Hair · Since the '90s

The science of keeping and regrowing hair.

Three decades of patient experience, condensed into what the evidence supports.

The biology

Why hair is lost.

Androgenetic alopecia

The most common cause in men and women. Genetically sensitive follicles shrink (miniaturize) over years in response to DHT, producing the Norwood pattern in men and diffuse Ludwig thinning in women.

DHT

Dihydrotestosterone is made from testosterone by the 5-alpha reductase enzyme. It binds receptors in scalp follicles and shortens their growth phase. Blocking its production is the backbone of medical treatment.

Telogen effluvium

Sudden diffuse shedding 2–3 months after a stressor — illness, surgery, crash dieting, childbirth, low ferritin. Usually reversible once the trigger resolves.

The treatment ladder

From first line to surgical.

Most people climb a few rungs, combined. Evidence grade reflects human data for androgenetic alopecia.

  1. 01

    Ketoconazole shampoo

    Anti-fungal, mild anti-androgen effect on the scalp. Adjunct, not a standalone.

    GRADE C
  2. 02

    Topical minoxidil

    FDA-approved for men and women. Extends the growth phase; needs daily consistency.

    GRADE A
  3. 03

    Finasteride / dutasteride

    Lowers DHT. Finasteride is FDA-approved for men; dutasteride is a stronger off-label option. Discuss sexual and mood side effects.

    GRADE A
  4. 04

    Oral minoxidil (low dose)

    Increasingly prescribed by dermatologists; watch for body hair growth and fluid retention.

    GRADE B
  5. 05

    Tretinoin + minoxidil

    Tretinoin may boost minoxidil response in low responders.

    GRADE C
  6. 06

    Low-level laser (LLLT)

    FDA-cleared devices show modest density gains in trials.

    GRADE B
  7. 07

    PRP

    Platelet-rich plasma injections; protocols vary widely, results mixed.

    GRADE C
  8. 08

    Peptides (GHK-Cu)

    Copper peptide topicals; supportive data is limited.

    GRADE C
  9. 09

    Hair transplant

    FUE/FUT relocates DHT-resistant follicles. Medical therapy still needed to protect native hair.

    GRADE A
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Regrowth.com Archive

Since the '90s.

Before forums and social media, Regrowth.com was a newsgroup where patients, physicians, dermatologists and trichologists traded real-world results. It grew past 50,000 members and became one of the first places online to separate working treatments from snake oil.

That archive of lived experience still shapes how we grade evidence today. Read Scott's 30-year perspective →

Not medical advice — talk to a licensed clinician. Content is educational, reflects published literature, and is not a recommendation to start, stop or change any treatment.