The molecules under study for baldness: where things really stand

Only two drugs are approved for androgenetic alopecia: minoxidil and finasteride. The first dates from 1988, the second from 1997. Since then, research has produced a great many announcements and very few approvals. Three molecules stand out today, because they have cleared the stage of human trials and published measured results.

This article says where they stand, and above all what they have not yet shown. None can be prescribed. None will be offered at the clinic before it is approved.

PP405: waking up dormant follicles

This is the molecule most talked about, and the one furthest removed from the two existing treatments. Minoxidil acts on blood supply, finasteride on the hormone. PP405 aims at something else: the stem cells of the follicle, which are still present in a bald scalp but stop producing hair. The molecule seeks to restart their activity by acting on their metabolism.

The phase 2a trial involved 78 participants, who applied a 0.05% solution or a placebo daily for four weeks. Among men with advanced baldness, 31% gained more than 20% in density by the eighth week, against none in the placebo group. The hairs obtained were terminal hairs, thick and visible, in areas that no longer carried any.

Two points deserve emphasis. The first is that the study found no systemic absorption: the molecule stays where it is applied, which in principle rules out the general effects held against finasteride. The second is duration: four weeks of application, eight weeks of observation. That is short. Nobody knows today what PP405 does over a year, nor what becomes of the hairs obtained once treatment stops.

GT20029: destroying the receptor rather than blocking the hormone

GT20029 takes an unusual route, known as PROTAC. Rather than blocking the androgen receptor, the molecule tags it so that the cell degrades it itself. The receptor is not neutralised, it disappears.

A phase 2 trial conducted in China on 180 men reports a gain of 16.8 hairs per square centimetre at the 0.5% daily dose, with no worrying safety signal. The molecule has moved into phase 3.

The appeal of the topical route is the same as for pyrilutamide below: to act on the scalp without lowering androgens throughout the body, and therefore without the sexual side effects that lead some patients to give up finasteride.

Pyrilutamide: an anti-androgen that stays put

Pyrilutamide, also called KX-826, is a non-steroidal anti-androgen designed to act locally. Its systemic absorption is low, plasma concentrations stay low and the product does not accumulate, which makes general effects unlikely.

It too is in phase 3. As with GT20029, the question that will decide its future is not efficacy, already measured, but the margin between the effect obtained on the scalp and the effect obtained elsewhere.

What to take from this today

These three molecules are real, so are their trials, and their results are published. They could reach Europe between 2028 and 2030 if the phase 3 trials confirm the phase 2 findings, which is never a given: half the molecules that enter phase 3 do not come out of it.

None of them changes what should be done in 2026. A patient losing his hair today has nothing to gain by waiting for 2029: a follicle that has gone does not wake up, and the molecules under study all work on follicles that are still alive. Minoxidil and finasteride, for all their age, remain the two treatments whose behaviour at ten years is known.

Finally, be wary of products sold online under these names. None of these three molecules is on the market. What circulates is either a diverted research compound, or something else entirely.

Sources

• Pelage Pharmaceuticals, phase 2a results for PP405, presented at the American Academy of Dermatology, 2026.
• Phase 2 trial of GT20029, 180 participants, China.
• Kintor Pharmaceutical, pharmacokinetic data for pyrilutamide (KX-826).
• Clinical trials registry, NCT06692465.