Hormones and testicles
Men make 95% of testosterone in their testicles
Disclaimer: This information isn’t a substitute for professional medical advice, diagnosis, or treatment. You should never rely upon this article for specific medical advice. If you have any questions or concerns, please talk to your doctor.
How men make testosterone
Men make nearly all of their testosterone in the testicles. When your brain senses low testosterone in your blood, it triggers a complicated chain reaction of hormones. This ramps up testosterone production in the Leydig cells of the testicles. (Testosterone production in women mostly happens in the ovaries). Your adrenal glands also produce a little testosterone.
The steps of testosterone production
- In the brain, the hypothalamus releases GnRH hormone
- This causes the pituitary gland to makes two more hormones—Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH)
- FSH is important for sperm production. LH starts testosterone production in your testicles
- Testosterone gets released into your bloodstream
- Testosterone in the bloodstream acts as part of a feedback loop. When testosterone levels are high, it inhibits the release of GnRH, FSH, and LH from the brain.
Your testosterone levels are always changing
Think of testosterone production like a brain-to-balls thermostat. When testosterone levels get low, production increases. When you produce “enough” testosterone, production decreases. Testosterone levels are highest in the morning and vary throughout the day.