Plenty of women start losing more hair in their early or mid-40s, while they're still having periods, and assume menopause has started. Usually they're in the years before it, and hormonally those years look surprisingly little like menopause, which changes what's worth doing about your hair.

Jerilynn Prior, an endocrinologist at the University of British Columbia, is one of the researchers who has shown this most clearly. In her group's hormone measurements, about a third of perimenopausal cycles had an estrogen spike late in the cycle, right when it would normally be dropping. So estrogen in these years isn't simply falling. Some months it's higher than it was when you were 30. Only after menopause does it drop and stay down.

A hormonal picture that keeps changing

Progesterone is usually the first thing to slip. It's made after ovulation, and in your early to mid-40s, sometimes earlier, ovulation stops happening every month. Some cycles release an egg; some don't. Each cycle that doesn't produces very little progesterone.

Estrogen doesn't follow that tidy logic, partly because the brain keeps pushing the slowing ovaries harder with follicle-stimulating hormone (FSH), and in some months the push overshoots so that estrogen ends up above normal, while in others very little happens. Prior's work describes perimenopause as a time of erratically high estrogen, falling progesterone, and disrupted feedback between the ovaries and the brain, which is a long way from the "estrogen is running out" story most women hear.

This stage lasts longer than people expect. On average it begins about five years before your final period, and it can start as many as ten years ahead. Menopause itself is officially a single point: twelve months in a row without a period. Everything after it is postmenopause, and that's when the picture finally settles, with estrogen and progesterone staying low and steady.

One practical consequence is easy to miss. Because some cycles still release an egg, pregnancy remains possible during perimenopause, and that matters for several hair loss treatments, including some botanicals.

Two ways it can show up in your hair

For a lot of women the first sign is shedding that arrives in waves, with six or eight weeks of hair on the pillow and wound around the brush, a quieter couple of months, and then another round, a pattern dermatologists named chronic telogen effluvium when they described it in middle-aged women in the 1990s.

About twenty years later, the California dermatologist Paradi Mirmirani asked whether the transition itself might be setting it off. Her 2016 paper in Dermatology Online Journal pointed out that sex hormones feed into the body's internal clock genes, and suggested that the swings of perimenopause could throw off the timing of the hair cycle. She was careful to call it a hypothesis, and it still is one. The part of her paper I'd most want a worried reader to see is about outcome. In plenty of women it comes and goes for years, and the hair never ends up looking thinner.

Pattern thinning is quieter, since the follicles shrink a little with each cycle and the new hairs come in finer and shorter, so women tend to notice it in a mirror, at a part that looks wider or a crown that shows more scalp, rather than in the drain. It builds with age. An Australian community study found that about 25% of women had some degree of it by age 49. After menopause, a 2022 study of 178 women at a Thai menopause clinic found it in just over half.

What makes perimenopause confusing is that both can happen at once. A woman whose pattern thinning was quietly getting started in her early 40s may first notice it during a bout of heavy shedding, and assume the shedding is the whole story.

I should be clear about the limits here. Very little research has studied hair in perimenopause specifically. Most studies group women as pre- or postmenopausal, and much of what's said about the transition years is inferred from the hormones rather than measured in hair. So treat the hormone-hair connection in these years as my best reading of the evidence, not settled perimenopause data.

Perimenopause vs. menopause hair loss

	Perimenopause	After menopause
Estrogen	Swings, sometimes high	Low, steady
Progesterone	Falling, often first	Low
Typical hair complaint	Shedding that comes and goes	Gradual thinning, wider part
Periods	Irregular, sometimes heavy	Stopped
Pregnancy	Still possible	No

The causes hiding behind the hormones

Back in the mid-1990s, researchers at seven US sites signed up a few thousand women in their 40s and early 50s for a study called SWAN (the Study of Women's Health Across the Nation), and they've been checking in with them ever since. Somewhere in their transition, about one in three had stretches of heavy or prolonged bleeding. In a 2025 analysis of 2,329 of those women, heavy bleeding went along with lower hemoglobin and ferritin, the body's main measure of stored iron, and with more fatigue.

That matters for hair because low iron stores are one of the classic triggers for shedding. So if your periods have become heavier and you're also more tired than usual, those may be the same story, and a blood test is a reasonable next step.

Thyroid problems can produce hair loss of their own, along with fatigue and mood changes that are easy to put down to perimenopause. So can sustained stress, poor sleep, and crash dieting, all of which tend to cluster in these same years. None of them shows up in the mirror as anything other than "more hair falling out," which is why I'd rule them out before blaming hormones alone.

A few kinds of midlife hair loss shouldn't be blamed on hormones at all. Round, smooth bald patches are one, and an itchy, burning, or flaky scalp is another, as is a hairline that has crept back over a year or two, especially if the eyebrows have thinned along with it. These need a dermatologist's diagnosis rather than a hormone explanation.

What to do about it

Blood work comes first, for the reasons above. A panel with ferritin and thyroid function is a reasonable thing to ask your doctor for, particularly if your periods have changed or you're more tired than usual. Some clinics and apps also sell FSH or estrogen tests as a way to confirm perimenopause. The trouble is that in perimenopause those levels can be high one week and low the next, which is why the Cleveland Clinic cautions that one result can mislead. I'd much rather see a ferritin or thyroid number, since if either comes back off, there's something to treat.

A simple record kept over a few months helps more than most people would guess. What I'd suggest is a monthly photo of your part, taken in the same spot under the same light, with a one-word note beside it on how heavy the shedding has been. Three months of that usually says more than any single visit. If the shedding goes up and down but the part never changes, you're most likely looking at the cyclical kind. A part that's slowly getting wider suggests pattern thinning is involved too, and those photos are worth bringing to a dermatologist.

For pattern thinning, the best-studied over-the-counter option is topical minoxidil. The women's version is 2%. Its FDA approval covers mild-to-moderate androgenetic hair loss, which is the medical name for pattern thinning, and not shedding on its own. Results take several months to judge. Minoxidil also isn't recommended in pregnancy, which brings back the last row of the table.

Dermatologists sometimes go further with prescriptions. Spironolactone is the one women hear about most. Originally it was a diuretic for blood pressure. It also happens to block androgens, and that's why dermatologists use it off-label for pattern loss. It can harm a developing pregnancy, though, so a woman who could still conceive is normally asked to be on reliable contraception while she takes it.

Then there's hormone therapy, which a lot of women hope will fix their hair along with everything else. For hot flashes and night sweats it often works well, and your gynecologist or a menopause specialist is the right person to weigh it with you. For hair, the evidence amounts to a handful of small studies, and it isn't approved for that use.

Say your labs are fine and your part looks the same in every photo. Then the odds are on your side. This kind of shedding tends to settle as the transition goes on and hormone levels even out, and in the meantime it's worth cutting down on breakage, with looser styles, a bit less heat, and enough protein and iron in your meals.

Where MDhair fits

Regrowth Supplements ($42) are built around saw palmetto and pygeum, combined with more than 20 vitamins and plant-based complexes, including an adaptogen blend aimed at the stress side of these years. Restore Serum ($44) is a leave-on scalp serum from our bond-building Restore line, and one of our DHT-blocker formulations, with topical saw palmetto in its formula. If it ever irritates your scalp, stop using it.

Both include saw palmetto, which has hormonal activity, and the Merck Manual advises that women who are pregnant or could become pregnant shouldn't take it by mouth. Since pregnancy is still possible in perimenopause, talk to your doctor before starting either product if there's any chance of it, and especially before the supplement. If you're managing a medical condition or taking hormone-related medication, the same applies.

My team and I ran a six-month clinical trial of MDhair's personalized regimen, published in the Journal of Drugs in Dermatology in 2025. It wasn't a perimenopause study. We compared our regimen against one specific competitor, the leading hair loss supplement brand, so I'd read what follows as support for personalizing a routine and not as a forecast for your own hair. At 90 days, hair growth had improved about 2.8 times as much. For hair quality the figure was about 3.0 times.

As for what's regulated: Regrowth Supplements are a dietary supplement, and the FDA hasn't evaluated the claims made for them. Restore Serum is a cosmetic. Neither product is a drug, and neither is meant to diagnose, treat, cure, or prevent any disease, whatever this category's marketing tends to suggest. In our lineup, drug status belongs only to minoxidil, approved over the counter for mild-to-moderate androgenetic hair loss.

Our free AI hair and scalp assessment starts with a short quiz and a scalp photo, and it's designed to tell shedding apart from pattern thinning and match a regimen to which one you have. Every MDhair regimen also includes unlimited chat access to our dermatologist team.

Dr. Yoram Harth is a board-certified dermatologist and Co-Founder and Chief Medical Officer of MDalgorithms Inc., the company behind MDhair and MDacne. A magna cum laude graduate of Tel Aviv University's Sackler School of Medicine, he trained in dermatology at Rambam Medical Center and completed a research fellowship at Columbia-Presbyterian Medical Center in New York. His work spans phototherapy, photodynamic therapy, and AI-personalized skin and hair care.

Sources

Studies were located through PubMed and the publishing journals' own sites.

1. Prior JC, Hitchcock CL. The endocrinology of perimenopause: need for a paradigm shift. Front Biosci (Schol Ed). 2011;3:474-486. doi:10.2741/s166
2. Mirmirani P. Hormones and clocks: do they disrupt the locks? Fluctuating estrogen levels during menopausal transition may influence clock genes and trigger chronic telogen effluvium. Dermatol Online J. 2016;22(5). escholarship.org
3. Gan EK, Sinclair RD. 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.x
4. Chaikittisilpa S, Rattanasirisin N, Panchaprateep R, et al. Prevalence of female pattern hair loss in postmenopausal women: a cross-sectional study. Menopause. 2022;29(4):415-420. doi:10.1097/GME.0000000000001927
5. Harlow SD, Gold EB, Hood MM, Mukwege AA, Randolph JF, Greendale GA. Abnormal uterine bleeding is associated with fatigue during the menopause transition. Menopause. 2025;32(6):499-504. doi:10.1097/GME.0000000000002525
6. Cleveland Clinic. Perimenopause. my.clevelandclinic.org
7. Merck Manual Consumer Version. Saw palmetto. merckmanuals.com
8. Bhardwaj V, Rodgers N, Harth O, Harth Y. Artificial intelligence-based personalization of treatment regimen for hair loss: a 6-month clinical trial. J Drugs Dermatol. 2025;24(3):233-238. doi:10.36849/JDD.8611

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