About Testosterone, Free
Free testosterone refers to the portion of testosterone that is not bound to proteins in the blood such as sex hormone-binding globulin (SHBG) or albumin. Only free testosterone and albumin-bound testosterone are considered bioavailable and able to bind to androgen receptors to exert biological effects.
Reference Values
Optimal Range
≥ 15.0 pg/mL
Women's Optimal Range
1.0 - 5.0 pg/mL
Elite Value
25.0 pg/mL
Health Implications
{'high': 'Elevated levels may indicate conditions such as polycystic ovary syndrome (PCOS) in females, or testosterone therapy or anabolic steroid use in males, potentially increasing the risk of heart disease.', 'low': 'Low levels may be associated with decreased libido, fatigue, depression, and reduced muscle mass in males, and can indicate adrenal insufficiency or pituitary disorders in both genders.'}
Symptoms
High
Increased aggression, mood swings, anxiety, headaches, excessive sweating, acne outbreaks, and decreased sperm count.
Low
Decreased libido, depression, fatigue, muscle weakness, weight gain, difficulty concentrating, and reduced bone mass.
Lifestyle Factors
Specimen Type
Testing Methods
Also Known As
Scientific Sources
- Whittaker, J., & Wu, K. (2022). Low-fat diets and testosterone in men: Systematic review and meta-analysis of intervention studies. *arXiv preprint*. |