Hair loss, honestly — what actually regrows hair

Hair loss is a huge market built on a small amount of real medicine. The honest headline: for common pattern hair loss, minoxidil and finasteride are the two treatments that genuinely work, they must be used continuously, they have real side effects worth understanding, and almost everything else — biotin gummies, "thickening" shampoos, most supplements — does little unless you have a specific deficiency. Some sudden or patchy hair loss is a different problem that needs a doctor.

First, what kind of hair loss is it?

Most hair loss is androgenetic alopecia — "male-pattern" or "female-pattern" — a gradual, genetically driven thinning (receding hairline and crown in men, widening part in women) caused by hair follicles shrinking under the influence of hormones. This is the type the well-known treatments target.

But not all hair loss is this. Sudden shedding weeks after illness, stress, childbirth or crash dieting (telogen effluvium) usually recovers on its own. Patchy, round bald spots (alopecia areata) are autoimmune. Loss with scarring, redness or itch can be a scarring alopecia that needs urgent treatment to prevent permanent loss. And thyroid disease or low iron can cause thinning. Getting the type right decides everything.

What actually works

For pattern hair loss — the evidence-backed options.

• Minoxidil regrows hair — Topical minoxidil (the "5%" solution/foam) is proven to slow loss and partially regrow hair in both men and women, by prolonging the growth phase of follicles. Low-dose oral minoxidil is an increasingly used alternative. It works while you use it — stop, and the benefit fades over months. (established)
• Finasteride works in men — by blocking the hormone — Finasteride blocks the enzyme that makes DHT, the hormone that shrinks follicles. In men it stops progression in most and regrows hair in many, with the best results on the crown. Combining it with minoxidil works better than either alone. (It is not used this way in most women and is unsafe in pregnancy.) (established)
• A few procedures have emerging evidence — Low-level laser therapy, microneedling (often alongside minoxidil) and platelet-rich plasma (PRP) injections show promise in studies of variable quality. Hair transplantation is a genuine surgical option for suitable candidates. These are real but pricier and less certain than the two mainstays. (emerging)

The side effects to understand

• Finasteride and sexual side effects — A minority of men report reduced libido or erectile problems on finasteride; these usually resolve on stopping. A small number describe persistent symptoms after stopping ("post-finasteride syndrome") — genuinely debated, not fully established, but worth knowing before starting. A mood/depression signal has also been raised. Discuss honestly with a doctor. (note)
• Minoxidil quirks — Topical minoxidil can irritate the scalp; an early "shedding" phase in the first weeks is normal as follicles reset. Applied to the face it can grow unwanted hair; oral minoxidil can cause fluid retention or unwanted body-hair growth and needs medical supervision. (note)
• You have to keep using them — Both treatments maintain and regrow hair only while continued. Stop, and the hair you gained is typically lost within months — an honest, ongoing commitment, not a one-off cure. (note)

What’s oversold

• Biotin does nothing unless you’re deficient — Biotin ("hair, skin and nails") supplements only help hair if you have a genuine biotin deficiency, which is rare. In everyone else they do nothing for hair — and biotin can distort some lab tests (including thyroid and heart tests). The gummy market is built on a deficiency most people don’t have. (hype)
• "Thickening" shampoos and most supplements — Shampoos can coat hair to look fuller temporarily but don’t treat the follicle. Most "hair growth" supplement blends lack good evidence; the exception is correcting a real deficiency (notably low iron/ferritin) found on testing. (hype)
• Ketoconazole shampoo — a minor helper at best — Anti-dandruff ketoconazole shampoo has weak evidence as an add-on for pattern hair loss (possibly via reducing scalp inflammation). Harmless as an adjunct, not a stand-alone fix. (note)

What we still don’t know

• How real and how common persistent finasteride effects are Post-finasteride syndrome is reported by some men but hard to study and separate from other causes; its true frequency and mechanism remain genuinely unresolved.
• How well PRP, lasers and microneedling really work Trials are small and methods vary; they look promising but the size and durability of benefit — and who responds — aren’t nailed down.

The practical takeaways

For gradual pattern thinning, the evidence-based path is minoxidil (topical or low-dose oral) and, for men, finasteride — ideally discussed with a doctor who can weigh the side effects. Combining them works better than either alone. Don’t waste money on biotin gummies or "thickening" miracle products, and get iron/ferritin and thyroid checked if thinning is diffuse.

See a doctor promptly for hair loss that is sudden, patchy, or comes with scalp redness, scaling, pain or scarring, or with other symptoms (fatigue, weight change) — these point to autoimmune, scarring or medical causes where early treatment protects the hair you still have.

Key terms

• Androgenetic alopecia Common pattern hair loss (male- or female-pattern); gradual follicle shrinking driven by genes and hormones.
• DHT (dihydrotestosterone) The hormone that shrinks susceptible scalp follicles in pattern hair loss; finasteride lowers it.
• Minoxidil A proven topical (or low-dose oral) treatment that prolongs the hair growth phase; works only while used.
• Finasteride A pill that blocks DHT, effective for male pattern loss; has debated sexual side effects and is unsafe in pregnancy.
• Telogen effluvium Temporary diffuse shedding after stress, illness, childbirth or dieting; usually recovers on its own.
• Alopecia areata Autoimmune hair loss causing round patches; a different condition needing a doctor.