Adequate
testosterone levels are vital for maintaining muscular growth, libido, and energy levels.
Thus, supplement companies have toiled to produce elaborate concoctions aimed at elevating testosterone, and some have been scientifically proven to work. Interestingly, a study published in Biological Trace Element Research suggests that taking a daily calcium supplement may provide testosterone support in those who exercise to exhaustion.
Using a basic research design, 30 healthy males between the ages of 17-21 were randomly assigned to one of the following three groups: Group 1- 35 mg/kg/day calcium gluconate, without training; Group 2- 35 mg /kg/day of a calcium gluconate, exhaustive training 90 min/day, 5 days/week; and Group 3- exhaustive training 90 min/day, 5 days/week, without calcium supplementation. Although exercise is known to increase testosterone levels, the scientists reported that calcium supplementation provided increases in testosterone beyond that of exercise alone. Although calcium-induced increases in testosterone were modest, this evidence supports the use of daily calcium in athletes to (at least) maintain post-exercise testosterone levels.
Reference:
Cinar V, Baltaci AK, Mogulkoc R, Kilic M. Testosterone levels in athletes at rest and exhaustion: effects of calcium supplementation. Biol Trace Elem Res. 2009 Summer;129(1-3):65-9.