Topical vs. oral finasteride: what is the difference?

Topical and oral finasteride contain the same active ingredient and work in the same way, but how each one enters your body changes the side effect profile, cost, and daily routine. 

If you're weighing topical vs. oral finasteride for hair loss, here's what to know before choosing.

While they come in different forms, topical and oral finasteride both treat hair loss by blocking the enzyme that turns testosterone into DHT, the hormone that contributes to the gradual shrinking of scalp hair follicles.

Topical and oral finasteride contain the same active ingredient but differ in how they enter the body. 

• Oral finasteride is absorbed through the digestive system and lowers DHT in both the blood and scalp. 

• Topical finasteride is applied directly to the scalp and intended to limit systemic exposure, but some medication still enters the bloodstream and lowers circulating DHT.

This difference in application is why the two forms have different side-effect profiles, costs, and daily routines. 

Note: The topical finasteride results in this table come from a trial of specific spray formulations. So other compounded formulas may not lead to the same amount of medication in the bloodstream.

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Finasteride is sold under the brand names Propecia (1 mg) and Proscar (5 mg). It belongs to a class of drugs called 5-alpha-reductase inhibitors. 

These work by blocking the enzyme that turns testosterone into DHT. Since DHT is the hormone that shrinks hair follicles in people with male pattern baldness, lowering it can slow hair loss and, in some cases, help hair grow back.

At a dose of 1 mg, finasteride is prescribed for hair loss. The higher dose of 5 mg treats benign prostatic hyperplasia (BPH), or an enlarged prostate. 

Finasteride is often used alongside minoxidil (Rogaine), an over-the-counter treatment that targets hair loss through a different mechanism. Because the two drugs work in different ways, using them together may be more effective than either one alone.

Here's a closer look at how each form of finasteride works.

Oral finasteride comes as a once-daily tablet that can be taken with or without food. It's widely available as a generic medication, making it one of the more affordable prescription hair loss treatments.

Oral finasteride lowers DHT levels throughout the whole body, not just at the scalp. In clinical studies, 83% of men who took finasteride for two years kept their hair or saw gains at the crown, compared to 28% of men on a placebo. Longer-term data show that results can last five years, possibly more, with steady use.

Results aren't instant, though. It typically takes 3–6 months of daily use before changes become noticeable, and up to 12–24 months for the full effect. If you stop taking it, hair loss generally resumes within several months.

Oral finasteride is also simple to use. There's just one pill a day, with no topical application to your scalp.

Topical finasteride comes as a liquid spray or solution that you apply directly to the scalp, usually once a day. It's designed to deliver the drug to the hair follicle while limiting how much reaches the rest of the body, but some finasteride is absorbed into the bloodstream

Topical finasteride is not approved by the US Food and Drug Administration (FDA) for hair loss, but it's commonly prescribed off-label and prepared by compounding pharmacies. Some formulas combine finasteride with minoxidil, which some research suggests may work better together than either one alone.

In a 2022 clinical trial of a 0.25% finasteride spray topical finasteride performed nearly as well as the oral version and significantly better than placebo, with gains visible as early as week 12. The key difference was how much drug reached the bloodstream: peak blood levels were more than 100 times lower with topical, and DHT in the blood dropped by 34.5% compared to 55.6% with oral. 

This suggests it works at the scalp with lower systemic effects, but it does not eliminate the possibility of systemic side effects. The tradeoff is convenience. Topical finasteride means a daily scalp routine rather than a once-a-day pill.

Because oral and topical finasteride contain the same active ingredient, they share many of the same potential side effects. These effects can vary from person to person. It's important to discuss what works best for you with your healthcare provider.

Both oral and topical finasteride may cause:

• Lower sex drive

• Erectile dysfunction (ED)

• Lower semen volume

• Breast swelling or tenderness (gynecomastia)

• Mood changes, including depression or anxiety

In clinical trials of oral finasteride (1 mg), sexual side effects occurred in 3.8% of men. Topical finasteride appears to have a lower risk of systemic side effects because some formulations produce lower blood levels. In one large clinical trial, sexual side effects tied to treatment were reported in 2.8% of men on topical finasteride, versus 4.8% on oral and 3.3% on placebo. 

Topical finasteride may also cause local side effects that don't apply to the pill form:

• Scalp itching or redness

• Dryness or scaling

• Stinging or burning

• Irritation at the application site

The FDA also notes a risk of inadvertent transfer to others through skin contact, something to be aware of if you live with or are in close contact with someone who is pregnant or may become pregnant,

Cost is another factor worth weighing before you decide.

Cost can vary depending on whether you go with a brand-name or generic product and whether you use an oral or topical product.

• Generic oral finasteride is one of the cheaper hair loss treatments. On Ro, it costs $16–$20 per month, depending on the plan (if prescribed). Brand-name oral finasteride, known as Propecia (1 mg), typically costs more — roughly $118 per month without insurance.

• Topical finasteride is manufactured by compounding pharmacies and tends to cost more than the generic oral form. Prices vary by pharmacy and formula, but you can expect to pay around $30–$60 per month, depending on the provider and whether other ingredients (like minoxidil) are included. Ro Mane Spray, for example, combines finasteride, minoxidil, and tretinoin and costs $43–$50 per month, depending on the plan (if prescribed). 

Insurance typically does not cover finasteride when it's prescribed for hair loss. Going with the generic oral version is often the simplest way to keep costs down.

Choosing between topical and oral finasteride comes down to what matters most to you: ease of use, side-effect risk, or cost.

If ease of use is at the top of your list, oral finasteride can be hard to beat. It's one pill a day, no mess, no waiting for a product to dry. It also has decades of research behind it and is FDA-approved.

If lowering side-effect risk is your main goal, topical finasteride may be worth a look. Less of the drug gets into the bloodstream, which may mean a lower chance of sexual side effects, though this varies from person to person.

Both forms require a prescription. A healthcare provider can help you weigh the tradeoffs and decide which option makes sense based on your health history, hair loss pattern, and treatment goals. 

Finasteride works by preserving the hair follicles you still have rather than reviving inactive ones. So, starting treatment while follicles are still active generally leads to better outcomes, regardless of which form you choose.

Whether you go with oral or topical finasteride, many people see even better results when they combine it with other treatments.

Minoxidil

Minoxidil is the most well-known over-the-counter (OTC) topical treatment for hair loss, but it also comes as a prescription oral drug. It works differently from finasteride: Rather than blocking DHT, minoxidil is thought to boost blood flow to hair follicles and extend the growth phase of hair. 

The topical form (Rogaine) comes as a foam or liquid applied to the scalp. Oral minoxidil is also available by prescription, though it's not FDA-approved for hair loss. 

Topical finasteride combinations

Some topical formulas combine finasteride with other active ingredients like minoxidil or tretinoin. These ingredients work through different mechanisms; finasteride, for example,  blocks DHT at the follicle, while minoxidil boosts blood flow to the scalp. So combining them may produce better results than either one alone. Ro Mane Spray* is one option, available by prescription on Ro. 

*This particular formulation is not FDA-approved; it includes active ingredients, specifically finasteride and minoxidil, that are individually FDA-approved for hair loss. 

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Both topical and oral finasteride block DHT to slow hair loss, and they can work equally well. The right choice usually comes down to your priorities around potential side effects, cost, and convenience.

• Oral finasteride tends to be simpler and cheaper than topical finasteride, but it works throughout the whole body. In clinical trials, sexual side effects occurred in 3.8% of men compared with 2.1% taking a placebo.

• In one study, topical finasteride delivered similar hair growth with less of the drug in the bloodstream. The main downsides are the daily scalp routine and higher cost.

• Cost varies between oral and topical versions. Generic oral finasteride costs $16–$20 per month, depending on the plan, if prescribed on Ro. Topical runs roughly $30–$60 per month, with Ro Mane Spray costing $43–$50 per month, depending on the plan ( if prescribed).

• Starting early is key to seeing results. Finasteride works best on hair follicles that are still there but starting to shrink. It may help those hairs grow thicker, but it cannot bring back follicles that are no longer active. Starting earlier generally leads to better results, whichever form you choose.