Supplements for Hair Growth & Thickness

A potassium-channel-opening vasodilator — originally an oral antihypertensive — whose well-documented hypertrichosis side effect made it the first FDA-approved hair-loss drug. Topical 2–5% (Rogaine) is OTC and proven in androgenetic alopecia; low-dose ORAL minoxidil (LDOM, ~0.25–5 mg) is an off-label, rapidly adopted alternative with real but generally mild cardiovascular/hypertrichosis side effects. A drug, not a supplement — and not a longevity compound.

Caffeine applied to the scalp or skin — popular in anti-hair-loss shampoos, eye creams, and cellulite products. The honest framing: the hair use has the most behind it. In lab studies caffeine counteracts testosterone-induced suppression of hair follicles and prolongs the growth (anagen) phase, and a 6-month trial found a 0.2% caffeine solution non-inferior to 5% minoxidil for male pattern hair loss. But the human evidence is thin and conflicted — the lead trial was open-label and industry-linked, the women's trial used a multi-ingredient 'phyto-caffeine' shampoo (not caffeine alone), and there's no large independent RCT. For cellulite it's weakest: the best systematic review of cellulite treatments doesn't flag topical therapy as effective at all. Mechanistically plausible and well-tolerated, but standalone cosmetic evidence is modest.

A plant essential oil applied (diluted) to the scalp for hair growth — a topical cosmetic, NOT ingested. Rosemary oil became popular as a 'natural minoxidil' after a single 6-month randomized trial (100 people) found it matched 2% minoxidil for hair-count gain in androgenetic alopecia, with less scalp itching. The honest framing: that one open-design trial carries almost the entire human case. A plausible mechanism exists (rosemary inhibits the DHT-making enzyme 5-alpha-reductase in lab/animal studies), but the often-cited 'aromatherapy' hair trial used a four-oil mixture (not rosemary alone) for a different condition, and a 2023 systematic review rated essential-oil hair evidence sparse and low-quality. As an essential oil it must be diluted to avoid scalp irritation. This is a cosmetic appearance use, not a proven medical treatment.

An imidazole antifungal best known as a topical shampoo (Nizoral, 1% OTC / 2% Rx). Topically it is well-evidenced for seborrheic dermatitis and dandruff by suppressing scalp Malassezia, and is used off-label in androgenetic alopecia, where it shows modest anti-inflammatory and anti-DHT scalp effects. ORAL ketoconazole is a different story: the FDA and EMA severely restricted it in 2013 after reports of fatal liver injury and adrenal suppression, so systemic use is now rare. Prescription drug, not a supplement — informational only.

A buzzy 'regenerative' skincare ingredient — nanoscale vesicles (usually from stem cells, platelets, or plants) applied to skin, almost always with microneedling or laser, for anti-aging and hair. The honest framing: this is early, low-confidence, and largely unregulated. The few human studies are small (n=25-30), short, mostly from overlapping industry-linked groups, and every one delivers exosomes alongside a procedure (microneedling/CO2 laser) that itself improves skin and hair — so the exosomes' own contribution can't be isolated. The mechanism (microRNA/protein cargo nudging fibroblasts to make collagen) is plausible but mostly shown in cells/animals. A major complications review specifically flags exosomes as an unregulated, escalating-risk aesthetic therapy, and products are unstandardized. Treat all claims as preliminary.

A grey-market 'research chemical' sold online to hair-loss communities as a topical finasteride alternative — RU58841 (PSK-3841 / HMR-3841) is a non-steroidal androgen-receptor antagonist developed in the late 1980s–90s (Roussel-Uclaf) as a TOPICAL treatment for androgenetic alopecia and acne, designed to block DHT at the hair follicle locally without the systemic anti-androgen effects of oral drugs. The CRITICAL fact is the ABSENCE of evidence in people: development was abandoned, RU58841 was NEVER approved, and there are essentially NO published human clinical trials of it. The entire evidence base is PRECLINICAL — rodent and stumptail-macaque models, an ex-vivo study of human balding-scalp grafts maintained on nude mice, and in-vitro androgen-receptor pharmacology — showing local hair regrowth and AR blockade in animals/tissue, not proven benefit or safety in humans. It is sold as a powder or topical solution of unverified identity, purity and concentration, used off-label to avoid the systemic DHT suppression of finasteride. The honest harms are mostly UNKNOWNS: no human safety data, uncharacterised systemic absorption and endocrine effects with chronic use, grey-market identity/purity risk, and scalp irritation. It is NOT an approved medicine and NOT a dietary supplement. Informational, harm-reduction entry only — the responsible takeaway is that RU58841's benefit and safety in humans are unproven.

A dual 5α-reductase (type I + II) inhibitor approved for benign prostatic hyperplasia and used off-label for male pattern hair loss. It suppresses DHT more deeply than finasteride (which blocks only type II), and head-to-head it beats finasteride for hair regrowth. It carries the same sexual and mood side-effect concerns as finasteride — with a much longer half-life, so any persistent effects clear more slowly. A prescription drug, not a supplement, and not a longevity drug.

A prescription 5α-reductase type-II inhibitor that lowers DHT to treat male pattern hair loss (1 mg, Propecia) and benign prostatic hyperplasia (5 mg, Proscar). The hair and prostate benefits are well-proven in large RCTs. The honest caveats are real and prominent: sexual side effects (erectile dysfunction, decreased libido) in a minority of men, a disputed but important 'post-finasteride syndrome' with persistent symptoms, and a depression/suicidality safety signal in pharmacovigilance data. It is NOT a longevity drug.