Hormone Therapy and Hair Loss: Why It Happens and What Helps
Short answer: hormones control how long each hair spends growing, so any therapy that changes oestrogen, testosterone or thyroid levels can change your hair. Most of the time the shedding that follows is temporary and settles within six to nine months as the follicles resynchronise. Sometimes it signals something that needs adjusting. The one thing you should never do is stop or alter a prescribed hormone therapy because of your hair. Speak to the prescriber who started it, because they can weigh your hair against everything else the treatment is doing for you.
Important: this article is general information, not medical advice. Do not stop, reduce or change the timing of any prescribed hormone therapy on your own. If your hair is shedding, book a review with your GP, endocrinologist, oncologist or gender clinic and raise it there.
Key Takeaways
- Oestrogen tends to hold hairs in the growing anagen phase. Androgens shorten it in follicles that are genetically sensitive to DHT. Hormone therapy shifts that balance, and hair responds.
- Shedding usually starts two to three months after a hormonal change, not immediately. That delay is why the cause is so often missed.
- Most hormone related shedding is telogen effluvium and is temporary. Pattern hair loss unmasked by an androgen shift is progressive and behaves differently.
- Hair loss is also caused by the things that often accompany hormone therapy: illness, surgery, weight change, iron deficiency and stress. Blood tests separate them.
- Ask your prescriber about the specific preparation, the dose and the timeline. Sometimes an adjustment is possible, sometimes the treatment is too important to change.
- Cosmetic hair care can make hair look and feel better while you wait. It cannot alter what hormones are doing at the follicle.
How do hormones control hair growth?
Every follicle cycles through three phases. Anagen is active growth and lasts two to seven years. Catagen is a short transition of a few weeks. Telogen is a resting phase of around three months, after which the hair is released and a new one begins. At any moment roughly 85 to 90 percent of your hairs are in anagen, which is why shedding 50 to 100 hairs a day is entirely normal.
Hormones set the length of anagen. Oestrogen tends to prolong it, which is why hair often feels thicker in pregnancy and thins after childbirth or through the menopause. Androgens, principally dihydrotestosterone, shorten anagen in follicles carrying the genetic sensitivity, so each cycle produces a finer, shorter hair until eventually it barely breaks the surface. Thyroid hormones regulate the metabolic rate of the follicle itself, and both too much and too little disrupt it.
Change any of those inputs and the cycle resets. A large group of follicles moves into telogen together, and about two to three months later they shed together. That is why the hair loss you notice in March often traces back to something that happened in December. Our explainer on the three stages of the hair growth cycle sets out the timings in more detail.
Hormone related shedding typically begins two to three months after the change and settles six to nine months later. The delay is the single most useful clue you have.
Which hormone therapies affect hair, and how?
The pattern differs depending on which hormone is moving and in which direction.
| Therapy | What changes | Typical hair effect |
|---|---|---|
| HRT for menopause | Oestrogen replaced, progestogen added | Often stabilises hair over time. Some people shed in the first months as the cycle resets, and certain progestogens are more androgenic than others. |
| Feminising hormone therapy | Oestrogen up, androgens suppressed | Usually slows existing pattern loss and can improve density over one to two years. Body hair thins. Regrowth of an already receded hairline is limited. |
| Masculinising hormone therapy | Testosterone introduced | Body and facial hair increase. Scalp hair may recede at the temples if there is a family history of pattern loss. |
| Androgen deprivation therapy | Testosterone suppressed for prostate cancer | Body hair usually thins. Scalp hair often stabilises. Fatigue and other effects are usually the bigger concern. |
| Anti-oestrogen therapy | Oestrogen blocked or reduced for breast cancer | Diffuse thinning is common and is well recognised by oncology teams. Raise it with them rather than stopping treatment. |
| Thyroid replacement | Thyroid hormone corrected | Shedding can occur both from the untreated thyroid problem and from the early weeks of correction. It usually settles once levels are stable. |
| Hormonal contraception | Starting, switching or stopping | Stopping is a classic trigger for shedding a few months later. Progestogen type matters for people prone to pattern loss. |
If you are on HRT specifically, we cover the detail in HRT and hair loss, what you need to know. For gender-affirming care there are dedicated guides on how HRT affects hair in transgender people and on hair changes during an FTM transition.
Is it shedding or is it thinning?
These are two different processes and the distinction shapes everything that follows.
Telogen effluvium is diffuse shedding. Hair comes out from all over the scalp, in handfuls, often two to three months after a trigger. The hairs are full length with a small white bulb at the root. The follicles are intact, so once the trigger has passed the hair regrows, usually over six to nine months. You may see a fringe of short new hairs along the hairline as recovery begins. More on the pattern in what causes telogen effluvium.
Androgenetic alopecia is gradual thinning in a pattern. There is no dramatic shedding phase. The parting widens over months or years, or the temples recede, and the hairs that grow back are progressively finer. Hormone therapy does not create this condition, but by shifting the androgen balance it can unmask or accelerate a tendency that was already there.
It is entirely possible to have both. That is one reason a proper assessment beats self diagnosis.
What else could be causing it?
Hormone therapy rarely arrives on its own. It usually comes with a diagnosis, a surgery, a life change or a stressful period, and each of those is an independent trigger for shedding. Before concluding the hormones are responsible, it is worth ruling out:
- Iron deficiency. Low ferritin is one of the most common and most correctable causes of diffuse shedding, particularly in menstruating people.
- Thyroid dysfunction. Both underactive and overactive thyroid disrupt the hair cycle, and symptoms overlap heavily with menopause.
- Recent illness or surgery. Anything that raises the body’s stress load can push follicles into telogen together.
- Rapid weight loss. A sharp calorie or protein deficit is a reliable trigger.
- Vitamin D and B12 status. Worth checking, though correcting them only helps if you were genuinely low.
- Other medications. Some antidepressants, blood pressure medicines, retinoids and anticoagulants list hair loss as a possible effect.
A GP can request ferritin, full blood count, thyroid function and vitamin D free of charge. Doing that before you spend money privately is almost always the better sequence. Thyroid issues in particular are covered in our guide to thyroid related hair loss.
What should you ask your prescriber?
Take this list to the appointment. It keeps a ten minute consultation focused.
- Is hair shedding a recognised effect of this specific preparation and dose?
- Given when I started, does the timing fit, or should we look for another cause?
- Can we check ferritin, full blood count, thyroid function and vitamin D?
- Is there an alternative preparation with a different profile that would suit me equally well?
- If this is temporary, roughly when should I expect it to settle?
- Would a dermatology referral be appropriate if it has not improved by then?
- Are any of my other medications likely to be contributing?
Bring evidence: photograph your scalp weekly in daylight, at the crown, the parting and the temples, and note the date you started or changed the therapy. A timeline plus photographs turns a vague complaint into something a clinician can actually work with.
When should you seek medical advice urgently?
Book promptly rather than waiting for a routine review if you notice:
- Smooth, round bald patches appearing over days or weeks.
- A shiny area of scalp where follicle openings are no longer visible, which can indicate scarring.
- Scalp pain, burning, sores or bleeding.
- Hair loss with new fatigue, palpitations, unexplained weight change or heavy bleeding.
- A receding frontal hairline together with loss of eyebrow hair.
- Shedding that is still worsening nine months after the hormonal change.
These need a doctor rather than a hair product or a private hair clinic, and some of them are time sensitive.
What can you do while you wait?
None of the following changes what hormones are doing at the follicle. What they do is stop you losing more hair to avoidable damage, and make what you have look and feel better in the meantime.
- Reduce tension. Loosen ponytails and clips, and avoid styles that pull on the hairline. Tension damage compounds any underlying shedding.
- Turn the heat down. Lower the setting on straighteners and dryers and use a heat protectant. Breakage on top of shedding makes hair look far thinner than it is.
- Detangle gently. Wide tooth comb, from the ends upwards, on conditioned hair.
- Eat enough protein. Especially if the hormonal change coincided with weight loss or appetite change.
- Wash regularly. Washing does not cause shedding. It simply collects the hairs that were going to come out anyway. A clean scalp is a comfortable one.
- Look after your sleep and stress. Stress is a genuine, well documented trigger for telogen effluvium, and hormone therapy is often started during an already difficult period.
Gentle everyday care
If your current shampoo leaves the scalp tight or itchy, switching to something milder is a reasonable, low stakes change. This is cosmetic care for the condition and appearance of hair. It is not a treatment for hormone related hair loss, and it is not a reason to delay a conversation with your prescriber.
Grow Me® Hair Growth Shampoo, £14.95
A sulfate free everyday shampoo with biotin, niacinamide, rosemary and hydrolysed lupine protein. It cleanses without stripping and helps hair look fuller. Vegan and made in the UK. Cosmetic care only, and no substitute for medical review.
Frequently asked questions
Should I stop my hormone therapy if my hair is falling out?
No. Never stop or change a prescribed hormone therapy on your own. Some of these treatments are managing serious conditions, and stopping abruptly carries its own risks. Book a review and discuss it with the clinician who prescribed it.
How long does hormone related shedding last?
Telogen effluvium linked to a hormonal change typically peaks a few months in and settles within six to nine months once levels stabilise. If it is still worsening after nine months, ask for further investigation.
Will my hair grow back?
If the cause is telogen effluvium, the follicles are intact and regrowth is the usual outcome. If an androgen shift has unmasked pattern hair loss, that is progressive and is managed rather than reversed. A clinician can tell which you are dealing with.
Does HRT cause or prevent hair loss?
Both are reported. Replacing oestrogen often stabilises hair over time, but the first few months can involve shedding as the cycle resets, and some progestogens are more androgenic than others. This is a genuinely useful conversation to have with your prescriber.
Can I take biotin or a hair supplement?
Supplements only help if you are actually deficient, and high dose biotin can interfere with some blood tests including thyroid and cardiac markers. Tell your doctor about anything you are taking, and ideally test before supplementing.
Is minoxidil safe alongside hormone therapy?
That is a question for your prescriber or pharmacist, who knows your full medication list and medical history. It is available over the counter, but it should not be started alongside hormone therapy without that conversation.
Why did the shedding start months after I began treatment?
Because follicles pushed into the resting phase do not release the hair immediately. They hold it for roughly three months first. That built in delay is why the timing feels so confusing.
Does washing my hair less reduce the shedding?
No. The hairs you see on wash day were already released. Washing less simply collects them over more days, and an unwashed, irritated scalp is not a better environment for hair.
Should I see a trichologist or a doctor?
A doctor first, every time, when hormone therapy is involved. Only a doctor can review your prescription, order blood tests and refer you to dermatology. A trichologist can be useful afterwards for monitoring and day to day care.
Where to start
Write down the date your hormone therapy started or changed, take weekly scalp photographs, and book a review with your prescriber. Ask for ferritin, full blood count, thyroid function and vitamin D. In most cases the picture becomes clear quickly, and in most cases the shedding settles.
While you wait, be gentle with your hair. Watermans has sold over 5 million bottles since 2012, and the range is vegan and made in the UK, formulated to clean and condition without stripping. If you would find a fuller routine helpful during the menopause specifically, our guide to menopause hair loss and thinning goes into more depth.
