Finasteride vs Dutasteride: Which DHT Blocker Is Right for Your Hair Loss?

If you have started researching prescription hair loss treatments, you have almost certainly come across Finasteride. It is the most widely used and heavily studied DHT blocker for male pattern baldness. But the deeper you dig, the more likely you are to run into its lesser-known, more potent cousin: Dutasteride.

A lot of men reach the same question. If both drugs work the same way, and Dutasteride is stronger, why isn’t everyone just taking Dutasteride? And is “stronger” actually better when it comes to your hair?

At Magna Health, we prescribe both. Which one is right depends on your hair loss, your medical history, and how you have responded to treatment so far. Here is the honest, science-backed comparison so you can understand the difference before you speak to a doctor.

First, the Common Ground: How DHT Blockers Work

To understand the difference between Finasteride and Dutasteride, you first need to understand what they have in common.

Male pattern baldness (androgenetic alopecia) is driven by a hormone called Dihydrotestosterone, or DHT. Your body produces an enzyme called 5-alpha reductase, which converts a portion of your testosterone into DHT. In men who are genetically predisposed to hair loss, the follicles on the scalp are highly sensitive to DHT. When DHT binds to these follicles, it triggers follicular miniaturisation — the follicle shrinks, the hair it produces becomes finer and shorter, and eventually it stops producing hair altogether [1].

Both Finasteride and Dutasteride are 5-alpha reductase inhibitors. They work by blocking the enzyme that converts testosterone into DHT, lowering the DHT levels attacking your follicles. Less DHT means the miniaturisation process slows, stops, or partially reverses, allowing your follicles to recover.

The crucial difference between the two comes down to which version of the enzyme each drug blocks — and how completely.

The Key Difference: Type 1 vs Type 2

The 5-alpha reductase enzyme exists in two main forms in the body: type 1 and type 2. Both are involved in producing DHT, though type 2 is the dominant form in the scalp and hair follicles.

Finasteride selectively blocks the type 2 enzyme. At the standard 1mg daily dose, it reduces scalp and serum DHT by roughly 60 to 70 percent [2].

Dutasteride blocks both type 1 and type 2 enzymes. This dual action makes it substantially more powerful at suppressing DHT. At a 0.5mg daily dose, Dutasteride can reduce serum DHT by over 90 percent — a significantly deeper level of suppression than Finasteride achieves [3].

In simple terms: Finasteride blocks most of the DHT, and Dutasteride blocks nearly all of it.

What the Clinical Data Says About Results

More DHT suppression sounds like it should automatically mean more hair. The clinical evidence suggests it often does — but with important nuance.

A frequently cited randomised controlled trial compared Dutasteride 0.5mg against Finasteride 1mg in men with male pattern baldness. After 24 weeks, the men taking Dutasteride showed greater improvements in hair count and hair width than those on Finasteride [4]. A 2019 network meta-analysis that pooled multiple studies reached a similar conclusion, ranking Dutasteride 0.5mg as the most effective of the oral treatments assessed for increasing hair count [5].

So Dutasteride tends to produce stronger results on paper. But “stronger” is not automatically “better” for every man. Finasteride has a far longer track record, a larger body of long-term safety data, and is Medsafe-approved specifically for hair loss in New Zealand. For most men, Finasteride is highly effective on its own — clinical trials show it halts further loss in roughly 83 to 90 percent of men and produces visible regrowth in around two-thirds [6].

Dutasteride is generally considered when a man either wants the most aggressive DHT suppression available, or has been on Finasteride and found it wasn’t delivering the results he was hoping for. It is a logical next step, not necessarily a default first move.

Side Effects: What to Know

Because both medications work by reducing DHT, they share a similar side effect profile. The most discussed concern is sexual side effects — decreased libido, erectile difficulties, or reduced ejaculate volume.

For Finasteride, the clinical trials and Medsafe data put the rate of sexual side effects at approximately 1 to 2 percent of men [7]. For most men who do experience them, the effects resolve once the medication is stopped, and in many cases subside with continued use as the body adjusts.

Because Dutasteride suppresses DHT more completely and stays in the body far longer — its half-life is around five weeks, compared to a matter of hours for Finasteride — the potential for side effects is generally considered comparable but worth closer medical attention. The longer half-life means that if side effects do occur, they can take longer to clear after stopping. This is one of the reasons Dutasteride is used more selectively and under careful medical guidance.

Both medications carry the same critical safety rule: they must not be handled or taken by women who are or may become pregnant, as DHT inhibitors can cause birth defects. This is why these are prescription-only medications that require a proper medical assessment.

It is worth being clear that the vast majority of men tolerate both medications well. The fear of side effects is often far larger than the statistical reality — but the right approach is always an honest conversation with a doctor who can weigh your individual health profile, not a decision made from internet forums.

Topical and Combination Options

Just as with Finasteride, the conversation is no longer limited to a single daily oral tablet.

Both medications can be combined with Minoxidil, which stimulates the follicle and increases blood flow, addressing hair loss from two angles at once — blocking the hormone that shrinks the follicle while stimulating the follicle to grow. Compounded topical formulations, prepared by a compounding pharmacy and prescribed as part of a tailored plan, can also deliver these medications directly to the scalp while keeping systemic absorption lower than oral alternatives [8].

These tailored formulations are not available off the shelf at a standard pharmacy. They require a prescription and are prepared specifically for each patient — one of the advantages of working with a telehealth clinic that has a compounding pharmacy.

So, Which One Should You Take?

There is no single right answer, which is exactly why this is a medical decision rather than a shopping choice.

As a general guide:

• Finasteride is the proven, well-established first-line treatment for most men. It is Medsafe-approved for hair loss, has decades of safety data behind it, and is highly effective for the majority of men with pattern thinning.
• Dutasteride offers more powerful DHT suppression and stronger results in clinical comparisons. It is often considered for men who want the most aggressive approach, or who have not seen the results they wanted on Finasteride.

The right choice depends on the stage of your hair loss, your medical history, how you have responded to previous treatment, and your own preferences around oral versus topical formulations. A registered doctor will weigh all of this with you.

Taking Action

Hair loss is progressive. The follicles you have today are far easier to protect than the ones you have already lost are to revive. Whether Finasteride or Dutasteride turns out to be the right fit, the most important factor is starting before those follicles go dormant for good.

At Magna Health, our registered New Zealand doctors prescribe both Finasteride and Dutasteride — in oral, topical, and compounded formulations — tailored to your specific hair loss pattern, medical history, and lifestyle. Your treatment is delivered discreetly to your door, with ongoing medical support included.

Start your free assessment at getmagna.co.nz

References

[1] Asfour, L., et al. (2023). Male Androgenetic Alopecia. Endotext – NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK278957/[2] StatPearls. (2024). Finasteride. https://www.ncbi.nlm.nih.gov/books/NBK513329/[3] Clark, R.V., et al. (2004). Marked suppression of dihydrotestosterone in men with benign prostatic hyperplasia by dutasteride, a dual 5α-reductase inhibitor. Journal of Clinical Endocrinology & Metabolism, 89(5), 2179-2184. https://pubmed.ncbi.nlm.nih.gov/15126539/[4] Gubelin Harcha, W., et al. (2014). A randomized, active- and placebo-controlled study of the efficacy and safety of different doses of dutasteride versus placebo and finasteride in the treatment of male subjects with androgenetic alopecia. Journal of the American Academy of Dermatology, 70(3), 489-498. https://pubmed.ncbi.nlm.nih.gov/24411083/[5] Gupta, A.K., et al. (2019). The effect of treatments for androgenetic alopecia: a network meta-analysis. Journal of Dermatological Treatment, 30(8). https://pubmed.ncbi.nlm.nih.gov/30606088/[6] Journal of the American Academy of Dermatology. (1998). Finasteride in the treatment of men with androgenetic alopecia. https://www.sciencedirect.com/science/article/pii/S0190962298700076[7] Mayo Clinic. (2026). Finasteride (oral route) – Side effects. https://www.mayoclinic.org/drugs-supplements/finasteride-oral-route/description/drg-20063819[8] JMIR Dermatology. (2026). Patient Satisfaction, Side Effects, and Other Reactions Reported by Adult Men Prescribed Compounded Topical Fin