Medically reviewed by our in-house trichology committee.
The short answer
An independent review published in 2023 went through eleven human studies covering 2,267 people with diagnosed hair loss and concluded that there is evidence supporting melatonin for scalp hair growth, particularly in men with androgenetic alopecia. That is a real finding, from a team with nothing to sell, and it is why this page exists.
Three things sit next to it. The only randomized placebo-controlled trial in the whole file calls itself a pilot and was published in 2004. The most quoted number in the file — shedding dropping from 61.6% to 7.8% — comes from work with no control group, commissioned by a company that markets the solution tested. And nobody has ever run melatonin head to head against topical minoxidil.
So the honest position is narrow and useful: a modest, mostly favourable file on a cheap cosmetic, worth layering on top of something that already works, and a poor choice as your first move. The rest of this piece is about how to tell those two situations apart.
Your follicle makes melatonin of its own
The instinct when you see melatonin on a hair shelf is to roll your eyes. You know this molecule from jet lag and bad nights. Pouring it on your head looks like one of those marketing migrations this site spends its time taking apart.
Except the biology holds up here. The reference review on melatonin and the hair follicle, published in 2008 in the Journal of Pineal Research, describes melatonin being produced inside the follicle itself — not only in the pineal gland — and a possible role in hair cycle control. The molecule is not arriving from somewhere else. It is already there, made locally, in the organ you are proposing to treat.
That is a better starting point than most of what sits beside it on the shelf. It is still only a starting point. A mechanism is not an outcome, and this site applies that rule without exceptions: caffeine acts clearly on an isolated follicle and the clinical demonstration never followed.
One research group, one product line
Here is the structural fact about this file that nobody mentions, and it shapes everything that follows.
Look at the author lists. The 2004 trial, the 2012 paper, the 2008 mechanism review — Fischer appears on all three. The clinical evidence for topical melatonin was built very largely by one research group, around one product. That is not misconduct, and it is common for a molecule nobody has a patent fight over. But it is the reason the 2023 review matters so much: it is the first look at the whole file by people who were not part of building it.
It also explains why the practical details are so specific. The concentrations that come out of this file are 0.1% and 0.0033%, applied once daily to the scalp, over 90 to 180 days. Those numbers come from particular products in particular studies, which has an immediate consequence for you: if the bottle in your hand does not print a concentration, you have no way of knowing whether it resembles what was studied.
Two more filters follow from the same place. The file was built on solutions that stay put — a lotion, a serum, applied and left alone. Not a shampoo, which you rinse off before it can do the thing a daily leave-on is supposed to do. And it was built on melatonin as the active, not melatonin as the eighth ingredient in a blend, in which case a good result will never tell you what produced it.
See melatonin scalp solutions →Affiliate linkThree lines to check before you pay: a concentration actually printed on the bottle, a product meant for the scalp rather than the lengths, and a formula where melatonin is not buried among other actives. A cosmetic is not a drug, and it does not replace medical advice.
The 2004 trial, read as its authors wrote it
There is one randomized placebo-controlled trial on this question. One, and it is more than twenty years old.
Published in 2004 in the British Journal of Dermatology, it tested a 0.1% melatonin solution applied once daily to the scalp against placebo, for six months, in women with androgenetic alopecia or diffuse shedding. The measurement was the trichogram: you count the share of hairs in the active growth phase. One subgroup showed a significant rise in that share.
What interests me is not the result. It is how the authors framed it.
They call their own work a pilot — the word is in the title. And they state that the mode of action remains unknown. The team that produced the firmest result in this file took care to say it was a first marker, not a demonstration. Twenty-two years later, no larger randomized trial has come along to take over.
Sit with what that means. In nearly every other subject on this site, a file that stops at a pilot trial gets filed under “interesting signal, no proof”. What makes melatonin different is that a tier was added on top — and that tier is exactly the one you need to know how to read.
61.6% to 7.8%, and the arm that was missing
Search for melatonin and hair and you will meet a number: shedding collapsing from 61.6% to 7.8%. It comes from a 2012 paper in the International Journal of Trichology that gathers several studies around the same solution. Among them, a three-month multi-centre study in more than 1,800 volunteers across some 200 centres, where the share of participants with a strongly positive hair-pull test falls from 61.6% to 7.8%. The same paper reports an observational study in 30 people, with a significant reduction in alopecia severity at 30 and 90 days.
Eighteen hundred people is a lot. It is the largest sample anywhere in this file. It is also the weakest demonstration in it.
Two reasons, and they are independent of each other.
The first is that there is no control group. That sounds like a technicality. It is the central objection, and you do not need any statistics to follow it. When do people go looking for help with hair loss? Not in a calm month. They go when it is falling worst, when the shower is frightening, when they have waited until they could no longer reassure themselves. A pull test done at that moment is done at the worst possible moment — and a worst moment is, by definition, followed by something else. The seasonal shed recedes. Whatever set it off moves further away. Ferritin comes back up. Three months later the test improves in a lot of people, whether they applied a lotion or nothing at all.
With no comparison arm, that natural return cannot be separated from the product’s effect. The study is not making an error; it simply does not have the design that would answer the question. What it shows is that people were better after three months. What it cannot show is why.
The second reason belongs on the table without being turned into an accusation: the work was commissioned by a company that markets the solution tested. That invalidates nothing automatically — plenty of good trials are industry-funded, and declaring it is the rule. But when an uncontrolled study of its sponsor’s own product generates the most striking figure in a file, caution is not bad faith.
The diagram below walks the four tiers of this file and what each one can carry.
Interactive diagram
Four tiers of evidence, and one word on the bottle: "melatonin"
Tap a tier to see what it establishes — and where it stops.
Four tiers, four different reaches. Pick one above.
What the diagram shows
The two bottom tiers are the ones you get quoted, and they are the two that prove least. The mechanism explains why the molecule is not an arbitrary thing to put on a scalp; it says nothing about what a lotion achieves. The large open series produces the most striking figure in the whole file with no control group behind it. The two upper tiers are smaller and more serious, and they are the ones to decide on: a controlled trial its own authors present as a pilot, and an independent review that concludes in melatonin's favour while asking for larger studies.
The correction
It is not to rule melatonin out, but to put it where it belongs: a low-cost cosmetic experiment, layered on top of a routine that already holds, and never a substitute for a diagnosis. If you want to try it, buy the thing that resembles what was studied — a scalp solution with its concentration printed on the bottle, where melatonin is not buried in a blend of other actives. That is the only way to know what you are applying. And if your shedding is diffuse and recent, the move is not a bottle but a hunt for the cause.
Affiliate link
Worth checking before you buy: a concentration actually printed on the bottle, a solution meant for the scalp rather than the lengths, and an ingredient list where melatonin is not keeping company with six other actives — otherwise you will never know what did the work. A cosmetic is not medical advice.
What an independent review added in 2023
This is the tier that changes the conclusion, and the reason melatonin earns a page here rather than a paragraph.
In 2023 a team at the University of California, Irvine — no connection to the earlier work — went back over the file in the Journal of Drugs in Dermatology. Eleven human studies, 2,267 people with a diagnosed alopecia. Most studies report improved scalp hair growth, several report improved density, two report an increase in hair shaft thickness.
Their conclusion is favourable and carefully worded: there is evidence to support melatonin use to facilitate scalp hair growth, particularly in men with androgenetic alopecia. In the same conclusion they call for studies with more patients and work on the mechanism of action.
This is where the concentrations above come from, and it is what gives the file its weight: people with nothing to sell looked at the whole thing and did not conclude placebo.
One absence remains, and it decides what you should buy. Nowhere in this file is there a head-to-head comparison between melatonin and topical minoxidil. No trial has put them against each other. That silence is not a criticism of melatonin — it is simply why melatonin cannot be offered as an alternative to a drug whose protocol and side effects have been documented for decades. You cannot replace what you have never compared.
It is the same reasoning this site applies to aminexil against minoxidil: two unequal files are not compared by reading their promises, but by looking at what was measured in each.
Swallowing it is a different question
This is the costliest confusion on the subject, and an easy one to fall into. Melatonin is one of the few hair actives you can also buy as a capsule, in the same store, usually cheaper — and in the US it sits on the shelf as a dietary supplement, bought without anyone asking a question.
Almost all of this file was built on the applied route. The 2023 review does log an oral arm — 1.5 mg twice daily over 180 days — but it is the thinnest part of what it gathers, and it does not support the idea that swallowing melatonin grows hair.
There is also a safety point a health article cannot skip. In France, the food-safety agency ANSES issued an opinion in February 2018 on food supplements containing melatonin, following adverse-effect reports collected through its nutrivigilance scheme. It advises against these supplements in pregnancy and breastfeeding, in children and adolescents, in people who need to maintain sustained alertness, and in people on medication — and recommends telling your doctor you are taking them.
That opinion is French, and most readers of this page are not. The reason to care is that it describes the product, not the country. A molecule that acts on alertness and can interact with prescriptions behaves the same way in Ohio as in Lyon; what differs is how easily you can buy it without being warned. In the US it is easier, which is an argument for more caution rather than less.
Put the two facts side by side. On one side, a hair benefit that is not established by this route. On the other, a product that affects alertness, can interact with treatments, and that a national agency asks people to be careful with in several situations. The trade is not worth making.
If you already take melatonin for sleep on medical advice, this article asks nothing of you, and certainly not to increase anything for your hair.
Does melatonin make sense for you?
None of the above decides anything for you, because the value of this product depends less on it than on the pattern of your loss and what you have already managed to stick with. Diffuse shedding that started in September, temples receding for ten years, a bare patch that appeared in three weeks, and hair that has been fine since childhood are not the same question — and in three of those four situations, the right answer is not a bottle.
Check · 3 questions
Does melatonin make sense for you ?
Question 1 of 3
What does your hair loss look like ?
💡 Reading grid put together by Thomas R., hair restoration specialist, from the sources listed at the end of this article. It steers a buying decision. It diagnoses nothing and does not replace a consultation. Swallowed melatonin and applied melatonin are two different questions, and they are not decided the same way.
Reading the label before you pay
Three habits, in this order, and they apply to any anti-shedding cosmetic.
Find the concentration, and walk away if it is not there. The file’s reference points are 0.0033% and 0.1%. A bottle announcing “with melatonin” and no number leaves you unable to tell whether you are buying what was studied or a trace of it.
Check that the product stays on the scalp. Lotion, serum, solution with an applicator: yes. Shampoo, mask, rinse-out conditioner: you are rinsing the active away.
Count the actives. One is readable. Eight, and the outcome — good or bad — tells you nothing about melatonin. That is the limitation the 2023 review names itself in the studies it pooled.
A word on what a label is allowed to claim, because the habit is worth having. A solution like this sells as a cosmetic. It therefore does not have to demonstrate therapeutic efficacy to reach the shelf, unlike a drug, which has to file a dossier and print its side effects. That is not a scandal; it is how the aisle works. But it explains how a product with a thin file and a product with a thick one end up side by side, with claims written in the same tone of voice.
One last practical point: introduce one new thing at a time. Add a melatonin lotion in the same month you switch shampoos and start a supplement, and you will have spent three times and learned nothing. The method for getting a usable baseline is in our piece on tracking loss that never shows up in a number.
Limits, and when to see a doctor
This article diagnoses nothing, prescribes nothing and does not replace an examination. It describes what publications measured, and no more. No dosing instructions appear in it, and the concentrations quoted are those of published trials rather than a personal recommendation.
What warrants medical advice without waiting, and before any spending:
- sudden, heavy shedding, coming out in handfuls, or clearly accelerating;
- well-defined bare patches, especially with eyebrows, lashes or nails also involved;
- a smooth, shiny or firm area with no visible follicular openings;
- a scalp that is red, painful, scaly or changed in appearance;
- shedding alongside unusual fatigue, weight change or cycle changes — those pairings point to a systemic cause that gets found in a blood test, and that no lotion will treat;
- lasting irritation, redness or itching after application: stop the product and get advice.
On melatonin itself, four limits hold together. The only randomized placebo-controlled trial presents itself as a pilot and dates from 2004. The work carrying the most impressive number has no control group and was commissioned by a manufacturer. The independent review that concludes favourably asks, in the same sentence, for larger studies. And no direct comparison with the reference treatment exists.
None of that makes melatonin a product to avoid: the cost is a cosmetic’s and the tolerance described is good. All of it makes melatonin a reasonable add-on to a base that already holds, and a bad first move. If your shedding is recent, diffuse, or comes with other signs, the priority is not picking a bottle: it is getting a cause looked for, and telogen effluvium often turns around on its own once its cause is corrected.
Frequently asked questions
Does melatonin regrow hair? An independent 2023 review of eleven human studies and 2,267 people concludes that there is evidence supporting melatonin for scalp hair growth, particularly in men with androgenetic alopecia — while asking for larger studies. So it is more accurate to describe a favourable signal on a young file than demonstrated regrowth. No percentage and no timeline can be promised.
Topical or oral? Topical. Almost the entire clinical file concerns a solution applied to the scalp, at 0.0033% or 0.1%, once daily. The oral route is the thinnest part of what has been studied, and ANSES advises caution with melatonin supplements in several situations, including pregnancy, breastfeeding, childhood and adolescence, and concurrent medication.
Can I use it alongside topical minoxidil? In practice that is the most defensible case — an add-on over a treatment that already holds. But no study in this file tested the combination, and minoxidil is a drug with its own rules of use. Put the question to your doctor or pharmacist rather than to an article, and add one thing at a time.
How long before judging it? The durations in the studies run 90 to 180 days of daily application, and the controlled trial ran six months. Three weeks will teach you nothing, and switching products every three weeks guarantees you never observe anything.
Sources and references
- Babadjouni A, Reddy M, Zhang R, Raffi J, Phong CH, Atanaskova Mesinkovska N. — Melatonin and the Human Hair Follicle. Journal of Drugs in Dermatology, 2023;22(3):260–264. DOI 10.36849/JDD.6921. PMID 36877877. Literature review by a team at the University of California, Irvine, with no connection to the work cited below. Eleven human studies retained, 2,267 people with a diagnosed alopecia. Most studies report improved scalp hair growth, several improved density, two an increase in hair shaft thickness. The authors describe effective dosing as a 0.0033% or 0.1% solution applied once daily for 90 to 180 days, versus 1.5 mg twice-daily oral melatonin for 180 days. Their conclusion holds that there is evidence to support melatonin use to facilitate scalp hair growth, particularly in men with androgenetic alopecia, and calls for studies including more patients and investigating the mechanism of action.
- Fischer TW, Burmeister G, Schmid HW, Elsner P. — Melatonin increases anagen hair rate in women with androgenetic alopecia or diffuse alopecia: results of a pilot randomized controlled trial. British Journal of Dermatology, 2004;150(2):341–345. DOI 10.1111/j.1365-2133.2004.05685.x. PMID 14996107. The only randomized placebo-controlled trial in the file. A 0.1% melatonin solution applied once daily to the scalp for six months, in women with androgenetic alopecia or diffuse hair loss, with trichograms measuring anagen and telogen hair rates. A significant increase in anagen rate is reported at subgroup level. The authors describe their work as a pilot trial — the term is in the title — and state that the mode of action remains unknown. Subgroup sizes and p-values are reported inconsistently across the secondary sources available for this piece, so they are not quoted in the body text, which sticks to the design, the concentration, the duration and the pilot status the authors claim for themselves.
- Fischer TW, Trüeb RM, Hänggi G, Innocenti M, Elsner P. — Topical melatonin for treatment of androgenetic alopecia. International Journal of Trichology, 2012;4(4):236–245. DOI 10.4103/0974-7753.111199. Open access (PMC3681103). A paper gathering several studies around the same topical melatonin solution, including a three-month multi-centre study in more than 1,800 volunteers across some 200 centres — the share of patients with a strongly positive hair-pull test falling from 61.6% to 7.8% — and an observational study in 30 men and women showing a significant reduction in alopecia severity at 30 and 90 days. The authors describe good tolerability and present the solution as a treatment option for androgenetic alopecia. Both of those are uncontrolled series: that is the limitation discussed under “61.6% to 7.8%”. Several secondary sources state that the work was commissioned by a company marketing the solution tested; the exact enrolment of the large study is reported with slight variation between sources, hence “more than 1,800”.
- Fischer TW, Slominski A, Tobin DJ, Paus R. — Melatonin and the hair follicle. Journal of Pineal Research, 2008;44(1):1–15. DOI 10.1111/j.1600-079X.2007.00512.x. The reference review on melatonin and the hair follicle. Points used here: melatonin production within the hair follicle itself, enhanced by catecholamines as classically occurs in the pineal gland; a possible role for melatonin in hair cycle control; and a proposed local cytoprotective role for the anagen hair bulb linked to melatonin’s free-radical scavenging activity. This is mechanistic work, partly from animal models and cultured tissue. It establishes the molecule’s relevance at follicle level, not a clinical benefit.
- ANSES (French Agency for Food, Environmental and Occupational Health & Safety) — Opinion on the risks associated with the consumption of food supplements containing melatonin, examined 23 February 2018, published 11 April 2018. Based on adverse-effect reports collected through the agency’s nutrivigilance scheme. Points used here: the recommendation to avoid these supplements in pregnant and breastfeeding women, in children and adolescents, in people who must maintain sustained alertness, and in people on medication; the advice to keep use occasional, to seek a health professional’s opinion and to tell one’s doctor about them; and the fact that supplements sold in France contain less than 2 mg of melatonin per day. This opinion concerns the oral route and sleep, not hair. It is cited solely to support the warning under “Swallowing it is a different question”.
The sources above are cited by journal, year, volume, DOI and PubMed identifier where they exist. Direct access to PubMed, Europe PMC and PubMed Central was blocked by this session’s network policy, so each reference was verified by cross-checking several independent searches on title, authors, journal, pagination and DOI, and anything drawn from full text is reported at abstract level or expressed qualitatively. No head-to-head comparison between topical melatonin and topical minoxidil was found in the literature consulted; that is an absence, and it is flagged as such in the article rather than filled with an estimate. No regrowth percentage, responder rate or guaranteed timeline is asserted here beyond what the cited publications report themselves, and no prices are quoted.
