The Weight Loss Effects of Branched Chain Amino Acids and Vitamin B6: A Randomized Controlled Trial on Obese and Overweight Women

Int J Vitam Nutr Res. 2018 Feb;88(1-2):80-89. doi: 10.1024/0300-9831/a000511. Epub 2019 Mar 6.


Branched chain amino acids (BCAA), with vitamin B6 have been reported to improve fat metabolism and muscle synthesis. We hypothesized that supplementation with BCAA and vitamin B6 would result in more weight loss and improve body composition and blood markers related to cardiovascular diseases. Our aim was to determine whether the mentioned supplementation would affect weight loss, body composition, and cardiovascular risk factors during weight loss intervention. To this end, we performed a placebo-controlled randomized clinical trial in 42 overweight and obese women (BMI = 25-34.9 kg/m2). Taking a four-week moderate deficit calorie diet (-500 kcal/day), participants were randomized to receive BCAA (6 g/day) with vitamin B6 (40 mg/day) or placebo. Body composition variables measured with the use of bioelectrical impedance analysis, homeostatic model assessment, and plasma insulin, Low density lipoprotein, High density lipoprotein, Total Cholesterol, Triglyceride, and fasting blood sugar were measured. The result indicated that, weight loss was not significantly affected by BCAA and vitamin B6 supplementation (-2.43 ± 1.02 kg) or placebo (-1.64 ± 1.48 kg). However, significant time × treatment interactions in waist to hip ratio (P = 0.005), left leg lean (P = 0.004) and right leg lean (P = 0.023) were observed. Overall, supplementation with BCAA and vitamin B6 could preserve legs lean and also attenuated waist to hip ratio.

Keywords: Weight Loss; body composition; branched-chain amino acids; insulin resistance; vitamin B 6.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Amino Acids, Branched-Chain*
  • Female
  • Humans
  • Obesity
  • Overweight
  • Vitamin B 6 / chemistry
  • Vitamin B 6 / metabolism*
  • Weight Loss*


  • Amino Acids, Branched-Chain
  • Vitamin B 6