The suppressive effect of testosterone is directly related to the dose and duration of treatment. The way testosterone is given, such a shots, pills or creams is not as important. All types of testosterone supplementation will shut off sperm production. The most important factors determining successful return of sperm production is the duration of testosterone and dosage used. The extreme supplementation used by bodybuilders and athletes cause a profound suppression and loss of sperm producing cells. These are the most challenging patients to help regain their fertility. These patients typically need every other day shots of HCG and an anti-estrogen for at least 3 months and often longer. The first thing any man who decreased his fertility by taking testosterone supplementation is to stop using the testosterone. Often, all that is needed is 3-6 months off the testosterone to restore fertility. The semen analysis is checked every 3 months for improved counts.