Why is my hair thinning? A Consultant’s honest answer
September 2026
Written by Dr Geeta Moor, MBBS MRCP FRCA MD(Res) — Medical Director, The Selborne Clinic
Most people who come to me about their hair have already spent somewhere between two hundred and two thousand pounds on things that were probably not going to work. Supplements. Shampoos. A scalp massager. And I completely understand the reasons why that money was spent.
It is a completely rational response to a problem nobody will properly explain to you. You noticed more hair in the shower, or a photograph caught the light on your crown, and when you looked it up, it came up with stress, or hormones, your age, and maybe a biotin tablet would help.
So here is the explanation. It is long, because the answer genuinely is not simple, and because the first thing you need is a diagnosis rather than a product.
Is it shedding or is it thinning?
These are two different problems and they need different answers. Getting this wrong is the most common reason people waste money.
Shedding means more hair is coming out than usual. You see it on the pillow, in the plughole, on the brush. It comes on fairly suddenly, and — this is the important part — it is usually triggered by something that happened two to three months earlier. An illness. A general anaesthetic. A crash diet. A bereavement. Childbirth. Starting or stopping a medication.
That delay is why almost nobody makes the connection. Your hair is telling you about what happened.
The medical term is telogen effluvium, and in most cases it recovers on its own once the trigger has passed. It does not need a laser-assisted delivery. It needs the cause found, and the reassurance that this is not going to continue indefinitely.
Thinning is different. The number of hairs coming out may not have changed at all. What has changed is the hair itself. With each growth cycle, individual hairs emerge finer, shorter and lighter, until eventually they stop reaching a length you would notice. That process is called miniaturisation.
This is pattern hair loss, and it does not recover on its own. It progresses slowly, over years.
You can have both at once, and often a shedding episode is simply what makes someone notice a pattern loss that has been quietly progressing for a decade.
Is male and female pattern loss the same condition?
It is related, but not the same, and this matters because it changes what works.
Both are driven by follicles becoming sensitive to androgens, principally dihydrotestosterone, which is converted from testosterone by the enzyme 5-alpha reductase. In men that androgen pathway is the dominant mechanism. In women it is one part of a more complicated picture, which is why the treatments that work best in men are less reliable in women.
The patterns are different too.
In men, loss typically begins at the temples and at the crown, and the two areas gradually meet. It often starts in the twenties or thirties. It can move quickly.
In women, the frontal hairline is usually preserved while the parting widens progressively from the front backwards. It more often becomes noticeable around the perimenopause, though it can start much earlier.
How can I tell which I have?
Look at your hair dry, in daylight, with a mirror.
If you are a woman: compare your parting at the front with the parting at the back of your head, near the nape. In pattern loss the front is wider, and the hairs along it are visibly finer and more variable in thickness — some thick, some wispy. That variability is the way to tell. In telogen effluvium the thinning is even all over, and the remaining hairs are all roughly the same calibre.
If you are a man: photograph your crown from above, in overhead light, and compare it with a photograph from a few years ago. The crown is the area you never see and the area that goes first. Temporal recession you will already have noticed. What people underestimate is how much has changed on top.
I do this with a trichoscope — a magnifying camera that shows hair calibre and follicular density at 20 to 70 times magnification — and I photograph it, so that in four months we are comparing images rather than memories.
What blood tests actually matter?
If you take one thing from this article, take this. Before anyone treats your hair, someone should have checked:
Ferritin. Iron stores, not haemoglobin. You can be comfortably non-anaemic and still have iron stores low enough to affect hair growth. Standard lab reference ranges are set for anaemia, not for hair.
Thyroid function. Both underactive and overactive thyroid cause hair loss, and both are easily missed.
Vitamin D.
Full blood count.
A hormonal screen — testosterone, DHEAS and related tests — if you are a woman with irregular periods, acne, or unusual hair growth on the face or body, which together may point to polycystic ovary syndrome.
Your GP can do all of these. If you have not had them and someone is selling you a treatment course, that is the wrong order of events.
I will not start a hair course at The Selborne Clinic without seeing recent bloods. Treating androgen-driven miniaturisation in someone whose actual problem is a low ferritin is taking money for nothing.
What actually works — in men
The evidence here is better than most people assume, and better than it is in women.
A 2025 network meta-analysis of monotherapies found dutasteride 0.5mg daily to be the most effective option overall. Among approved treatments, topical minoxidil 5% was the most effective topical monotherapy and finasteride 1mg daily the most effective oral one.
These work in different ways. Finasteride and dutasteride are 5-alpha reductase inhibitors, so their effect depends on the androgen pathway. Minoxidil appears to work largely independently of androgen metabolism, which is why the two are often used together rather than instead of one another.
All of these are prescription decisions in the UK. I can prescribe private prescriptions to you.
The point men most need to hear is about timing. These treatments hold ground far better than they regain it. A follicle that has miniaturised beyond a certain point does not come back. If you are in your late twenties and you have noticed your crown, the useful action is now, not when it bothers you enough to do something.
What actually works — in women
The picture is thinner, and I would rather say so.
Topical minoxidil is the only topical agent approved specifically for female pattern hair loss and the only therapy with genuinely strong clinical evidence behind it. It shortens the resting phase, extends the growing phase, and enlarges follicles that have begun to shrink.
It also has a problem: roughly 40% of women do not respond to it. That figure is not printed on the box, and it is the honest reason people go looking for something else.
Beyond it, low-dose oral minoxidil, spironolactone and finasteride are all used in women, with varying evidence and varying suitability.
What about the laser treatment you offer?
Fair question, and I will answer it the way I would want it answered if I were the patient.
The service I run uses a non-ablative 1927nm thulium fractional laser followed immediately by a topical growth factor serum.
The mechanism is well established. The stratum corneum is a barrier that limits how much of any topical agent gets in. Fractional laser creates microscopic channels through it. Imaging work has shown that the 1927nm thulium laser creates channels still closing at 24 hours — a genuine, measurable window during which a topical agent reaches depths it otherwise would not. Laser-assisted drug delivery is a well-supported principle across dermatology.
The specific combination has pilot data, not large trials. A pilot study of fractional thulium laser with a topical growth factor serum reported increased hair density and thickness in both men and women with androgenetic alopecia. A separate pilot combined a non-ablative 1927nm thulium fractional laser with platelet-rich plasma in male pattern loss. Pilot studies are how evidence begins. They are not randomised controlled trials.
So the delivery mechanism is sound and well evidenced, the specific protocol is supported by early data, and I photograph and trichoscope every patient at every stage precisely.
What doesn't work
Biotin, unless you are genuinely deficient, which is rare. Worse, biotin supplements interfere with several common blood assays, including thyroid function and troponin — the test used to diagnose a heart attack. Tell any doctor taking your blood that you take it.
Thickening shampoos. They coat the hair shaft. They change nothing about the follicle.
Scalp massage on its own.
Anything promising results in four weeks. Hair cycles in months. Any treatment that genuinely works takes four to six months to show, and anything visible faster than that is cosmetic rather than biological.
When should you see a doctor rather than a clinic?
Go to your GP, not an aesthetic clinic, if you have:
Hair loss in defined patches with smooth, empty scalp
Redness, scaling, pain, itching or burning of the scalp
Any area where the scalp looks shiny and the follicular openings have disappeared
Sudden, dramatic loss
Loss of eyebrows, eyelashes or body hair alongside scalp hair
Hair loss in a child
Some of these are scarring alopecias, in which follicles are permanently destroyed. There the priority is stopping the process urgently, and cosmetic treatment is not only useless but may delay a diagnosis that matters. I will refer you, and I will not treat you.
Why I do it this way
I have spent more than twenty years in the NHS as a doctor. The job trains you to understand that the most important part of any procedure is the conversation you have before it.
Hair loss is an area where people feel quietly distressed and rarely say so, and where distress is easy to sell to. I would rather assess you properly, send you for bloods, and tell you honestly that your best evidence-based first step is something I do not sell — than take a course payment for something that was never going to work.
If your hair is changing and nobody has explained why, that is where we would start.
Consultations at The Selborne Clinic, Hampshire. Assessment includes trichoscopy, standardised photography and an honest conversation.
