by Alan Gaspari Nutrient Journal
N,N-Dimethylglycine (short: DMG) is an intermediate of choline metabolism. Betaine (metabolized from choline and is metabolic precursor to dimethylglycine) donates a methyl group to homocysteine to form methionine . By this removal of one methyl group from betaine, dimethylglycine is formed . Dimethylglycine is often sold commercially as hydrocloride salt (dimethylglycine HCL).
Dimethylglycine’s Effects on Athletic Performance
Dimethylglycine has been claimed to be an athletic performance enhancer and can be found in various sport supplements. Since dimethylglycine donates methyl groups to transmethylating process it is claimed to improved energy usage. Therefore, it is often marketed and sold as energiser.
The interest in dimethylglycine arose from a report indicating that N,N-Dimethylglycine reduces lactic acid concentration in blood in response to surgical stress in animals . Further human and animal studies yielded inconsistent results. A study on dimethylglycine-treated horses by Moffit et al.  reported lower plasma lactate concentrations after treadmill exercise. However, this study raised doubts about dimethylglycines effectiveness due to unbalanced design used. Rose et al.  found no differences in muscle lactate concentrations in horses treated with dimethylglycine and horses receiving placebo.
In trained athletes, Pipes  noted a 23,6% increase in time to fatigue after dimethylglycine supplementation. In contrast, Gray and Larry  reported no significant changes in short-term maximal treadmill performance between group receiving pangamic acid (calcium gluconate and N, N-Dimethylglycine) and control. No improvements in aerobic and anaerobic performance was also reported when 400 mg of dimethylglycine per/kg of body weight was administered to elite basketball players . Dimethylglycine also failed to improve maximal treadmill exercise to exhaustion in well-trained college women . Authors of this study concluded that there is no evidence to recommend dimethylglycine as an ergogenic aid to endurance athletes.
Dimethylglycine supplementation seems to have little to no effect on athletic performance besides evidence available is limited and conflicting. More well-researched clinical trials should be done before any definitive conclusions can be made.
Other Dimethylglycine Uses
Treatment of Autism
N,N-dimethylglycine has also been reported to be beneficial in children with autism . Kern et al.  reported that some children seem to respond positively to the dimethylglycine supplementation but overall behavioral assessments were not significantly different from children receiving placebo. Same was reported by Bolman and assistants  , however, the weakness of this study is low dosage used in a small number of children. According to available evidence, subjects treated with DMG show little to no difference compared to untreated subjects for treatment of autism spectrum disorder .
Dimethylglycine may improve body’s immune system as reported by Graber and others . Results of their study suggests that dimethylglycine supplementation improves humoral as well as cell-mediated immune responses in humans .
Very large doses up to 200 mg/kg given to animal models caused no adverse events . This is not surprising as dimethylglycine is a natural metabolite which doesn’t build up in the body.
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Meduski, J. W., et al.. 1980. “Decrease of lactic acid concentration in blood of animals given N,N-dimethylglycine.” Presented at Pacific Slope Biomedical Conference, Univ. of California, San Diego, (1980) 7-9.
Moffitt, P., et al. “Venous lactic acid levels in exercising horses fed N, N-dimethylglycine.” Proceedings of the 9th Equine Nutrition and physiology Symposium, E., Lansing, Michigan. 1985.
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Graber, Charles D., et al. “Immunomodulating properties of dimethylglycine in humans.” Journal of Infectious Diseases 143.1 (1981): 101-105.