L-Glutamine
L-Glutamine has long been considered a staple in many athletes’ supplement regiments dating back to the early 1990s and beyond. This naturally occurring amino acid is found in high levels in meat and eggs, as well as extremely high levels in whey/casein protein powders.
Most associate glutamine with increasing muscle mass and helping to reduce muscle soreness from weight training, however, numerous studies have shown that glutamine is most likely not capable of either unless being utilized by users who have muscle wasting diseases.
This is not to say glutamine does not have benefits however, as both old and newer science shows it can have an important place in any athletes’ daily intake.
What it does
As of now, glutamine has not been proven to increase lean muscle mass or help enhance the recovery period in healthy users.
Studies do however suggest that glutamine may be capable of lowering blood ammonia levels when taken for at least 5 consecutive days[3].
Glutamine may also help enhance digestion for users, in particularly those suffering from Crohn’s disease[4].
How it works
If one looks past the lack of science (or direct evidence) of glutamine’s benefits for building muscle/enhancing recovery, the supposed mechanism of action for the benefits of glutamine would be the enhancement of nitrogen retention caused by glutamine. Increasing nitrogen retention helps place the body in an anabolic or muscle building state, thereby making glutamine a theoretical muscle builder.
The most logical reasoning for why glutamine does not provide these supposed benefits, however, is that the human body is capable of producing all the glutamine it needs for the average person, and in times of extreme stress (such as intense exercise) the body is provided all the additional glutamine needed via the average diet.
Dosing
The anecdotal suggested dosing for glutamine is 5g 1-2x/day, traditionally taken prior to and after training. For actual benefits from glutamine, a significantly higher dose may be necessary to reap benefits, as oral bioavailability of glutamine when provided as an individual amino acid appears to be somewhat low[1]. Studies showing changes start at the 30g/day dosage mark[2].