Clascoterone for Hair Regrowth

Evidence Review created on 04/22/2026 using AI4L / Opus 4.7

Also known as: CB-03-01, Cortexolone 17α-Propionate, Breezula, Winlevi

Motivation

Clascoterone (also marketed as Winlevi for acne, and in development as Breezula for hair loss) is a topical compound that blocks the androgen receptor directly at the hair follicle. By acting locally on the scalp rather than lowering hormone levels throughout the body, it aims to address the root driver of pattern hair loss — the gradual shrinking of follicles driven by a male-hormone metabolite — without the systemic hormonal effects associated with oral antiandrogens.

Pattern hair loss affects a majority of men by age 50 and a substantial proportion of women, yet the pharmacological toolkit has remained essentially unchanged for more than three decades, anchored on topical minoxidil and oral hormone-blocking drugs. Clascoterone is notable as the first topical androgen receptor inhibitor to reach late-stage clinical development for pattern hair loss, following its 2020 approval by U.S. regulators for acne.

This review examines what is currently known about clascoterone’s effectiveness and safety for hair growth, the mechanism that sets it apart from existing options, how it compares to alternatives, and the practical considerations for those tracking this emerging intervention.

Benefits - Risks - Protocol - Conclusion

Grokipedia

Clascoterone

A reference article covering clascoterone’s chemistry (cortexolone 17α-propionate), its mechanism as a competitive androgen receptor antagonist, FDA approval history for acne, and its emerging role in androgenetic alopecia.

Examine

Examine.com does not currently have a dedicated article on clascoterone. Examine.com does not typically cover prescription medications, focusing instead on dietary supplements and natural compounds.

ConsumerLab

ConsumerLab does not currently have a dedicated article on clascoterone. ConsumerLab does not typically cover prescription medications, focusing on third-party testing of dietary supplements and consumer health products.

Systematic Reviews

No systematic reviews or meta-analyses for Clascoterone were found on PubMed as of 04/22/2026.

Mechanism of Action

Clascoterone acts through a fundamentally different route than existing androgenetic alopecia treatments. Whereas finasteride and dutasteride reduce dihydrotestosterone (DHT) production systemically by inhibiting 5α-reductase (the enzyme that converts testosterone to DHT), and minoxidil stimulates growth without addressing the hormonal driver, clascoterone blocks DHT at its receptor directly within the hair follicle.

The key steps are:

Competitive androgen receptor (AR) binding: Clascoterone’s structure closely resembles DHT, allowing it to compete with DHT for the androgen receptor (the protein that relays male-hormone signals into the cell nucleus) in dermal papilla cells (the specialized cells at the base of hair follicles that regulate the hair growth cycle). In vitro studies show clascoterone binds the AR with affinity comparable to or higher than DHT itself.
Inhibition of AR-mediated transcription: By occupying the receptor, clascoterone prevents DHT from activating the gene programs that drive follicular miniaturization — the progressive shortening of the growth phase and thinning of the hair shaft that defines pattern hair loss.
Reduction of local inflammatory signaling: Clascoterone lowers DHT-stimulated IL-6 (interleukin-6, a pro-inflammatory cytokine implicated in hair loss) release from dermal papilla cells. Perifollicular inflammation is recognized as an accelerant of androgenetic alopecia, so this anti-inflammatory effect may contribute to benefit beyond receptor blockade alone.
Local-only pharmacology: After topical application, clascoterone is rapidly hydrolyzed in the skin to cortexolone, an inactive metabolite. Systemic plasma concentrations are very low (mean Cmax around 4.4–4.6 ng/mL with twice-daily 1% cream), reaching steady state within roughly 5 days.

Some mechanistic commentators note that receptor blockade without suppressing DHT production could, in theory, leave elevated local DHT that might act through non-receptor pathways, but direct clinical evidence for this competing view is limited. In practice, the efficacy data to date support the dominant receptor-antagonist model.

Key pharmacological properties:

Half-life: Very short systemic plasma half-life; rapidly metabolized to cortexolone in skin. Local dermal half-life supports twice-daily application.
Selectivity: Selective androgen receptor antagonist with no clinically meaningful activity at progesterone, estrogen, or glucocorticoid receptors at therapeutic exposures.
Tissue distribution: Designed for localized dermal action; minimal systemic absorption due to skin esterases that rapidly cleave it.
Metabolism: Hydrolyzed in skin and plasma by esterases to cortexolone (an endogenous cortisol precursor) and propionic acid; minimal involvement of CYP (cytochrome P450, a family of liver enzymes responsible for metabolizing most drugs) enzymes.

Historical Context & Evolution

Clascoterone was discovered and developed in Italy by Cosmo Pharmaceuticals, later spun out through its dermatology subsidiary Cassiopea SpA (now part of Cosmo again). The compound, designated CB-03-01, was identified in the early 2000s as a potent, topically active androgen receptor antagonist derived from cortexolone, a natural intermediate in cortisol biosynthesis.

Key milestones:

Early 2000s–2010: Preclinical and early-phase studies established antiandrogen activity on skin targets with a favorable local safety profile.
2011–2015: A phase 2 trial (NCT02279823) in 95 men with androgenetic alopecia compared clascoterone 5% solution against minoxidil 5% and vehicle over 26 weeks, providing the first clinical signal for hair growth efficacy with topical AR blockade.
2015–2018: Pivotal phase 3 programs were conducted for the acne indication.
August 2020: The U.S. FDA approved clascoterone 1% cream (Winlevi) for acne vulgaris in patients 12 years and older — the first new mechanism approved for acne in roughly four decades.
2023–2025: Two phase 3 trials, SCALP-1 and SCALP-2, enrolled a combined 1,400+ men with androgenetic alopecia to evaluate a 5% topical solution.
December 2025: Topline phase 3 results were announced, reporting statistically significant hair count improvements over vehicle.
2026: The 12-month safety follow-up is expected to complete, supporting regulatory submissions to the FDA and EMA (European Medicines Agency, the European Union’s drug regulator).

The motivation for pursuing a topical antiandrogen for pattern hair loss arose from long-standing recognition that systemic antiandrogens (e.g., spironolactone, oral finasteride, dutasteride) can improve hair loss but carry dose-dependent hormonal side effects, particularly in men. A locally acting antiandrogen had long been a sought-after but elusive goal. Clascoterone’s reported phase 3 results have not closed the debate — some clinicians note the current data are topline rather than fully published, and historical enthusiasm for novel hair loss drugs has not always translated to durable real-world benefit. The evidence base is evolving, and independent peer-reviewed publication of the complete SCALP-1 and SCALP-2 datasets is awaited.

Expected Benefits

A dedicated search for clascoterone’s benefit profile was performed across the SCALP-1/SCALP-2 phase 3 reports, the phase 2 program, the Winlevi prescribing information, mechanistic publications, and recent dermatology commentary before writing this section. The phase 3 SCALP trials were sponsored by Cosmo Pharmaceuticals/Cassiopea, the commercial developer of clascoterone; this constitutes a direct financial conflict of interest, relevant to the interpretation of topline results that have not yet been fully peer-reviewed.

Medium 🟩 🟩

Increased Hair Count Versus Placebo

Across the SCALP-1 and SCALP-2 phase 3 trials (combined enrollment of roughly 1,400+ men with androgenetic alopecia), twice-daily application of clascoterone 5% solution for 6 months produced statistically significant increases in target area hair count (TAHC) versus vehicle. Topline reports from the sponsor (Cosmo/Cassiopea, which has a direct financial interest in the outcome) describe substantial relative improvement over vehicle across the pooled analysis, with individual trial results consistent with a meaningful treatment effect. Full peer-reviewed publication of absolute hair-count changes is still pending, which tempers the quantitative interpretation and keeps the evidence at a medium tier pending independent scrutiny.

Magnitude: Statistically significant increases in target area hair count versus vehicle in each phase 3 trial; pooled relative improvement reported in the low hundreds of percent range per sponsor topline (full absolute numbers pending peer-reviewed publication).

Local Safety Profile Comparable to Vehicle

Across the acne program and the SCALP trials, clascoterone produced adverse event rates similar to vehicle. Treatment-emergent events were predominantly mild and local (scalp/application-site erythema, scaling, pruritus). No signal of systemic androgen-related adverse effects was observed, and no meaningful changes in serum testosterone or DHT were detected with topical application.

Magnitude: Overall adverse event rates comparable to vehicle in trials totaling >1,400 men; most treatment-emergent events were mild and resolved with continued use or dose adjustment.

Preservation of Systemic Androgen Status

Unlike oral finasteride or dutasteride, clascoterone does not meaningfully reduce circulating DHT or testosterone. This preserves systemic androgen-dependent functions — libido, erectile function, muscle maintenance, and mood regulation — that can be affected by oral 5α-reductase inhibitors in a subset of users. Plasma clascoterone concentrations remain very low with topical application and return to baseline rapidly after discontinuation.

Magnitude: No clinically relevant changes in serum testosterone or DHT observed in controlled trials; steady-state plasma clascoterone in the low ng/mL range.

Patient-Reported Improvement in Hair Appearance

Patient-reported outcome instruments used in the SCALP phase 3 program showed improvement in self-assessed hair growth and appearance in treated versus vehicle-treated men, with statistical significance in pooled analyses and at least one of the individual trials reaching significance on its own.

Magnitude: Statistically significant improvement versus vehicle in pooled patient-reported outcomes across the two phase 3 trials.

Low 🟩

Reduction in Local Follicular Inflammation

Preclinical and ex vivo work shows that clascoterone decreases DHT-stimulated IL-6 secretion in scalp dermal papilla cells, and recent ex vivo data on balding scalp samples indicate it restores markers of dermal papilla inductivity. These anti-inflammatory and pro-inductive actions likely contribute to the clinical benefit, but they have not been quantified directly in clinical trials.

Magnitude: Not quantified in available studies.

Potential for Additive Use with Other Hair Loss Treatments ⚠️ Conflicted

Because clascoterone blocks the androgen receptor locally while minoxidil acts through vasodilation and growth factor signaling, and oral finasteride lowers systemic DHT production, the three mechanisms are non-overlapping and plausibly additive. Some sponsor and expert commentary supports this combination rationale. However, other clinicians caution that interaction effects, sensitization risk, and skin penetration of multiple topicals applied together have not been formally studied, and that responders and non-responders to each agent may not stack predictably. Formal combination efficacy and safety trials have not been published.

Magnitude: Not quantified in available studies.

Speculative 🟨

Benefit in Female Pattern Hair Loss

Given clascoterone’s topical, non-systemic mechanism, it could in principle provide an androgen-blocking option for women with pattern hair loss without the systemic hormonal effects that limit oral antiandrogens such as spironolactone. However, the phase 3 SCALP program enrolled only men, and no large controlled trials have evaluated clascoterone specifically in women with androgenetic alopecia. The mechanistic case is attractive but clinical evidence remains mechanistic/anecdotal at this stage.

Benefit-Modifying Factors

Genetic polymorphisms: Variation in the AR gene (located on the X chromosome) — notably CAG repeat length (a trinucleotide sequence whose length inversely correlates with androgen receptor sensitivity) — influences how strongly a follicle responds to DHT and may modulate individual response to receptor-level blockade. Polymorphisms in skin esterase pathways could influence local metabolism, but pharmacogenomic data for clascoterone specifically are absent.
Baseline biomarker levels: Baseline scalp and systemic DHT levels, along with free and total testosterone, set the context for how much androgenic drive a follicle is exposed to; individuals with higher baseline androgen exposure may have more to gain from receptor-level blockade, although clascoterone does not measurably lower these circulating levels. Baseline follicular miniaturization indicators (trichoscopy-measured hair diameter diversity) and scalp inflammatory markers may also influence response magnitude, though none have been validated as predictive biomarkers for clascoterone specifically.
Baseline hair loss severity: Miniaturized but still-living follicles respond to antiandrogen therapy; fully atrophied or scarred follicles do not. Earlier-stage androgenetic alopecia (Norwood II–IV in men, lower Ludwig stages in women) generally benefits more than advanced baldness where follicular units are irreversibly lost.
Sex-based differences: The clinical dataset is largely male. Women with androgenetic alopecia differ in hormonal milieu and pattern (diffuse thinning rather than temporal recession), and scalp androgen sensitivity profiles differ. The local mechanism is theoretically attractive for women, but controlled efficacy data are lacking.
Pre-existing conditions: Patients with coexisting scalp disorders (seborrheic dermatitis, psoriasis, telogen effluvium — a stress- or illness-triggered, non-androgenic form of diffuse hair shedding) may see a muted or confounded response until those conditions are addressed. Inflammatory scalp states may also alter drug absorption.
Age: Younger patients with a shorter duration of miniaturization typically respond better to any pharmacological AGA treatment. For those at the older end of the target range — adults in their 50s, 60s, and beyond — response may be slower and ceilings lower, though baseline androgen signaling at the follicle remains clinically relevant and topical blockade continues to have a mechanistic rationale.

Potential Risks & Side Effects

A dedicated search for clascoterone’s safety profile was performed across the Winlevi prescribing information, the SCALP program topline reports, the phase 2 trial publication, the FDA approval package, and drug references including drugs.com before writing this section.

High 🟥 🟥 🟥

Local Skin Reactions at Application Site

The most consistently observed adverse effects across the clascoterone program are mild, localized scalp or skin reactions including erythema (redness), scaling, dryness, and pruritus (itching). Rates in the SCALP phase 3 trials were broadly similar to vehicle, suggesting the topical solution vehicle itself contributes. In the acne program with 1% cream, application-site reactions were the most frequent adverse events and generally resolved without discontinuation.

Magnitude: Application-site reactions (erythema, scaling, pruritus) reported in a substantial minority of treated patients in the acne program; overall rates in the SCALP trials comparable to vehicle.

Low 🟥

HPA Axis Suppression (Subclinical)

Because clascoterone is structurally related to cortexolone (a cortisol precursor), topical application can, rarely, suppress the HPA (hypothalamic-pituitary-adrenal, the body’s central stress response system) axis. A pharmacokinetic study of the 1% cream for acne found a small proportion of patients with borderline cosyntropin stimulation responses that normalized within approximately 4 weeks of discontinuation. No clinical adrenal insufficiency was observed. The signal is most relevant for large-surface or very high-dose application and is expected to be even less relevant for localized scalp treatment.

Magnitude: Single-digit percentage incidence of subclinical HPA axis abnormalities in a small PK study of the 1% cream; fully reversible within about 4 weeks of discontinuation; no clinical adrenal insufficiency reported.

Mild Hyperkalemia (Elevated Potassium)

Small elevations in serum potassium have been reported at low frequency, plausibly related to cortexolone’s weak mineralocurticoid-modulating effects. In the acne trials, rates were marginally higher than placebo and of limited clinical significance at the doses studied. The signal warrants attention in patients already predisposed to hyperkalemia (e.g., those on potassium-sparing diuretics).

Magnitude: Low single-digit percentage of treated patients in the acne program, only marginally above vehicle.

Speculative 🟨

Unknown Long-Term Safety Beyond One Year

The SCALP phase 3 trials included 6 months of double-blind treatment with 6-month single-blind extensions. Longer-term safety over years of continuous daily application — the pattern expected for real-world androgenetic alopecia use — has not been characterized. Cumulative effects on local skin, scalp microbiome, HPA axis, or sensitization risk are plausible but not yet documented.

Contact Sensitization

As with any chronically applied topical medication, clascoterone carries a theoretical risk of contact dermatitis or delayed hypersensitivity developing over time. Rare contact dermatitis cases were reported in the acne program. Risk is likely higher on already-sensitized scalp skin or with shared vehicle ingredients used in multiple concurrent topical treatments.

Risk-Modifying Factors

Genetic polymorphisms: Variants in skin esterase pathways or adrenal steroidogenesis could theoretically influence local clearance and HPA axis susceptibility; no pharmacogenomic studies have been published.
Baseline biomarker levels: Pre-existing borderline or low morning cortisol, or elevated serum potassium, may amplify the relevance of the HPA and hyperkalemia signals and warrants baseline measurement.
Sex-based differences: The phase 3 dataset is men-only. Women — especially those of reproductive potential — face additional considerations given clascoterone’s classification as an antiandrogen, animal reproductive toxicity data at high systemic doses, and the theoretical risk to a developing male fetus from any systemic exposure.
Pre-existing conditions: Adrenal insufficiency, chronic systemic corticosteroid use, advanced renal impairment (impairs potassium excretion), and concomitant use of potassium-sparing diuretics or ACE inhibitors (angiotensin-converting enzyme inhibitors, a class of blood pressure drugs)/ARBs (angiotensin II receptor blockers, another class of blood pressure drugs) increase the relevance of HPA axis and hyperkalemia signals. Active scalp inflammatory conditions may increase local irritation and drug absorption.
Age: Adolescents may be more susceptible to HPA axis effects per pharmacokinetic data from the acne program; phase 3 hair loss data are in adults. For older adults (e.g., 60+), data are limited; response may be slower and baseline renal function should be considered in the context of the potassium signal.

Key Interactions & Contraindications

Prescription drug interactions: No formal drug-drug interaction trials have been conducted for the hair loss indication. In vitro, clascoterone does not meaningfully inhibit or induce major CYP enzymes (1A2, 2B6, 2C8, 2C9, 2C19, 2D6, 2E1, 3A4) at exposures expected from topical use, implying low systemic interaction potential. Systemic corticosteroids (e.g., prednisone, dexamethasone) may compound HPA axis effects — monitor. Potassium-sparing diuretics (spironolactone, eplerenone), ACE inhibitors (angiotensin-converting enzyme inhibitors, a class of blood pressure drugs that block the conversion of angiotensin I to II; e.g., lisinopril, enalapril, ramipril), and ARBs (angiotensin II receptor blockers, blood pressure drugs that block the angiotensin II receptor directly; e.g., losartan, valsartan) can elevate potassium; use with caution and monitor serum potassium.
Over-the-counter medication interactions: Topical products applied to the same scalp area — other antiandrogens, corticosteroids, retinoids, minoxidil — could alter absorption or increase local irritation. NSAIDs (non-steroidal anti-inflammatory drugs, e.g., ibuprofen, naproxen) can reduce renal potassium excretion and may additively modestly raise serum potassium in susceptible users.
Supplement interactions: Supplements with antiandrogenic activity (saw palmetto, green tea extract, stinging nettle root) could theoretically add to local or systemic androgen blockade; clinical significance is unknown. High-dose potassium supplements should be used cautiously.
Additive effects with other hair loss treatments: Concomitant use with oral finasteride, dutasteride, or spironolactone would stack receptor-level blockade on systemic DHT reduction. While this is often cited as a rationale for combination therapy, formal safety and efficacy data for combinations are absent — caution.
Populations who should avoid this intervention:
- Pregnant or breastfeeding women (animal reproductive toxicity at high systemic doses; theoretical fetal antiandrogen exposure).
- Individuals with known hypersensitivity to clascoterone or excipients.
- Patients with untreated primary or secondary adrenal insufficiency (caution and medical supervision).
- Children below studied age ranges; adolescents only under medical supervision given the pharmacokinetic HPA signal.
- Patients with severe chronic kidney disease (eGFR (estimated glomerular filtration rate, a measure of kidney filtration capacity) <30 mL/min/1.73 m²) or serum potassium persistently >5.0 mEq/L without close monitoring.

Risk Mitigation Strategies

Patch test before full application: Apply a small amount to a limited scalp area for 48–72 hours to screen for contact irritation or sensitization before committing to full twice-daily use; mitigates local reactions and contact sensitization risk.
Use lowest effective application volume: Apply the amount specified by the protocol (e.g., a few mL twice daily) rather than “more is better” over-application; reduces systemic absorption, HPA axis risk, and local irritation.
Baseline and periodic HPA axis surveillance: Check morning serum cortisol at baseline and roughly every 6 months, with cosyntropin stimulation testing only if cortisol is below 10 µg/dL or symptoms suggestive of adrenal insufficiency (fatigue, lightheadedness, weight loss) develop; mitigates the HPA suppression signal.
Baseline and periodic serum potassium: Check potassium at baseline, at roughly 3 months, and at least annually thereafter, more frequently for patients on ACE inhibitors, ARBs, potassium-sparing diuretics, or potassium supplements; mitigates the hyperkalemia signal.
Effective contraception for women of reproductive potential: Any woman using clascoterone should use effective contraception given animal reproductive toxicity data and the theoretical antiandrogenic exposure risk; mitigates potential teratogenicity.
Stop and reassess for significant local reactions: For persistent erythema, scaling, or pruritus beyond the first few weeks, reduce frequency or temporarily discontinue; mitigates escalation to contact dermatitis.
Physician supervision for off-label or pre-approval use: Until the 5% solution is approved for androgenetic alopecia, use (compounded or off-label) should be under a prescribing clinician who can coordinate baseline and follow-up labs and assess formulation quality; mitigates formulation, dosing, and monitoring risks.

Therapeutic Protocol

Clascoterone for androgenetic alopecia is investigational and not yet FDA-approved for this indication as of 04/22/2026. The protocol below reflects the SCALP phase 3 trial design, the approved Winlevi acne regimen, and published commentary from Cosmo/Cassiopea and independent dermatologists. A competing approach used by some clinicians — off-label compounded solutions with non-standard concentrations or vehicles — is common in practice but is not evidence-based at the SCALP protocol level; the pros and cons are noted without endorsing one as default.

Formulation and concentration: A 5% topical solution developed specifically for scalp penetration. Compounded solutions at other concentrations exist but are not equivalent to the investigational formulation.
Application: Twice daily (morning and evening, roughly 12 hours apart), applied directly to affected scalp areas via dropper or spray applicator; massage lightly; allow to dry before styling or covering.
Best time of day: Morning and evening to maintain continuous receptor occupancy; no specific food requirement since absorption is topical. Post-shower application on clean, dry scalp is often recommended by clinicians for consistency, though not required by the trial protocol.
Half-life considerations: Clascoterone is rapidly hydrolyzed in skin; the local effect window is short, which is why twice-daily dosing is used. Systemic steady state is reached in roughly 5 days.
Single vs. split doses: Split twice-daily dosing is the studied regimen. Once-daily dosing has not been formally evaluated for androgenetic alopecia and likely under-delivers receptor blockade across a 24-hour window.
Genetic polymorphisms: Pharmacogenomic guidance specific to clascoterone is not available. Patients with AR polymorphisms associated with greater androgen sensitivity (e.g., shorter CAG repeats) may theoretically benefit more, but this is not a standard testing parameter.
Sex-based differences: Studied primarily in men. Women — particularly post-menopausal women or those with confirmed androgen-driven patterns — may be candidates on a case-by-case basis with a prescriber; pre-menopausal women must use effective contraception and understand the lack of phase 3 data in women.
Age considerations: Phase 3 data are in adult men (typically 18+). Younger men with earlier-stage miniaturization may respond more robustly; older men may still benefit but should expect slower response and have renal/potassium status checked, especially if on interacting medications.
Baseline biomarkers: Morning serum cortisol, serum potassium, and a basic metabolic panel (including creatinine and eGFR) are reasonable baseline measurements, particularly in patients with risk factors for adrenal insufficiency or hyperkalemia.
Pre-existing conditions: Adrenal insufficiency, renal impairment, concomitant potassium-altering medications, and active scalp inflammatory conditions all warrant closer follow-up and, in some cases, pre-treatment management (e.g., addressing seborrheic dermatitis) before starting.

Discontinuation & Cycling

Duration of use: Androgenetic alopecia is chronic and progressive; any pharmacological benefit (from clascoterone or other agents) requires continuous use. Expected use is long-term daily application, not a short course.
Withdrawal effects: No pharmacological withdrawal syndrome is expected. Unlike systemic antiandrogens, clascoterone does not suppress endogenous hormone production, so there is no androgen rebound. Subclinical HPA axis suppression, if it occurred, reverses within roughly 4 weeks of discontinuation.
Tapering: No tapering schedule is required. Treatment can be stopped abruptly without physiological withdrawal concerns. Gradual reversion to the pre-treatment hair loss trajectory should be expected over the months following discontinuation.
Cycling: Cycling (periods on and off) has not been studied and is not a recommended strategy; continuous receptor blockade is needed to sustain the clinical effect. Pauses simply allow DHT to resume driving follicular miniaturization.

Sourcing and Quality

Approved product (1% cream for acne): Winlevi (clascoterone 1% cream) is available by prescription in the United States (FDA approval, 2020), Canada, the EU, and several other markets. This formulation is not designed for scalp use and has not been shown efficacious for hair loss.
Investigational product (5% solution for hair loss): Not yet commercially available as an approved product as of 04/22/2026; pending regulatory submissions following 12-month safety follow-up. When approved, the branded product is expected under the Breezula name (or successor branding) from Cosmo/Cassiopea.
Compounding pharmacies: Some compounding pharmacies prepare topical clascoterone solutions off-label at higher concentrations. If this route is used, prefer pharmacies accredited by the Pharmacy Compounding Accreditation Board (PCAB) or equivalent state licensure, and request certificates of analysis documenting identity, potency, and purity.
Research-chemical suppliers: Raw clascoterone (CB-03-01) is offered by research-chemical vendors. These products are not pharmaceutical-grade, lack quality assurance, and may vary widely in purity, solvent, and vehicle suitability for scalp application; they are not recommended for human use.
What to look for: Pharmaceutical-grade manufacturing, verified 5% concentration (for hair loss protocols), a vehicle designed for scalp penetration (typically ethanol-based), sealed packaging, and lot traceability.

Practical Considerations

Time to effect: Meaningful hair count improvement was observed in the SCALP trials at 6 months of continuous twice-daily use. Early visible changes may occur around 3–4 months; a fair trial period is 6–12 months before concluding non-response.
Common pitfalls: Inconsistent daily application undermines the continuous receptor-blockade mechanism. Using the 1% acne cream expecting hair regrowth is ineffective because it is formulated for different skin and at lower concentration. Over-application does not enhance efficacy and can increase systemic exposure and local irritation. Applying to fully scarred or long-atrophied regions will not produce regrowth.
Regulatory status: Clascoterone 1% cream (Winlevi) is FDA-approved for acne vulgaris (2020) with further approvals in Canada, the EU, and other regions. The 5% solution for androgenetic alopecia is investigational, with regulatory submissions anticipated after the 12-month safety follow-up completes.
Cost and accessibility: Winlevi retails in the several-hundred-dollars-per-tube range in the U.S. without insurance. The 5% solution’s pricing is not set, but as a branded prescription product for a cosmetic-adjacent indication, out-of-pocket cost is expected to be significant and insurance coverage limited; health plans typically do not reimburse AGA treatment.

Interaction with Foundational Habits

Sleep: Clascoterone is a local-acting topical with minimal systemic exposure and no known central pharmacology; direct interaction with sleep architecture or quality is not expected. Evening application should not disrupt sleep if applied well before bedtime to allow drying. No published studies document sleep effects.
Nutrition: No specific dietary requirements or interactions. Absorption is topical and independent of food intake. Patients with risk factors for hyperkalemia should moderate very high-potassium intakes (e.g., large servings of potassium-rich foods combined with potassium supplements and potassium-sparing drugs), though the clinical relevance is modest.
Exercise: Clascoterone does not measurably alter systemic androgens, so anabolic signaling and performance should be unaffected — a potentiating contrast to oral 5α-reductase inhibitors for those concerned about training response. Heavy sweating shortly after application may reduce local drug concentration; applying after showering post-exercise, once the scalp is dry, is a practical workaround. No controlled studies on exercise interaction are available.
Stress management: Psychological stress can precipitate telogen effluvium, a non-androgenic form of hair shedding that clascoterone does not address. Stress does not have a direct pharmacodynamic interaction with topical clascoterone, but patients under significant chronic stress may see attenuated visible benefit until stress-related shedding resolves. The theoretical HPA axis signal is an indirect consideration for individuals already in a state of adrenal strain; baseline cortisol testing can clarify.

Monitoring Protocol & Defining Success

Baseline laboratory testing establishes reference values for monitoring potential systemic effects before the first dose is applied. Ongoing monitoring is recommended at approximately 3 months after starting, at 6 months, and then every 6–12 months thereafter, with additional checks prompted by symptoms or interacting medications.

Baseline Labs

Biomarker	Optimal Functional Range	Why Measure It?	Context/Notes
Morning serum cortisol	10–20 µg/dL	Screens for pre-existing adrenal insufficiency before starting a drug with a rare HPA suppression signal	Fasting AM draw (6–8 AM); conventional reference range typically 5–25 µg/dL; if borderline, consider cosyntropin stimulation test
Serum potassium	4.0–4.5 mEq/L	Establishes baseline given the mild hyperkalemia signal observed with clascoterone	Conventional reference 3.5–5.0 mEq/L; critical if >5.5 mEq/L; repeat if result is abnormal
Comprehensive metabolic panel (CMP)	Within standard reference ranges	Captures kidney function (creatinine, eGFR) and electrolyte baseline relevant to potassium monitoring	CMP is a blood test covering electrolytes, kidney and liver function; eGFR ideally >60 mL/min/1.73 m²; reduced eGFR heightens hyperkalemia concern
Serum DHT (dihydrotestosterone)	30–85 ng/dL (males)	Documents pre-treatment systemic DHT as a reference; clascoterone should not meaningfully change this	Optional; useful for comparison if oral antiandrogens are later added; conventional lab-specific ranges vary
Total and free testosterone	Total 500–900 ng/dL; free 10–25 pg/mL (males)	Documents baseline systemic androgen status; should remain stable on topical clascoterone	AM fasting draw preferred; conventional ranges vary by age and lab

Ongoing Labs

Biomarker	Optimal Functional Range	Why Measure It?	Context/Notes
Serum potassium	4.0–4.5 mEq/L	Monitors for cumulative hyperkalemia, especially with interacting medications	Check at ~3 months, then every 6–12 months; more frequently for patients on ACE inhibitors, ARBs, potassium-sparing diuretics, or potassium supplements
Morning serum cortisol	10–20 µg/dL	Monitors for subclinical HPA axis suppression	Every 6–12 months or sooner if symptoms of adrenal insufficiency appear; cosyntropin stimulation test if cortisol <10 µg/dL
Clinical skin assessment (qualitative entry)	No signs of contact dermatitis or persistent irritation	Detects emerging contact sensitization or chronic local reaction	At each follow-up; prompt reduction or pause of application if persistent reaction

Qualitative Markers

Global hair photographs: Standardized global and macro photographs at baseline, 3, 6, and 12 months allow objective visual tracking of density and coverage changes.
Hair pull test and shedding self-report: A transient uptick in shedding in the first 4–8 weeks can occur as follicles shift cycles; persistent heavy shedding warrants reassessment.
Scalp comfort and irritation: Track irritation, itching, flaking, or redness to distinguish treatment-related local reactions from underlying dermatological conditions.
Patient-reported satisfaction: Periodic self-assessment of hair thickness, coverage, and overall satisfaction, ideally via a standardized instrument at each follow-up.

Emerging Research

Several ongoing and planned studies will shape how clascoterone is used for hair growth. These include trials that could strengthen the case (long-term efficacy/safety, female AGA, combination therapy) as well as analyses that could weaken it (peer-reviewed publication of SCALP data, long-term durability, real-world evidence).

SCALP-1 (NCT05910450): A phase 3, multicenter, randomized, double-blind, vehicle-controlled study of clascoterone 5% solution in 703 men with androgenetic alopecia; primary endpoint is change from baseline in non-vellus Target Area Hair Count (TAHC) and a co-primary hair-coverage patient-reported outcome at month 6. 6-month double-blind phase complete; 6-month single-blind extension anticipated to complete in 2026.
SCALP-2 (NCT05914805): A phase 3 study (762 enrolled) with a design paralleling SCALP-1, same TAHC and patient-reported co-primary endpoints at 6 months, supporting the registrational package.
Phase 2 dose-ranging study (NCT02279823): Completed 26-week phase 2 trial in 95 men with AGA comparing clascoterone 5% solution versus minoxidil 5% versus vehicle; primary endpoint was change in TAHC at 6 months, providing the proof-of-concept and dose rationale for SCALP.
Ex vivo balding scalp study: A 2025 report in the Journal of Investigative Dermatology examined clascoterone’s effects on balding scalp samples ex vivo, showing promotion of dermal papilla inductivity and reduction in IL-6 secretion — mechanistic support for the clinical hair count findings (article).
Female pattern hair loss studies: Formal phase 2/3 studies of clascoterone in women with androgenetic alopecia have not been reported; this is a logical next step given the topical, non-systemic mechanism.
Combination therapy trials: Head-to-head and combination studies with minoxidil and/or oral finasteride are anticipated but not yet published; their results could strengthen or temper the case for multi-agent regimens.
Long-term durability: Post-approval studies or registry analyses beyond 12 months will be needed to characterize persistence of benefit and late-emerging safety signals.
Peer-reviewed SCALP publications: Full publication of the SCALP-1 and SCALP-2 datasets will be critical; topline sponsor statements are promising but have not yet been subjected to open scientific scrutiny.

Conclusion

Clascoterone is emerging as the first topical androgen receptor antagonist to reach late-stage development for pattern hair loss, offering a mechanism that addresses the hormonal driver of androgenetic alopecia directly at the follicle while leaving circulating hormone levels largely untouched. Phase 3 topline results in men report statistically meaningful hair count improvements with a safety profile similar to vehicle over six months, and the related acne formulation has several years of real-world use supporting its local tolerability. These attributes make the intervention a credible candidate for those tracking emerging options for pattern hair loss.

The evidence base has important limits. The phase 3 trials were sponsored by the commercial developer Cosmo/Cassiopea, and current claims rest largely on sponsor-announced topline results that have not yet undergone independent peer review — a structural financial conflict that merits weighing in the interpretation. Longer-term durability, data in women, and combination use with existing therapies have not been characterized in published controlled trials. Noted safety signals — mild subclinical adrenal axis effects and small shifts in potassium — appear uncommon but warrant baseline and periodic monitoring, particularly in those with relevant co-medications or conditions. Because the 5% solution for hair loss is not yet approved, current access depends on off-label or compounded routes with variable quality assurance.

For health- and longevity-oriented adults tracking treatment options, clascoterone represents a mechanistically distinct and evidence-supported candidate whose full profile remains evolving as regulatory submissions and longer-term data mature.

Top - Benefits - Risks - Protocol

Clascoterone for Hair Regrowth

Motivation

Recommended Reading

Grokipedia

Examine

ConsumerLab

Systematic Reviews

Mechanism of Action

Historical Context & Evolution

Expected Benefits

Medium 🟩 🟩

Increased Hair Count Versus Placebo

Local Safety Profile Comparable to Vehicle

Preservation of Systemic Androgen Status

Patient-Reported Improvement in Hair Appearance

Low 🟩

Reduction in Local Follicular Inflammation

Potential for Additive Use with Other Hair Loss Treatments ⚠️ Conflicted

Speculative 🟨

Benefit in Female Pattern Hair Loss

Benefit-Modifying Factors

Potential Risks & Side Effects

High 🟥 🟥 🟥

Local Skin Reactions at Application Site

Low 🟥

HPA Axis Suppression (Subclinical)

Mild Hyperkalemia (Elevated Potassium)

Speculative 🟨

Unknown Long-Term Safety Beyond One Year

Contact Sensitization

Risk-Modifying Factors

Key Interactions & Contraindications

Risk Mitigation Strategies

Therapeutic Protocol

Discontinuation & Cycling

Sourcing and Quality

Practical Considerations

Interaction with Foundational Habits

Monitoring Protocol & Defining Success

Baseline Labs

Ongoing Labs

Qualitative Markers

Emerging Research

Conclusion