Dihydrotestosterone (DHT) is a hormone that plays a role throughout the body. It helps with male development, body hair growth and changes that happen during puberty. DHT is also active in the skin and in the hair follicles. Depending on how sensitive the follicles are, it can affect the way hair grows. In this article, you will learn what DHT is, what it does in the body and why it can play a role in hereditary hair loss for some people.
What is the hormone Dihydrotestosterone (DHT)?
Dihydrotestosterone (DHT) is a hormone that is made from testosterone in the body. It belongs to the androgens, the group of hormones that help develop male characteristics. From a young age, DHT affects several processes in the body. During puberty, for example, it supports the growth of body and facial hair, a deeper voice and changes in the skin. DHT is also active in the oil glands of the skin and can influence how much oil the skin produces. In some people, the hormone may also play a role in sexual behaviour and libido, although this differs from person to person and depends on several hormonal factors.
The conversion of testosterone into DHT happens through the enzyme 5α-reductase. This enzyme is found in the skin, oil glands and hair follicles. Men generally have higher DHT levels than women, but women also produce this hormone and it has similar functions in their bodies.
How does DHT affect the hair follicles?
DHT can affect hair follicles because it attaches to small ‘receptors’ inside the follicle. In people who are sensitive to it, this can make the follicle slowly become smaller. This process is called miniaturisation.
When a hair follicle becomes smaller:
- the hair grows for a shorter time,
- the hair becomes thinner,
- and it falls out more quickly.
This only happens in people who are genetically sensitive to it (androgenetic alopecia). Their hair follicles react more strongly to DHT. With every hair growth cycle, the follicle becomes a little smaller, which makes the hairs finer and eventually hardly visible.
The pattern is often different in men and women:
- Men usually notice changes at the hairline or on the crown (Norwood scale).
- Women often see a wider parting and thinning on the top of the head, while the hairline usually stays the same (Ludwig scale).
DHT levels in men and women
Men generally have higher testosterone and DHT levels than women, but even in men it is mainly genetic sensitivity that decides how strongly the hair follicles react to DHT. For women it works a little differently. They produce less DHT, but their hair follicles can still be sensitive to this hormone. This sensitivity can become more noticeable during periods when hormone levels change, such as around the menopause, after pregnancy or when starting or stopping certain types of contraception.
Factors that influence your sensitivity to DHT
We now know that the sensitivity of the hair follicles mostly decides how strongly DHT affects the hair. But where does this sensitivity come from? Several factors can play a role:
- Genetics: look at your family; do your uncles or parents show early hair thinning
- Age: sensitivity to DHT can increase as you get older.
- Hormonal changes: for example after pregnancy, during the menopause or when hormones shift for other reasons.
Can you reduce DHT?
DHT cannot be fully removed from the body. You cannot change how much of the hormone is made, but you can support factors that help keep the hair growth cycle healthy, such as good scalp care. DHT-blockers may help reduce the effect of DHT on the hair follicles. Want to learn more about ingredients that can support this process? Read our article about DHT blockers.
How is DHT measured and what does it mean?
Although DHT can be measured through a blood test, the number on its own says little about hair loss. Dermatologists mainly look at:
- the pattern of the hair loss
- how quickly the hair changes
- signs of miniaturisation
- family history
DHT levels can appear normal in a blood test, even when someone shows clear signs of hereditary hair loss. This is because, as explained earlier, the amount of DHT is not the most important factor. It is the sensitivity of the hair follicles that matters. Someone with ‘normal’ DHT levels can still experience hair loss if their follicles react strongly to this hormone.
FAQ
Does DHT play a role in beard growth and acne?
Yes. DHT plays a role in different types of hair, but not in the same way. On the scalp, DHT can make hair follicles become smaller if you are sensitive to it, which can make the hair thinner. In beard hair, it works the opposite way: DHT stimulates the growth of thicker and stronger beard hairs. This is why boys develop more facial hair during puberty.
DHT can also affect how much oil the skin produces. For some people, this can lead to a greasier skin or more frequent spots. How strong this effect is differs from person to person and depends on how sensitive your skin and hair follicles are to DHT.
What is the difference between DHT and testosterone?
Testosterone is a well-known hormone that has many different roles in the body, such as supporting energy, muscles and mood. DHT is a form of testosterone. It is made locally in the skin and hair follicles and works more strongly there than testosterone. You can see it as a more powerful, more local version that mainly affects the skin and hair.
Conclusion
Dihydrotestosterone (DHT) is a powerful hormone that works in different ways throughout the body. It plays a role in male development, body and beard hair, the skin and sometimes in libido. Its effect on the hair varies from person to person and is mainly influenced by the genetic sensitivity of the hair follicles. In people with this sensitivity, DHT can contribute to hereditary hair loss, while others with similar hormone levels may not notice any changes. By understanding how DHT works and why people react so differently to it, it becomes clear that hair loss is often the result of a combination of genetics, hormones and the sensitivity of the follicles.
Sources
Kaufman, K. D. (1996). Androgen metabolism as it affects hair growth in androgenetic alopecia.
Urysiak-Czubatka, I., Kmieć, M. L., Broniarczyk-Dyła, G. (2014). Assessment of the usefulness of dihydrotestosterone in the diagnostics of patients with androgenetic alopecia.
Trüeb, R. M. (2002). Molecular mechanisms of androgenetic alopecia.
