DHT blockers for hair loss: what actually blocks DHT, how good the evidence is, and what people reported

DHT (dihydrotestosterone) is the hormone behind male pattern hair loss. “DHT blocker” is used for anything from prescription drugs to pumpkin seed oil and shampoos. This page sorts them by what they actually do, puts each next to the size of its evidence and the side effects on its official label, and adds what was said in 3,231 reddit threads (2012–2026) about DHT and natural blockers, including 2,099 people who described their own use.

In short: two drugs actually lower DHT: finasteride (approved for male hair loss, tested in trials with over 1,500 men) and dutasteride (approved in the US for the prostate; it lowers DHT further and grew more hair than finasteride in a 24-week trial run with its maker). Topical finasteride lowers it too, with less in the blood. Spironolactone, RU58841 and clascoterone don’t lower DHT; they block the receptor it acts on, and RU58841 has never been tested in a published human trial. The “natural” ones (saw palmetto, pumpkin seed oil, rosemary, green tea) rest on one or a few small studies each, often funded by the seller or without a placebo, and none showed it lowered DHT in the scalp. On reddit, when people asked about natural blockers, commenters most often said they don’t work (51% of 943 threads with a verdict); of 352 people who described taking saw palmetto, 74 said it helped their hair.

What DHT is, and why it matters for hair loss

Testosterone is turned into DHT by an enzyme, 5-alpha-reductase, which comes in two types. In men who are genetically prone to it, DHT shrinks the hair follicles on the top of the head until they grow only thin, short hairs (miniaturisation); the sides and back are usually spared. The strongest evidence that DHT is the driver: men born without the type 2 enzyme, who make little DHT, have not been reported to go bald. Blood DHT levels on their own don’t predict balding; it depends on how sensitive the follicles are, which is why commenters on reddit so often told people not to bother testing their DHT (340 threads).

In women, DHT’s role is less clear. Finasteride did not help postmenopausal women with pattern hair loss in a placebo-controlled trial, which led a Merck researcher to call male and female pattern hair loss “distinct clinical entities”. Treatments for women more often block androgens at the receptor (spironolactone) or use minoxidil.

[4] Androgens and alopecia

Kaufman KD (Merck Research Laboratories, the maker of finasteride) · Molecular and Cellular Endocrinology, 2002 · A review by a Merck researcher. Abstract quoted.

Scalp hair grows without androgens; body hair needs them. “Scalp hair grows constitutively in the absence of androgens, while body hair growth is dependent on the action of androgens.”
Men who make little DHT (eunuchs, men born with 5-alpha-reductase deficiency) point to DHT as the key hormone in male pattern hair loss. “Observations in both eunuchs, who have low levels of testicular androgens, and males with genetic 5alpha-reductase (5alphaR) deficiency, who have low levels of dihydrotestosterone (DHT), implicate DHT as a key androgen in the pathogenesis of MPHL in men.”
In postmenopausal women, finasteride didn't help; the author concludes male and female pattern hair loss work differently. “These findings suggest that MPHL and FPHL are distinct clinical entities, with disparate pathophysiologies.”

[5] Androgens and male physiology: the syndrome of 5alpha-reductase-2 deficiency

Imperato-McGinley J, Zhu YS (Weill Cornell) · Molecular and Cellular Endocrinology, 2002 · A review of men born without working type 2 5-alpha-reductase, the enzyme finasteride blocks. Abstract quoted.

DHT is made from testosterone by two enzymes, type 1 and type 2. “Dihydrotestosterone (DHT), a potent androgen, is converted from testosterone by 5alpha-reductase isozymes.”
In men born without the type 2 enzyme, balding has not been reported. “The prostate in adulthood is small and rudimentary, and facial and body hair is absent or decreased. Balding has not been reported.”

The DHT blockers, side by side

“How it works” is what the label or the studies say; “evidence” is the biggest study we found on hair. The last column counts people on reddit who described their own use in these threads (each person once per blocker), and how many of them said it helped their hair.

Blocker	How it works	Evidence for hair [source]	Status	Reddit: people · said it helped
Finasteride (pill)	Lowers DHT: blocks the type 2 enzyme	Large placebo-controlled trials: 1,553 men over 2 years [1, 7]	Approved for male hair loss (1 mg)	1,048 · 236
Dutasteride (pill)	Lowers DHT: blocks both enzymes	A 917-man trial against finasteride, 24 weeks [8]	Approved for an enlarged prostate; off-label for hair in the US	306 · 69
Topical finasteride	Lowers DHT, less of it in the blood	One 458-man phase III trial, 24 weeks [9]	Sold in some countries; compounded elsewhere	159 · 45
Spironolactone	Blocks the receptor (and lowers androgens); doesn’t lower DHT	Small studies in women; one with 80 women and no placebo [11]	Off-label; used for women	12 · 5
RU58841	Blocks the receptor on the scalp	Mouse and monkey studies from the 1990s; no published human trial found [12, 13]	Not approved anywhere; sold as a “research chemical”	50 · 18
Clascoterone	Blocks the receptor on the skin	Approved as an acne cream; hair-loss trials of a stronger solution were underway [3, 23]	Not approved for hair loss	2 · 1
Saw palmetto	Said to block the enzyme; not shown in hair studies	100 men without placebo: 38% improved vs 68% on finasteride [14]; small mixed trials [15]	Supplement	352 · 74
Pumpkin seed oil	Said to block the enzyme; DHT not measured	One 76-man trial, funded by the capsule maker [17]	Supplement	83 · 15
Rosemary oil	Unclear; DHT not measured	One 100-person trial against minoxidil 2%, no placebo [18]	Cosmetic oil	257 · 75
Ketoconazole shampoo	An antifungal; anti-androgen effect proposed	Five small human studies, 318 people; no placebo-controlled trial for hair [20]	Approved for dandruff and fungal skin infections	105 · 23
Green tea (EGCG)	Enzyme effect reported in the lab	Lab studies on cells and follicles, not people [19]	Supplement / drink	11 · 3

Reddit numbers are people’s own accounts, often of a whole regimen (finasteride plus minoxidil, for instance), not trial results. Finasteride and dutasteride have far more reports on our results pages, which read every progress post, not only threads with DHT in the title.

The drugs that lower DHT: finasteride and dutasteride

Finasteride 1 mg cuts blood DHT by about two-thirds within a day; dutasteride, which blocks both enzymes, by about 90% within two weeks. Both are tested in placebo-controlled trials in men, mostly run by their makers (Merck for finasteride, GlaxoSmithKline for dutasteride; we flag this on each study). Both labels list sexual side effects (lower libido, erection and ejaculation problems) in a few percent of men, and dutasteride’s adds breast tenderness or enlargement. Neither is for women who are or could become pregnant. For what people reported month by month, see finasteride results and dutasteride results; for how finasteride compares with minoxidil, see minoxidil vs finasteride.

[1] PROPECIA (finasteride) 1 mg tablets: US prescribing information

Organon · DailyMed (US National Library of Medicine), label version 9, Oct 2024, 2024 · The official US label of the original finasteride brand for hair loss. Its trial figures come from the manufacturer's own studies in men aged 18 to 41. Archived as the full label text from the DailyMed XML.

Finasteride blocks one of the two enzymes (type II 5-alpha-reductase) that turn testosterone into DHT. “Finasteride is a competitive and specific inhibitor of Type II 5α-reductase, an intracellular enzyme that converts the androgen testosterone into DHT.”
Within a day, 1 mg cuts the DHT in the blood by about two-thirds. “Finasteride produces a rapid reduction in serum DHT concentration, reaching 65% suppression within 24 hours of oral dosing with a 1-mg tablet.”
Balding scalp holds more DHT than hairy scalp; the label calls DHT a key factor in men who are genetically predisposed. “In men with male pattern hair loss (androgenetic alopecia), the balding scalp contains miniaturized hair follicles and increased amounts of DHT compared with hairy scalp.”
It is approved for men only. “PROPECIA® is indicated for the treatment of male pattern hair loss (androgenetic alopecia) in MEN ONLY.”
It takes three months or more, and the effect goes away within a year of stopping. “In general, daily use for three months or more is necessary before benefit is observed. Continued use is recommended to sustain benefit, which should be re-evaluated periodically. Withdrawal of treatment leads to reversal of effect within 12 months.”
Over 5 years, every man left on placebo lost hair, against about a third of men on finasteride. “At 5 years, 100% of men in the placebo group demonstrated hair loss, compared with 35% of men treated with PROPECIA.”
Sexual side effects in the 1-year trials: 3.8% on finasteride against 2.1% on placebo; they went away in men who stopped and in most who carried on. “Integrated analysis of clinical adverse experiences showed that during treatment with PROPECIA, 36 (3.8%) of 945 men had reported one or more of these adverse experiences as compared to 20 (2.1%) of 934 men treated with placebo (p=0.04). Resolution occurred in men who discontinued therapy with PROPECIA due to these side effects and in most of those who continued therapy.”
Since approval, the label lists reports of sexual problems that continued after stopping, and of depression and suicidal thoughts. Post-marketing reports can't show how often these happen or whether the drug caused them. “Reproductive System: sexual dysfunction that continued after discontinuation of treatment, including erectile dysfunction, libido disorders, ejaculation disorders, and orgasm disorders”
The same section of the label: “Nervous System/Psychiatric: depression, suicidal ideation and behavior.”
In postmenopausal women with pattern hair loss, finasteride did no better than placebo. “In a study involving 137 postmenopausal women with androgenetic alopecia who were treated with PROPECIA (n=67) or placebo (n=70) for 12 months, effectiveness could not be demonstrated.”
It must not be used by women who are or may become pregnant: it can harm a male fetus. “Finasteride use is contraindicated in women when they are or may potentially be pregnant.”

[6] The effects of finasteride on scalp skin and serum androgen levels in men with androgenetic alopecia

Drake L, Hordinsky M, Fiedler V, et al. · Journal of the American Academy of Dermatology, 1999 · 249 men, scalp biopsies before and after 42 days of finasteride at five doses or placebo. Abstract quoted; it lists only the first author's affiliation.

Finasteride 1 mg lowered DHT in the blood by about 71% (and in the scalp skin by about 64%, against 13% on placebo). “Serum DHT levels declined significantly (P <.001) by 49.5%, 68.6%, 71.4%, and 72.2% in the 0.05, 0.2, 1, and 5 mg finasteride treatment groups, respectively.”
In the scalp skin, DHT fell even on placebo: “Scalp skin DHT levels declined significantly by 13.0% with placebo”
Doses from 0.2 mg already gave the full drop. “In this study, doses of finasteride as low as 0.2 mg per day maximally decreased both scalp skin and serum DHT levels.”

[7] Finasteride in the treatment of men with androgenetic alopecia

Kaufman KD (Merck Research Laboratories), Olsen EA, Whiting D, et al. · Journal of the American Academy of Dermatology, 1998 · The two placebo-controlled trials behind finasteride's approval for hair loss: 1,553 men aged 18 to 41, 1 year plus a 1-year extension. Run by the manufacturer (first author at Merck). Abstract quoted.

1,553 men, finasteride 1 mg or placebo. “In two 1-year trials, 1553 men (18 to 41 years of age) with male pattern hair loss received oral finasteride 1 mg/d or placebo, and 1215 men continued in blinded extension studies for a second year.”
On finasteride, hair counts in a 1-inch circle were 107 hairs higher than placebo at 1 year and 138 at 2 years (from about 876 at the start). “Clinically significant increases in hair count (baseline = 876 hairs), measured in a 1-inch diameter circular area (5.1 cm2) of balding vertex scalp, were observed with finasteride treatment (107 and 138 hairs vs placebo at 1 and 2 years, respectively; P < .001).”

[24] Sexual dysfunction associated with 5α-reductase inhibitors in the treatment of androgenetic alopecia: a systematic review

Złotowska, Jastrząb-Miśkiewicz, Krajewski (Wrocław) · Frontiers in Medicine, 2026 · A systematic review of 41 studies of sexual side effects of finasteride and dutasteride in hair-loss patients. Authors declare no conflicts. Abstract quoted.

Oral finasteride 1 mg: sexual side effects in 1.9-6.7% of men in placebo-controlled trials, against 0.9-3.9% on placebo. “Across placebo-controlled RCTs evaluating oral finasteride 1 mg in men with AGA, sexual adverse events were reported in 1.9-6.7% of treated patients compared with 0.9-3.9% in placebo groups, with most events mild and reversible upon discontinuation.”
Topical finasteride: lower rates than the pill. “Topical finasteride 0.25% was associated with lower rates of sexual adverse events (2.8%) compared with oral finasteride (4.8%).”
Dutasteride 0.5 mg: 4.1-12.0%, against 4.0-5.0% on placebo. “For dutasteride 0.5 mg, sexual adverse events ranged from 4.1 to 12.0% across RCTs, compared with 4.0-5.0% in placebo groups.”
The authors: infrequent and mostly reversible, but individual risk varies. “Overall, clinicians should counsel patients that most sexual side effects reported in controlled AGA studies are infrequent, mild, and reversible, but individual susceptibility varies.”

[2] AVODART (dutasteride) 0.5 mg capsules: US prescribing information

Waylis Therapeutics · DailyMed (US National Library of Medicine), label version 4, Mar 2025, 2025 · The official US label. In the US dutasteride is approved only for an enlarged prostate (BPH); for hair it is prescribed off-label. Its side-effect figures come from men with BPH, mean age 66. Archived as the full label text from the DailyMed XML.

Dutasteride blocks both enzymes that make DHT (type 1 and type 2), where finasteride blocks mainly type 2. “AVODART is a synthetic 4-azasteroid compound that is a selective inhibitor of both the type 1 and type 2 isoforms of steroid 5 alpha-reductase, an intracellular enzyme that converts testosterone to DHT.”
It lowers blood DHT by about 90% within two weeks. “After 1 and 2 weeks of daily dosing with dutasteride 0.5 mg, median serum DHT concentrations were reduced by 85% and 90%, respectively.”
Its US approval is for an enlarged prostate, not hair loss. “AVODART is a 5 alpha-reductase inhibitor indicated for the treatment of symptomatic benign prostatic hyperplasia (BPH) in men with an enlarged prostate”
The most common side effects: “The most common adverse reactions, reported in ≥1% of subjects treated with AVODART and more commonly than in subjects treated with placebo, are impotence, decreased libido, ejaculation disorders, and breast disorders.”
It stays in the body for months: a half-life of about 5 weeks. The label also says not to donate blood until 6 months after the last dose. “The terminal elimination half-life of dutasteride is approximately 5 weeks at steady state.”

[8] A randomized, active- and placebo-controlled study of the efficacy and safety of different doses of dutasteride versus placebo and finasteride in the treatment of male subjects with androgenetic alopecia

Gubelin Harcha W, Barboza Martínez J, Tsai TF, et al. (three authors at GlaxoSmithKline, the maker of Avodart) · Journal of the American Academy of Dermatology, 2014 · 917 men aged 20 to 50, 24 weeks: three doses of dutasteride, finasteride 1 mg, or placebo. Abstract quoted.

917 men took part. “In total, 917 men were randomized. Hair count and width increased dose dependently with dutasteride.”
Dutasteride 0.5 mg grew more hair than finasteride 1 mg at 24 weeks, with similar side effects. “Dutasteride 0.5 mg significantly increased hair count and width in a 2.54-cm diameter and improved hair growth (frontal view; panel photographic assessment) at week 24 compared with finasteride (P = .003, P = .004, and P = .002, respectively) and placebo (all P < .001).”
It lasted only 24 weeks. “The study was limited to 24 weeks.”

Topical finasteride

Finasteride applied to the scalp grew about as much hair as the pill in one 24-week trial, run with the spray’s maker. It is not DHT-free for the rest of the body: blood DHT still fell by about a third, against just over half on the pill. A 2026 review found lower rates of sexual side effects with it than with the pill. On reddit, commenters suggested topical finasteride in 146 threads, usually to someone worried about side effects.

[9] Efficacy and safety of topical finasteride spray solution for male androgenetic alopecia: a phase III, randomized, controlled clinical trial

Piraccini BM, Blume-Peytavi U, Scarci F, et al. (seven of the ten named authors at Almirall, the maker of the spray) · Journal of the European Academy of Dermatology and Venereology, 2022 · 458 men at 45 European sites, 24 weeks: topical finasteride spray, oral finasteride or placebo. Abstract quoted.

On the spray, hair counts rose more than on placebo (about 20 vs 7 hairs in the target area). “Change from baseline in target area hair count (TAHC) at week 24 (primary efficacy endpoint) was significantly greater with topical finasteride than placebo (adjusted mean change 20.2 vs. 6.7 hairs; P < 0.001), and numerically similar between topical and oral finasteride.”
It still lowered blood DHT, by about a third, against just over half with the pill. “reduction from baseline in mean serum DHT concentration was lower (34.5 vs. 55.6%), with topical vs. oral finasteride”
323 of the 458 men completed the study. “Of 458 randomized patients, 323 completed the study and 446 were evaluated for safety.”

Blockers that block the receptor, not DHT: spironolactone, RU58841, clascoterone

These don’t lower DHT. They sit on the androgen receptor in the follicle so DHT can’t act on it. Spironolactone is a blood-pressure pill prescribed off-label to women; we cover its studies and what people reported on our spironolactone page. RU58841 is a topical anti-androgen from the 1990s that was never brought to market; the studies we found are on mice carrying human scalp grafts and on balding monkeys, and one notes it blocks the receptor about as strongly as a prostate-cancer drug. It is sold online as a research chemical. Our corpus has 1,300 threads with RU58841 in the title (not read for this page); in the DHT threads, 31 had a commenter warning that it is unregulated or untested. Clascoterone is approved in the US only as a 1% acne cream; a stronger solution for hair loss was in trials, and a 2026 review still lists it as an emerging treatment (225 threads in our corpus name it in the title).

[3] WINLEVI (clascoterone) cream 1%: US prescribing information

Sun Pharmaceutical Industries / Cosmo · DailyMed (US National Library of Medicine), label version 8, Jan 2025, 2025 · The only approved clascoterone product in the US is a 1% cream for acne. It doesn't lower DHT; it blocks the receptor DHT acts on. Archived as the full label text from the DailyMed XML.

Approved for acne, not hair loss; it works on the androgen receptor. “WINLEVI (clascoterone) cream is an androgen receptor inhibitor indicated for the topical treatment of acne vulgaris in patients 12 years of age and older.”
Even on skin, it can suppress the body's stress-hormone (HPA) axis in some users; this reversed after stopping. “HPA axis suppression indicated by 30-minute post-stimulation serum cortisol level of ≤18 mcg/dL was observed in 1/20 (5%) of adult subjects and 2/22 (9%) of adolescent subjects at Day 14.”

[11] Treatment of female pattern hair loss with oral antiandrogens

Sinclair R, Wewerinke M, Jolley D (University of Melbourne) · British Journal of Dermatology, 2005 · 80 women on spironolactone or cyproterone acetate, open study without a placebo group. Abstract quoted. More studies on our spironolactone page.

44% regrew hair, 44% held steady and 12% kept losing hair (both drugs combined). “Thirty-five (44%) women had hair regrowth, 35 (44%) had no clear change in hair density before and after treatment, and 10 (12%) experienced continuing hair loss during the treatment period.”
The authors say a placebo-controlled study is still needed. “A placebo-controlled study is required to compare this outcome to the natural history of FPHL.”

[12] A controlled study of the effects of RU58841, a non-steroidal antiandrogen, on human hair production by balding scalp grafts maintained on testosterone-conditioned nude mice

De Brouwer B, Tételin C, Leroy T, Bonfils A, Van Neste D (Skin Study Centre, Tournai) · British Journal of Dermatology, 1997 · 20 grafts of balding human scalp kept on mice, half treated with RU58841 1%. Abstract quoted. We found no published trial of RU58841 in people.

20 scalp grafts from balding men, on mice. “Twenty productive scalp grafts from balding men were maintained for 8 months after grafting on to nude mice, and hair production was monitored monthly for 6 months.”
The authors called for a clinical trial. “encourage a clinical trial to evaluate its potential in the treatment of androgen-dependent alopecia.”

[13] Evaluation of RU58841 as an anti-androgen in prostate PC3 cells and a topical anti-alopecia agent in the bald scalp of stumptailed macaques

Pan HJ, Wilding G, Uno H, et al. (University of Rochester and others) · Endocrine, 1998 · Cell and monkey study. Abstract quoted.

RU58841 blocks the androgen receptor about as strongly as hydroxyflutamide, a prostate-cancer drug; the authors say that on the skin it may still cause effects elsewhere in the body. “The potency of RU58841 was comparable to that of hydroxyflutamide. From this result, topical application of RU58841, which is considered to be a potential therapy for skin diseases, may induce systemic side effects.”
In balding macaques, it thickened and lengthened hair. “RU58841, on topical application, revealed a potent increase in density, thickening, and length of hair in the macaque model of androgenetic alopecia, whereas no systemic effects were detected.”

[22] Emerging pharmacotherapies for androgenetic alopecia

Agrawal A, Dreifus EM, Tosti A (AIIMS Bhopal and University of Miami) · Expert Opinion on Pharmacotherapy, 2026 · A review of treatments in development, through December 2025. Abstract quoted.

The standard treatments today: minoxidil, 5-alpha-reductase inhibitors and oral anti-androgens. “To date, topical and oral minoxidil, 5-α-reductase inhibitors and oral antiandrogens remain the mainstay of treatment”
Clascoterone for hair is listed among emerging treatments, still in trials. “These include topical androgen-receptor antagonists and degraders (clascoterone, GT20029)”

[23] Clascoterone: First Approval

Adis (Springer Nature) drug profile · Drugs, 2020 · Drug-approval profile. Abstract quoted.

Clascoterone competes with DHT for the androgen receptor; it doesn't lower DHT. “the drug is believed to compete with the androgen dihydrotestosterone for binding to androgen receptors in the sebaceous gland and hair follicles”
For hair loss, a stronger solution was in trials. “Clinical studies of a different formulation of clascoterone (a solution containing a higher concentration of the drug) for the treatment of androgenetic alopecia are underway in Germany and the USA.”

“Natural” DHT blockers: saw palmetto, pumpkin seed oil, rosemary, green tea

Each rests on one or a few small studies. Saw palmetto’s biggest hair study (100 men) had no placebo group and found 38% improved against 68% on finasteride; a 2020 review found seven small studies, most of supplements mixing saw palmetto with other ingredients. Pumpkin seed oil has one 76-man placebo-controlled trial, funded by the company that supplied the capsules and held the randomisation codes; it did not measure DHT. Rosemary oil’s trial compared it with the weaker 2% minoxidil, without a placebo. Green tea’s evidence is from cells and follicles in a dish. A 2026 network meta-analysis of 19 supplement trials found positive results but called the studies small, varied and hard to compare. None of these showed that it lowered DHT in the scalp of people taking it. Saw palmetto’s own side effects are mostly mild, but its review lists decreased libido among the most common.

[14] Comparative effectiveness of finasteride vs Serenoa repens in male androgenetic alopecia: a two-year study

Rossi A, Mari E, Scarno M, et al. · International Journal of Immunopathology and Pharmacology, 2012 · 100 men, open label (everyone knew what they took), 2 years: saw palmetto 320 mg or finasteride 1 mg. No placebo group. Abstract quoted.

100 men, saw palmetto 320 mg or finasteride 1 mg daily for 24 months. “One group received Serenoa repens 320 mg every day for 24 months, while the other received finasteride 1 mg every day for the same period.”
38% improved on saw palmetto, 68% on finasteride. “The results showed that only 38% of patients treated with Serenoa repens had an increase in hair growth, while 68% of those treated with finasteride noted an improvement.”

[15] Natural Hair Supplement: Friend or Foe? Saw Palmetto, a Systematic Review in Alopecia

Evron E, Juhasz M, Babadjouni A, Mesinkovska NA · Skin Appendage Disorders, 2020 · A systematic review of saw palmetto for hair: 5 randomised trials and 2 cohort studies, most testing supplements that contain saw palmetto among other things. Authors declare no conflicts. Abstract quoted.

Seven studies in all. “Five randomized clinical trials (RCTs) and 2 prospective cohort studies demonstrated positive effects of topical and oral supplements containing SP (100-320 mg) among patients with androgenetic alopecia (AGA) and telogen effluvium.”
The authors say good data are lacking, and that trials of saw palmetto on its own are still needed. “Although robust high-quality data are lacking, supplements containing SP may be a treatment option for patients with AGA, telogen effluvium, and self-perceived hair thinning.”
The same abstract: “Further large-scale RCTs focusing on the sole contribution of SP to hair growth outcomes are needed to confirm efficacy and determine long-term adverse events.”

[16] Serenoa repens (saw palmetto): a systematic review of adverse events

Agbabiaka TB, Pittler MH, Wider B, Ernst E (Peninsula Medical School, Exeter) · Drug Safety, 2009 · A review of 40 articles on saw palmetto side effects, mostly in older men taking it for the prostate. Abstract quoted.

Side effects are mild and similar to placebo; the most common include decreased libido. “The most frequently reported adverse events are abdominal pain, diarrhoea, nausea, fatigue, headache, decreased libido and rhinitis.”
40 articles, 26 of them randomised trials. “Forty articles (26 randomized controlled trials, 4 non-randomized controlled trials, 6 uncontrolled trials and 4 case reports/series) were included.”

[17] Effect of pumpkin seed oil on hair growth in men with androgenetic alopecia: a randomized, double-blind, placebo-controlled trial

Cho YH, Lee SY, Jeong DW, et al. (Pusan National University); funded by Dreamplus Co., which supplied the capsules · Evidence-Based Complementary and Alternative Medicine, 2014 · 76 Korean men, 24 weeks, 400 mg a day of a branded pumpkin seed oil capsule (Octa Sabal Plus) or placebo. Funded by the company that supplied the capsules and held the randomisation codes. Quoted from the open-access full text.

76 men, 400 mg a day or placebo for 24 weeks. “76 male patients with AGA received 400 mg of PSO per day or a placebo for 24 weeks.”
Hair counts rose 40% on the capsules and 10% on placebo. “Mean hair count increases of 40% were observed in PSO-treated men at 24 weeks, whereas increases of 10% were observed in placebo-treated men”
DHT was not measured, so the study can't say whether it blocked DHT. “In addition, DHT and prostate specific antigen (PSA) levels were not measured for identification of mechanism of PSO; therefore we could not explain the exact action of PSO on AGA patients.”
Funding: “This study was supported by a grant from Dreamplus Co., Ltd. (2012).”
The capsule maker also held the randomisation codes. “Randomization codes were held by Dreamplus Co., Ltd.”

[18] Rosemary oil vs minoxidil 2% for the treatment of androgenetic alopecia: a randomized comparative trial

Panahi Y, Taghizadeh M, Marzony ET, Sahebkar A · Skinmed, 2015 · 100 people, 6 months, rosemary oil or minoxidil 2% (the weaker strength). No placebo group, and it measured hair counts, not DHT. Abstract quoted.

50 people on rosemary oil, 50 on minoxidil 2%, for 6 months. “Patients with AGA were randomly assigned to rosemary oil (n = 50) or minoxidil 2% (n = 50) for a period of 6 months.”
Both groups gained hair by 6 months, with no difference between them. “No significant difference was found between the study groups regarding hair count either at month 3 or month 6 (> .05).”

[19] Human hair growth enhancement in vitro by green tea epigallocatechin-3-gallate (EGCG)

Kwon OS, Han JH, Yoo HG, et al. (Seoul National University) · Phytomedicine, 2007 · Lab study on hair follicles and cells in culture, not people taking green tea. Abstract quoted.

The idea that green tea's EGCG blocks DHT came from earlier reports; this study looked at hair growth in the lab. “Recently, it was reported that EGCG might be useful in the prevention or treatment of androgenetic alopecia by selectively inhibiting 5alpha-reductase activity.”
What it found was in cultured follicles and cells. “EGCG promoted hair growth in hair follicles ex vivo culture and the proliferation of cultured DPCs.”

[20] Topical ketoconazole for the treatment of androgenetic alopecia: A systematic review

Fields JR, Vonu PM, Monir RL, Schoch JJ (University of Florida) · Dermatologic Therapy, 2020 · A systematic review: 5 human studies (318 people) and 2 animal studies. Abstract quoted. More on our ketoconazole page.

Seven studies, five in people. “Seven articles were included in the qualitative synthesis, including two animal studies (total of 40 participants) and five human studies (total of 318 participants).”
The authors call it promising as an add-on, and say randomised trials are needed. “Topical ketoconazole is a promising adjunctive or alternative therapy in the treatment of AGA. Randomized controlled trials are needed.”

[21] Effects of dietary supplements on androgenetic alopecia: a systematic review and network meta-analysis

Zhou L, Zhu W, Chen Y (Guang'anmen Hospital, Beijing, and Guangzhou Medical University) · Frontiers in Nutrition, 2026 · A network meta-analysis of 19 randomised trials of 16 different supplements. Authors declare no conflicts. Abstract quoted.

19 trials, 1,658 patients, 16 supplements: a few trials per supplement. “A total of 19 RCTs involving 1,658 AGA patients were included, with 894 patients in the supplement group and 764 in the control group. Sixteen dietary supplements were investigated.”
The authors name the existing studies' limits. “However, existing studies have limitations, including the diversity of supplements, small sample sizes, and the lack of direct comparisons among different supplements, making it unclear how they compare in terms of efficacy and safety.”
They conclude larger, better trials are needed. “Future large-scale, high-quality RCTs are needed to verify these findings.”

What reddit commenters said about natural blockers

732 threads asked mainly about natural or supplement blockers. In 943 threads where a natural blocker came up, commenters gave a verdict on it. The main verdict:

it works: 5% (50)
small effect at best, an add-on: 22% (209)
answers split: 21% (199)
doesn’t work, take a proven drug: 51% (485)

saw palmetto (361 threads): it works 4%, small effect 28%, split 18%, doesn’t work 49%
rosemary oil (290 threads): it works 9%, small effect 19%, split 31%, doesn’t work 41%
pumpkin seed oil (112 threads): it works 2%, small effect 27%, split 21%, doesn’t work 51%
other supplements, oils and “DHT-blocking” shampoos (437 threads): it works 3%, small effect 19%, split 21%, doesn’t work 57%

“Saw palmetto is an absolute waste of time and money.”

A reply to Can I stack DHT blockers in a safe manner? I am currently on dutasteride. Finasteride did not work. I bought saw palmetto berry tablets. (reddit, May 2026)
“There’s a reason you don’t find many success stories of natural oils/supplements, it’s because the results are simply not comparable to the leading pharmaceuticals.”

A reply to Can anyone speak to success with Rosemary oil +/- microneedling/other treatments? (reddit, Jun 2023)
“I wouldn’t substitute it for finasteride but as an add on to a regimen it will probably be beneficial”

A reply to Using Rosemary Oil for Hair Growth? (reddit, Dec 2022)
“It's certainly no replacement for the big boys, but if you're already on those and want to throw rosemary oil on with those, I don't see any harm :)”

A reply to How do you use oils (rosemary etc)? (reddit, Feb 2024)
“My personal experience with rosemary was that it helped slow the hair loss, quite a lot.”

A reply to Mielle Rosemary Oil for Straight Thin Hair (reddit, Aug 2023)

Which DHT blocker did commenters recommend?

In the 851 threads where someone asked which DHT blocker to take or about natural ones, the number of threads in which at least one commenter recommended each:

288finasteride (pill)
127rosemary oil
118other supplements, oils and “DHT-blocking” shampoos
102dutasteride
95saw palmetto
65ketoconazole shampoo
60topical finasteride
44pumpkin seed oil
37RU58841
8spironolactone
5clascoterone
5green tea / EGCG

Everything commenters said, in all 3,231 threads

Number of threads where at least one commenter said it:

596natural DHT blockers don’t work, are a waste of money or marketing
340blood DHT levels don’t tell you much: it’s how sensitive your follicles are
327a natural blocker has some or a small effect
246use minoxidil, alongside or instead
209see a doctor or dermatologist
187side effects of finasteride are rare, overblown, or go away
146try topical finasteride
136add ketoconazole (Nizoral) shampoo
135DHT does things in the body; lowering it has a cost
132saw palmetto has side effects too / is no safer than finasteride
122only finasteride or dutasteride really block DHT
99side effects are real or can persist (post-finasteride syndrome)
31RU58841 is unregulated, with unknown long-term safety
10women who could get pregnant shouldn’t take finasteride/dutasteride

“If you're satisfied to just maintain the hair you have, then fin should be able to do that for you.”

A reply to I've been using minoxidil & saw palmetto for 15 months with no results, should I start fin? [pictures] (reddit, Jul 2016)
“I’d only jump on dut if I was still losing ground on fin after 3+ years.”

A reply to How is fin enough if it only cuts scalp DHT by half…? (reddit, Aug 2022)
“topical is your best bet however it can get tedious trying to apply it to your entire scalp”

A reply to DHT blockers for someone who had Finasteride pill side effects. (reddit, Sept 2022)
“Total DHT levels are completely irrelevant, sensitivities to DHT is what matters”

A reply to Low normal DHT but still losing the hairs from the front scalp. Looking for suggestions on what treatment can be used to treat hair loss ? (reddit, Oct 2023)
“There are topical anti-androgens like alfatradiol, fluridil, RU58841 and pyrilutamide which have questionable efficiacy and safety data.”

A reply to Is there something to reduce androgen(especially DHT) sensitivity? Instead of reducing DHT/T (reddit, Feb 2024)

What people said happened to their own hair

2,099 people (askers and commenters) described their own use of a DHT blocker in these threads; some named more than one. Per blocker, each person counted once:

Blocker	People	Helped	No change	Worse	Named a side effect
finasteride (pill)	1,048	236	93	70	271
saw palmetto	352	74	74	19	99
dutasteride	306	69	40	29	48
rosemary oil	257	75	45	15	12
other supplements, oils and “DHT-blocking” shampoos	245	71	72	14	15
topical finasteride	159	45	11	4	27
ketoconazole shampoo	105	23	12	5	11
pumpkin seed oil	83	15	25	2	9
RU58841	50	18	7	3	5
spironolactone	12	5	2	0	2
green tea / EGCG	11	3	4	1	0

The rest had just started or didn’t say what happened. These are people who chose to post, often using several things at once, so the table shows what was reported, not how well each one works. Small numbers (under 30 people) say little.

On saw palmetto and other natural blockers

“I've used it for 20 years for light recession. I think it works.”

From Anyone got benefit from Saw Palmetto here? (reddit, Sept 2024)
“I've been taking it for 6 months and have felt no different than I did before, while my hair has continued to get worse.”

From Does anyone know if I would react the same way I did to saw palmetto on propecia? (reddit, Aug 2015)
“Saw palmetto worked well for me in the early years but once things accelerated it was pretty much useless by itself.”

From Best no-nonsense OTC DHT suppressors (reddit, Mar 2022)
“Used rosemary oil for 4 months did absolutely nothing if anything my hair loss progressed even more”

From Study on rosemary oil being as effective as minoxidil 2 percent? (reddit, Feb 2020)
“Been using it for about six weeks, I'm seeing a few baby hairs pop up”

From Is it okay to mix rosemary oil with topical fin? (reddit, Mar 2023)
“I drank green tea all the time for years and my hair continued thinning.”

From Anyone added green tea as a drink to combat hair loss? (reddit, Jan 2023)

On finasteride, dutasteride and topical finasteride

“I don't see any regrowth but I am keeping the hair I have with finasteride.”

From Does finasteride block DHT while on TRT (reddit, Aug 2022)
“I have been on finasteride for nearly 5 months now, and largely I'd say it’s been successful.”

From My facial hair has thinned on finasteride. Is this a warning sign of something wrong happening hormonally, or simply a natural byproduct of lowered DHT levels? (reddit, Jun 2020)
“On fin, I remember a month and a half in, I had way less shed.”

From My dht levels make absolutely no sense (reddit, Jun 2026)
“There is a high success rate but for many people me included it didn’t work (at least fin, well see about dut).”

From Dutasteride doesn't seem to be working (DHT results) (reddit, May 2019)
“I started taking fin 2.5 years ago and have lost a full inch in my hairline.”

From How is it possible for one to have hair visibly not effected by DHT and suddenly rapidly recede and thin and unable to be stopped by even Finasteride? (reddit, Jul 2019)

Side effects

On the labels: in finasteride’s 1-year trials, 3.8% of men on it reported a sexual side effect against 2.1% on placebo, and the label also lists reports, since approval, of sexual problems continuing after stopping and of depression and suicidal thoughts, which can’t show how often they happen or whether the drug caused them. Dutasteride’s label lists impotence, lower libido, ejaculation problems and breast changes. A 2026 review puts sexual side effects at 1.9-6.7% of men on finasteride 1 mg (0.9-3.9% on placebo), 4.1-12% on dutasteride and lower with topical finasteride. Saw palmetto isn’t free of them either: decreased libido is among its most reported side effects.

On reddit, 335 threads were mainly about side effects or the risks of lowering DHT. Of the 1,048 people who described taking finasteride in these threads, 271 named a side effect (77 a sexual one), 87 said they had none and 176 said they stopped. Commenters said side effects are rare or overblown in 187 threads and that they are real or can persist in 99; in 132 someone pointed out that saw palmetto, taken to avoid finasteride’s side effects, can have them too.

“Can’t say which is more effective, but I had SEVERE side effects from oral, and no side effects from topical, so there’s that.”

From Topical Fin vs. Oral Fin. Which one decreases scalp DHT (not serum!) more? (reddit, May 2022)
“There were definitely some gradual side effects when I took it, but the loss of libido was immediate for me.”

From Why is the importance of DHT so convoluted? (reddit, Dec 2018)
“On Fin. I think for the first 2 weeks i was less horny but it didnt impact anything once im getting down with the deeds.”

From Orgasms on dht blockers, share your experience (reddit, Jan 2025)
“I stopped taking it because it was giving me sexual side effects.”

From Can rogain and saw palmetto cause post finasteride syndrome? (reddit, May 2020)

DHT blockers for women

Finasteride is labelled for men only and must not be used by women who are or could become pregnant, as it can harm a male fetus; dutasteride carries the same warning. A 2019 review of 65 studies found finasteride “may” help female pattern hair loss in non-randomised studies, and the one placebo-controlled trial in postmenopausal women found no benefit. Spironolactone is the anti-androgen more often prescribed to women; see our spironolactone page. Few askers in these threads said they were women (26 of 3,231).

[10] The efficacy and use of finasteride in women: a systematic review

Hu AC, Chapman LW, Mesinkovska NA (University of California) · International Journal of Dermatology, 2019 · A systematic review of 65 studies (1997-2017) of finasteride in women, for hair loss and other conditions. Abstract quoted.

65 studies with 2,683 women. “A total of 2,683 patients participated in 65 studies involving finasteride use in women published between January 1997 and July 2017.”
For female pattern hair loss, the evidence beyond randomised trials is that finasteride 'may' help. “Other prospective and retrospective studies report that finasteride may improve hair loss in women with female pattern hair loss or frontal fibrosing alopecia.”

More on the treatments: finasteride results, dutasteride results, minoxidil vs finasteride, spironolactone, ketoconazole shampoo and shampoos for thinning hair (including the “DHT-blocking” ones).

How this page was made

We took every live reddit thread in our corpus whose title names DHT, saw palmetto, pumpkin seed (oil), rosemary, green tea or EGCG, or asks about a natural or herbal treatment, and read the asker’s post, their replies and the top comments by other people (12 threads that turned out not to be about hair loss were left out). Threads that name only RU58841 or clascoterone were counted by title, not read. Each person who described their own use is counted once per blocker, even if they posted in several threads; gender is counted only where the person said it. Each quote is copied word for word from the comment or post it links to; we picked them by hand so each states the view it is shown under. Each label and study quote is copied from the archived text on DailyMed, PubMed or PubMed Central, checked 17 Oct 2026, and industry authors or funders are named where the paper discloses them. Removed posts are left out, usernames are not shown, and posts that mention suicide or self-harm are never quoted. Data as of Oct 2026. This is not medical advice: finasteride, dutasteride and spironolactone are prescription drugs; talk to a doctor before starting or stopping one.

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