.
Research also indicates that beta-alanine increases lactate threshold, improves the ability to maintain maximal power output during high-intensity exercise, and decreases neuromuscular fatigue. By elevating carnosine level, nerves fire at a faster rate. For example, instead of one's body operating at 80% the day after exercise, carnosine may help it perform closer to the highest possible levels. Beta-alanine is mainly useful for athletes who are constantly using the same muscles, without the ability to take a break and recover for a few days.
One study compared orally administered beta-alanine in 10, 20, and 40 mg/kg levels in humans. Results showed that less than 5% was excreted in urine and, in the above amounts, increases in muscle carnosine stores were 42.1, 64.2 and 65.8%, respectively. In addition, workout volume increased by 13% after four weeks and 16.2% after 10 weeks. Results suggest that for a 220 lb athlete, 4g per day is more than enough. Real world feedback, in addition to dozens of human studies on strength, endurance, strength/endurance, and power/endurance athletes, shows increases in muscular strength, size, workout volume, and general work capacity of all three types of muscle fibers.