This study examined the effect of glycerol ingestion on fluid homeostasis, thermoregulation, and metabolism during rest and exercise. Six endurance-trained men ingested either 1 g/kg glycerol in 20 ml H2O/kg body weight vs. 20 ml H2O/kg body weight. Results demonstrate that glycerol, when ingested with a bolus of water 2 hours prior to exercise, results in fluid retention, which is capable of reducing cardiovascular strain and enhancing thermoregulation. Furthermore, this practice increases exercise performance in the heat by mechanisms other than alterations in muscle metabolism.
I tried this more than 20 years ago, when it was legal (indeed, there was a product on the market that was exactly this). On a hot summer day, I did a 40+mile hilly ride, and I felt really good. Like amazingly good (I typically sweat a lot).
I then tried it for a 50mi bike road race. Unfortunately, weather delayed the start of the race, and I found myself peeing literally every five minutes as my body started to unload all the stored water. By the time the race began, I think I had lost all the retained water.
Some people reported stomach problems (try drinking ~60oz of that stuff and you’ll understand why!), but I had no issues.
As the other poster indicated, it is banned, because it can be used as a masking agent.
Bumping this thread to update that glycerol was removed from banned list in 2018 confirmed by USADA 14 May 2021 for anyone else that stumbles upon this thread looking for heat management solutions.
I remember playing with glycerol about 25 years ago. It works. Word was that Quaker Oats (Gatorade) was considering it BUT it was hypothesized that the glycerol would NOT hyperhydrate the brain the same way it would the other compartments. So imagine hyperhydrating with glycerol then wringing yourself dry with a ten hour effort. A -4% dehydration would really net out to be like -6-7% dehydration of the brain. No bueno. Any biochem folks out there able to weigh in on this/ blood brain barrier of glycerol, etc . . . As opposed to Na+ loading?
i also remember this being a thing back in the 90s - you could buy glycerol at GNC and add it to a bottle of sports drink. you could also buy choline, if i remember. crazy times! i mixed up a super bottle of ‘rocket fuel’ to use in a half ironman - who knows if it worked, but i definitely thought i had the inside advantage.
if i remember, the theory was that it would reduce cramping (?) or improve neuromuscular coordination late in the race. anything to that?
i also remember going to GNC in the 90s to buy some electrolyte crystals - i couldn’t be bothered to go buy gatorade at the store across town. the woman behind the till said, “will you be drug tested?” and i said, “uh . . . why?” and she said, “oh, you’ll test positive for ephedrine if you take this stuff.” i think i was 17 at the time.
I used a glycerol product named Glycerate back in the 90s for a short time. It definitely helped on long rides in the summer heat, I would notice a lower heart rate, less cramping and being ‘super-hydrated’ for hours. Like others said, you would add packets to 1 or 2-L sized bottles, and load up in the hours before your event. My LBS had it in stock ( heard about it from some cycling friends back then) and I do remember it then getting banned.
yes I used it using a limited protocol and had great results in training. then like a moron when I raced my first ironman I went for full protocol, yes more glycerine and 2 litres of water and from 3/4 thro teh swim I hit all teh potential side effects.
headache nausea for the entire bike finally throwing up water. I couldnt or feel like eating a thing and soft peddled around hawaii bike course. I came around towards the end of the bike and managed some food and drink and had an ok marathon.