What is the best dose of topical finasteride? Is there a dose that maximizes hair gains and minimizes side effects? Do higher doses get better regrowth while still protecting you from side effects versus oral formulations? We’ll answer these questions and more in this article.
Today, we’re tackling a huge question that comes up all the time: What’s the best dose of topical finasteride? Is there a “sweet spot” dose that maximizes hair gains and minimizes side effects? And does switching to a higher dose allow for better regrowth while still protecting you from the side effects of oral finasteride? We’ll dive into the data, the unknowns, and the doses available –– so you can start making more informed treatment decisions.
What is Finasteride?
For background, finasteride is a drug that inhibits 5-alpha-reductase. That’s the enzyme that converts testosterone into dihydrotestosterone, or DHT. DHT is the hormone that causes androgenic alopecia, also called pattern hair loss. Studies show that oral finasteride, taken at 1 mg daily, can lower DHT by more than 60% and slow, stop, or partially reverse hair loss for 80-90% of men.{{Drake, L., Hordinsky, M., Fiedler, V., Swinehart, J., Unger, W.P., Cotterill, P.C., Thiboutot, D.M., Lowe, N., Jacobson, C., Whiting, D., Stieglitz, S., Kraus, S.J., Griffin, E.I., Weiss, D, Carrington, P., Gencheff, C., Cole, G.W., Parise, D.M., Epstein, E.S., Tanaka, W., Dallob, A., Vandormael, K., Geissler, L., Waldstreicher, J. (1999). The effects of finasteride on scalp skin and serum androgen levels in men with androgenetic alopecia. Journal of the American Academy of Dermatology. 41(4). 550-554. Available at: PMID - 10495374}}
However, the drug can also cause side effects –– often in the form of low libido or sexual dysfunction –– which is why some people turn to topical formulations.{{Irwig, M.S., Kolukula, S. (2011). Persistent sexual side effects of finasteride for male pattern hair loss. The Journal of Sexual Medicine. 8(6). 1747-1753. Available at: https://doi/org/10.1111/j.1743-6109.2011.02255.x.}} They think that by using topical finasteride, they can localize the DHT-lowering effects of the drug to the scalp –– rather than the whole body –– and still get the same hair growth benefits. And you can’t blame them.
After all, clinical studies show that, in target area hair zones, topical finasteride is nearly as effective as oral finasteride.{{Piraccini, B.M., Peytavi, U.B., Scarci, F., Jansat, J.M., Falques, M., Otero, R., Tamarit, M.L., Galvan, J., Tebbs, V., Massana, E. (2021). Efficacy and safety of topical finasteride spray solution for male androgenetic alopecia: a phase III, randomized, controlled trial. Journal of the European Academy of Dermatology and Venereology. 36(2). 286-294. Available at: https://doi.org/10.1111/jdv.17738}}
Figure 1. Effect of topical finasteride, oral finasteride, or a placebo on mean target area hair count at baseline, week 12, and week 24. ***p<0.001 vs. placebo.{{Piraccini, B.M., Peytavi, U.B., Scarci, F., Jansat, J.M., Falques, M., Otero, R., Tamarit, M.L., Galvan, J., Tebbs, V., Massana, E. (2021). Efficacy and safety of topical finasteride spray solution for male androgenetic alopecia: a phase III, randomized, controlled trial. Journal of the European Academy of Dermatology and Venereology. 36(2). 286-294. Available at: https://doi.org/10.1111/jdv.17738}}
But as we’ll cover below, the dose matters a great deal, and this idea that we can localize finasteride’s effects just to the scalp –– doesn’t always work, especially at the doses sold to you by major telehealth brands.
Dosing Ranges for Topical Finasteride
Based on clinical studies, we see two distinct dosing categories for topical finasteride: low-dose and standard-strength. And we’ll evaluate both depending on their levels of hair regrowth, systemic absorption, and side effect risk.
Low-dose topical finasteride (0.005-0.01% x 1-2 mL daily)
First, we have low-dose topical finasteride—anything from 0.005% to 0.01% applied daily, typically 1-2 mL daily. This works out to about 0.05 to 0.2 mg of finasteride exposure per day, which is just a fraction of the standard 1 mg oral dose.
Right now, this topical formulation appears to be the minimum effective dose. It’s the lowest dose of topical finasteride that, according to one study, improved hair parameters, and it did so without altering the blood level of DHT during 16 months of treatment.{{Mazzarella, G.F., Loconsole, G.F., Cammisa, G.A., Mastrolonardo, G.M., Vena, G.A. (2009). Topical finasteride in the treatment of androgenic alopecia. Preliminary evaluations after a 16-month therapy course. Journal of Dermatological Treatment. 8(3).189-192. Available at: https://doi.org/10.3109/09546639709160517}}
Figure 2. Effect of finasteride 0.005% solution or a placebo on hair counts over 16 months.{{Mazzarella, G.F., Loconsole, G.F., Cammisa, G.A., Mastrolonardo, G.M., Vena, G.A. (2009). Topical finasteride in the treatment of androgenic alopecia. Preliminary evaluations after a 16-month therapy course. Journal of Dermatological Treatment. 8(3).189-192. Available at: https://doi.org/10.3109/09546639709160517}}
This is important because blood DHT levels are a good way to approximate how much topical finasteride is leaking from our scalps into our circulatory system, where it could travel and impact DHT levels elsewhere in the body. Because it’s DHT reduction in places like the eyes, the brain, or the testes that likely cause these off-target effects for finasteride. And the only way for topical finasteride to get there is to leak into the bloodstream and travel there.
So DHT in the blood is sort of like our “canary in the coalmine”. It’s a very sensitive barometer. No DHT changes in the blood? Then, it’s unlikely that you’ll see DHT changes in other organ sites.
With that, low-dose topical finasteride is probably best for people who want to minimize the systemic effects of the drug while still getting some hair benefits. It’s also probably better for people with side effects from higher topical or oral doses and who need to limit their systemic exposure.
If that’s you, great. Maybe give this dose a try. If you want, you can make low-dose finasteride at home. Just use our topical finasteride calculator. To access it, check out the link here. It’s 100% free. You can crush up finasteride pills and mix them into a solvent, or you can dilute a previously purchased topical finasteride into another solvent. However, with this approach, dosing accuracy and stability can be challenging.
You can read more about making your own low-dose topical finasteride in our articles here and here.
Alternatively, if you’re in the U.S., there is now, finally, a telehealth brand that offers low-dose topical finasteride to qualifying candidates. It’s a brand I co-founded, and it’s called Ulo. Ulo’s medical providers can assess your hair and help determine if low-dose topical finasteride might be right for you. These formulations have gone through over 18 months of building, testing, & iterating. They apply easily, dry quickly, penetrate the scalp, and are devoid of irritants like propylene glycol. And if you’re interested in that assessment, you can visit our website here.
And if you are going to try low-dose topical finasteride, keep in mind some important details.
First, even at low doses, topical finasteride can still go systemic. Studies show that finasteride has a logarithmic, dose-dependent effect on DHT reduction.{{Drake, L., Hordinsky, M., Fiedler, V., Swinhart, J., Unger, W.P., Cotterill, P.C., Thiboutot, D.M., Lowe, N., Jacobson, C., Whiting, D., Stieglitz, S., Kraus, S.J., Griffin, E.J., Weiss, D., Carrington, P., Gencheff, C., Cole, G.W., Pariser, D.M., Epstein, E.S., Tanaka, W., Dallob, A., Vandormael, K., Geissler, L., Waldsteicher, J. (1999). The effects of finasteride on scalp skin and serum androgen levels in men with androgenetic alopecia. Journal of the American Academy of Dermatology. 41(4). 550-554. Available at: https://doi.org/10.1016/S01920-9622(99)80051-6}} In other words, if just a small amount of the drug enters the bloodstream, it can cause a drop in blood DHT levels on par with that of oral finasteride.
We’ve even seen this in members of our community who’ve done blood tests before and during low-dose topical finasteride use. So far, about half report no changes in blood DHT after starting the topical, just like that study suggests.
However, the other half do report significant DHT drops: 35%, 45%, and even a 70% decline. So, for some users, there’s this discrepancy between the results of that clinical study and the experience of real-world people trying the low-dose topical. Why? If I were to guess, it’s because, again, it only takes a tiny bit of finasteride to leak into the blood to reduce serum DHT by almost as much as oral finasteride.
Furthermore, when you account for all factors influencing the absorption rate of finasteride –– the delivery vehicles used, the milliliters applied, the scalp contact time before washing out the topical, the use of other ingredients or therapies that increase skin penetration – like retinoic acid and microneedling – you end up with a lot of individual variances, especially in uncontrolled environments like the real world.
So, if this matters to you, maybe do blood DHT testing before and during your use. This will help estimate your systemic absorption, and you can always adjust your dose up or down based on the results. If you’re interested in directions, check out our earlier video on topical finasteride for a step-by-step guide on DHT testing.
Secondly, it’s worth mentioning that low-dose topical finasteride may lead to less regrowth than higher concentrations. For a proxy example, take oral finasteride. Daily doses of 0.2, 1, and 5 mg all basically reduce the same amount of blood DHT. Just see these charts.
Figure 3. Effect of finasteride dose on serum DHT reduction (%).
But, as the dose gets higher, up until about 5 mg, the regrowth actually gets directionally better.
Figure 4. Efficacy of oral finasteride in pilot and dose-ranging studies.{{Roberts JL, Fiedler V, Imperato-McGinley J, Whiting D, Olsen E, Shupack J, Stough D, DeVillez R, Rietschel R, Savin R, Bergfeld W, Swinehart J, Funicella T, Hordinsky M, Lowe N, Katz I, Lucky A, Drake L, Price VH, Weiss D, Whitmore E, Millikan L, Muller S, Gencheff C, Carrington, P., Binkowitz, B., Kotey, P., He, W., Bruno, K., Jacobson, C., Terranella, L., Gormley, G.J., Kaufman, K.D. (1999). Clinical dose ranging studies with finasteride, a type 2 5alpha-reductase inhibitor, in men with male pattern hair loss. J Am Acad Dermatol. 41(4):555-63. PMID: 10495375.}}
This same relationship might also exist with certain doses of topical finasteride.
And we also see this reflected in our members. The lower doses do work for a lot of people, and they do remain better localized to the scalp. But there’s often another level of hair regrowth unlocked for people who switch to the higher-strength formulations. So, keep these dynamics in mind while weighing your dosing options.
Standard-Dose Topical Finasteride (0.1-0.3% x 0.5 to 2 mL daily)
Next up, we have standard-dose topical finasteride, typically in the range of 0.1-0.3%. At this dose, you’re looking at 0.5 mg up to 6 mg daily of finasteride exposure. That’s a big range, with the upper end representing 6 times more finasteride than the standard oral dose of 1 mg.
These formulations are probably most appropriate for people who want more noticeable hair regrowth and are comfortable with more finasteride going systemic. Because, with doses this high, we can virtually guarantee that you’ll see blood DHT reductions on par with oral finasteride. So, at this dose, you might be wondering… Why not just use oral finasteride? It’s cheaper; it’s easier to use, and if you’re already tanking your blood DHT, why not make the switch?
There is, however, some limited evidence that even standard-dose topical finasteride might lower the risk of side effects compared to oral. We’ve even seen these effects in members, like our video on Alessandro. I’ll walk you through the science, and you can decide if you buy it or not.
Two Markers to Track
For topical finasteride, there are two markers we can use to gauge our side effect risks. The first is blood DHT levels. We discussed these already; they’re the first markers to fall; they’re our canaries in the coal mine.
However, the second marker is circulating levels of finasteride. That’s the amount of finasteride in our blood that didn’t get used up to reduce blood DHT levels and is now getting transported from the blood to other organ sites – our brain, our eyes, our testes – where it will start lowering DHT levels. Again, these organ sites are most likely where the real risk of side effects comes from: not blood DHT, but DHT level changes in off-target organ sites.
In 2022, a study out of Italy tested a 0.25% topical finasteride spray, applied at doses totaling, according to our estimates, up to 0.9 mg daily.{{Piraccini, B.M., Blume-Peytavi, U., Scarci, F., Jansat, J.M., Falques, M., Otero, R., Tamarit, M.L., Galvan J., Tebbs, V., Massana, E., Topical Finasteride Study Group. (2022). Efficacy and safety of topical finasteride spray solution for male androgenetic alopecia: a phase III randomized, controlled clinical trial. Journal of the European Academy of Dermatology and Venereology. 36(2). 286-294. Available at: https://doi.org/10.1111/jdv.17738}}
In that study, topical finasteride users saw blood DHT levels decline by almost as much as those on oral finasteride. No shocker there. But there was a silver lining: the topical finasteride group saw circulating levels of finasteride that were just 1/100th to 1/200th that of the oral finasteride group. That’s a huge difference, and that’s the amount of finasteride traveling out of the blood to other tissue sites. So you might argue that at levels that low, perhaps DHT reductions in other organ sites –– might not be as severe as those on oral finasteride.
Figure 5. Mean serum DHT concentrations during treatment for 24 weeks with topical finasteride, placebo, or oral finasteride. The difference in mean values from baseline to week 24 is shown at the end of each line. *p<0.05 vs. placebo and oral finasteride at all time points; **p<0.05 vs. placebo at all time points.{{Piraccini, B.M., Peytavi, U.B., Scarci, F., Jansat, J.M., Falques, M., Otero, R., Tamarit, M.L., Galvan, J., Tebbs, V., Massana, E. (2021). Efficacy and safety of topical finasteride spray solution for male androgenetic alopecia: a phase III, randomized, controlled trial. Journal of the European Academy of Dermatology and Venereology. 36(2). 286-294. Available at: https://doi.org/10.1111/jdv.17738}}
So, even with significant blood DHT declines, maybe these standard-strength topical finasteride formulations do still offer some protection against side effect risks. After all, we’ve seen this anecdotally in some members switching from oral finasteride to standard-strength topical finasteride. But is this due to substantially lower circulating finasteride levels, or is it perhaps due to the nocebo effect of finasteride and then the placebo effect triggered by a finasteride formulation switch? With such limited data, you can currently make an argument in either direction. So you can decide how you want to feel about these higher-strength formulations.
Availability of Standard Dose
If you’re looking for standard-dose topical finasteride, look no further than nearly all telehealth brands: Hims, Keeps, Roman, Strut, HappyHead, and, of course, Ulo. Each brand has its offerings, so explore your options. And remember, if you’re tolerating this dose of finasteride without side effects, you might want to seriously consider trying oral finasteride for its ease of use and broader scalp coverage.
Final Thoughts and Takeaways
All in, here’s where we currently land on topical finasteride.
Both low-dose and standard-dose topical finasteride work, but your dose should align with your goals for regrowth and tolerance for systemic absorption.
Low-dose formulations might better localize the drug to the scalp, which could mean fewer side effects but also potentially less regrowth.
Standard-dose formulations generally produce better regrowth but will also go systemic, similar to oral finasteride. Even still, there’s a possibility they may carry a lower side effect risk versus oral finasteride.
If you’re interested in low-dose finasteride, you can make it at home, but it’s tricky. For those in the U.S., you can check out Ulo, the only telehealth provider we know of offering the lower doses. And for standard doses, Ulo and other major telehealth brands have you covered, or you can discuss it with your doctor.
Keep in mind that oral finasteride carries a low risk of side effects overall, and if I were to guess, standard strength topical finasteride might further cut down that risk –– maybe by 25%, while low-dose topical finasteride might cut down that risk another 50-75%. With more robust clinical studies, we’ll be able to answer these unknowns.
Lastly, if you commit to topical finasteride, remember that results take time. Clinical studies show that peak results don’t come in three or six months—they often take 18 to 24 months. That’s two years of consistent use. So stay patient, commit to the process, and set realistic expectations.