What is a DHT blocker and do I need one?Updated 17 hours ago
Quick answer
DHT (dihydrotestosterone) is the hormone responsible for pattern hair loss. A "DHT blocker" is a treatment that reduces DHT's effect on the hair follicle. Finasteride and dutasteride are the two oral medications most commonly used. Whether you need one depends on your stage of loss, the pattern of your thinning, your medical history, and your goals. The HairIQ™ assessment and your telehealth physician will guide you to the right answer.
What Is DHT?
First, some reassurance: DHT is not the enemy. It's a normal, natural form of testosterone, and your body needs it for healthy processes. The goal of treatment isn't to eliminate DHT from your body: it's to stop it from restricting blood flow at the hair follicle.
DHT is a byproduct of testosterone, converted in the body by an enzyme called 5-alpha reductase. In men and women with pattern hair loss, DHT binds to androgen receptors at the hair follicle and gradually restricts blood flow to that follicle. When that blood supply is restricted, the follicle gets less of the oxygen and nutrients it needs to stay healthy. That's also why hair vitamins and supplements alone don't fix the problem: the issue isn't a lack of nutrients in your diet, it's that they can't reach a follicle with a restricted blood supply. Over time, this causes a process called miniaturization: follicles produce thinner, weaker hairs until they stop producing terminal hair altogether.
How DHT Blockers Work
Finasteride and dutasteride both work by inhibiting 5-alpha reductase, the enzyme that converts testosterone into DHT.
- Finasteride inhibits the type II form of the enzyme. It reduces serum DHT by roughly 70%.
- Dutasteride inhibits both type I and type II forms. It reduces serum DHT by roughly 90%.
Both can be prescribed as oral medications. Both are also available as topical add-ons inside Adegen's A5F/A15F (finasteride) and A5D/A15D (dutasteride) formulas, where they work locally with meaningful systemic absorption typically in the 30–50% range.
Do I Need One?
There is no single answer, because pattern hair loss varies. A few honest signals that a DHT blocker tends to help:
- Your hair loss follows a clear genetic pattern (receding hairline, crown thinning, family history)
- You've been on minoxidil-only treatment for 6+ months without the response you wanted
- Your loss is progressing actively, not stabilized
- You're early enough that prevention is still on the table
The HairIQ™ assessment factors these in and recommends an appropriate path. From there, your telehealth physician makes the final clinical call based on your full health history.
What About Side Effects?
This is the question almost everyone asks, and you deserve an honest answer. The short version: the absolute incidence of sexual side effects from finasteride in the largest controlled trials is around 1.7 percentage points above placebo, and by year 5 of treatment reported rates fall to 0.3% or less. Dutasteride's profile is similar.
We've written a full article on this (see our guide on side effects from finasteride or dutasteride), and Adegen also offers Oral Tadalafil 5mg as a protective option for customers who want additional peace of mind. See our guide on how Tadalafil helps with DHT blocker side effects.
When DHT Blockers Are Not Appropriate
- During pregnancy or while trying to conceive
- For women of childbearing potential in most cases (oral DHT blockers are typically not prescribed)
- Certain medical histories: your telehealth physician will screen for these
Next steps
- For a personalized recommendation, take the HairIQ™ assessment.
- For specific questions about whether a DHT blocker is right for you, please connect with your Adegen provider, and we can route you.