What is androgenetic alopecia, and what causes it?
Androgenetic alopecia (AGA) — commonly called male-pattern or female-pattern hair loss — is the most prevalent cause of hair thinning and loss, affecting approximately 50% of men by age 50 and up to 40% of women at some point in their lives. It is driven by the action of dihydrotestosterone (DHT) on genetically susceptible hair follicles.
In susceptible follicles, DHT binds to androgen receptors and progressively shortens the anagen (growth) phase and extends the telogen (resting) phase. Over successive hair cycles, the follicle miniaturizes — producing progressively thinner, shorter, lighter hairs until terminal hair production ceases. This process is gradual and, in its early stages, reversible with appropriate treatment.
The earlier treatment begins, the more follicular function there is to preserve. Waiting until hair loss is advanced means fewer viable follicles to work with. This is why clinicians typically recommend starting evidence-based treatment at the first signs of patterned thinning, not after significant loss has occurred.
What does finasteride do for hair loss?
Finasteride 1 mg daily is FDA-approved for androgenetic alopecia in men and is among the most consistently recommended hair loss treatments in clinical guidelines. It works by inhibiting 5-alpha reductase type II, the enzyme responsible for converting testosterone to DHT in scalp tissue and prostate. At the standard 1 mg dose, it reduces scalp DHT by approximately 60 to 70%.
Clinical trials consistently demonstrate that finasteride stabilizes hair loss in the majority of men who take it and produces measurable regrowth in a meaningful proportion — particularly at the crown and mid-scalp. The frontal hairline responds less reliably. Benefits are maintained only while the medication is continued; stopping finasteride typically reverses gains within 6 to 12 months.
Side effects and the post-finasteride syndrome question
Finasteride is generally well-tolerated. The most discussed side effects are sexual — reduced libido, erectile dysfunction, and ejaculatory changes — reported in a minority of trial participants and typically resolving after discontinuation. A smaller subset of men report persistent sexual or cognitive symptoms after stopping finasteride, a cluster sometimes called “post-finasteride syndrome.” The mechanistic basis and true prevalence of this syndrome are contested in the literature, but it is a legitimate consideration that a prescribing clinician should discuss before starting therapy.
Finasteride lowers PSA levels by approximately 50% — relevant for any patient who is also being monitored for prostate health.
The evidence consistently favors finasteride and minoxidil together, because each addresses a different driver of pattern hair loss.
How does minoxidil work on the growth cycle?
Minoxidil was originally developed as an oral antihypertensive. Its hair-growth effects were discovered as a side effect and subsequently developed into a topical treatment. It is FDA-approved in 2% concentration for women and 5% for men, and is available OTC — though low-dose oral minoxidil (typically 0.625 mg to 2.5 mg daily) has emerged as a clinician-prescribed option with a growing evidence base and systemic rather than purely local delivery.
Minoxidil extends the anagen phase of the hair growth cycle and improves blood flow and nutrient delivery to follicles. It does not address the DHT mechanism — it works alongside the follicle rather than by altering the hormonal environment. This is why the evidence for combination therapy (finasteride plus minoxidil) is stronger than either alone: they address complementary mechanisms.
How do finasteride and minoxidil compare?
A 2015 randomized controlled trial published in Dermatology and Therapycompared finasteride alone, minoxidil alone, and the combination. The combination arm produced significantly greater improvements in hair count, hair shaft diameter, and patient-reported satisfaction than either monotherapy. This finding aligns with the clinical logic: finasteride addresses the hormonal cause; minoxidil addresses the growth cycle. Used together, they reinforce each other.
Combination therapy is now the approach most commonly recommended by dermatologists for men with AGA who are appropriate candidates for both agents.
| Feature | Finasteride | Minoxidil |
|---|---|---|
| Mechanism | Reduces DHT via 5-alpha reductase inhibition | Extends anagen phase; improves follicular blood flow |
| FDA-approved use | Men (androgenetic alopecia, 1 mg daily) | Men (5% topical) and women (2% topical) |
| Route | Oral daily tablet | Topical solution/foam or low-dose oral (off-label) |
| Primary target area | Crown and mid-scalp (frontal responds less) | Vertex and diffuse thinning |
| Key consideration | Potential sexual side effects; lowers PSA ~50% | Must continue use; does not address DHT driver |
What does a telehealth hair loss evaluation look like?
Clinician-supervised hair loss treatment via telehealth follows the same clinical logic as an in-person visit for this indication. A clinician reviews:
- Pattern of hair loss: Is this consistent with androgenetic alopecia, or does the pattern suggest another cause (alopecia areata, telogen effluvium, traction alopecia)?
- Medical history and medications: Several medications and conditions cause or worsen hair loss and must be ruled out before prescribing.
- Contraindications: Finasteride is contraindicated in women who are pregnant or may become pregnant. Sexual health history is reviewed for men given the potential side effect profile.
- Labs (when indicated): Thyroid dysfunction, iron deficiency, and hormonal imbalances are common and treatable causes of diffuse hair loss. If the pattern is not straightforwardly AGA, a lab panel helps exclude these.
This evaluation can be completed entirely online in a short intake session. Medications are prescribed electronically and dispensed through licensed pharmacies.
What does not work for hair loss? Separating evidence from marketing
The hair loss supplement market is large and largely unsupported by clinical evidence. Biotin supplementation improves hair in patients with biotin deficiency — but biotin deficiency is rare, and most adults who take biotin supplements are not deficient. Caffeine shampoos, collagen supplements, and DHT-blocking shampoos lack the randomized trial evidence base that finasteride and minoxidil have. They are not harmful, but they should not be expected to meaningfully arrest androgenetic alopecia.
Platelet-rich plasma (PRP) injection is an emerging option with growing evidence, but it requires in-office procedures and is not a substitute for medical therapy.
Hair transplant surgery is a definitive option for patients who want to restore coverage in areas of complete loss, but it does not stop ongoing hair loss in remaining follicles — medical therapy is still needed alongside surgical restoration.
Frequently asked questions
What is the most recommended hair loss treatment for men?
Finasteride and minoxidil are the two FDA-approved medications most consistently recommended by clinicians for androgenetic alopecia (male-pattern hair loss). Finasteride targets the hormonal driver of follicle miniaturization; minoxidil supports blood flow and the follicular growth cycle. Most evidence supports the combination as more effective than either alone.
How does finasteride work for hair loss?
Finasteride inhibits 5-alpha reductase type II, the enzyme that converts testosterone to dihydrotestosterone (DHT). DHT is the androgen primarily responsible for follicle miniaturization in androgenetic alopecia. By reducing scalp DHT levels by approximately 60 to 70 percent, finasteride slows and often stops further hair loss, and allows some regrowth in responsive follicles.
How does minoxidil work for hair loss?
Minoxidil is a vasodilator that, when applied topically or taken orally at low dose, extends the anagen (growth) phase of the hair cycle and shortens the telogen (resting/shedding) phase. It increases blood flow and nutrient delivery to hair follicles. It does not address the DHT-driven hormonal mechanism — which is why it is often used in combination with finasteride.
Can women use finasteride for hair loss?
Finasteride is FDA-approved only for men. It is contraindicated in women who are pregnant or may become pregnant due to the risk of fetal harm (specifically, feminization of a male fetus). Some clinicians prescribe it off-label in postmenopausal women, but this requires individual evaluation. Minoxidil is FDA-approved for women at 2% concentration.
How long does it take to see results from hair loss treatment?
Most patients should not expect visible results in the first 3 months. Hair cycles operate on timescales of months. At 6 months, many patients see stabilization of shedding; at 12 months, regrowth may become apparent in responsive follicles. Patience and consistency are required — stopping treatment typically reverses gains.
Can I get hair loss treatment online without an in-person visit?
Yes. Clinician-supervised hair loss treatment is available via telehealth in most US states. A clinician reviews your intake, health history, and any contraindications before prescribing. For finasteride, this typically includes a brief medical history review. Labs may be recommended if there is any concern about hormonal or thyroid causes of hair loss.