TLDR The normal range for the hair pull test is 2 hairs or fewer, and washing or brushing hair before the test does not affect the results.
The study "Hair pull test: Evidence-based update and revision of guidelines" involved 181 participants and aimed to establish normal values for the hair pull test, a diagnostic tool for hair loss. The researchers concluded that the normal range for the hair pull test is 2 hairs or fewer removed per pull, which is a revision from the previously suggested value of less than 5 to 6 hairs. The study also found that pretest hair washing and brushing did not significantly affect the results, allowing these activities to be performed at any time before the test. The findings indicated no significant difference in test results based on sex, hair texture, or use of oral contraceptives. The updated guidelines suggest that ≤2 hairs removed is normal, and pretest hair washing and brushing are permissible at any time. Further research is needed, particularly for Afro-textured hair and in individuals with hair loss disorders.
Cited in this study
5 / 5 results
76 citations
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July 2011 in “Clinical, Cosmetic and Investigational Dermatology” The document concludes that proper diagnosis and FDA-approved treatments for different types of hair loss exist, but treatments for severe cases often fail and future improvements may focus on hair follicle stem cells.
1 citations
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December 2010 in “InnovAiT” The document concludes that accurate diagnosis and appropriate management are crucial for treating various hair disorders, which have significant psychological impacts.
73 citations
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March 2009 in “Seminars in Cutaneous Medicine and Surgery” The document concludes that accurate diagnosis of hair disorders is crucial and requires a range of diagnostic methods.
91 citations
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January 2009 in “International Journal of Trichology” Different hair evaluation methods have their own pros and cons, and using multiple methods together is best for accurate hair loss diagnosis and tracking.
41 citations
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July 2002 in “Clinical and Experimental Dermatology” Effective hair loss assessment requires a mix of precise measurement methods.
1 citations
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October 2022 in “PubMed” Patients generally have positive attitudes towards using topical Minoxidil for hair loss treatment.
January 2021 in “International journal of dermatology, venereology and leprosy sciences” Most adult women experiencing hair loss are aged 21-40, with the most common type being female pattern hair loss. Trichoscopy is a useful tool for diagnosing different types of hair loss.
January 2020 in “Hair therapy & transplantation” 
August 2018 in “Oxford University Press eBooks” The document's conclusion cannot be provided because the document cannot be parsed.
June 2018 Baldness is often hereditary and linked to male hormones, becoming noticeable when half the hair is lost.
36 citations
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March 2017 in “Journal of The American Academy of Dermatology” The normal range for the hair pull test is 2 hairs or fewer, and washing or brushing hair before the test does not affect the results.
43 citations
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August 2013 in “Pediatric Dermatology” Trichoscopy is good for diagnosing and monitoring hair and scalp problems in children but needs more research for certain conditions.
