Testosterone boosters are dietary supplements that manufacturers claim increase testosterone levels. These products often contain ingredients from traditional remedies, such as fenugreek, zinc, maca, and ashwagandha. Testosterone is the primary male sex hormone. It contributes to muscle mass, facial and body hair growth, libido, and sperm production. The body naturally produces less testosterone in men around the age of 30 (reliable source). A typical testosterone level in men is between 300 and 1,000 nanograms per deciliter (ng/dL), depending on age. Low testosterone can be due to age or conditions affecting the testes, pituitary gland, and thyroid. Other factors can also influence testosterone levels. Testosterone levels peak in the morning and evening. Excessive exercise, poor diet, medications, and illness can also decrease testosterone levels.