If you want to understand male hair loss, you have to understand DHT. Dihydrotestosterone, or DHT, is the hormone behind most male pattern baldness, and knowing how it works explains why certain treatments succeed where others do not. This guide covers what DHT is, how it shrinks hair follicles, and the proven ways to block its effect. Treatments such as finasteride target DHT directly, and you can read about the full range on our hair loss page, with any prescription issued only after a clinical assessment.
Table of Contents
1. What Is DHT?
3.1. Finasteride
3.2. Minoxidil
4. What About Natural DHT Blockers?
5. Setting Realistic Expectations
7.1. What is DHT, and how is it linked to hair loss?
7.2. Does blocking DHT stop hair loss?
7.3. What is the difference between finasteride and minoxidil?
What Is DHT?
DHT is a hormone made from testosterone. An enzyme called 5-alpha-reductase converts a portion of your testosterone into DHT, which is more potent at binding to receptors in certain tissues. DHT has important roles in male development, but in adulthood it is also the main driver of androgenetic alopecia, the medical name for male pattern baldness.
How DHT Causes Hair Loss
Hair grows in cycles: a long growth phase, a short transition, and a resting phase before the hair sheds and the cycle restarts. In men who are genetically sensitive to DHT, the hormone binds to receptors in the hair follicles of the scalp and gradually shrinks them, a process called miniaturisation.
With each cycle, the affected follicles produce finer, shorter, lighter hairs, and the growth phase gets shorter. Over time the follicles may stop producing visible hair altogether. This is why male pattern baldness follows a predictable pattern, typically starting at the temples and crown, where follicles are most sensitive to DHT.
Importantly, it is not that men with hair loss have too much DHT. It is that their follicles are genetically more sensitive to it. That is why hair loss runs in families.
How to Block DHT
Because DHT drives the process, reducing its effect is the most direct way to slow or halt this type of hair loss. There are two main evidence-based prescription approaches:
Finasteride
Finasteride works by inhibiting the 5-alpha-reductase enzyme, which lowers the amount of testosterone converted into DHT. Less DHT means less miniaturisation, which can slow loss and, for many men, lead to some regrowth. It is taken as a daily tablet, and you can read more on our finasteride page and in our guide to whether Propecia really works. Results build over several months, and the effect lasts only while you keep taking it.
Minoxidil
Minoxidil does not block DHT. It works differently, by prolonging the growth phase and improving blood flow to the follicles. It is often used alongside a DHT-blocking treatment because the two tackle the problem from different angles. Combining them tends to give better results than either alone for many men.
What About Natural DHT Blockers?
You will see supplements and ingredients such as saw palmetto marketed as natural DHT blockers. The evidence for these is far weaker than for finasteride, and they are not regulated as medicines for hair loss. If you want a treatment with solid evidence behind it, the prescription options are the better-studied route, used under clinical guidance.
Setting Realistic Expectations
DHT-blocking treatment is most effective at preserving the hair you still have and slowing further loss. It works best when started early, before follicles have been lost entirely. Regrowth is possible, but treatment cannot revive follicles that are long gone. Patience matters too, as it can take three to six months to see a difference and longer to judge the full effect.
Does DHT Affect Women Too?
Although this guide focuses on what DHT and hair loss mean for men, dihydrotestosterone plays a role in female pattern hair loss as well, just in a different way. Women have testosterone too, in smaller amounts, and some experience thinning linked to hormonal sensitivity, particularly around the menopause or with conditions such as polycystic ovary syndrome.
The treatments differ, though. Finasteride is not used in the same way for women and must never be taken by anyone who is or may become pregnant. Women experiencing hair thinning should be assessed individually, as the causes and safe options are distinct from those in men. Anyone unsure of the cause of their hair loss should seek a proper assessment rather than self-treating.
Important: Finasteride is a prescription-only medicine with potential side effects and is not suitable for everyone. It must not be handled by or used in women who are or may become pregnant. This article is general information; suitability must be assessed by a prescriber, and treatment is supplied only after a valid consultation. You can start a consultation where appropriate.
Frequently Asked Questions
What is DHT, and how is it linked to hair loss?
DHT (dihydrotestosterone) is a hormone made from testosterone. In men genetically sensitive to it, DHT shrinks scalp hair follicles over successive growth cycles, producing finer hair and eventually hair loss in the classic male pattern.
Does blocking DHT stop hair loss?
Reducing DHT with finasteride can slow or halt this type of hair loss and lead to some regrowth for many men. The effect lasts only while treatment continues, and it works best when started early.
What is the difference between finasteride and minoxidil?
Finasteride lowers DHT by blocking the enzyme that produces it, tackling the cause. Minoxidil does not affect DHT; it extends the hair growth phase. They are often combined because they work in different ways.
Do natural DHT blockers work?
Ingredients such as saw palmetto are marketed as natural DHT blockers, but the evidence is far weaker than for prescription finasteride, and they are not regulated as hair loss medicines.
