Care with Roscoe Nelson, MD, board-certified urologist.
It is a medical problem first
Hair loss gets treated as cosmetic, which is why so many people arrive with a bottle of biotin and no workup. The follicle is one of the most metabolically active structures you own, and it reacts to hormones, iron, thyroid, inflammation and stress. In the years around menopause several of those move at once.
Biotin does nothing unless you are truly deficient, and at high doses it interferes with thyroid and cardiac lab tests, which can hide the real cause. If you take it, say so before any blood draw.
What I check before I treat
Iron is the most commonly missed contributor, and a normal blood count does not exclude it. Hemoglobin can be fine while ferritin, the storage measure the follicle actually cares about, is low. I measure ferritin directly and bring it well above the bottom of the range, not barely into it. Years of heavy periods are the usual reason it is low.
Thyroid disease is the next most common miss, including the mild form that never made it onto a problem list. Vitamin D and zinc matter in restrictive diets. No hair medication, topical or oral, can make up for an uncorrected nutritional or hormonal cause, and if those are skipped the treatment gets blamed for failing.
Men, and the window that closes
In men the driver is DHT, which shortens each growth cycle until thick hairs become fine ones. The follicles worth fighting for are the ones still shrinking rather than gone, so earlier is better. There are several independent levers: lengthening the growth phase, blocking the DHT signal, calming the scalp, improving how well a topical actually gets in, and microneedling. Two or more levers beat one, which is why a single prescription and nothing else so often disappoints.
What treatment looks like here
Reversible causes first: ferritin to a real target, thyroid corrected, vitamin D repleted. Then a combination chosen for your pattern, with the choice constrained by whether you could become pregnant, because some of the most effective drugs in this space are strictly off limits in that case. Expect an early signal at about three months and a real read at six. Some treatments cause extra shedding in the first weeks as resting hairs are pushed out by new growth. That is the treatment working, and it is the most common reason people quit early.
Scalp pain, burning, scaling, redness, pustules, sharply outlined bald patches, a receding frontal hairline or fast progression need a dermatologist promptly rather than a growth regimen. Those patterns can scar the follicle permanently, and the window matters.
Peri opens Late 2026 in Draper, Utah. The waitlist hears first.