Perimenopause Hair Loss: Why It Starts Now, and What to Check First

Iron deficiency. Heavier perimenopausal periods drain iron, and iron deficiency is a recognized shedding trigger. Ferritin shows it, and ferritin and hair loss explains why it is checked even when the blood count looks ordinary. If your periods have changed, the spotting and heavy periods page belongs in the same conversation.

Thyroid disease. Thyroid disorders cause thinning and cluster in the same decade as the transition, with overlapping symptoms. Midlife or thyroid covers the overlap.

Medications. Beta blockers and retinoids, including excess vitamin A, are the most commonly implicated. Anticoagulants, the antithyroid drug propylthiouracil, carbamazepine, some gout medicines and some blood pressure medicines are also on the list, and stopping birth control pills is a trigger in its own right.

Illness, surgery and rapid weight loss. A high fever, a serious infection, an operation or a crash diet with too little protein pushes many follicles into their resting phase at once. The shedding shows up months later, when the event has been forgotten.

Scalp conditions and scarring alopecia. Scalp psoriasis, fungal infection and inflammatory conditions that destroy the follicle produce loss with itch, scaling, redness or tenderness, and the follicle can be lost for good. Styles that pull continuously at the same hairs do lasting damage too.

Excess androgen. Less commonly, thinning arrives with new facial hair, midlife acne or irregular cycles. That combination points to a hormonal cause such as polycystic ovary syndrome rather than to the transition. Perimenopause acne covers the skin side.

A clinician separates these by asking how long the loss has been going on and how fast it came, by examining the scalp and the pattern, by a gentle pull test and, where the history suggests it, by blood tests or a scalp biopsy.

For hair loss in a woman in her late forties or fifties, the useful blood work is not primarily hormonal. Ferritin and a complete blood count show iron status. TSH, with free T4 where indicated, shows thyroid function. Vitamin D, zinc and B vitamins are commonly included, because deficiencies of each have been linked to hair loss, though the strength of that evidence varies. Together these are a baseline panel; what blood work covers explains each marker.

Androgen markers such as testosterone and DHEA-S earn their place only when there are signs of androgen excess. In the ordinary pattern they are usually unremarkable.

What a lab cannot settle is whether you are in perimenopause. Estradiol and FSH swing across the transition, so a single draw does not date it, and no hormone result says whether hair loss is "hormonal". The pattern on the scalp does that. Hormones behind hair loss in women goes deeper, and the hair and skin FAQ collects the shorter questions.

ACT 2 Health is a telehealth practice: no scalp examination, pull test or biopsy is possible over video, and some hair loss needs exactly those. Book an in-person visit, preferably with a dermatologist, within a couple of weeks if any of these applies.

• Patchy loss rather than diffuse thinning: round bare areas, or loss confined to one region.
• Scalp changes at the site of loss: scaling, redness, pain, burning, itch, pustules, or skin that looks shiny and smooth where hair used to be. These are signs of a scarring process, and inflamed follicles can be lost for good.
• Hair loss with facial hair growth, a deepening voice or new acne in midlife. This needs a hormonal evaluation that goes beyond the transition.
• Sudden heavy shedding in the months after a serious illness, an operation or a large weight loss, particularly if you also feel unwell.

None of these are emergencies. All are reasons not to spend a year treating the wrong cause.

Hair has a built-in delay. A follicle pushed into its resting phase holds the hair for roughly a season before releasing it, so shedding noticed in spring often began in winter. That lag is why hair loss gets blamed on whatever is happening now, and for a woman in her late forties, what is happening now is perimenopause.

Before the assessment, work backwards. Write down, with dates, everything from the months before the shedding began: any illness with a fever, any operation or anesthetic, any diet that dropped your weight quickly or cut protein hard, any period of intense stress. Then list every medication and supplement with the month it started or stopped: blood pressure medicines, beta blockers, anticoagulants, thyroid or antithyroid drugs, anticonvulsants, gout medicines, retinoids and vitamin A products, and anything sold for "hormone balance". Include contraception, because coming off an estrogen-containing pill is itself a trigger.

Two rules. Do not stop a prescribed medicine because it appears on a list; that conversation belongs with the prescriber. And do not assume a trigger exonerates hormones, because both can be present at once. A trigger you can name is a cause you can remove, and that is a better first step than a hormone conversation that may not apply.