Testosterone affects many body tissues, including skin and hair follicles. Although most of its effects are beneficial, one of testosterone's least popular effects is its role in pattern balding. This condition, officially known as androgenic alopecia, can occur in men or women. Testosterone is not the only cause of balding, but it is one of the most common.
Total Testosterone
Testosterone can be found in the bloodstream in three basic forms. Muscles use free, or unbound, testosterone directly. Other body tissues require testosterone to be converted into dihydrotestosterone, or DHT. This conversion occurs through interaction with an enzyme called 5-alpha reductase. Testosterone in the blood is also commonly bound to albumin, an amino acid, or a similar substance called sex-hormone binding globulin. Though these bonds are easily reversed and so these forms are generally considered biologically available, free T is usually a measure of only the unbound, unconverted testosterone. Total testosterone is a measure of all of these forms of testosterone in the blood.
Baldness and Free T
Early studies linked baldness with free T in the bloodstream. The September/October 1997 issue of the "Journal of Andrology" contained a study that explored the potential of male pattern baldness as an indicator of risk for hormon- related diseases. This early data found a correlation between higher levels of circulating free testosterone and male pattern baldness. Men with frontal baldness, in which the hair line recedes from the forehead, had less free testosterone and total testosterone than those with vertex baldness, which is loss of hair at the top of the head. Men with neither form of baldness, as a group, had the lowest free testosterone levels.
DHT
According to the American Hair Loss Association, the cause of most hair loss is DHT. This form of testosterone binds with hair follicles and causes them to shrink. As a result, blood flow to the follicles is choked off and eventually they lose the capacity to produce hair. Though elevated levels of free T and total T are associated with hair loss, it's also possible to have normal levels of testosterone but a higher proportion of DHT, which would still produce hair loss.
Hair Patterning
A study published in the February 1999 issue of the "Journal of the American Academy of Dermatology" concluded that testosterone levels affect overall hair patterning in men. The study reported that men with higher levels of total circulating testosterone levels were more likely to have vertex baldness and less likely to have dense hair on their chest. The study looked at testosterone levels and hair patterning in 51 healthy men over the age of 65, finding that higher levels of SHBG, or bound testosterone, was particularly linked with less hair on the chest.
Treatments
Baldness cannot be cured, says the Mayo Clinic, but there are treatments that can help reverse certain types of alopecia related to testosterone. A drug called Finasteride, which is marketed as Propecia, functions by preventing the conversion of testosterone into DHT. The drug is taken as a once-daily pill, with results appearing after several months. Unfortunately, the benefits of Propecia end if the drug is discontinued, and Propecia is not considered to be safe for use by women.
References
- Harvard Medical School: Testosterone, prostate cancer, and balding: Is there a link?
- JAAD: Hormones and hair patterning in men
- Journal of Andrology: Serum Androgens
- Mesomorphosis Website: DHT
- American Association for Clinical Chemistry: Free and Bioavailable Testosterone
- American Hair Loss Association: Causes of Hair Loss
