Two groups of 12 female students, with no experience strength training, worked out with weights for 9 weeks. They followed the same training schedule: twice a week they trained their lower body, and once a week they trained their upper body. The workouts were based on basic multi-joint exercises.
One group took 2.5 grams of betaine daily. The other took a placebo.
“In summary, the major findings of the present study are that 9 weeks of betaine supplementation improved body composition by reducing fat mass and tended to improve high-volume work capacity, but not strength or power performance in young, active, resistance training naive females”, write the researchers.
“Dietary factors, specifically suboptimal total energy and protein intake, were a limitation in the present study. While we attempted to clarify food journals to ensure accurate dietary analysis, and although under reporting of food intakes are common in the literature, subjects in the present study were likely in a caloric deficit.”
“Despite these limitations, we can glean some practical information from the results. In particular, the results of this study suggest that betaine may be an effective fat loss supplement for females on a restricted calorie diet engaged in a resistance training program.”
“Additionally, the trend for some enhancements in work capacity may be particularly useful to coaches working with female athletes in the aesthetic sports who commonly consume very little calories and have high training volumes in the weeks leading up to competition.”
J Int Soc Sports Nutr. 2018 Jul 31;15(1):37.