HMB - beta-hydroxy-beta-methylbutyrate
A slightly less studied supplement, but which may have benefits for athletes, particular slightly older ones.
HMB - beta-hydroxy-beta-methylbutyrate - may help reduce muscle breakdown in athletes and help reduce recovery times, with benefits for both power and endurance athletes.
HMB is a metabolite of the amino acid, leucine, which it is believed has a role to play in the synthesis of proteins. Studies undertaken to date have produced mixed results with some showing athletes increasing strength when taking the supplement and others showing no gain.
Initially, it was believed that the biggest difference would be seen by power athletes, who regularly lift weights, although it is also now thought that there may be a benefit to endurance athletes as it appears it may reduce recovery times.
It is currently thought that doses of 3g / day would benefit athletes, whereas we generally will have about 0.5g in a standard diet.
Photo HMB is thought to reduce muscle atrophy with age
There are currently no known safety issues or any known drug interactions - and it is not on any banned lists (although as always, cross-contamination is possible).
Overall, it may well benefit athletes to take this supplement, but with the benefits as yet not substantively proven, it could just be a way of burning a hole in your pocket. You need to decide on this.
The information here is written by athletics coaches who have read widely into the subject and not a sports nutritionist, so is about gearing your food and drink to the practicalities of running.