About 95% of thinning hair is caused by male pattern baldness, also known as androgenetic alopecia. This type of hair loss is caused by a hormone called dihydrotestosterone (DHT for short). In this article, we explain the influence of DHT on hair loss.

While DHT is crucial for the formation of pubic and body hair, it can also cause you to lose hair on your scalp. Researchers aren't sure why. By age 50, more than half of men will experience hair loss caused by DHT.

What is DHT?

DHT is a potent form of testosterone, a male sex hormone you've probably heard of before. This is called an androgen, a hormone that contributes to typical male characteristics like a deeper voice, increased muscle mass and body hair. DHT, in particular, aids in the development of male genitalia during fetal development and growth during puberty.

In men, testosterone is converted into DHT. After its creation, DHT flows freely through your bloodstream to other parts of the body. So how exactly does this relate to hair loss? DHT can bind to receptors in the hair follicles on your scalp, especially if you're genetically predisposed to hair loss. This causes the follicles to shrink, gradually producing less robust hair that is more prone to breakage, and eventually stops hair growth altogether.

And it seems that men who lose their hair have more of this type of testosterone than men with luscious locks. Research has shown that they have more receptors for DHT, which makes them more sensitive to its effects, as well as higher levels of the enzyme that produces it, resulting in more of the final product. In addition to hair loss, high levels of DHT can contribute to prostate problems, including an enlarged prostate.

DHT and hair loss

It is estimated that each of us has about 100,000 hairs on our scalp and we lose (and germinate) about 100 hairs per day. This is part of the hair's natural cycle. The hair follicles on our scalp continually grow and lose their hair in a cycle that has three distinct phases:

Growth phase

Also called the anagen phase, the hairs remain there for 2 to 6 years. Most of the hair on your scalp (about 80-90%) is currently in this phase.

Catagen phase

During this very short phase (14 to 21 days), the hair stops growing and detaches from its blood supply in preparation for the resting phase.

Resting phase

The last phase of the cycle is the resting (telogen) phase. Here, the follicles sleep for about three months until the hair falls out. Between 10 and 20% of all hair on your head is in the resting phase at any given time.

Once the telogen phase is complete, the anagen phase begins again. However, higher levels of DHT shrink the hair follicles, shorten the growth phase, and create thinner hair. It can be alarming to notice that hair thins or falls out. There are treatments that can be successful in regrowing your hair. Some medications can actually reverse hair loss by increasing the size of the follicles and promoting the growth of new hair.

However, there is a window of time for the reversal to work. The more time passes without treatment, the more the changes will continue to make hair regrowth less likely.

DHT and Hair Loss – Genetics

Some people have a full head of hair well into their 60s and beyond, while others start losing it in their twenties.

You may have heard that hair loss in men comes from your mother's father. While this may be true in some people, genetics are a bit more complicated. Research has discovered more than 250 genes that influence hair loss, which can be inherited from either parent.

Science suggests that some people are more susceptible to DHT's damaging effects on hair due to variations in their genes. These variations can increase the sensitivity of your scalp's androgen receptors, making you more likely to experience hair loss.

How to Reduce DHT Levels

If you suffer from hair loss, there are things you can do to stop the loss and increase hair growth.

Treatments that block or inhibit the production of DHT can slow or reverse baldness. A DHT blocker is an oral or topical medication that works by preventing testosterone from being converted into DHT.

Finasteride

Finasteride is a drug known as a 5-alpha-reductase inhibitor. Since 5-alpha-reductase is responsible for converting testosterone into DHT, the inhibition also blocks the production of DHT.

DHT Blocking Shampoo

Several varieties of shampoo claim to block the effects of DHT on hair follicles. They are considered less effective than finasteride. Some of these shampoos contain zinc, vitamin B12, or an antifungal medication.

Minoxidil

Minoxidil is an over-the-counter liquid or foam that is applied to the scalp twice a day. It acts as a peripheral vasodilator, which means it opens blood vessels to increase blood flow and promote new hair growth.

Minoxidil does not have a direct effect on DHT, but studies show that using this topical treatment and finasteride together is more effective than using either alone.

Conclusion

If you have any medical questions or concerns, please speak to your doctor. This article is supported by peer-reviewed research and information from medical societies and government agencies. However, it is not a substitute for professional medical advice, diagnosis, or treatment.