Hair pull test: what it shows and why washing matters
Reviewed by The Wellness Team. Last reviewed October 2026.
Short answer: the hair pull test is a simple check where a clinician gently pulls a small group of hairs to see whether more come out than expected. The British Association of Dermatologists (BAD) says it can be falsely negative if the hair was washed within 48 hours beforehand. One test on one day cannot tell you why your hair is shedding. It is a clue, not a diagnosis.
What the test is
BAD describes the pull test in its guide to telogen effluvium, a condition where more hair than usual falls out. A hair pull test can be carried out by gently pulling the hair to see if more hair comes out than usual. It sits alongside a look at the scalp and a medical history, which is how telogen effluvium is usually diagnosed.
Why the 48 hours matters
BAD says that if the hair has been washed within 48 hours beforehand, the test may be falsely negative. Washing removes loose hairs that were ready to shed, so there is less to find. If you are booking a hair assessment, ask what to do about washing beforehand rather than guessing.
What a pull test cannot tell you
Normal shedding is 30 to 150 hairs a day, according to BAD. A pull test cannot say why more are coming out. BAD lists common triggers of telogen effluvium: childbirth, severe illness or high fever, stressful life events, surgery, marked weight loss or extreme dieting, starting new medications and stopping a hormone treatment such as the contraceptive pill. For 1 in 3 people with the diagnosis, no cause is found.
Pattern thinning, patchy loss and scarring conditions need different checks. A pull test is not the way to rule those in or out.
What else may be checked
BAD says hairs can be plucked and looked at under a microscope, and very rarely a skin biopsy is needed when the diagnosis is uncertain. A blood test may be done to exclude other causes such as thyroid conditions and iron deficiency.
What to expect afterwards
BAD says telogen effluvium usually gets completely better without treatment. The shedding phase lasts 3 to 6 months, and it can take many months for hair to return to normal volume. It is considered chronic if it lasts more than 6 months, and it can come back if an underlying cause such as iron deficiency is not treated.
Where PRP fits
Platelet-rich plasma (PRP) is made from a small sample of your own blood and injected into the scalp. It is not a treatment for a temporary shed that will settle by itself, and we would say so. It is an option to discuss for ongoing thinning once the cause has been assessed. The research is mixed and results vary. We do not guarantee an outcome.
Our prices are plain: PRP for hair is £450 a session, or £1,215 for three. A hair consultation with dermoscopic imaging is £150.
Next step
If you are not sure whether you are shedding or thinning, message us. We will tell you honestly what we would check first.
Message us on WhatsApp or read our hair PRP guide.
Sources: British Association of Dermatologists, Telogen effluvium patient information leaflet (bad.org.uk/pils/telogen-effluvium). This article is general information and not a diagnosis.