Noticing more hair in the brush, a widening parting or a thinner ponytail can be distressing. Hair loss in women is common and often has more than one cause working together. Some of those causes are measurable in the blood — and finding them means they can be addressed. A targeted panel is a sensible first step when thinning is persistent.
The common blood-related causes
Several deficiencies and imbalances are well recognised contributors to hair thinning in women. A hair-focused panel typically checks:
- Ferritin and iron — low iron stores are one of the most common and reversible causes, especially with heavy periods.
- Thyroid function — both an under- and overactive thyroid can cause shedding.
- Vitamin D — often low in the UK and linked to hair health.
- Vitamin B12 and folate — important for healthy hair growth.
- Androgens — hormones that can drive a pattern of thinning, sometimes linked to PCOS.
Why iron matters so much
Ferritin, which reflects your iron stores, is worth singling out. Hair follicles are sensitive to low iron, and levels can be depleted long before a standard blood count shows anaemia. This is why measuring ferritin specifically — rather than relying on haemoglobin alone — is important when investigating hair loss.
Telogen effluvium and shedding
Many women experience a diffuse, temporary shedding known as telogen effluvium, often triggered a few months after a stressful event, illness, childbirth, significant weight loss or a period of poor nutrition. Blood tests help by ruling out an ongoing deficiency, reassuring you that the shedding should recover as the trigger resolves.
Investigate hair loss
A hair health panel checks the common blood causes of hair thinning — iron and ferritin, thyroid, vitamin D, B12 and hormones in one appointment.
Investigate hair lossWhen hormones are involved
A gradual thinning at the crown or a widening parting can reflect female-pattern hair loss, which has a hormonal and genetic basis. If androgens are raised or there are other signs such as irregular periods or acne, your clinician may consider PCOS. Where hormone timing matters, samples are often best taken early in the cycle, around day 2 to 5.
When to get checked
Consider testing if hair thinning has continued for more than a couple of months, seems more than seasonal shedding, or comes with other symptoms such as fatigue, irregular periods or changes in weight. Sudden patchy loss, scalp inflammation or scarring should be seen by a clinician directly, as these need examination rather than bloods alone.
Investigate hair loss
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Specialist interest: Cardiovascular Medicine · OneMedicine, CQC-registered clinic