Sources

The journal short version of the European S3 guideline; it notes that pattern hair loss affects up to 80% of white men and 42% of women.

Kanti V, Messenger A, Dobos G, et al. (2018). Evidence-based (S3) guideline for the treatment of androgenetic alopecia in women and in men – short version. J Eur Acad Dermatol Venereol 2018;32(1):11–22

DOI 10.1111/jdv.14624PubMed 29178529

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Kept for reference; not cited in a guide yet.

The 2017 European guideline recommends topical minoxidil for women and men and finasteride 1 mg for men, suggests low-level laser as an add-on, makes no recommendation on PRP, and advises judging results at 6 months. Its own expiry date was June 2020, and we found no newer version.

Kanti V, Messenger A, Dobos G, et al. (2017). S3 – European Dermatology Forum Guideline for the Treatment of Androgenetic Alopecia in Women and in Men. European Dermatology Forum, S3 guideline (literature to Oct 2015, expiry 06/2020)

guidelines.edf.one

Cited in: The hair cycle, explained · Pattern hair loss, explained · Minoxidil: how it works and how to use it · Finasteride: what to know before you start · Red light therapy: caps, helmets and combs · Hair loss in women · Finasteride spray: what we know · Microneedling for hair loss · Ketoconazole shampoo for hair loss · Hair supplements: what has evidence · Rosemary oil: does it work? · How to use minoxidil lotion and foam · Starting minoxidil tablets · Your first months on finasteride · Using a red light device · How to take progress photos

Pooling 12 trials with 631 patients, microneedling plus minoxidil raised hair counts more than minoxidil alone, but results varied widely and side effects, mostly mild, were more common.

Ahmed KMA, Kozaa YA, Abuawwad MT, et al. (2025). Evaluating the efficacy and safety of combined microneedling therapy versus topical Minoxidil in androgenetic alopecia: a systematic review and meta-analysis. Arch Dermatol Res 2025;317(1):528

DOI 10.1007/s00403-025-04032-1PubMed 40056230

Cited in: Pattern hair loss, explained · Microneedling for hair loss · Microneedling at home, step by step · What results really look like

Pooling 14 trials with 431 patients, PRP added about 28 hairs/cm² over placebo, but the authors rate the evidence as low quality and highly inconsistent.

Kieling L, Konzen AT, Zanella RK, et al. (2024). Is autologous platelet-rich plasma capable of increasing hair density in patients with androgenic alopecia? A systematic review and meta-analysis of randomized clinical trials. An Bras Dermatol 2024;99(6):847–862

DOI 10.1016/j.abd.2024.01.002PubMed 39013743

Cited in: Pattern hair loss, explained

A second pooled analysis of 10 trials with 466 patients also found higher hair counts when microneedling was added to minoxidil, with no scarring or serious side effects.

Abdi P, Awad C, Anthony MR, et al. (2023). Efficacy and safety of combinational therapy using topical minoxidil and microneedling for the treatment of androgenetic alopecia: a systematic review and meta-analysis. Arch Dermatol Res 2023;315(10):2775–2785

DOI 10.1007/s00403-023-02688-1PubMed 37665358

Cited in: Microneedling for hair loss · Microneedling at home, step by step

Across 23 studies in men, dutasteride, finasteride 5 mg and topical minoxidil 5% added about 15 to 19 hairs/cm² over placebo at 24 weeks, but the evidence was rated low quality for several comparisons.

Gupta AK, Venkataraman M, Talukder M, et al. (2022). Relative Efficacy of Minoxidil and the 5-α Reductase Inhibitors in Androgenetic Alopecia Treatment of Male Patients: A Network Meta-analysis. JAMA Dermatol 2022;158(3):266–274

DOI 10.1001/jamadermatol.2021.5743PubMed 35107565

Cited in: Minoxidil: how it works and how to use it · Finasteride: what to know before you start · What results really look like

Five small human studies (318 people) suggested ketoconazole shampoo may thicken hair shafts; the authors call it a promising add-on and say proper randomised trials are still needed.

Fields JR, Vonu PM, Monir RL, Schoch JJ (2020). Topical ketoconazole for the treatment of androgenetic alopecia: a systematic review. Dermatol Ther 2020;33(1):e13202

DOI 10.1111/dth.13202PubMed 31858672

Cited in: Ketoconazole shampoo for hair loss

Five small trials and two cohort studies suggest saw palmetto supplements may help a little and are well tolerated, but the authors say robust, high-quality data are lacking.

Evron E, Juhasz M, Babadjouni A, Mesinkovska NA (2020). Natural hair supplement: friend or foe? Saw palmetto, a systematic review in alopecia. Skin Appendage Disord 2020

DOI 10.1159/000509905PubMed 33313047

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Cited in: Hair supplements: what has evidence

Pooled trials found that minoxidil (in men and women), finasteride 1 mg and low-level laser all worked better than placebo, although the studies varied a lot.

Adil A, Godwin M (2017). The effectiveness of treatments for androgenetic alopecia: A systematic review and meta-analysis. J Am Acad Dermatol 2017;77(1):136–141.e5

DOI 10.1016/j.jaad.2017.02.054PubMed 28396101

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Cited in: Red light therapy: caps, helmets and combs

Across trials in women, minoxidil nearly doubled the chance of moderate or marked regrowth compared with placebo, 2% and 5% did about the same, and finasteride 1 mg did no better than placebo.

van Zuuren EJ, Fedorowicz Z, Schoones J (2016). Interventions for female pattern hair loss. Cochrane Database Syst Rev 2016;(5):CD007628

DOI 10.1002/14651858.CD007628.pub4PubMed 27225981

Cited in: Pattern hair loss, explained · Minoxidil: how it works and how to use it · Finasteride: what to know before you start · Red light therapy: caps, helmets and combs · Hair loss in women · What results really look like

In a 24-week pilot in 48 premenopausal women also using minoxidil, spironolactone 100 mg did not clearly raise hair counts, though more improved moderately or markedly (38% against 9%) and 37.5% had irregular periods.

Werachattawatchai P, Khunkhet S, Harnchoowong S, et al. (2025). Efficacy and safety of oral spironolactone for female pattern hair loss in premenopausal women: a randomized, double-blind, placebo-controlled, parallel-group pilot study. Int J Womens Dermatol 2025;11(3):e227

DOI 10.1097/JW9.0000000000000227PubMed 40978669

Cited in: Pattern hair loss, explained · Hair loss in women

In a 24-week trial in men, oral minoxidil 5 mg was not better than topical minoxidil 5%, and 49% of men on the tablet grew unwanted hair elsewhere on the body.

Penha MA, Miot HA, Kasprzak M, et al. (2024). Oral Minoxidil vs Topical Minoxidil for Male Androgenetic Alopecia: A Randomized Clinical Trial. JAMA Dermatol 2024;160(6):600–605

DOI 10.1001/jamadermatol.2024.0284PubMed 38598226

Cited in: Minoxidil: how it works and how to use it · Starting minoxidil tablets

In 458 men over 24 weeks, a 0.25% finasteride spray added about 20 hairs in the target area against 7 with placebo, close to the finasteride tablet (21), while lowering blood DHT less (about 35% against 56%).

Piraccini BM, Blume-Peytavi U, Scarci F, et al. (2022). Efficacy and safety of topical finasteride spray solution for male androgenetic alopecia: a phase III, randomized, controlled clinical trial. J Eur Acad Dermatol Venereol 2022;36(2):286–294

DOI 10.1111/jdv.17738PubMed 34634163

Cited in: Finasteride spray: what we know · What results really look like

In 100 people over six months, hair counts rose about equally with rosemary oil and with minoxidil 2%; neither changed at three months. Scalp itching was more common with minoxidil.

Panahi Y, Taghizadeh M, Marzony ET, Sahebkar A (2015). Rosemary oil vs minoxidil 2% for the treatment of androgenetic alopecia: a randomized comparative trial. Skinmed 2015;13(1):15–21

PubMed 25842469

Cited in: Rosemary oil: does it work?

In four sham-controlled trials, laser combs added about 18 to 26 terminal hairs/cm² in men and about 20 in women over 26 weeks, against about 2 to 9 with sham devices.

Jimenez JJ, Wikramanayake TC, Bergfeld W, et al. (2014). Efficacy and safety of a low-level laser device in the treatment of male and female pattern hair loss: a multicenter, randomized, sham device-controlled, double-blind study. Am J Clin Dermatol 2014;15(2):115–127

DOI 10.1007/s40257-013-0060-6PubMed 24474647

Cited in: Red light therapy: caps, helmets and combs · Hair loss in women · Using a red light device · What results really look like

In 42 women, the same red-light helmet gave 37% more hair growth than a sham device over 16 weeks, with no side effects reported.

Lanzafame RJ, Blanche RR, Chiacchierini RP, et al. (2014). The growth of human scalp hair in females using visible red light laser and LED sources. Lasers Surg Med 2014;46(8):601–607

DOI 10.1002/lsm.22277PubMed 25124964

Cited in: Red light therapy: caps, helmets and combs · Hair loss in women · What results really look like

In 76 men over 24 weeks, hair counts rose 40% with a pumpkin seed oil supplement against 10% with placebo. The capsules were a branded mix, and the maker funded the trial.

Cho YH, Lee SY, Jeong DW, et al. (2014). Effect of pumpkin seed oil on hair growth in men with androgenetic alopecia: a randomized, double-blind, placebo-controlled trial. Evid Based Complement Alternat Med 2014;2014:549721

DOI 10.1155/2014/549721PubMed 24864154

Cited in: Hair supplements: what has evidence

In 41 men, a red-light laser helmet used every other day for 16 weeks gave 39% more hair growth than a placebo helmet, with no side effects reported.

Lanzafame RJ, Blanche RR, Bodian AB, et al. (2013). The growth of human scalp hair mediated by visible red light laser and LED sources in males. Lasers Surg Med 2013;45(8):487–495

DOI 10.1002/lsm.22173PubMed 24078483

Cited in: Red light therapy: caps, helmets and combs · Using a red light device

In a small 12-week pilot in 100 men, weekly microneedling plus minoxidil 5% raised hair counts much more than minoxidil alone (91.4 against 22.2 hairs in the target area).

Dhurat R, Sukesh M, Avhad G, et al. (2013). A randomized evaluator blinded study of effect of microneedling in androgenetic alopecia: a pilot study. Int J Trichology 2013;5(1):6–11

DOI 10.4103/0974-7753.114700PubMed 23960389

Cited in: Microneedling for hair loss · Microneedling at home, step by step

In a 26-week sham-controlled trial in 110 men, a laser comb increased terminal hair density more than a sham device, with no serious side effects.

Leavitt M, Charles G, Heyman E, et al. (2009). HairMax LaserComb laser phototherapy device in the treatment of male androgenetic alopecia: A randomized, double-blind, sham device-controlled, multicentre trial. Clin Drug Investig 2009;29(5):283–292

DOI 10.2165/00044011-200929050-00001PubMed 19366270

Cited in: Red light therapy: caps, helmets and combs

In 393 men over 48 weeks, minoxidil 5% gave 45% more regrowth than 2%, with more scalp itching and irritation.

Olsen EA, Dunlap FE, Funicella T, et al. (2002). A randomized clinical trial of 5% topical minoxidil versus 2% topical minoxidil and placebo in the treatment of androgenetic alopecia in men. J Am Acad Dermatol 2002;47(3):377–385

DOI 10.1067/mjd.2002.124088PubMed 12196747

Cited in: Pattern hair loss, explained · Minoxidil: how it works and how to use it · Rosemary oil: does it work? · How to use minoxidil lotion and foam

In 1553 men, finasteride 1 mg gave about 107 more hairs than placebo at 1 year and 138 more at 2 years in a 5.1 cm² crown area, while hair loss kept getting worse on placebo.

Kaufman KD, Olsen EA, Whiting D, et al. (1998). Finasteride in the treatment of men with androgenetic alopecia. J Am Acad Dermatol 1998;39(4 Pt 1):578–589

DOI 10.1016/s0190-9622(98)70007-6PubMed 9777765

Cited in: Pattern hair loss, explained · Finasteride: what to know before you start · Your first months on finasteride · What results really look like

A controlled study suggested 2% ketoconazole shampoo improved hair density about as much as 2% minoxidil, but the authors say a larger controlled study is needed.

Piérard-Franchimont C, De Doncker P, Cauwenbergh G, et al. (1998). Ketoconazole shampoo: effect of long-term use in androgenic alopecia. Dermatology 1998;196(4):474–477

DOI 10.1159/000017954PubMed 9669136

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Cited in: Ketoconazole shampoo for hair loss

Of 156 popular hair-loss videos on YouTube, TikTok and Instagram, only 6.5% discussed risks or side effects; videos by dermatologists recommended guideline treatments about twice as often as others.

Healio, reporting Hwang J, et al. (Int J Dermatol 2026) (2026). Hair loss videos on social media often lack reliable treatment information. Healio Dermatology news, 21 August 2026; study doi 10.1111/ijd.70600

healio.com

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Kept for reference; not cited in a guide yet.

A review of 17 studies with 634 patients found oral minoxidil an effective, well-tolerated option for healthy people who struggle with topical minoxidil, but says larger randomised trials are needed.

Randolph M, Tosti A (2021). Oral minoxidil treatment for hair loss: A review of efficacy and safety. J Am Acad Dermatol 2021;84(3):737–746

DOI 10.1016/j.jaad.2020.06.1009PubMed 32622136

Cited in: Shedding after stress, illness or birth · Minoxidil: how it works and how to use it · Starting minoxidil tablets

In 1404 people taking low-dose minoxidil tablets for hair loss, the most common side effect was unwanted hair growth (15.1%); 1.7% stopped because of side effects such as light-headedness, fluid retention or a fast heartbeat. The study looked back at records and had no control group.

Vañó-Galván S, Pirmez R, Hermosa-Gelbard A, et al. (2021). Safety of low-dose oral minoxidil for hair loss: a multicenter study of 1404 patients. J Am Acad Dermatol 2021;84(6):1644–1651

DOI 10.1016/j.jaad.2021.02.054PubMed 33639244

Cited in: Starting minoxidil tablets

Low vitamin D is often found alongside several kinds of hair loss, but there is no conclusive evidence that taking vitamin D corrects hair loss.

Saini K, Mysore V (2021). Role of vitamin D in hair loss: a short review. J Cosmet Dermatol 2021;20(11):3407–3414

DOI 10.1111/jocd.14421PubMed 34553483

Cited in: When to see a doctor about hair loss · Hair supplements: what has evidence

Defines acute telogen effluvium as shedding that lasts less than 6 months, lists triggers including high fever, surgery, childbirth, thyroid disease, iron deficiency and some medicines, and notes it settles once the trigger is removed.

Asghar F, Shamim N, Farooque U, et al. (2020). Telogen Effluvium: A Review of the Literature. Cureus 2020;12(5):e8320

DOI 10.7759/cureus.8320PubMed 32607303

Cited in: The hair cycle, explained · Shedding after stress, illness or birth · When to see a doctor about hair loss · Hair loss in women · Hair supplements: what has evidence

Shedding begins months after a trigger such as fever, childbirth, surgery, stress or a severe diet; it is called chronic after 6 months, and shedding after childbirth is usually followed by full recovery.

Rebora A (2019). Telogen effluvium: a comprehensive review. Clin Cosmet Investig Dermatol 2019;12:583–590

DOI 10.2147/ccid.s200471PubMed 31686886

Cited in: The hair cycle, explained · Shedding after stress, illness or birth · When to see a doctor about hair loss · Hair loss in women · Hair supplements: what has evidence · How to take progress photos

All 18 reported cases where biotin helped hair or nails involved an underlying cause such as deficiency; the authors found no good evidence for biotin in healthy people.

Patel DP, Swink SM, Castelo-Soccio L (2017). A review of the use of biotin for hair loss. Skin Appendage Disord 2017;3(3):166–169

DOI 10.1159/000462981PubMed 28879195

Cited in: Hair loss in women · Hair supplements: what has evidence

Ferritin confirms iron deficiency, and anaemia should be treated; there is not enough evidence to screen everyone with hair loss or to give iron to people who are not deficient.

Trost LB, Bergfeld WF, Calogeras E (2006). The diagnosis and treatment of iron deficiency and its potential relationship to hair loss. J Am Acad Dermatol 2006;54(5):824–844

PubMed 16635664

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Cited in: When to see a doctor about hair loss · Hair loss in women · Hair supplements: what has evidence

Describes five ways telogen effluvium can happen, such as growing hairs being released into the resting phase early, and reviews shedding caused by medicines.

Headington JT (1993). Telogen effluvium. New concepts and review. Arch Dermatol 1993;129(3):356–363

DOI 10.1001/archderm.129.3.356PubMed 8447677

Cited in: The hair cycle, explained · Shedding after stress, illness or birth

In an Australian town survey, hair loss at the front and top became more common with age, affecting 73.5% of men and 57% of women aged 80 and over.

Gan DC, Sinclair RD (2005). Prevalence of male and female pattern hair loss in Maryborough. J Investig Dermatol Symp Proc 2005;10(3):184–189

DOI 10.1111/j.1087-0024.2005.10102.xPubMed 16382660

Kept for reference; not cited in a guide yet.

In 1006 women aged 20 and over, female pattern hair loss was common from the late twenties and most common after age 50.

Norwood OT (2001). Incidence of female androgenetic alopecia (female pattern alopecia). Dermatol Surg 2001;27(1):53–54

DOI 10.1111/j.1524-4725.2001.00124.xPubMed 11231244

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Cited in: Pattern hair loss, explained · Hair loss in women

Classified the pattern of hair loss in 1000 white adult men; the source of the stages used in the Hamilton–Norwood scale.

Norwood OT (1975). Male pattern baldness: classification and incidence. South Med J 1975;68(11):1359–1365

DOI 10.1097/00007611-197511000-00009PubMed 1188424

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Cited in: Pattern hair loss, explained

Hamilton's original description of the types of patterned hair loss in men; we cite it only as the origin of the Hamilton–Norwood scale.

Hamilton JB (1951). Patterned loss of hair in man; types and incidence. Ann N Y Acad Sci 1951;53(3):708–728

DOI 10.1111/j.1749-6632.1951.tb31971.xPubMed 14819896

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Cited in: Pattern hair loss, explained

The EU regulator confirmed suicidal thoughts as a side effect of finasteride tablets with unknown frequency, added a patient card to 1 mg packs, found no link for finasteride skin spray, and judged that benefits still outweigh risks.

European Medicines Agency (2025). Measures to minimise risk of suicidal thoughts with finasteride and dutasteride medicines. EMA/142716/2025, 8 May 2025

ema.europa.eu

Cited in: Pattern hair loss, explained · Finasteride: what to know before you start · Finasteride spray: what we know · Your first months on finasteride

High-dose biotin, common in hair, skin and nail supplements, can make some blood tests give false results, including tests used to diagnose a heart attack. Tell your doctor if you take it.

US Food and Drug Administration (2019). UPDATE: The FDA warns that biotin may interfere with lab tests: FDA safety communication. FDA safety communication, 5 November 2019 (update to 28 November 2017)

drugs.com

Cited in: When to see a doctor about hair loss · Hair loss in women · Hair supplements: what has evidence

Poland's medicines register lists finasteride 1 mg tablets as prescription-only and minoxidil 2% and 5% solutions as available without a prescription.

Rejestr Produktów Leczniczych (Poland) (2026). Register entries for finasteride 1 mg tablets and minoxidil 2% and 5% solutions. Polish medicinal products register, availability category, checked 5 Nov 2026

rejestry.ezdrowie.gov.pl

Cited in: Pattern hair loss, explained · Minoxidil: how it works and how to use it · Finasteride: what to know before you start

Czechia's medicines register lists minoxidil 2% and 5% solutions as available without a prescription; we did not find an oral finasteride 1 mg entry there.

SÚKL (Czechia) (2026). Register entries for minoxidil 20 mg/ml and 50 mg/ml solutions. SÚKL medicines database, dispensing mode, checked 5 Nov 2026

prehledy.sukl.cz

Partly checked: we could read the record but not every number.

Cited in: Pattern hair loss, explained · Minoxidil: how it works and how to use it · Finasteride spray: what we know

Hungarian labelling texts show that minoxidil 5% solutions can be supplied without a prescription.

OGYÉI (Hungary) (2026). Labelling texts for minoxidil 50 mg/ml solutions. OGYÉI labelling texts, checked 5 Nov 2026

ogyei.gov.hu

Partly checked: we could read the record but not every number.

Cited in: Minoxidil: how it works and how to use it

A drug database drawing on Slovak regulator data lists a minoxidil 5% solution as not requiring a prescription in Slovakia.

Mediately (data from ŠÚKL and EMA) (2026). Minoxidil 5% dermal solution: dispensing status in Slovakia. Mediately drug database, Slovakia, checked 5 Nov 2026

mediately.co

Partly checked: we could read the record but not every number.

Cited in: Minoxidil: how it works and how to use it

Ireland's regulator lists finasteride 1 mg tablets as prescription-only and supplied through pharmacies only.

HPRA (Ireland) (2026). Finasteride 1 mg film-coated tablets: authorised medicine details. Health Products Regulatory Authority, PA22753/002/001, checked 5 Nov 2026

hpra.ie

Cited in: Pattern hair loss, explained · Finasteride: what to know before you start