September. The shed has probably started. Here is what that means — and the one thing to do differently this month.

The shed has probably started.

Not dramatically — not yet. But the Kunz study mapped the telogen peak in summer and the October shedding wave across six years and 823 women, and September is the month those summer-peak telogen hairs are completing their three-month rest phase. The wave hasn't crested. It is building.

The August 31 Sunday said: test now, tighten the ritual, reduce the cortisol load. Today is the Sunday to check whether you did those things — and if not, to do them now. September is still early enough that testing makes a difference. October, when the shed peaks, is when results come back and options narrow.

What to notice this month — without over-monitoring.

Normal daily shedding is 50-100 hairs. The seasonal shift pushes this toward 100-150 in September, building toward 150-200 in October at peak. More than 200 hairs daily consistently for more than eight weeks warrants investigation. The word "consistently" matters — daily variability is enormous and meaningless. Three consecutive high-shed days followed by normal shedding is not a crisis. It is hair biology doing what hair biology does.

The most useful comparison is not day-to-day. It is year-to-year. How does September 2026 compare to September 2025? If you don't remember September 2025 in detail — which most people don't — the six-month photograph protocol from the August 16 Sunday article is the comparison that actually holds information. The mirror today vs the photograph from February or March. That is a meaningful data point. The brush count today vs yesterday is not.

The one thing to do differently in September.

Test.

Ferritin and CRP. Vitamin D. Full thyroid panel — TSH, free T3, free T4, TPO antibodies. The August 19 blood test guide is the complete reference.

Here is why September specifically matters for timing: blood test results take 1-3 weeks depending on your clinician and lab. Correcting a ferritin deficiency takes 3 months of supplementation to move meaningfully. A ferritin of 22 ng/mL discovered in October — mid-shed — cannot be corrected before the shed peaks. A ferritin of 22 ng/mL discovered in September can be supplemented immediately, giving 4-6 weeks of correction before the peak and a fuller repletion trajectory into November.

The same timing argument applies to vitamin D: autumn and winter dramatically reduce synthesis from sun exposure. If your vitamin D is at 28 ng/mL going into September — below the hair-optimal 40-60 ng/mL — the next six months of reduced UV exposure will not improve it without supplementation. This is the last month where starting supplementation makes a difference before the winter deficit compounds the seasonal shed.

Stop biotin supplements 3-5 days before the draw. The August 12 biotin article explained why — thyroid and hormone tests are unreliable with high-dose biotin in the system.

What the series has been doing — and where it goes next.

August was the series' most intensive month — ninety-something articles across four months, covering every mechanism from DHT to prostaglandin D2 to osteopontin. September is when the series turns from mechanism to maintenance: what does consistent practice look like when the biology is fully understood? What does the ritual mean in an autumn that is about supporting the baseline rather than investigating it?

The autumn shed is coming regardless of how much is understood about it. The biology does not care about the reading list. What the reading list changes is the response — investigation instead of panic, six-month assessment instead of daily mirror anxiety, nutritional correction instead of supplement guessing, pattern recognition instead of symptom alarm.

That is what four months of daily articles has been for. Not to prevent the shed. To be ready for it.