Brief: hair-care

Research brief — `hair-care`

Field	Value
Slug	hair-care
Primary query / `seo_intent`	Pattern hair loss and heat, not vitamin A or invented product percents
Template (A–G)	E
Evidence tier (1–3)	1
Audience (one line)	Someone with a full shower shelf and a vitamin they added for growth
AI authors credited	ChatGPT-4o (original), Grok 4.7 (rewrite)
Reviewer or checker (optional)	none this pass; not dermatology
Date	2026-09-22

In hair, common thinning concentrates in pattern loss and chosen damage from heat, while bottles and vitamin A claims do not.

StatPearls, androgenetic alopecia. https://www.ncbi.nlm.nih.gov/books/NBK430924/. About 50% of Caucasian men by age 50 and about 80% by age 70. Prevalence, not a product result.
MedlinePlus Genetics. https://medlineplus.gov/genetics/condition/androgenetic-alopecia/. About 50 million men and 30 million women in the U.S. More than half of men over 50 have some loss.
Almohanna et al., Dermatology and Therapy, 2019. https://link.springer.com/article/10.1007/s13555-018-0278-6. Excess vitamin A can contribute to hair loss. Adult upper level cited at 10,000 IU preformed vitamin A a day. Biotin not supported as a general hair treatment.

Approx % claim	Field	Source	Where
About 80% of Caucasian men by age 70	Pattern hair loss prevalence	StatPearls	Opening evidence, explicitly not a product split
Intro 20/80 of bottles	shopping rule, not a clinic	prose hedge	Intro

A two-week shelf drill: shampoo, conditioner, heat protection only on heat days. Stop and get seen for patches or a sudden shed.

A new oil every week, trims sold as preventing 80% of problems, vitamins added for growth.

Scenario	Keep as Illustrative?
Eleven bottles plus a vitamin A softgel	Yes

Template E. One shelf drill. One table. One 8020 move. No viz.

StatPearls, MedlinePlus, Almohanna 2019. Internal: /diet, /skin-care, /self-care.