Finasteride

A follicle that produces increasingly fine hair

In androgenetic alopecia, certain follicles are particularly sensitive to androgens due to genetic factors. As the cycles progress, their growth phase shortens and the hair produced becomes less thick and less visible. This is miniaturization. Two people with similar hormonal levels can therefore lose their hair very differently: the sensitivity of the follicles matters as much as the presence of the hormone.

Finasteride mainly inhibits 5-alpha-reductase type II, which converts part of the testosterone into DHT. It thus reduces DHT in the blood and scalp, which studies with samples have measured. It does not suppress testosterone production. The goal is to reduce a signal involved in miniaturization, without creating new follicles where they no longer produce visible hair.

Preserve, then sometimes thicken

When this signal decreases, the follicles still able to respond can maintain better activity and produce thicker hair. The difference appears slowly, at the rhythm of hair cycles. A rapid drop in DHT cannot therefore be read immediately in the mirror: you must give the hair time to grow so that a possible modification of the follicle changes the coverage of the scalp.

Long-term trials show that stabilization is a major benefit. Some men also gain density, while others mainly avoid aggravation. Similar hair after several years can be a useful result, even if the photos don't give the impression of a transformation. The relevant comparison is also what would have happened without treatment, which placebo groups allow us to approach in studies.

Why balding areas don't grow back

Trial results mainly concern mild to moderate androgenetic hair loss with follicles still present. They do not promise to restore a hairline that disappeared long ago. Evidence is less established for isolated temple recession and very advanced loss. Earlier diagnosis may leave more hair to preserve, but does not guarantee a response; the locally approved indication still needs to be checked.

Treatment does not permanently correct the genetic predisposition. After stopping, its protective effect fades and the progression of alopecia resumes; Hair benefits can be lost within a few months, usually within a year. This explains the long-term commitment. The decision to continue nevertheless remains reevaluable: keeping your hair does not justify ignoring an adverse effect or a change in personal priority.

An effectiveness that does not sum up tolerance

The trials included in the SPC report drug-related sexual effects in 3.8% of men on finasteride compared to 2.1% on placebo during the first year. This comparison places a risk observed in these trials, without describing all the patients or all the durations of use. Persistent problems after stopping have also been reported; their exact frequency remains unknown.

The psychological effects are also part of the decision. Their frequency cannot be deduced by simply dividing reports by a number of users: spontaneous reports do not identify all cases and do not follow people like a trial. The rating of 3/3 therefore reflects the strength of the capillary effect, not a guarantee of safety or a treatment recommendation for each reader.

What the skin shape changes

In a phase III trial published in 2022, a finasteride spray increased the number of hairs in the measured area more than placebo after 24 weeks. Blood exposure to the drug is significantly lower than with the oral form studied. However, blood DHT also drops: applying to the scalp does not mean that the action remains strictly local.

These results concern a precise formulation and application device. They cannot be attributed to any lotion prepared or purchased online, nor can they demonstrate long-term equivalence to tablets alone. The oral or cutaneous choice is discussed with the doctor according to availability, instructions, tolerance and application constraints. You should not make your own lotion by dissolving tablets.

Do finasteride and minoxidil complement each other?

minoxidil acts on the activity and cycle of the follicle by a mechanism different from the reduction of DHT. A 12-month comparative trial observed more improvements with the combination of oral finasteride and topical minoxidil than with either alone. This can justify a discussion when additional density is sought, without making the association a mandatory step for all people treated.

Dutasteride also acts on 5-alpha-reductase, but on several forms of the enzyme, with a different prescription framework. A greater reduction in DHT alone does not mean the best treatment for a person. Rather than looking for the most complicated protocol, the challenge is to choose with the doctor an option whose benefits, risks and follow-up correspond to your situation.