Hair Thinning

What Hair Thinning Reflects

On a healthy scalp, roughly 85 to 90% of follicles are in anagen, the growth phase that runs 2 to 6 years, while the rest are in telogen, a resting phase of about three months that ends with the hair shedding. Around 100 shed hairs a day is typical.^[1] Density falls when that balance shifts. Under significant physiologic stress, a much larger share of growing follicles can drop into telogen at once, and shedding rises weeks to months later.^[2]

Androgens are one population-level influence on scalp density. In androgen-related thinning, follicles in affected scalp areas show more 5-alpha-reductase, more androgen receptors, and higher DHT, and they gradually miniaturize into finer, shorter hairs.^[3] It's a site-specific effect: the same androgens that push terminal-hair growth on the face and body can inhibit follicles on the scalp.^[4]

How It's Measured

Outside a clinic, hair thinning is a logged observation. You note shedding you see on the pillow or in the brush, or changes like a wider part, and date them. Density shifts play out over months, so the dated series is the useful part.

Why People Track Hair Thinning

Hair density changes too slowly to judge from memory. The postpartum period is a well-described physiologic example of why timing context matters: the hormonal shift after birth, particularly falling estrogen, can move many follicles into telogen at once, with the shedding (researchers call it telogen effluvium) appearing one to six months after the trigger.^[2] Without dates, a lag like that is easy to misread. People also log hair thinning alongside hirsutism and hormonal acne, and next to labs like free testosterone, SHBG, and estradiol.

How Go Go Gaia Tracks Hair Thinning

Go Go Gaia logs hair thinning as a 1-click entry, dated automatically and charted against your cycle. Upload lab results and hormone values like free testosterone, SHBG, and estradiol land on the same timeline as your logs, so a slow-moving symptom and the labs people usually check with it sit in one view.

What the Research Shows

Androgen-related hair thinning is common in both sexes, affecting roughly half of men and women at some point. In women it usually looks different than in men: the frontal hairline holds while density drops diffusely at the crown, often showing first as a wider center part.^[3]

Diffuse shedding after a trigger follows a documented lag. The event that shifts follicles into telogen typically sits about three months before the shedding starts, with a range of one to six months.^[2]

Related Terms

Frequently Asked Questions

Educational information based on published sources. Not medical advice. For personal concerns, please consult your doctor.

How much daily hair shedding is typical?

Around 100 hairs a day is the commonly cited figure for a healthy scalp, where roughly 85 to 90% of follicles are growing (anagen) and the rest are resting (telogen) at any one time.^[1]

Why does hair shed after pregnancy?

The hormonal shift after birth, particularly the fall in estrogen, can push a larger share of follicles into the resting telogen phase at once. The resulting shedding, which researchers call telogen effluvium, typically appears one to six months after the trigger, most often around three.^[2]

What's the difference between shedding and thinning?

Shedding is the release of resting-phase hairs, which happens daily on every scalp.^[1] Thinning is a change in overall density over time. Diffuse shedding reflects more follicles resting at once,^[2] while in androgen-related thinning the follicles themselves gradually miniaturize and make finer, shorter hairs.^[3]