top of page

Will Testosterone Replacement Therapy (TRT) cause Hair Loss

Testosterone therapy causing male pattern baldness, androgenic alopecia

Keywords: Male Pattern Baldness, Androgenic Alopecia, TRT, Testosterone, Androgens and Hair Loss, Finasteride, Proscar, Dutasteride, Avodart, Propecia, Hair Transplant.

Will Testosterone replacement cause male pattern hair loss?

The most common regulator of human hair growth in men are androgens, principally testosterone. Androgenic alopecia, also known as male pattern baldness, affects approximately 80% of men. Male pattern baldness is characterized by a recession, thinning and loss of hair primarily from the temporal zones and vertex of the scalp. Men who have androgenic alopecia or male pattern baldness are genetically predisposed to hair loss, principally from the actions of Dihydrotestosterone (DHT). DHT is similar to testosteron, but it is much more potent androgen. DHT acts upon the bulb of the hair follicle to induce hair thinning and eventual hair loss. Unlike hair on the vertex and temporal zones of the scalp, hair located on the side the scalp are resistant to androgens.

DHT is an androgen that is derived from the breakdown of testosterone. Testosterone is broken down into DHT by an enzyme called 5-α (alpha)-reductase. For men who are genetically predisposed to have male pattern baldness the use of testosterone replacement therapy may accelerate the hair loss cycle by increasing the amount of circulating DHT. Testosterone replacement therapy may not cause hair loss in men who are not genetically susceptible to androgenic alopecia. Some hairs are resistant to the presence of DHT or testosterone and this explains why some men present with baldness and others do not.

From clinical studies men on testosterone replacement therapy (TRT) who are at risk of experiencing androgenic alopecia will present with hair loss most often after the first year of being on TRT. Developing hair loss during the first year of TRT was found to be low, even in males who had preexisting male pattern baldness.

Furthermore, studies have shown that the duration of testosterone supplementation may correlate with hair loss, with longer exposures to exogenous testosterone increasing the risk of male pattern baldness. There been no difference in the type testosterone used (gel, injection, pellet) and loss of hair.

While men on testosterone replacement therapy may accelerate androgenic alopecia, testosterone use has been shown to increase facial and body hair growth.

In men who are on TRT and are showing signs of hair loss, the use of finasteride (Propecia) can slow and mitigate male pattern baldness.

How does Finasteride (Propecia, Proscar) prevent hair loss?

Finasteride is a 5-Alpha-reductase inhibitor. Finasteride is the generic form of Proscar and Propecia. Finasteride works to prevent hair loss in men who are predisposed to androgenic alopecia by reducing the amount of circulating DHT. Less DHT prevents less hair recession, regression and loss.

What is the difference between Finasteride (Proscar, Propecia) and Dutasteride (Avodart)?

There are several noticeable and important difference between Finasteride and Dutasteride. Foremost; Finasteride is a competitive inhibitor of the Type -2, 5-Alpha-reductase isoform that is principally found in the prostate and scalp. Dutasteride is a competitive inhibitor of both Type-2, and Type -1, 5-Alpha-reductase (more common in liver and skin) owing to a more complete reduction in DHT levels by approximately 20-24 weeks. The half life of Dutasteride is 35 days compared to the half life of Finasteride of 0.3 days. Dutasteride stays around longer in circulation. Dutasteride reduces prostate size and decrease urinary symptoms more so than Finasteride. The sexual side effect profile of both Dutasteride and Finasteride are the same.

Are there sexual side effects of Dutasteride (Avodart) or Finasteride (Proscar, Propecia)?

Dutasteride and Finasteride can both have sexual side effects that can impair ejaculatory function and erections. The rate of ED in men who use Finasteride is approximately 5% to 9%.

According to the Proscar Long Term Efficacy and Safety (PLESS) study, sexual side effects from Finasteride were reported in 15% of subjects only after 1 year of treatment. In the PLESS Study 5mg Finasteride was used for the treatment of an enlarged prostate (BPH). For men with male pattern baldness or androgenic alopecia the recommended dosage is only 1mg of Finasteride. The sexual side effects for men who take Finasteride for hair loss may be substantially lower than the 5mg dosing of Finasteride man take for an enlarged prostate.

In a study called, The Finasteride Male Pattern Hair Loss Study, 1553 men between the ages of 18 and 41 years of age and with male pattern hair loss received either Finasteride 1mg daily or a placebo. The study observed both groups for hair growth (hair counts), hair loss rate, appearance of hair and sexual side effects. Sexual side effects were found to be only 3.8% vs 2.1% in the finasteride treated group compared to the placebo group. Sexual side effects included loss of sex drive, decrease in ejaculatory volume and erectile dysfunction.

According the medication package insert for Propecia, men who take finasteride 1mg daily for 48 weeks may experience a decrease in ejaculatory volume of 0.3mL.

What is the difference between Proscar and Propecia?

Propecia and Proscar are both medications with the active ingredient Finasteride. Propecia and Proscar provide difference dosages of the active ingredient, Finasteride. Propecia is 1mg of Finasteride with an FDA approved use for male pattern baldness. Proscar is 5mg of Finasteride and indicated for use in men with an enlarged prostate and associated lower urinary tract symptoms.

Is Dutasteride or Finasteride better to prevent hair loss?

In a randomized controlled open label study, Dutasteride was shown to have more efficacy compared to Finasteride towards improving 1) new hair growth 2) decrease thin hair count in men with androgenic alopecia (male pattern baldness).

What is the dosage of Finasteride for male pattern baldness?

1mg per day of Finasteride, also known as Propecia, is used to treat male pattern baldness.

Can I take Finasteride (Propecia) with or without food?

Finasteride (Propecia) for male pattern baldness can be taken with or without food. Food does not affect the absorption of the medication. Most men take Propecia in the AM as part of the morning routine.


bottom of page