Benefits of Glycerol Bodybuilding Supplement
By Steven Y.
Glycerol is a naturally occurring 3-carbon alcohol which has been shown to increase total body water by up to 700ml, a phenomenon known as "glycerol hyperhydration" (8,11). With dehydration as small as 1% of bodyweight decreasing your work capacity, it is easy to see why this supplement could be so useful (5,7). Taken a few hours before an endurance event, glycerol will help you stay cooler, more energized, and better hydrated. Many research experiments have shown the effectiveness of this supplement in increasing athletic abilities.
One such study was done by Monter P, et al. for the department of medicine at the Veterans Affairs Medical Center. In his study, Monter analyzed the effects of pre-exercise glycerol hyperhydration on the subsequent workouts. His study focused primarily on the compound's effect on endurance cycling. The results were undeniable: After glycerol hyperhydration, the average heart rate during endurance cycling was reduced by 2.8 beats per minute. The average time that the cyclists could last was prolonged during the bouts in which they were glycerol hyperhydrated. The difference of 77.4 minutes to 93.8 minutes is not an insignificant one by any stretch of the imagination. (2)
In the department of biology at the University of New Mexico, Lyons TP, et al. studied another beneficial effect of glycerol hyperhydration. He postulated that this hyperhydration would increase exercise performance and thermo-regulatory capacity in an environment of heat. In other words, he thought that glycerol supplementation would better allow your body to maintain a cooler temperature as you exercised in a hot environment. In a hot and dry climate-controlled area, Lyons had his test subjects perform moderate exercise. During the exercise following the glycerol hyperhydration, there was an elevated sweat rate in the participants. This excess sweat helped to cool them off. Rectal temperatures were taken and to no surprise, core body temperatures were lower than without the hyperhydration. His studies showed that glycerol supplementation helped the body fight over-heating - even in a hot climate. Robergs RA, et al. (center for exercise and physiology, University of New Mexico) has also taken look into this specific effect of glycerol. Like Lyons, Robergs concluded that "it appears to be an effective method of improving tolerance to exercise and other heat related stressors" (8). (10)
Combining the controls of both the previous studies mentioned, Hitchens S, et al. (Department of physiology and pharmacology, James Cook University, Australia) did a study in which he combined both extreme endurance cycling with a hot and extremely humid controlled-climate. Giving his participants and average dose of glycerol with excess water (1g glycerol/kg body mass and 22ml water/kg body mass), Hitchens was able to increase his subjects' body water by 600ml. His studies proved that "glycerol treatment significantly increased performance" in endurance cycling in a hot and humid climate. He concluded that, - "during the glycerol trial, subjects maintained a higher power output without increased perception of effort or thermal strain." His is another study that proves glycerol supplementation is beneficial to endurance athletics as well as an effective way of helping your body maintain a lower core temperature during exercise and in hot climates thus helping to prevent heat-stroke and the such. (11)
So as you can clearly see, glycerol hyperhydration is an extremely beneficial state to be in prior to engaging in strenuous endurance activities and/or being in a hot climate. But how safe is it? The answer is that glycerol is extremely safe.
Does it have any negative effects on the blood? Plasma insulin levels and resting blood glucose are not affected by glycerol supplementation (1). No changes in hemoglobin, hematocrit, or serum electrolyte concentrations resulted from the glycerol supplementation (3,9,10). Glycerol also had no effect on plasma atrial natriuretic concentrations (6). Nor where any physiologically significant differences in plasma sodium or renin seen (9).
"But it's bad for you. I have this feeling inside me that it just is." How do I respond to such a statement? All the previously cited studies have shown no negative short-term effect that resulted from glycerol supplementation. It has been proven that there is no difference between its effect on men or women (3). Glycerol has also been used in many situations. The studies didn't just show that it had no noted negative short-term side effects, but showed that there were no noted ill-effects with supplementation and extreme fatigue and endurance training (1,6,13), extended periods of up to 49 hours (5), hot climates (10,11,12), and even during a 3-hour dive in freezing waters, no ill-effects were noted (4).
As for long term ill effects, that should not be a worry either. Glycerol has been used in research settings for almost 60 years now, with widespread clinical use for a period of about 20 years (8). I'm sure that if there were any long-term damage caused by this supplement, then it would have been noted by now.
In my opinion, glycerol supplementation is safe. And, in lure of all the studies provided, claims otherwise have to be taken with a grain of salt. So now that I've proven to you the benefits and safety of glycerol, I'm sure you'd like me to get into the proper way to supplement it.
The benefits of glycerol hyperhydration are evident. Depending on your event, it may or may not be for you. Events that require sudden bursts of energy (i.e.- powerlifting and sprinting) may not warrant the use of glycerol. But other sports like football, boxing, long-distance running, soccer, etc - would definitely prove glycerol supplementation useful.
If your event will last a few hours, I suggest you follow the protocol used in most of the studies cited here. That would be to take 1 gram of glycerol (a little more than 1ml) for every kilogram of body mass. Take this with 1.5-2 liters of water about 2-3 hours prior to your event.
Now if your event will last for days, glycerol may still be beneficial to you. A study done by Koenigsberg PS, et al. shows that the effects of glycerol may be drawn out to days. By taking 3grams of glycerol per kilogram of body mass per day (spread out through the day), along with 50ml of water per kilogram per day spread out through the day (spread out through the day), Koenigsberg's study shows that the participants lost less water and in turn needed to drink less water in a 49-hour period. So if your event involves carrying your water with you for an extended period of time, glycerol may help you by making less water necessary. (5)
I don't suggest you use this supplement too often. Just before an important event or an unusually grueling workout. Limit usage to under 2-3 times a week. Glycerol Fuel made by Twinlab should run under $10 per 500ml bottle. So it is also a very cheap supplement.
References:
1) Gleeson M, et al. "Comparison of the effects of pre-exercise feeding of glucose, glycerol, and placebo on endurance and fuel hemeostasis in man." Eur J appl Physiol. 1986;55(6):645-53.
2) Montner P, et al. "Pre-exercise glycerol hydration improves cycling endurance time." Int J Sports Med. 1996 Jan;17(1):27-33.
3) Riedesel ML, et al. "Hyperhydration with glycerol solutions." J Appl Physiol. 1987 Dec;63(6):2262-8.
4) Arnall DA, et al. "Failure to reduce body water loss in cold-water immersion by glycerol ingestion." Undersea Hyperb Med. 1993 Dec;20(4):309-20.
5) Koenigsberg PS, et al. "Sustained hyperhydration with glycerol ingestion." Life Sci, 1995;57(7):645-53
6) Freund BJ, et al. "Glycerol hyperhydration: hormonal, renal, and vascular fluid responses." J appl Physiol. 1995 Dec;79(6):2069-77.
7) Wagner Dr. "Hyperhydrating with glycerol: implications for athletic performance." J Am Diet Assoc. 1999 Feb;99(2):207-12.
8) Robergs RA, et al. "Glycerol. Biochemistry, pharmacokinetics and clinical and practical applications." Sports Med. 1998 Sep;26(3):145-67.
9) Inder WJ, et al. "The effect of glycerol and desmopressin on exercise performance and hydration in triathletes." Med Sci Sports Exerc. 1998 Aug;30(8):1263-9.
10) Lyons TP, et al. "Effects of glycerol induced hyperhydration prior to exercise in the heat on sweating and core temperature." Med Sci Sports Exerc. 1990 Aug;22(4):477-83.
11) Hitchins S, et al. "Glycerol hyperhydration improves cycle time trial performance in hot humid conditions." Eur J Appl Physiol. 1999 Oct;80(5):494-501.
12) Meyer LG, et al. "Effects of three hydration beverages on exercise performance during 60 hours of heat exposure." Aviat Space Environ Med. 1995 Nov;66(11):1052-7.
13) Miller JM, et al. "Effect of glycerol feeding on endurance and metabolism during prolonged exercise in man." Med Sci Sports Exerc. 1983;15(3):237-42
14) Klein S, et al. "Effect of endurance training on glycerol kinetics during strenuous exercise in humans." Metabolism. 1996 Mar;45(3):357-61.
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