Applying Minoxidil Correctly: Topical or Oral 2025

What is Minoxidil and How Does It Work?

Minoxidil was originally developed in the 1970s as a blood pressure medication. During clinical use, doctors discovered a surprising side effect: increased hair growth. ^[1] This discovery led to the development of topical minoxidil, which was approved by the US FDA for men in 1988 and for women in 1992. ^[1] Today, minoxidil is available in two forms: as a topical solution or foam for scalp application and as a tablet for oral intake.

Minoxidil promotes hair growth through several biological mechanisms. The medication dilates blood vessels and thereby improves scalp circulation, allowing hair follicles to be better supplied with oxygen, nutrients, and growth factors. ^[1] Additionally, minoxidil stimulates the formation of new blood vessels and shortens the resting phase of hairs while extending the growth phase. ^[1] This makes hairs grow longer and thicker. This mechanism also explains initial shedding in the first weeks, as old, thin hairs fall out to make room for new, stronger hairs. Recent studies also show that minoxidil activates important signaling pathways in hair roots that are crucial for healthy hair growth. ^[3]

Topical Minoxidil

Topical minoxidil is available as an over-the-counter solution or foam and is applied directly to the scalp. In Switzerland, various products are approved, including Alopexy (2% and 5%), Neocapil (2% and 5%), and Minoxidil Leman (2% and 5%). ^[8] These are available in pharmacies without prescription.

Efficacy depends on whether your scalp possesses a certain enzyme in sufficient quantity that converts minoxidil into its active form. This enzyme is called sulfotransferase (SULT1A1) and is located in hair follicles. ^[4] This enzyme's activity varies greatly individually. In a study with 120 patients, 40.8 percent had low enzyme activity in the scalp. ^[4] These people respond less well to topical minoxidil. Additionally, only about 1.4 percent of applied minoxidil is actually absorbed into the scalp under normal conditions.

Dosage and Application Frequency

Clinical studies show that once-daily application of 5 percent topical minoxidil achieves comparable improvements to twice-daily application of the 2 percent solution. ^[2] However, twice-daily application of 5 percent can offer an additional benefit: about 10 to 15 percent more hair growth, though with higher risk of skin irritation. ^[2] For women, once-daily 5 percent foam has been shown to be as effective as twice-daily 2 percent solution, with better tolerability and easier integration into daily routine.

Which Concentration is Right?

5 percent minoxidil is the best-studied and FDA-approved concentration. It consistently outperforms 2 percent and is considered the best balance between efficacy and tolerability. ^[2] Higher concentrations (7 to 15 percent) are individually compounded, not approved, and should only be considered in therapy-refractory cases under medical supervision. Evidence for additional benefit is contradictory while side effects increase.

Oral Minoxidil

Oral minoxidil is increasingly being used to treat hair loss. In Switzerland, it's not officially approved for this use and is therefore prescribed off-label by doctors. When taken orally, it's absorbed through the gastrointestinal tract and converted to its active form in the liver. ^{[5] [9]} In the liver, the activating enzyme is present in large quantities. This ensures that nearly all ingested minoxidil is activated, regardless of how much enzyme is present in your scalp. Oral minoxidil is particularly effective for people who don't respond to topical minoxidil due to low enzyme activity in the scalp. ^{[5] [9]}

Dosage and Efficacy

In men with androgenetic alopecia, one study showed a 100 percent response rate at 5 mg daily, with an average hair count increase of 19 percent after 24 weeks. ^[5] Another study showed a 90 percent response rate at 2.5 to 5 mg daily. ^[5] In women, oral minoxidil at 1 mg daily is as effective as topical 5 percent minoxidil, though with occasional hair growth outside the scalp. ^[5]

A recent 2025 study compared 2.5 mg with 5 mg daily over 24 weeks. After 24 weeks, there was no significant difference in hair density between both groups. Adverse events like peripheral edema and dizziness were more frequent in the 5-mg group. Study authors recommend 2.5 mg daily as an appropriate starting dose with better safety profile.

What to Expect Over Time

Understanding typical milestones during minoxidil treatment helps set realistic expectations and prevent premature discontinuation.

In weeks 4 to 6, many users notice an initial increase in hair loss. This effect occurs when minoxidil accelerates the transition of hair follicles from resting phase to growth phase. Older, thin hairs fall out to make room for new ones. This temporary shedding shows that treatment is beginning to work. Discontinuing due to early hair loss can negate later successes.

After 3 months, fine vellus hairs begin to thicken. With combination treatments like minoxidil plus microneedling, these changes are more pronounced. While visible improvements with minoxidil alone are still modest, 60 to 74 percent of users report improvement in hair density.

After 6 to 8 months, most visible thickening occurs. Studies show peak increases in hair count and density, about an increase of 12 to 15 percent. ^[2] Around this time, gains often plateau. If additional improvements are desired, this is the right time to add microneedling, retinoids, or antiandrogen therapies.

After 9 months or longer, many users see diminishing improvements. Minoxidil alone doesn't treat underlying drivers of androgenetic alopecia like dihydrotestosterone (DHT). Without combination with anti-DHT agents or regenerative therapies, the natural course often limits sustained gains. Long-term evidence shows that only about 30 percent of users remain satisfied after several years.

Best Practices for Maximum Efficacy

To achieve best results with minoxidil, follow these evidence-based application recommendations. Apply topical minoxidil only to a dry scalp, this maximizes absorption. Use exactly 1 ml for solutions (measure with included pipette), half a cap per application for foam. Gently massage the product into affected areas for about 30 seconds and wait at least 2 hours before shampooing or rinsing your scalp.

For oral minoxidil, start with the lowest effective dose: 2.5 mg daily for men and 0.25 to 1.25 mg daily for women. Increase gradually only if needed. Splitting the total daily dose into morning and evening halves can help keep blood levels more constant and reduce risk of side effects.

Combination with Other Therapies

Minoxidil's efficacy can be significantly increased by combination with other evidence-based treatments.

Recent clinical studies show that microneedling significantly improves response and regrowth rates. A landmark study reported a nearly fourfold greater increase in hair count (about 40 percent) compared to minoxidil alone after 12 weeks. ^[6] Another six-month study showed an efficacy rate of 85 percent for the combination. ^[6] Microneedling works by temporarily disrupting the scalp barrier and allowing minoxidil to penetrate more effectively. The procedure can also increase local activity of sulfotransferase enzymes needed to activate minoxidil.

Topical tretinoin (a vitamin A derivative) can be combined with minoxidil to increase enzyme activity in the scalp and thereby improve minoxidil activation. ^[7] This combination is particularly useful for patients with low enzyme activity. Tretinoin increases both skin permeability and formation of the activating enzyme in hair follicles.

Safety and Side Effects

Topical minoxidil is generally safe, with most side effects being local and mild. Skin irritation occurs in about 2 to 6 percent of users, mainly caused by the excipient propylene glycol and not by minoxidil itself. ^[1] Switching to propylene glycol-free foam formulations can resolve these symptoms. Scalp dryness and flaking are common; using gentle, sulfate-free shampoos helps. Mild, reversible facial hair growth may occur but typically disappears within one to five months after stopping or reducing application.

Discontinuing Minoxidil

Discontinuing minoxidil is a significant decision. Practically all clinical evidence shows that hair gains achieved during treatment are lost, normally within 3 to 12 months. When minoxidil is stopped, hair follicles return to their pre-treatment state within about three months. This leads to a synchronized shedding phase and temporary drop in hair density.

After discontinuation, most users experience significant shedding lasting 3 to 6 months, in some cases up to a year. The extent varies, but those who respond best are normally most affected. To mitigate rebound shedding, experts recommend gradual tapering over 6 months. Abrupt discontinuation leads to more severe shedding.

Supporting the scalp with additional therapies can improve retention. Microneedling with weekly sessions can activate growth factors and promote follicle health. Initiating topical or oral antiandrogens like Finasteride for hair loss before and during discontinuation can help compensate for DHT-driven miniaturization.

Conclusion

Minoxidil remains one of the best-researched and most effective treatments against androgenetic alopecia. Topical minoxidil offers a local, well-tolerated option with minimal systemic side effects. Oral minoxidil is a practical alternative for people who don't respond to topical treatment or have low SULT1A1 activity.

Efficacy can be significantly increased by combination with microneedling, retinoids, or antiandrogen therapies like finasteride topical vs. oral.

Important is to have realistic expectations. Most visible improvements occur after 6 to 8 months. Without combination with other active ingredients, effect often diminishes after about 9 months. Minoxidil is a long-term therapy. All gains are lost after discontinuation.

At orva, we offer personalized topical formulations that combine minoxidil with other evidence-based active ingredients. These are individually tailored to your needs and maximize efficacy while minimizing side effects. Start now with our Quiz and find out which treatment is best for you.