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People often think of testosterone as a virtual synonym for manliness, aggression, and strength—a bit of misrepresentation since women also have testosterone. But what about dihydrotestosterone or DHT? You may have read about the DHT hormone in relation to hair loss and seen ads for DHT blockers. Read on to learn more about the DHT hormone, what it does, and how it can affect hair loss.
What is DHT?
Dihydrotestosterone (DHT) is a male sex hormone (androgen) that plays a critical role in male sexual development. In the womb, the DHT hormone is responsible for genetically male babies developing male organs, like the penis, scrotum, and prostate (Kinter, 2021).
During puberty, DHT’s primary role is to encourage the growth of facial hair and body hair (including pubic hair and under-arm hair). It also helps with voice-deepening and increased muscle mass. Once you hit adulthood, DHT plays a role in certain medical conditions, like male pattern hair loss (otherwise known as androgenic alopecia), hirsutism (abnormal hair growth in females), benign prostatic hyperplasia (BPH), and prostate cancer (Kinter, 2021).
DHT vs. testosterone
Testosterone and DHT are both androgens, but the DHT hormone is much more potent. It binds to androgen receptors more strongly and sticks around longer than testosterone.
DHT is actually made from testosterone by 5-alpha-reductase, an enzyme mainly present in your skin, prostate, and liver. But only 10% of your circulating testosterone is turned into DHT (Kinter, 2021).
How to stop balding: 6 ways to reverse hair loss
DHT hormone and hair loss
There are several different causes of hair loss—some hair loss can be due to illnesses, while other types may stem from vitamin deficiencies. However, the most common cause of hair loss is androgenic alopecia (AGA), more commonly known as male pattern baldness. Half of all men will start losing their hair by 50, and the problem worsens with age (Ho, 2021).
DHT plays an important role in male pattern hair loss. People with AGA tend to be genetically predisposed to having hair follicles that are more sensitive to androgens like DHT, along with higher levels of DHT. DHT shortens the hair follicle’s growth stage in the scalp, resulting in thinner and shorter hairs. These miniaturized hairs eventually lead to visible hair loss in a recognizable pattern (Ho, 2021).
In men, AGA starts above the temples and at the vertex (crown) of the head, leading to the characteristic receding hairline. Hair loss will continue until only a thin rim of hair at the sides and rear of the head will be left (think Danny DeVito.)
Now that you’re up to speed on what DHT does, how can we stop it from causing problems?
There are two main treatments on the market that block the enzyme that makes DHT: finasteride (brand name Propecia or Proscar; see Important Safety Information) and dutasteride (brand name Avodart). Both medications are oral tablets and are approved treatments for BPH, but the FDA only approves finasteride to treat male pattern hair loss (although the dose is different depending on if you’re using it for BPH or hair loss).
Do testosterone boosters work?
How well do these medications work? Studies have shown that finasteride can slow balding and hair loss in more than 80% of men and stimulate hair growth in over 60% of men (DailyMed, 2021). Just keep in mind that it takes a few months to see results.
What about the DHT-blocking shampoos? Unfortunately, there’s no solid evidence that any shampoo blocks DHT in the scalp. Some shampoos, like ones containing ketoconazole, have been found to help with hair loss. Scientists theorize that ketoconazole may block testosterone synthesis, thereby decreasing DHT production. But more research is needed in this area (Fields, 2020).
The only FDA-approved topical medication for hair loss is minoxidil (brand name Rogaine). This medication does not block DHT. Rather, it treats hair loss by stimulating increased blood flow and nutrients to the hair follicles.
- DailyMed. (2021). PROPECIA- finasteride tablet, film coated. Retrieved from https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=4e07adb4-7807-47d3-b9a9-2332a3047410
- Fields, J. R., Vonu, P. M., Monir, R. L., et al. (2020). Topical ketoconazole for the treatment of androgenetic alopecia: A systematic review. Dermatologic Therapy, 33(1), e13202. doi:0.1111/dth.13202. Retrieved from https://pubmed.ncbi.nlm.nih.gov/31858672/
- Ho, C. H., Sood, T., & Zito, P. M. (2021) Androgenetic alopecia. [Updated Nov 15, 2021]. In: StatPearls [Internet]. Retrieved on Mar. 11, 2022 from https://www.ncbi.nlm.nih.gov/books/NBK430924/
- Kinter, K. J. & Anekar, A. A. (2021). Biochemistry, dihydrotestosterone. [Updated Mar 13, 2021]. In: StatPearls [Internet]. Retrieved on Mar. 11, 2022 from https://www.ncbi.nlm.nih.gov/books/NBK557634/
- Phillips, T. G., Slomiany, W. P., & Allison, R. (2017). Hair loss: common causes and treatment. American Family Physician, 96(6), 371–378. Retrieved from https://www.aafp.org/pubs/afp/issues/2017/0915/p371.html
Dr. Chimene Richa is a board-certified Ophthalmologist and Senior Medical Writer/Reviewer at Ro.