A skin-applied hormone blocker that occupies the docking sites male-type hormones use inside hair follicles, then breaks down into an inactive form in the bloodstream. Late-stage trials in men reported hair gains that built over a year and faded once treatment stopped, but were never published in full. No regulator has approved it for hair loss. (Full Review)

Protocol

Dose

1.5 mL of 5% solution

Applied with a dropper directly to the balding areas of the vertex and temples, parted through the hair onto the scalp surface

Frequency

Twice daily, continuously

Morning and evening at roughly twelve-hour intervals; split dosing is mandatory, not optional

Baseline biomarkers

Corrected before starting

Ferritin, thyroid-stimulating hormone and 25-hydroxyvitamin D; an uncorrected deficiency blunts the visible result and can be misread as non-response

Time to effect

Scalp hair count

6 months

Co-primary endpoints assessed here; the earliest reasonable decision point, with standardized photography

Continued accrual of hair

12 months

Hair kept accruing through month 12 in those who stayed on treatment; the fairer assessment point

First measurable change

3 months

Objective hair-count changes measurable; cosmetically visible change generally lags measurable change

Benefits

High: Reduction of androgen-driven sebum production and acne lesions; local androgen blockade without systemic hormonal disruption

Medium: Increased scalp hair count in men with mild-to-moderate pattern hair loss; continued accrual of hair with uninterrupted use through twelve months; improvement in self-rated hair coverage and treatment satisfaction

Low: Increased hair shaft width and partial reversal of follicle miniaturization; hair count improvement in younger women with female pattern hair loss

Speculative: Additive effect in combination with topical minoxidil; benefit in other androgen-driven skin and hair conditions

Contraindications

Pregnancy and breastfeeding

Women of childbearing potential not using effective contraception

Documented adrenal insufficiency or current systemic corticosteroid therapy

Chronic kidney disease at stage 3b or worse (estimated glomerular filtration rate below 45 mL/min/1.73 m²), or baseline serum potassium above 5.0 mEq/L

Active uncontrolled scalp disease (seborrhoeic dermatitis, scalp psoriasis, folliculitis, fungal infection, scalp atrophy)

Non-androgenetic hair loss (alopecia areata, scarring alopecias, telogen effluvium, trichotillomania)

Adolescents under 18 for the hair indication

Key Interactions

Potassium-raising prescription medications (ACE inhibitors, angiotensin receptor blockers, potassium-sparing diuretics, direct renin inhibitors)

Regular non-steroidal anti-inflammatory drugs (ibuprofen, naproxen, diclofenac)

Potassium supplements and potassium-based salt substitutes

Antiandrogenic supplements (saw palmetto, pygeum, stinging nettle root, reishi, pumpkin seed oil)

Licorice root

Over-the-counter topical minoxidil

Oral or topical finasteride and dutasteride

Microneedling (within 24 hours of application)

Topical scalp corticosteroids, calcineurin inhibitors and retinoids

Risk & Side Effects

High: Local skin reactions at the application site

Medium: Reversible suppression of the cortisol stress axis; elevated blood potassium

Low: Post-marketing signals for abnormal hair growth and skin striae; contact sensitization and allergic reaction

Speculative: Higher daily drug load from the 5% scalp solution; theoretical risk of feminizing effects on a male fetus; unknown consequences of multi-year androgen receptor blockade in scalp skin

Monitoring

Marker	Target	Why
Serum potassium	4.0–4.5 mEq/L	Detects the mineralocorticoid-mediated potassium rise seen in clinical trials
Morning serum cortisol	12–18 µg/dL	Screens the hypothalamic-pituitary-adrenal axis for the suppression noted in the approved labelling
Ferritin	70–100 ng/mL	Iron storage protein; low reserves cause diffuse shedding and cap the response to any hair treatment
Thyroid-stimulating hormone	0.5–2.0 mIU/L	Thyroid dysfunction produces diffuse hair loss that mimics or compounds pattern loss
25-hydroxyvitamin D	40–60 ng/mL	The vitamin D receptor is required for normal hair-follicle cycling
Comprehensive metabolic panel	Within conventional limits, with estimated glomerular filtration rate above 60 mL/min/1.73 m²	Kidney function determines how much capacity exists to excrete a potassium load
Total testosterone	500–900 ng/dL (men)	Establishes a systemic hormonal reference point and confirms that topical use has not altered circulating androgens

Cadence: Serum potassium and a symptom review at 4 weeks after reaching the full twice-daily regimen; standardized photography and a scalp examination at 3 months; potassium, morning cortisol and photography at 6 months; thereafter potassium and photography every 6 to 12 months for as long as treatment continues, with an additional potassium check within 4 weeks of starting any potassium-raising medication.

Qualitative Assessment

Daily shedding volume — hairs collected from pillow, shower drain and comb, counted on a fixed weekday
Scalp comfort — itching, burning, flaking or tightness
Hair texture and styling behaviour — whether hair holds volume, feels thicker between the fingers, or requires less styling to achieve coverage
Density at the part line and temples — the two areas where change becomes visible earliest in male pattern loss
Energy, morning alertness and blood-pressure symptoms on standing — the practical symptoms that would accompany meaningful cortisol-axis suppression
Confidence and appearance-related mood — the outcome that motivated treatment in the first place

Clascoterone for Hair Regrowth

Protocol

Benefits

Risk & Side Effects

Monitoring

Qualitative Assessment