Similar to creatine, muscle contains significant quantities of a substance called carnosine.
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Carnosine is a very important buffer in muscle, meaning that it helps to maintain a normal balance of acidity. Fatigue during high-intensity exercise such as sprinting and weight lifting is linked to acid build up in the muscles and blood. Carnosine is destroyed in the gastrointestinal tract and the muscle is not able to take up carnosine directly. That's why researchers have focused on the precursor beta-alanine, which is taken up by muscle and then converted to carnosine. Studies show that beta-alanine can increase muscle carnosine, but there has yet to be direct comparisons of different dosing protocols to determine the most effective method to increase muscle carnosine. Swiss researchers compared two 8 week dosing protocols on the time course of muscle carnosine loading and how long levels remained elevated after discontinuing beta-alanine supplementation. One group received a constant dose of beta-alanine of 1.6 grams/day divided into two 800 mg doses for 8 weeks. Another group received 3.2 grams/day for 4 weeks and then decreased the dose to 1.6 grams/day for the remaining 4 weeks. After just 2 weeks, the high dose group showed a 10% increase in carnosine content of the calf muscle compared to an 8% increase in the low dose group. By 4 weeks, the increase was even greater for the high dose group. During weeks 4 to 8 when both groups were consuming 1.6 grams/day there were continual increases in muscle carnosine. Although numerically higher, there was not a significant difference between groups in muscle carnosine at week 8. From week 8 to week 16 subjects stopped supplementing. Muscle carnosine decreased gradually but still remained above baseline levels after 8 weeks of no supplementation. There was a lot of variability between subjects in how they responded to beta-alanine supplementation, but on average the results indicate that the extent of muscle carnosine uptake is dependent on the total amount consumed over a period of time, and not impacted by other factors such as starting muscle carnosine content, muscle type, and daily dose.
. Stellingwerff T, Anwander H, Egger A, Buehler T, Kreis R, Decombaz J, Boesch C. Effect of two β-alanine dosing protocols on muscle carnosine synthesis and washout. Amino Acids. 2011 Aug 17.
