How density is measured
Trichoscopy is the examination of the scalp with a dermoscope, a magnifying camera that images the surface under controlled lighting. It lets a researcher count and measure individual hairs in a fixed area without taking any tissue.
It records the things that define density: the number of hairs per square centimetre, the split between thicker terminal hairs and fine vellus hairs, and shaft diameter. Because density changes gradually, in count and in calibre, these are the measurements that track it. Image the same marked area at intervals and you have a numbered record of change instead of an impression.
Two qualities make it right for a controlled study. It is non-invasive, so the same site can be imaged again and again. And it is quantitative: it produces counts, not opinions. It also lets a treated site be compared with a vehicle-treated one under identical conditions.
The independent study of the FGF·2 active that OF·27 cites used phototrichogram imaging (C-CUBE) as its primary measurement, over 12 weeks, against a vehicle control. Note 09 has the study. Note 18 borrows the same discipline for the two photographs you take at home.
What is trichoscopy?
Examination of the scalp and hair with a dermoscope, allowing shafts to be counted and measured in a fixed area without removing tissue.
How is hair density measured?
By counting hairs per square centimetre, distinguishing terminal from vellus hairs, and measuring shaft diameter, repeated on the same area over time.
The notes, by email.
One note at a time, in reading order, and a message when a new one is published.
An independent hair-science program.
The protocol the notes describe: The OF·27 Protocol
OF·27 is marketed as a cosmetic and is not intended to diagnose, treat, cure or prevent any disease.