Testosterone is the main sex hormone in males that is responsible for the development of male reproductive tissues as well as promoting secondary sexual characteristics such as increased muscle mass, bone mass, and growth of body hair. The majority of testosterone in the blood is bound to either sex hormone-binding globulin (SHBG) or albumin. Free testosterone refers to the fraction of testosterone in the blood that is not bound to transport proteins like SHBG or albumin.
- Key differences between total and free testosterone:
- Total testosterone measures all testosterone in the blood, both free and protein-bound
- Free testosterone measures only the unbound testosterone that is biologically available to tissues
- Free testosterone makes up about 2-3% of total testosterone
- Free testosterone is the active form that exerts effects on the body
- Total testosterone levels can be misleading if SHBG levels are abnormal
Some key points about the relationship between total and free testosterone:
- Higher SHBG levels result in lower levels of free testosterone
- Medical conditions that increase SHBG lower free testosterone
- Free testosterone correlates better with clinical symptoms than total T
- Calculating free T requires total T and SHBG blood measurements
- The free T calculation helps determine if low total T reflects low bioavailable T
Why measure free testosterone levels?
- Provides a measurement of the biologically active testosterone
- Better indicates the clinical effects of testosterone status
- More accurate than total T when SHBG is abnormal
- May be better for diagnosing testosterone deficiency
- Monitoring free T allows assessing treatment efficacy
Signs and symptoms associated with low free testosterone:
Treatments that influence free testosterone levels
Testosterone replacement therapy can effectively raise total and free T levels. Lifestyle modifications like exercise, weight loss and stress reduction can help balance hormones and reduce SHBG to increase free T. Adjunctive supplements like zinc, vitamin D and
DHEA support healthy testosterone.
We offer cutting-edge hormone testing and custom therapies to help patients optimize their free testosterone levels and restore energy, strength and vitality. Rejuvenate Hormone Clinic() uses advanced diagnostic testing to get to the root cause of low testosterone and help patients feel healthy and vibrant again.
I hope this breakdown helps explain the main differences between total and free testosterone as well as the importance of measuring and optimizing free testosterone levels! Let me know if you have any other hormone-related questions.
