HRT Hair Biomarkers: What to Track and How Often
HRT hair biomarkers are the measurable signs you can track on your own scalp while you are taking hormone therapy: shed counts, part width, fibre thickness, coverage and photographs taken the same way each month. None of them predicts anything. What they do is replace the unreliable memory of how your hair looked in spring with something you can actually compare.
Our hair growth shampoo
Grow Me® Hair Growth Shampoo, £14.95. A sulphate free daily shampoo that supports a healthy scalp environment and helps reduce breakage, so lengths hold on and look fuller.
Key takeaways
- The five markers worth tracking are a monthly parting photograph, part width, shed count, fibre feel and scalp coverage at the crown.
- Losing up to 50 to 100 hairs a day is normal, so a single count means very little and a trend across months means a lot.
- The resting phase runs about three to four months, so review at three months at the earliest and six months for an honest answer.
- Measure the same way every time. Same room, same light, same day of the week, same washing pattern, or the numbers are noise.
- A log is most useful in a GP appointment. It turns 'my hair feels thinner' into something someone can look at.
What are HRT hair biomarkers?
HRT hair biomarkers are simply the things about your hair that can be observed and recorded repeatedly while you are on hormone therapy. The word sounds clinical and the practice is not: a phone camera, a ruler and a note on the same day each month cover most of it. A marker earns its place if you can measure it the same way twice.
That last test rules out a surprising amount. How thick your hair feels after a blow-dry is not a marker, because it changes with the weather and with which product you used. The width of the visible scalp line at your parting is a marker, because a photograph of it in June can be laid beside a photograph of it in September and compared by someone other than you.
Which HRT hair biomarkers can you track at home?
Five markers do nearly all the useful work, and they cost nothing. The table below sets out how to record each one, how often, and how much weight to put on it, because some of these are far more trustworthy than others and treating them as equal is how people talk themselves into and out of progress.
| Marker | How to record it | How often | How much to trust it |
|---|---|---|---|
| Parting photograph | Same bathroom, same light, hair dry and parted the same side | Monthly | High. The most useful single thing you can do |
| Part width | Visible scalp line measured at a fixed point from the hairline | Monthly | High, if you use the same fixed point |
| Shed count | Hairs collected on one wash day, same day each week | Weekly at most | Low alone, useful as a three-month trend |
| Fibre calibre | Note whether strands feel finer than a year ago | Quarterly | Moderate. Subjective but genuinely meaningful |
| Crown coverage | Second photograph, taken from above with a helper | Monthly | High, and the area people check last |
Our page on HRT hair density and how to measure what changes goes further on the density question, and terminal hair density explains the measurement clinicians actually use.
How reliable is counting shed hairs?
Counting is the marker people trust most and should trust least. DermNet notes that it is normal to lose up to about 100 hairs a day through the ordinary hair cycle, because roughly 85 per cent of follicles are growing and 15 per cent are resting at any moment, and the resting ones release their fibre on their own schedule regardless of anything you do.
Washing frequency is the biggest distortion. Hairs that have already detached stay caught in the rest of your hair until something dislodges them, so washing twice a week produces a frightening handful and washing daily produces a reassuring few, with no difference at all in what the follicles are doing. Count on the same day, after the same gap, or the number is worse than useless because it feels like evidence.
What can a clinician measure that you cannot?
Two techniques go beyond what a phone can do. A phototrichogram involves clipping a small marked area, photographing it, then photographing the same area again a few days later, so growth between two timed images can be measured directly rather than estimated. Trichoscopy uses magnification to look at individual follicular openings and the variation in fibre width across an area.
Both answer questions a home log cannot: how many hairs per square centimetre, what share are growing, and how uneven the fibre widths have become. Neither is something we offer, and neither is a routine step for most people. Our pages on the phototrichogram and on six home checks for thinning hair explain both in plain terms.
Are you measuring hair loss, hair shedding or hair breakage?
Each of the three shows up differently in a log, and a log that does not tell them apart will mislead you. Check which one you are recording before you conclude anything from three months of numbers.
- Hair loss shows as part width slowly increasing and fibres feeling finer, with shed counts often looking normal. It is a follicular change and it moves over years.
- Hair shedding shows as a spike in the shed count with part width unchanged, usually settling within a few months. The follicles are working; too many are resting at once.
- Hair breakage shows as short broken pieces with blunt ends, a ragged outline and length that never seems to grow, while the scalp itself looks unchanged.
The bulb test separates the first two from the third in seconds: a small pale bulb means the hair was released, a blunt end with no bulb means it snapped. Our hair breakage guide covers what to do about the third case.
How do you build a monthly hair log that is worth keeping?
Pick one day a month and do four things in ten minutes. Photograph the parting in the same light. Photograph the crown from above. Write down the part width at a fixed point. Add one line on how hair felt that month and anything unusual, such as an illness, a new medicine or a stretch of poor sleep.
Keep the whole thing in one note on your phone so the photographs and the words stay together. After six months you will have something that answers a question memory cannot, and after twelve you will have something genuinely worth showing a GP. Our page on HRT hair outcomes sets out what usually changes and when, so you know what you are looking for.
A sulfate-free daily shampoo with caffeine, rosemary and hydrolysed lupine protein. It cleans without stripping, which keeps one variable in your log steady rather than swinging with whatever was on offer that month.
Condition Me® Hair Growth Conditioner
A breakage-defence conditioner for the mid-lengths and ends. If your log is showing short broken pieces rather than shed hairs with bulbs, this is the part of the routine to fix first.
The five-step menopause routine in one box, for hair that is changing through and after the menopause. Cosmetic support for fuller-looking hair while you and your GP handle the clinical side.
Get a discount on the menopausal hair range
Join the Watermans mailing list and we will email a discount code straight to your inbox, so you can try the menopausal hair range for less. Made in the UK, over 6.5 million bottles sold since 2012.
What will a hair log never tell you?
Three things sit outside what any home measurement can reach, and knowing the boundary keeps a useful habit from turning into an anxious one. A log cannot tell you why something changed, it cannot separate one cause from another, and it cannot tell you what would have happened if you had done nothing at all.
The last of those is the one that catches everybody. There is no control group in your bathroom. If part width holds steady across a year in which you started a new routine, you cannot know whether the routine held it or whether it was never going to move. That is not a reason to stop measuring; it is a reason to be modest about what your own numbers prove, and to change one variable at a time so the record stays readable.
Timing is the second trap. NHS guidance on hormone therapy describes a yearly review as the usual pattern, and a great deal can happen to hair in twelve months that has nothing to do with hormones at all. An illness with a fever, a period of weight loss, low iron and ordinary seasonal shedding all produce their effects with the same two to three month delay, so a spike in March may belong to something in December.
The third limit is the honest one about us. A cosmetic routine can change how much length survives and how the scalp feels, and that genuinely shows up in a photograph. It does not tell you what is happening below the skin, and nobody selling shampoo can read that from a picture of your parting. NICE guideline NG23 covers the clinical side of managing the menopause, which is where those questions belong.
When should you take your log to a GP?
Make an appointment if part width is clearly increasing across three or more monthly photographs, if hair is coming out in defined patches, if the scalp is sore, scaly or inflamed, or if a shedding spike has not settled after six months. The NHS advises seeing a GP to get an idea of what is causing hair loss before thinking about going to a commercial hair clinic, and a photograph series makes that appointment far more productive.
Bring the photographs, not the anxiety. Say when you first noticed the change, what has changed in your health and medicines, and whether it is affecting how you feel, which the NHS specifically suggests mentioning. Blood tests may be arranged if iron or thyroid function needs checking. If your question is about products or a routine rather than a medical one, you can talk to Gail Waterman, our co-founder, as an AI avatar on the Watermans homepage.
Frequently asked questions: what else do people ask about HRT hair biomarkers?
How often should I record HRT hair biomarkers?
Once a month is right for photographs and part width, and once a week at most for a shed count. Scalp hair grows at roughly one centimetre a month, so daily measurement records the weather rather than the climate. Monthly intervals are slow enough to show real change and frequent enough to catch a trend within a season.
Is counting shed hairs actually useful?
It is useful as a trend and useless as a single number. DermNet notes that losing up to 50 to 100 hairs a day is normal, and that count swings with how often you wash, how you style and how long since you last brushed. Count on the same day of the week, with the same washing pattern, or do not count at all.
Which single measurement tells me the most?
A photograph of the same parting, in the same bathroom, at the same time of day, once a month. It captures part width, coverage and the appearance of density at once, it takes ten seconds, and unlike your memory it does not adjust itself to match whatever you most recently bought.
What is a pull test and can I do it myself?
A gentle pull test means taking a small group of hairs between finger and thumb near the scalp and drawing slowly along them, then counting what comes away. A few hairs is ordinary. Doing it at home is fine as a rough check, but do it the same way each time, and take a striking result to a GP rather than to a search engine.
How long before hormone therapy shows up in these measurements?
Expect seasons, not weeks. The resting phase alone runs about three to four months before a hair is released, so anything that changes the cycle today produces visible evidence a quarter of a year from now. Three months is the earliest sensible review point and six months is the more honest one.
Do HRT hair biomarkers predict what will happen?
No, and any page promising prediction is overselling. What a good log does is tell you what has already happened, clearly enough to separate a real trend from a bad week. That is genuinely valuable in a GP appointment, and it is a different claim from forecasting.
Can a shampoo change these measurements?
A cosmetic product can change how hair looks and how much of it survives to be seen, which will show in a photograph. It does not change what the follicle is doing underneath. We would rather you knew which of those two you are measuring, because confusing them is how people conclude a product worked when the season changed.
Should I keep measuring if everything looks stable?
Yes, and stability is a result worth having. A flat line over twelve months is information, particularly at an age when DermNet reports around 40 per cent of women show signs of hair loss by 50. Knowing nothing is changing stops you chasing products for a problem you do not currently have.
What is the bottom line on HRT hair biomarkers?
HRT hair biomarkers are worth tracking for one reason: they replace an unreliable memory with a record. A monthly parting photograph, a part-width note and a same-day shed count will tell you more over six months than any amount of daily mirror-checking, and they turn a vague worry into something a GP can look at properly.
Keep the method boring and the interval long. Same room, same light, same day, three months minimum before you draw a conclusion and six before you act on it. Then change one thing at a time, so that when something does improve you know what to keep doing.
If you want the routine side of it settled in one decision, the menopause hair care kit keeps the products constant while you watch the numbers, which is exactly what a useful log needs.
Watermans products are 100% cosmetic and do not treat medical hair loss. Individual results may vary.
