Hair Loss & DHT

Androgenetic alopecia (AGA) is the most common form of hair loss, affecting roughly 50% of men by age 50. It is driven by a combination of genetic predisposition and androgen (hormone) activity — specifically DHT (dihydrotestosterone).

AGA follows a predictable pattern: hair follicles in genetically susceptible areas (temples, crown) miniaturize over time — each hair cycle producing a finer, shorter hair until eventually the follicle stops producing hair altogether.

The follicle doesn't die — it miniaturizes. This is why early intervention is so important.

DHT (dihydrotestosterone) is a potent androgen derived from testosterone via the enzyme 5-alpha reductase (5-AR). It is roughly 3–5x more potent than testosterone in binding to androgen receptors.

In hair follicles genetically sensitive to DHT, binding of DHT to the androgen receptor:

Paradox: DHT promotes hair loss on the scalp, but promotes body and facial hair growth. This is due to follicle-specific androgen receptor expression and sensitivity.

Finasteride is a Type II 5-alpha reductase inhibitor. It blocks the conversion of testosterone → DHT, reducing serum DHT by ~65–70% and scalp DHT by ~70%.

FDA approved: 1 mg/day (Propecia) for male pattern hair loss since 1997.

Efficacy:

Side effects (5–8% reported):

Key point: Stop taking it and DHT rebounds — any hair gained is typically lost within 6–12 months.

Minoxidil was originally developed as an oral antihypertensive. Hair growth was discovered as a side effect. Topical formulations (2% and 5%) are now first-line OTC treatments for AGA.

Mechanism (still not fully understood):

Topical (5% foam/liquid):

Oral Minoxidil (0.25–2.5 mg/day):

Finasteride and minoxidil work via different mechanisms and are synergistic:

Evidence-backed stack:

1. Finasteride 1 mg/day oral

2. Minoxidil 5% topical once daily (or oral low-dose 0.25–1mg/day)

3. Dermarolling (microneedling) 1.5mm — improves topical penetration and may stimulate growth factors independently

4. Ketoconazole shampoo 2% — mild anti-androgen effect at scalp level

Start early. Hair loss is easier to halt than reverse. Once follicles are gone, you need hair transplant.