Understanding what it means to “boost testosterone” isn't always easy. Aside from being responsible for facial hair and general feelings during puberty, we know testosterone helps us lift weights and pack on muscle. Why testosterone is so important“Testosterone plays a crucial role in building muscle,” explains Ali Malik, founder of Fit Labs Kensington. “When men have low testosterone levels, muscles can become weak. “Testosterone contributes to cognitive function, enhancing concentration, focus and mental clarity,” says Dr. Kerry Aston, founder of The Movement Medic.