Where hair-loss treatments act
Explore where established and investigational pattern-hair-loss treatments act. A plausible target and demonstrated regrowth are separate questions.
Reduce DHT production
Conceptual target map. Highlighted zones show a pathway of interest, not the only location where it acts.
Inhibits type II 5α-reductase, lowering scalp and circulating DHT. This reduces an androgen signal involved in follicle miniaturization.
Established drug target and clinical benefit
Finasteride
Oral 1 mg for male pattern hair loss; not approved for women.
Randomized trials found benefits in hair counts, photographs and patient assessments. Continued treatment is needed to maintain benefit.
Confidence interval unavailable in the label summary. Both arms of the selected 212-man phototrichogram study are shown; these are total counts, not non-vellus counts or the larger vertex trial.
17 more hairs/cm² than placebo; p<0.001. Total hair count, not the non-vellus count used by other trials. Confidence interval not reported in the label summary.
Response varies. Counts in a small scalp area do not equal full cosmetic restoration.
Trial context, safety & sources
- Study
- Label-reported phototrichogram study
- Population
- Men with vertex androgenetic alopecia
- Randomized
- 212 total
- Follow-up
- 48 weeks
- Dose / arms
- 1 mg daily
- Endpoint
- Change in total scalp hair count in a 1-cm² target area
- Measure
- Mean change from baseline; higher is better
- Treatment change
- 7 hairs/cm²
- Control change
- -10 hairs/cm²
17 more hairs/cm² than placebo; p<0.001. Total hair count, not the non-vellus count used by other trials. Confidence interval not reported in the label summary.
Read the trial source ↗Safety in context
Reduced libido, erection and ejaculation problems.
Year-1 sexual events: 3.8% (36/945) versus 2.1% (20/934).
Pregnancy exposure can harm a male fetus. Label includes persistent sexual dysfunction, depression and suicidal thoughts in postmarketing reports; their frequency and causality cannot be reliably estimated from those reports. Lowers PSA.
Source date: 2022-08 (label revision; DailyMed updated 2024-10-14) · Checked 2026-09-19
Hair-count methods, scalp areas, populations, doses and follow-up differ across studies. Select a treatment to see what its evidence can support.
Evidence records
All selected treatments, with primary sources and study limits.
FinasterideFDA-approved
Inhibits type II 5α-reductase, lowering scalp and circulating DHT. This reduces an androgen signal involved in follicle miniaturization.
Established drug target and clinical benefit
Oral 1 mg for male pattern hair loss; not approved for women.
Randomized trials found benefits in hair counts, photographs and patient assessments. Continued treatment is needed to maintain benefit.
Response varies. Counts in a small scalp area do not equal full cosmetic restoration.
- Study
- Label-reported phototrichogram study
- Population
- Men with vertex androgenetic alopecia
- Randomized
- 212 total
- Follow-up
- 48 weeks
- Dose / arms
- 1 mg daily
- Endpoint
- Change in total scalp hair count in a 1-cm² target area
- Measure
- Mean change from baseline; higher is better
- Treatment change
- 7 hairs/cm²
- Control change
- -10 hairs/cm²
17 more hairs/cm² than placebo; p<0.001. Total hair count, not the non-vellus count used by other trials. Confidence interval not reported in the label summary.
Read the trial source ↗Safety in context
Reduced libido, erection and ejaculation problems.
Year-1 sexual events: 3.8% (36/945) versus 2.1% (20/934).
Pregnancy exposure can harm a male fetus. Label includes persistent sexual dysfunction, depression and suicidal thoughts in postmarketing reports; their frequency and causality cannot be reliably estimated from those reports. Lowers PSA.
U.S. prescribing information and randomized trials · Source date: 2022-08 (label revision; DailyMed updated 2024-10-14)
Topical minoxidilFDA-approved
Potassium-channel activity in follicular cells is one proposed contributor. Human follicle experiments support an effect on anagen, but the complete regrowth mechanism remains uncertain.
Clinical benefit established; full mechanism unresolved
OTC topical products for pattern hair loss in men and women; concentrations, formulations and directions differ. Oral minoxidil for hair loss is off-label.
A 48-week randomized trial in 393 men found 5% solution superior to vehicle for non-vellus hair count and scalp-coverage assessments.
Benefits require continued use. A result for one concentration, formulation or population is not interchangeable with another.
Safety in context
Scalp irritation and unwanted facial hair can occur.
The 5% solution trial reported more itching and local irritation; this summary does not provide a pooled placebo-adjusted rate.
The topical label advises stopping and seeking advice for chest pain, rapid heartbeat, dizziness, swelling or sudden weight gain. Avoid use during pregnancy or breastfeeding.
U.S. OTC label, randomized trial and laboratory mechanism study · Source date: 2024-11-13 (label update); 2002-09 (randomized trial)
Clascoterone 5%Investigational
Designed to inhibit androgen signaling at scalp receptors. It targets receptor activity rather than reducing DHT production.
Established target; hair-loss formulation under clinical evaluation
Not U.S.-approved for hair loss. Sponsor targets Q1 2027 U.S. filing and Q2 2027 European filing. Approved acne cream is a different formulation and indication.
Sponsor-reported SCALP1/2 results: 1,465 men in the U.S. and Europe. Hair-count endpoints improved; the patient-reported endpoint was significant in one trial and a positive trend in the other.
Full absolute effects are needed to interpret relative-percentage headlines. The 12-month extension selected initial responders; it cannot estimate response in all users.
Safety in context
Sponsor reports similar overall tolerability to vehicle; detailed event rates require full results.
Vehicle-controlled evidence is more informative than claiming topical delivery eliminates systemic risk.
No significant systemic hormonal effects reported by the sponsor over 12 months; this does not establish absence of rare or longer-term harms.
Sponsor-reported phase 3 topline and selected-responder extension · Source date: 2025-12-03 (6 months); 2026-04-15 (extension)
GT20029Investigational
A PROTAC designed to recruit cellular protein-disposal machinery to degrade androgen receptors, reducing their ability to transmit the androgen signal.
Investigational target-degradation strategy
Not U.S.-approved. Published phase 2 evidence in China; sponsor forecast a China phase IIb/III start in H2 2026, but actual start is unverified.
A peer-reviewed 12-week trial randomized 180 Chinese men across six groups. Two regimens separated from their matched vehicles on non-vellus hair count.
Small regimen groups, short follow-up and men from one country. Significance in selected regimens is not proof of durable visible restoration.
- Study
- China phase 2 — NCT06692465
- Population
- Chinese men, Hamilton–Norwood IIIv–V
- Randomized
- 180 total
- Follow-up
- 12 weeks
- Dose / arms
- 0.5% once daily; selected arm of six (30 participants per randomized arm)
- Endpoint
- Change in target-area non-vellus hair count
- Measure
- Least-squares mean change from baseline; higher is better
- Treatment change
- 16.8 hairs/cm²
- Control change
- 10.1 hairs/cm²
6.70 hairs/cm² more than matched vehicle; p=0.032. Confidence interval not extracted. Other regimens had different results; this is one prespecified dose comparison, not the whole trial average.
Read the trial source ↗Safety in context
Most treatment-emergent events were mild.
Event incidence was similar across groups in this trial.
Short phase 2 follow-up cannot exclude uncommon or long-term systemic effects.
Peer-reviewed randomized phase 2 trial · Source date: 2025-12-02 (online publication)
PP405Investigational
Inhibits mitochondrial pyruvate transport. The proposed shift toward lactate-associated metabolism aims to activate existing follicle stem cells. Durable clinical regrowth remains under study.
Mechanistic and early human evidence; clinical promise unconfirmed
Investigational; no U.S. approval. Pelage’s October 14 announcement confirms first patient dosing in the 600-man Phase 2/3 AWAKEN study; the exact dosing day is undisclosed. A separate women’s Phase 2 start is forecast by end-2026.
Sponsor phase 2a report: 78 adults, four weeks of dosing. At week eight, 31% of a male subgroup with greater hair loss exceeded 20% density gain versus 0% on vehicle.
Exploratory phase 2a subgroup with no denominator stated in the release; not the full-sample response rate. AWAKEN will assess non-vellus hair count at week 24; no results yet. December 2027 primary completion is a registry estimate, not a results-release date. The September 22 posted results contain safety/PK outcomes without controlled hair-regrowth numbers; they do not validate the earlier exploratory subgroup headline.
Safety in context
Posted phase 2a results: treatment-emergent adverse events in 22/51 (43.1%) PP405 recipients; percentage calculated from counts.
Vehicle: 10/27 (37.0%) with treatment-emergent adverse events; no comparative interval.
Serious events: 0/51 active versus 1/27 vehicle (upper-extremity fracture); no deaths. Small, short follow-up cannot exclude rare/late harms. No detectable plasma measurements do not prove zero systemic exposure or risk.
Sponsor-reported exploratory phase 2a subgroup; later trial registry · Source date: 2025-06-17 (phase 2a report); 2026-10-02 (current AWAKEN registry); 2026-10-14 (dosing announcement)
ABS-201Investigational
Blocks prolactin-receptor signaling. Human scalp organ-culture work suggests this could reduce regression and support growth; laboratory tissue findings are not clinical regrowth results.
Proposed benefit supported by preclinical human-tissue work
Not U.S.-approved. HEADLINE is recruiting in Australia, with 227 planned participants. Its official title and reported human safety evidence describe phase 1; the September 3, 2026 registry design field lists phases 1/2.
June 2026 sponsor report covered blinded, pooled single-dose safety in 32 adults. Human regrowth benefit has not been established by that report.
Drug exposure and a long half-life are not hair-regrowth endpoints. Registry estimates final completion in July 2028; earlier interim readouts are separate sponsor forecasts.
Safety in context
Headache was reported in four participants; five had mild events judged treatment-related.
Data remained blinded and pooled across drug and placebo; treatment-specific rates cannot be inferred.
No serious events reported at the interim cutoff, but 32 adults cannot establish long-term or rare-event safety.
Sponsor-reported blinded, pooled interim phase 1 safety; preclinical mechanism work · Source date: 2026-06-24 (interim phase 1 safety); 2026-09-03 (registry phase-field clarification)
VDPHL01Investigational
A gel-matrix tablet changes minoxidil release and exposure. It retains minoxidil’s incompletely understood hair-growth biology; a new release profile is not a new follicular target.
Established active ingredient; formulation-specific benefit under evaluation
Not U.S.-approved. Phase 3 program underway; sponsor forecasts confirmatory male data in H2 2026 and female pivotal data in H1 2027.
Sponsor reports both co-primary endpoints met in male Study 302. Patient-rated improved/much-improved coverage: 48.4% once daily versus 13.4% placebo at month six.
Topline sponsor evidence; no direct comparison establishes greater safety or efficacy than immediate-release oral minoxidil.
- Study
- Study 302 — NCT06724614
- Population
- Men with mild-to-moderate pattern hair loss
- Randomized
- 519 total
- Follow-up
- 6 months
- Dose / arms
- 8.5 mg once daily; selected arm
- Endpoint
- Change in target-area non-vellus hair count
- Measure
- Reported mean change from baseline; higher is better
- Treatment change
- 30.3 hairs/cm²
- Control change
- 7.3 hairs/cm²
Calculated placebo-adjusted difference: 23.0 hairs/cm²; sponsor reports p<0.0001. Confidence interval not reported in the release. Separate twice-daily arm had different results.
Read the trial source ↗Safety in context
Detailed regimen-specific common-event rates are not summarized here.
Controlled data exist, but a headline of good tolerability is not a complete benefit–risk analysis.
Sponsor reports no treatment-related serious or specified cardiac events in Study 302. Oral minoxidil labeling warns about fluid retention and pericardial effusion; risks and frequencies cannot simply be transferred to this investigational formulation.
Sponsor-reported randomized phase 2/3 topline · Source date: 2026-04-27 (Study 302 topline report)
Scope & how to read this explorer
Scope: selected drug approaches for androgenetic (pattern) hair loss. Alopecia areata, scarring alopecia, graying, transplantation and devices are outside this mechanism map.
Mechanism markers are a simplified schematic, not a map of measured drug concentrations or exclusive receptor locations.
Compare each treatment with its own control. Different populations, durations, formulations, scalp areas and counting methods make these examples unsuitable for a cross-trial ranking.
Hair counts, visible coverage, satisfaction and durability are different outcomes. More counted hairs does not guarantee a particular appearance.
Regrowing a shaft from an existing follicle does not establish creation of a new follicle. No simulated before-and-after image represents a treatment result.
Investigational status applies to the formulation and indication shown. A registered trial does not establish efficacy, approval, current enrollment availability or a launch date.
Trial doses describe research; they are not personal dosing recommendations. Safety summaries are selective and cannot replace product labeling or clinician assessment.
Evidence checked September 19, 2026. This is a focused primer, not an exhaustive or automatically updated pipeline review.