Hair Health . Symptoms guide
Excessive Hair Shedding: When to Test
Losing 50 to 100 hairs a day is normal. When shedding stays above that for weeks, the most common drivers are nutritional (iron, vitamin D, B12), thyroid imbalance, recent illness, stress, post-pregnancy hormonal shifts, or a reaction to a medication. A targeted blood panel can identify almost all of these in one appointment.
This patient information is being clinically reviewed by our team. The factual content draws on UK guidance (NHS, NICE, British Association of Dermatologists, British Society for Sexual Medicine where cited).
What this might be
- Telogen effluvium. A reactive shed triggered by illness, surgery, stress, crash diets, or post-partum hormonal change. Usually peaks 2 to 4 months after the trigger and resolves within 6 to 12 months.
- Low ferritin (iron stores). Often the single most missed cause. Symptoms appear before standard anaemia tests turn abnormal.
- Thyroid imbalance. Both under- and over-active thyroid cause diffuse shedding.
- Vitamin D or B12 deficiency. Both contribute to disrupted follicle cycling.
- Androgenetic alopecia (pattern hair loss). If shedding comes with thinning at the crown or temples, the DHT axis may also be involved.
When to seek urgent advice
If any of the following apply, please contact your GP, NHS 111, or A&E in the first instance rather than waiting for private bloodwork.
- Patchy bald spots (could be alopecia areata)
- Scalp pain, burning, or visible scarring at the hair line
- Sudden total hair loss
Common features that suggest this
- More than 100 hairs lost a day for over 6 weeks
- Hair pulled away easily in the shower or on the pillow
- Reduced ponytail thickness
- Fatigue, brain fog, or feeling cold (thyroid or iron clues)
- A stressful life event, surgery, or illness in the past 3 to 4 months
Recommended tests
Same-day appointments at our Harley Street clinic, results clinician-reviewed.
Need a marker not in these panels? Build a custom panel and a GMC-registered clinician will design one for you.
Testing advice
No fasting required. Same-day appointments at our Harley Street clinic. Most results are clinician-reviewed and available within 4 hours.
Common questions
How long should I wait before testing?
If shedding has been heavy for 6 or more weeks and there is no obvious cause, testing now is reasonable. The earlier a deficiency is corrected, the faster regrowth follows.
Which panel should I choose?
Hair Loss Essentials covers ferritin, iron, vitamin D, B12, thyroid function and full blood count. If you also suspect a hormonal driver (pattern thinning, post-menopause, post-pill), the Advanced Hair and Hormone Check adds DHT, androgens and oestrogen.
Will my GP run these on the NHS?
NHS testing usually covers thyroid and ferritin once a clinical case is made. Private testing gives same-day access without referral, full iron studies (not just ferritin), and a doctor review of the result rather than a range comparison.
Does stress really cause shedding?
Yes. Physical or emotional stress can push a large proportion of follicles into their resting phase at the same time. The shed appears 2 to 4 months after the event.
Related symptoms
Sources and further reading
This page provides general information only and is not a substitute for medical advice. A GMC-registered clinician will review your results and tailor any recommendations to you personally.