Minoxidil vs Dutasteride

May 30, 2025/Andrew Le

Not all hair loss treatments work the same way. Minoxidil boosts blood flow to the scalp and pushes hair into its growth phase while Dutasteride blocks DHT, the hormone that causes hair follicles to shrink. 

Choosing one isn’t easy. You’ll need to think about how each drug works, how fast it takes effect, how you’ll take it, and what side effects might show up. One works on the outside, while the other works from the inside.

In this article, you’ll learn how minoxidil and dutasteride compare in action, dose, speed, safety, and cost.

🔑Key Takeaways

➤ Minoxidil helps regrow hair by boosting blood flow to the scalp and triggering the growth phase of hair follicles.

➤ Dutasteride blocks DHT, the hormone that causes hair loss,

➤ Minoxidil is applied to the scalp, while dutasteride is taken by mouth once a day.

➤ Minoxidil takes 2 to 4 months to work.

➤ Dutasteride shows results in about 6 months.

➤ Minoxidil may cause scalp irritation, while dutasteride can lead to sexual side effects in some users.

➤ Minoxidil is cheaper, costing around $5.83 for a 30-day supply, while dutasteride is likely more expensive.

➤ You can use both treatments together to target hair loss from the inside and outside.

Mechanism of Action

Minoxidil helps grow hair by improving blood flow, changing the hair cycle, and boosting growth signals, while dutasteride blocks DHT to stop hair loss at its root cause.

Minoxidil

According to a study, minoxidil is converted in the scalp to its active form, minoxidil sulfate, through the enzyme sulfotransferase. Once activated, minoxidil promotes hair growth in several ways.

  1. First, it affects the hair cycle. It shortens the telogen phase (resting phase), forcing hair follicles to enter the anagen phase (growth phase) earlier. At the same time, it prolongs the anagen phase, allowing more time for the hair to grow longer and thicker.
  1. Second, minoxidil opens potassium (KATP) channels in the smooth muscles of blood vessels around hair follicles. This causes arteriolar vasodilation, which boosts blood flow to the follicles. Increased blood flow delivers more oxygen and nutrients, supporting better hair growth.
  1. Third, minoxidil stimulates the production of vascular endothelial growth factor (VEGF). VEGF enhances the blood supply around hair follicles, reinforcing the conditions needed for growth. The drug also activates the prostaglandin-endoperoxide synthase-1 enzyme, another pathway that supports follicular stimulation.

Additionally, it may directly stimulate matrix cells in the follicle, acting like an epidermal growth factor. This slows aging and helps maintain the anagen phase through the beta-catenin signaling pathway. Minoxidil also shows antifibrotic effects, which may help in scarring-related hair loss by affecting collagen synthesis.

Dutasteride

According to a study, Dutasteride works by blocking the enzyme 5α-reductase, which converts testosterone into dihydrotestosterone (DHT). DHT is a powerful androgen that shrinks hair follicles, especially in people with androgenetic alopecia. 

Unlike finasteride, which only blocks type II 5α-reductase, dutasteride inhibits both type I and type II forms of the enzyme.

Type I 5α-reductase is found in sebaceous glands, sweat glands, and keratinocytes. It makes about 33% of circulating DHT. Type II is located mainly in the prostate, epididymis, seminal vesicles, and hair follicles, and is responsible for about 66% of circulating DHT.

By blocking both types, dutasteride reduces DHT levels in the blood by more than 90%. In contrast, finasteride only achieves about a 70% reduction. The drop in DHT leads to less binding of DHT to androgen receptors in hair follicles. These receptors normally trigger genetic signals that cause follicle shrinkage and shorter growth cycles. With less DHT, the miniaturization process slows down, which helps maintain or regrow thicker hair.

This DHT suppression slows down follicle aging, promotes epithelial cell apoptosis in the scalp’s sebaceous environment, and helps preserve follicular size. The consistent inhibition of both enzyme types makes dutasteride a more potent anti-androgenic agent, especially in men who don’t respond well to finasteride.

Dosage and Administration 

Minoxidil is used on the scalp as a foam or solution with different doses for men and women, while dutasteride is taken as a 0.5 mg capsule by mouth once a day.

Minoxidil

Minoxidil is applied topically as either a 5% foam or solution for men and 2% solution or 5% foam for women. The dosing varies by sex and formulation. 

For men, solution (5%) – Apply 1 mL twice daily directly to the scalp in the affected area. While for foam (5%) – Apply half a capful twice daily. Use your fingers to massage it into the scalp, not the hair.

For Women, solution (2%) – Apply 1 mL twice daily to the thinning area. Foam (5%) – Apply half a capful once daily to the scalp.

Use the product only on dry scalp and do not wash or wet the hair for at least 4 hours after applying. Let it dry completely (2 to 4 hours) before bed to avoid spreading the drug to fabrics or other skin areas. 

GroupFormulationDoseFrequency
Men5% Solution1 mL applied to scalpTwice daily
5% FoamHalf a capfulTwice daily
Women2% Solution1 mL applied to scalpTwice daily
5% FoamHalf a capfulOnce daily

Dutasteride 

Dutasteride is taken orally as a 0.5 mg capsule once daily. It can be used alone or with tamsulosin (0.4 mg) for treating benign prostatic hyperplasia (BPH) and is often used off-label for androgenic alopecia (male pattern hair loss).

Swallow the capsule whole—never chew, crush, or open it. The gel inside can irritate the mouth and throat. Take it with or without food.

It takes about 3 to 6 months to reach steady-state levels, and noticeable results often show after 3 to 12 months of daily use. Dutasteride has a long half-life—around 5 weeks—and about 12% of the drug can pass into semen.

GroupFormulationDoseFrequency
Men0.5 mg Oral Capsule0.5 mg taken by mouthOnce daily
WomenNot approved––
⚠️Warning!

Women who are pregnant or could become pregnant should never touch broken capsules due to the risk of birth defects in male fetuses. Men should not donate blood for 6 months after stopping dutasteride to avoid passing the drug to a pregnant transfusion recipient.

Onset of Effect and Duration (hair loss)

Minoxidil takes about 2 to 4 months to start working and needs regular use to keep results, while dutasteride shows visible hair growth by 6 months and lasts longer due to its long half-life.

Minoxidil 

Topical minoxidil requires consistent, long-term use to see visible results. You’ll need to apply it regularly for 2 to 4 months before noticing new hair growth. You may start seeing changes around the 3-month mark. 

However, the product needs to be used continuously. If you stop, any new hair will usually fall out within 3 months.

Researchers noted that topical 2% minoxidil showed peak hair regrowth by the end of year 1, but this effect declined in the following years. This suggests that while the onset is seen within a few months, the peak effectiveness may take up to 12 months, with gradual loss if discontinued. 

Oral minoxidil reached more significant results after 6 months, especially at a dose of 5 mg/day in men, and even outperformed the topical version in some studies.

So, if you’re using minoxidil, expect a gradual response starting within 4 months, but be prepared to wait up to a year for the best results—especially if you’re using lower concentrations.

Dutasteride

For dutasteride, the onset is also not immediate. Previous research using a randomized, placebo-controlled trial, reported that oral dutasteride 0.5 mg/day significantly increased hair count by week 24—that’s around 6 months. 

Improvements were seen earlier than that, but the 6-month mark showed measurable progress in both density and coverage.

In a different multicenter chart review, dutasteride outperformed finasteride across several metrics. This review confirmed that dutasteride showed visible hair regrowth faster than finasteride, and its longer half-life of 5 weeks helped sustain its effects over time.

TreatmentOnset of EffectPeak Effect TimingDuration of Effect
Minoxidil2–4 months (topical); 6 months (oral)Around 12 months (topical)Regrown hair usually falls out within 3 months after stopping
DutasterideNoticeable results by 6 months (oral)Around 6 months (oral)Long-lasting due to a 5-week half-life; effects persist longer

Efficacy 

Minoxidil helps reduce hair loss and boost regrowth in many users, but dutasteride has shown stronger and faster results in studies, with both treatments having a good safety profile.

Minoxidil

According to a 12-month observational study 5% topical minoxidil showed strong efficacy in men with androgenetic alopecia (AGA). Out of 984 patients, 561 (62%) had a smaller bald area by the end of the study. About 15.9% rated it as very effective, 47.8% said it was effective, and 20.6% found it moderately effective. Only 15.7% said it was ineffective. Hair shedding also significantly decreased—from a mean of 69.7 hairs per wash to 33.8 hairs. 

Despite mild skin-related side effects in 3.9% of users, overall satisfaction improved. Patients’ satisfaction scores rose from 2.9 to 4.4 out of 10 over 12 months, though doctors rated results higher than patients did.

In a separate 4-month surveillance study involving 743 men, 67.3% said their balding area became smaller, and 74.2% reported improved hair density. New hair growth was rated very effective by 7.5%, effective by 55%, and moderately effective by 31.3%. Most men noticed visible results within 2 to 3 months of treatment. 

Dutasteride

According to a multicenter chart review study, dutasteride showed better outcomes than finasteride in treating male AGA. The study tracked 600 men and compared hair regrowth using the BASP classification system. 

Among the patients who used recommended doses only, dutasteride users saw significantly greater hair improvement. The adjusted incidence rate ratio was 2.06, meaning dutasteride users were twice as likely to improve compared to finasteride users.

In a randomized controlled trial involving 917 men aged 20 to 50, dutasteride increased hair count and hair width more than both finasteride and placebo. This trial tested different doses of dutasteride against finasteride 1 mg/day and placebo. The highest dose (0.5 mg) showed the strongest effects, significantly improving hair growth at week 24. 

Side Effects 

Minoxidil may cause scalp irritation, shedding, or rarely heart issues, while dutasteride can lead to sexual side effects and, in rare cases, serious allergic or heart-related symptoms.

Side Effects of Minoxidil (Topical)

Topical minoxidil is generally safe but can cause both local and systemic side effects. Side effects can range from mild irritation to more serious cardiovascular symptoms.

Common side effects:

  • Excessive hair growth in unwanted areas (face or body)
  • Initial hair shedding
  • Scalp irritation
  • Itching
  • Redness
  • Burning sensation
  • Acne at the site of application

Serious or rare side effects:

  • Facial swelling
  • Inflammation or soreness at the root of the hair
  • Blurred vision or other visual changes
  • Dizziness or lightheadedness
  • Fainting
  • Fast or irregular heartbeat
  • Chest pain
  • Numbness or tingling in hands, feet, or face
  • Rapid weight gain
  • Swelling of the hands, feet, face, or lower legs
  • Unwanted facial hair growth (especially in women)
  • Severe allergic reactions: hives, trouble breathing, swelling of the lips, tongue, or throat
  • Nausea or vomiting
  • Skin rash or pale red bumps (hives)
  • Joint pain
  • Stomach cramps
  • Fever or general ill feeling
  • Flushing
  • Headache

Side Effects of Dutasteride (Oral)

Dutasteride is taken orally and affects hormone levels. It’s commonly used for benign prostatic hyperplasia (BPH), but can produce sexual, hormonal, and allergic reactions.

Common side effects:

  • Decreased libido (sex drive)
  • Difficulty with sexual performance
  • Erectile dysfunction
  • Abnormal ejaculation
  • Breast pain or tenderness

Serious or rare side effects:

  • Chest pain or discomfort
  • Swelling of the face, hands, feet, or lower legs
  • Trouble breathing
  • Rapid weight gain
  • Dilated neck veins
  • Irregular heartbeat
  • Extreme fatigue
  • Tightness in the chest
  • Dizziness
  • Skin rash, hives, or severe itching
  • Redness or peeling of the skin
  • Difficulty swallowing
  • Large hives or swelling on face, eyelids, lips, tongue, or throat
  • New lumps or nipple discharge (possible breast tissue changes in men)

Wrap Up

Minoxidil and dutasteride work in very different ways, but both aim to slow hair loss and boost regrowth. Minoxidil increases blood flow and growth signals in the scalp, while dutasteride targets DHT, a major cause of hair thinning in men. 

Choosing between them depends on several factors such as how fast you want results, how you prefer to take the drug, and how your body reacts. 

FAQs About Minoxidil vs Dutasteride

Can you use minoxidil and dutasteride at the same time? 

Yes, many doctors allow both together. Minoxidil works on the scalp, and dutasteride works inside your body. They target hair loss from two angles.

Is minoxidil better for early-stage hair loss? 

Yes. Minoxidil works well if you still have some active hair follicles. It helps slow shedding and improve thickness early on.

Can women use dutasteride? 

No. Dutasteride is not approved for women. It may cause serious risks in pregnancy, especially for male babies.

What happens if you stop using minoxidil? 

Hair that grew from minoxidil will fall out within about 3 months after stopping. It only works if you keep using it.

Sources

  • Puckey, M. (2024, July 22). Minoxidil. Drugs.com. Retrieved from https://www.drugs.com/mtm/minoxidil-topical.html
  • Gupta, A. K., Talukder, M., Venkataraman, M., & Bamimore, M. A. (2022). Minoxidil: A comprehensive review. Journal of Dermatological Treatment, 33(4), 1896–1906. Retrieved from https://doi.org/10.1080/09546634.2021.1945527 
  • International Society of Hair Restoration Surgery. (2025). Dutasteride for hair loss: Dosage, efficacy & side-effects. https://ishrs.org
  • Rundegren, J. (2004). A one-year observational study with minoxidil 5% solution in Germany: Results of independent efficacy evaluation by physicians and patients. Journal of the American Academy of Dermatology, 50(3, Suppl), P91. Retrieved from https://doi.org/10.1016/j.jaad.2003.10.285 
  • Choi, G.-S., Sim, W.-Y., Kang, H., Huh, C. H., Lee, Y. W., Shantakumar, S., Ho, Y.-F., Oh, E.-J., Duh, M. S., Cheng, W. Y., Bobbili, P., Thompson-Leduc, P., & Ong, G. (2022). Long-term effectiveness and safety of dutasteride versus finasteride in patients with male androgenic alopecia in South Korea: A multicentre chart review study. Annals of Dermatology, 34(5), 349–359. Retrieved from https://doi.org/10.5021/ad.22.027 
  • Gubelin Harcha, W., Barboza Martínez, J., Tsai, T.-F., Katsuoka, K., Kawashima, M., Tsuboi, R., Barnes, A., Ferron-Brady, G., & Chetty, D. (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.e3. Retrieved from https://doi.org/10.1016/j.jaad.2013.10.049 
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