What vitamin deficiencies cause hair loss?

Low iron (ferritin), vitamin D and B12 are commonly linked with increased shedding. A GP can test for these before you start any supplement.

Will supplements regrow my hair?

Supplements mainly help when a deficiency is present. If your levels are already adequate, more is unlikely to help and can sometimes cause harm — testing first is safer.

Hair

Which vitamins help with perimenopause hair loss?

Quick answer

Hair shedding and thinning are common in perimenopause as oestrogen and progesterone fluctuate. No supplement is a guaranteed fix, but a few nutrients are commonly linked with healthy hair — iron (ferritin), vitamin D, B12, and enough protein. Low levels are worth checking with a GP rather than guessing. Tracking your shedding alongside cycle, stress and diet usually makes the pattern clearer than any single supplement.

What might be happening

Falling oestrogen can shorten the hair's growth phase, so more hairs rest and shed at once. Perimenopause also overlaps with life stages where iron, vitamin D and B12 can run low, and where stress and under-eating protein are common — all of which are commonly linked with more shedding.

A sudden increase in shedding a couple of months after a stressful event, illness or big dietary change can be telogen effluvium, which often recovers. Gradual thinning at the crown or parting can be a more hormonal pattern.

What to notice

When the shedding started and whether it was sudden or gradual
Where it's most noticeable (parting, crown, temples, all over)
What changed two to three months before (stress, illness, dieting, cycle changes)
Diet — protein, iron-rich foods, overall intake
Any blood test results (ferritin, vitamin D, B12, thyroid)

Related patterns

Women tracking perimenopausal hair changes often also notice sleep disruption, mood shifts, irregular cycles and skin changes.

When to get support

Ask a GP for blood tests (ferritin, vitamin D, B12, thyroid) before starting supplements, especially if shedding is sudden, patchy, or paired with other symptoms. More isn't always better — high-dose supplements without testing can do harm.