How Does Testosterone Affect Your Body?

It boosts sex drive, fertility, and muscle growth

...but 98% of testosterone in your body is inactive

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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.

What Does Testosterone Do in Your Body?

Testosterone affects your body in a number of important ways. It’s directly responsible for growth, sexual health, and essential bodily functions in both men and women. Specifically, testosterone affects your:

  • Bone and muscle growth
  • Sex drive & performance
  • Fertility
  • Red blood cell production
  • Facial and body hair growth
  • The pitch of your voice
  • Even your mood

Testosterone also plays an important role in the testicles to promote healthy sperm production. But the most interesting thing about testosterone is that your body only uses about 2% of all the testosterone you make.

Most of Your Testosterone is Inactive

Nearly 98% of testosterone in your system is completely inactive. Seriously. It doesn’t do anything.

It’s complicated, but most of your testosterone gets tied up by other something called SBGH hormones in your blood. The remaining amount is either metabolized into another chemical, stored (by men) in the testes to help make sperm, or used by your body to accomplish all those important tasks listed above.

Testosterone Replacement

This also holds true for testosterone replacement therapy like testosterone creams or testosterone injections. Your body metabolizes or binds over 90% of testosterone, and secretes the rest in urine or feces, leaving just ~2% for use in your bloodstream.

That’s why low testosterone levels are so delicate. Even a small dip in your “free” testosterone (the unbound, active testosterone in your blood) can have a big impact on your overall health. And men’s testosterone levels naturally decrease with age.

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