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 has enough of a specific enzyme. This enzyme converts minoxidil into its active form and is called sulfotransferase (SULT1A1). It is located in the hair follicles. ^[4]

The activity of this enzyme varies greatly between individuals. 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. In addition, 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 can achieve comparable improvements to twice-daily application of the 2 percent solution. ^[2] Depending on the product, medicinal product information may specify once- or twice-daily use. As one example, the professional information for Alopexy 5% lists 1 ml twice daily and a maximum daily amount of 2 ml. ^[10] The actual frequency depends on the package leaflet or physician instructions.

In women, once-daily 5 percent foam has been shown to be as effective as twice-daily 2 percent solution. Tolerability is better and integration into the daily routine is easier.

Which Concentration is Right?

5 percent minoxidil is well studied and available in Switzerland as a topical product. In a 48-week randomized study in men, 5 percent minoxidil produced about 45 percent more hair regrowth than 2 percent minoxidil; both concentrations were superior to placebo. ^[2] Local irritation was more common with 5 percent.

Higher concentrations may be prescribed as individually compounded preparations. Evidence for additional benefit is mixed, while local side effects may increase. A physician should set the concentration and application schedule.

Oral Minoxidil

Oral minoxidil is increasingly being used to treat hair loss. In Switzerland, it is not officially approved for this use and is therefore prescribed off-label by physicians. When taken orally, it is absorbed through the gastrointestinal tract and converted to its active form in the liver. ^{[5] [9]}

The activating enzyme is present in large amounts in the liver. This means orally taken minoxidil is activated differently than topical minoxidil on the scalp. In studies, oral minoxidil is discussed among other things for people who do not respond sufficiently to topical products. ^{[5] [9]}

Dosage and Efficacy

Individual studies of low-dose oral minoxidil in men with androgenetic alopecia report high response rates and average hair-count increases after 24 weeks. ^[5] These data are relevant but do not replace an individual benefit-risk assessment.

Low-dose oral minoxidil has also been studied in women. Occasional hair growth outside the scalp may occur. ^[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. Which dose is appropriate must be determined by a physician.

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.

Putting Application Instructions in Context

The exact amount, frequency, and contact time depend on the package leaflet or prescription. For Alopexy 5%, hair and scalp should be completely dry before application; hands are washed thoroughly before and after application. The professional information also lists a pipette or dosing pump as application systems and 6 pump sprays for 1 ml of solution. ^[10]

For oral minoxidil, low-dose off-label regimens exist in studies. Dose, timing, and any increases must be determined and monitored by a physician.

Combination with Other Therapies

Minoxidil's efficacy can be influenced in certain cases 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 opening the scalp barrier. Minoxidil can then penetrate more effectively. The procedure can also increase local activity of the 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. Most side effects are local and mild. Skin irritation occurs in about 2 to 6 percent of users. This is 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. It 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, many users experience renewed shedding that can last several months. The extent varies. If minoxidil is to be discontinued, this should be discussed with a physician or pharmacist.

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 treatments for androgenetic alopecia. Topical minoxidil offers a local option with mostly local side effects. Oral minoxidil is not approved for hair loss and should only be used as part of physician-supervised off-label treatment.

Combinations with microneedling, retinoids, or antiandrogen therapies such as finasteride topical vs. oral are discussed in studies, but should be medically assessed.

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, a Swiss physician can assess whether a topical formulation with minoxidil and other active ingredients is suitable for you. Start with our online consultation so your information can be medically reviewed.