It's been suggested that testosterone levels affect athletic performance and fat-burning processes. Long-term testosterone therapy, for example, has been shown to result in "significant and sustained weight loss," improved motivation, and increased physical activity in men, according to one study. As a result, if your T levels are low, using the best testosterone supplements can help you lose weight if you combine them with a healthy diet and regular exercise. However, if your testosterone levels are already within normal limits, you may not notice much difference in weight loss.