This is the question I am asked most often in the fortnight after a first prescription, usually by someone who was hoping to feel different by now and is starting to wonder whether it is going to work at all.
The honest answer is that different symptoms respond at different speeds, and that the first dose is rarely the final one. Knowing roughly what to expect – and when it is reasonable to say this is not working – matters more than any single figure.
The short answer
Many women notice hot flushes and night sweats easing within the first few weeks. But the number to hold on to is three months: the NHS advises a review three months after starting HRT, or after changing type, to see how well it is working. That is when we judge whether this particular treatment is right for you – not whether HRT works.
Be a little wary of the detailed week-by-week charts you will find online. Most originate from commercial platforms rather than clinical sources, and they imply a precision that does not exist.
What tends to shift, and when
What follows is what I typically see in practice rather than a fixed schedule. Individual variation is wide, and only the three-month review is a formal recommendation.
First 2 weeks
Often the earliest change is sleep, particularly where night sweats were the thing waking you. Some women notice hot flushes becoming less intense before they become less frequent.
Mild side effects can also appear now - see below. They are usually a sign your body is adjusting, not that something is wrong.
2 to 4 weeks
Hot flushes and night sweats typically begin to improve measurably. This is the most reliably early responder, and for many women it is the point at which they first think something is happening.
6 to 8 weeks
Early side effects such as breast tenderness, nausea and leg cramps have usually settled by around now.
Mood, anxiety and concentration tend to be slower than hot flushes and often begin shifting around this stage. If nothing at all has changed by this point, it is worth getting in touch rather than waiting out the full three months.
3 months
The decision point, and the one the NHS formally recommends. By now the effect of your current dose should be apparent, early side effects should have settled, and we can tell whether this preparation and this route are right for you. Reviews are annual after that, once things are stable.
If you are still struggling at three months, that is information - not failure. It usually means the dose, the route or the progestogen needs changing.
Beyond 3 months
Vaginal and bladder symptoms treated with local oestrogen can take up to twelve weeks to improve properly, so patience is needed there specifically. Bone protection accrues over a longer horizon still, and continues for as long as you are taking treatment.
I have prescribed HRT for years, and I have also been the person waiting to see whether it would help. Perimenopause arrived for me in my early forties as brain fog rather than hot flushes, and later, after breast cancer treatment, I dealt with a sudden medically induced menopause and the harder question of what I could and could not safely take.
What that taught me is how much the waiting matters. Three weeks feels like a very long time when you are exhausted and hoping. It is worth knowing in advance that a slow start is usually a dose question, not a verdict.
Dr Katy Kasraie, BMS-accredited Menopause Specialist
What HRT is, and why the route matters
HRT replaces the oestrogen your ovaries have stopped producing. If you still have a womb, a progestogen is added to protect the lining – which is why almost everyone is on two components rather than one.
Oestrogen can be given as a patch, a gel, a spray or a tablet. This is not simply a matter of preference, and it is the thing I would most want you to take from this page:
Transdermal - patch, gel, spray
Absorbed through the skin, bypassing the liver. Does not carry the small increase in clot and stroke risk associated with tablets. Guidance is explicit that transdermal should be preferred for anyone at raised risk of clots, including women with a BMI over 30. This is what I prescribe where suitable.
Oral - tablets
Effective and convenient, but passes through the liver first, which is what accounts for the small increase in clot and stroke risk. Baseline risk in women under 60 is very low, so this suits some women perfectly well - it simply is not the automatic default.
For the progestogen component I use body-identical micronised progesterone where appropriate. This is chemically identical to what your body produces and is not the same as the older synthetic progestogens used in the studies that generated most of the anxiety about HRT. Alternatively, a levonorgestrel intrauterine system can provide endometrial protection alongside oestrogen given separately – useful if you also want contraception or have heavy bleeding.
Vaginal and bladder symptoms are treated separately with local oestrogen, which acts on the tissues directly. It is safe for long-term use and can usually be used even by women who cannot take systemic HRT.
What affects how quickly it works
Dose
The commonest reason HRT appears not to be working is that the dose has not yet been optimised. Starting low and adjusting is deliberate.
Route
Absorption of gels can vary with skin, application site and how well the product dries. Sometimes a switch of route resolves what looked like a dose problem.
Which symptoms
Vasomotor symptoms respond fastest. Mood, concentration and libido take longer. Vaginal symptoms on local treatment take longer again.
Other causes
Thyroid dysfunction, low ferritin, low B12 or vitamin D deficiency produce fatigue and poor concentration that HRT will not fix. Worth excluding rather than assuming.
Consistency
Patches that lift, gel applied irregularly, or doses missed will all blunt the effect. Not a criticism - just worth mentioning honestly at review.
Early side effects
In the first weeks some women notice breast tenderness, headaches, mild nausea, bloating, or spotting and irregular bleeding. These usually settle as your body adjusts, and they are not a reason to stop.
What they are a reason to do is get in touch if they persist beyond a few weeks or are troubling you, because dose or route can often be adjusted. Any unexpected or heavy bleeding should always be reported rather than waited out.
The risks, honestly
You deserve better than a list of frightening words, so here is the actual shape of it.
Clots and stroke. Oral oestrogen carries a small increase in risk. Transdermal does not. Baseline risk in women under 60 is very low to begin with. This is precisely why route matters and why it is worth discussing rather than being handed the first thing on the formulary.
Breast cancer. This is what most women are actually worried about, so it should be addressed properly rather than listed. Combined HRT is associated with a small increase in risk, which relates to duration of use and reduces after stopping. Oestrogen-only HRT, used by women without a womb, carries little or no increase. Body-identical micronised progesterone is not the synthetic progestogen used in the trials that produced the headlines. For most women the absolute numbers are smaller than they expect, and they are worth going through against your own history rather than in the abstract.
Cardiovascular disease. Current guidance is that HRT started before the age of 60 does not increase cardiovascular risk and does not affect the risk of dying from cardiovascular disease. Existing cardiovascular risk factors are not in themselves a barrier to treatment, provided they are being properly managed.
On the benefit side, HRT reduces the risk of fragility fracture while you are taking it – the British Menopause Society regards it as first-line for bone protection in women under 60 and in premature ovarian insufficiency. That benefit is maintained during treatment and diminishes once it stops.
If you have had breast cancer, this is still a conversation worth having rather than avoiding. Whether HRT is appropriate depends on your cancer type, your treatment and your individual risk – it is not automatically no, and effective non-hormonal and local options exist either way. Having been through breast cancer treatment myself, I would rather discuss it with you than have you assume there is nothing available.
If HRT is not working for you
A significant proportion of the patients I see are already taking HRT. It has simply never been optimised – the dose was never increased, the route was never reconsidered, or a progestogen that does not suit them was never changed. Getting those three things right makes a considerable difference.
As a Menopause Specialist accredited by the British Menopause Society, I prescribe against current evidence rather than received wisdom – which matters in a field where guidance has shifted substantially and a good deal of what patients are told is a decade out of date. An initial appointment runs 45 to 60 minutes, which is long enough to go through what has been tried, why it did not work, and what to do about it, and to leave you with a written plan.
Bring any current prescriptions or records with you. No referral is needed, and most major UK insurers are accepted.
Frequently asked questions
How long does HRT take to work?
Many women notice hot flushes and night sweats easing within the first few weeks. The formal marker is three months: the NHS advises a review at that point, or after any change of preparation, to see how well it is working. Mood and concentration tend to be slower than hot flushes; vaginal symptoms treated with local oestrogen can take longer again.
It has been six weeks and I feel no different. Has it failed?
Almost certainly not. A low dose is prescribed to begin with and increased later if needed, so it is common to require more than one adjustment before you land on what suits you. Six weeks is early. That said, if nothing has changed at all, get in touch rather than waiting silently to the three-month mark – and never stop on your own.
Can my hot flushes get worse before they get better?
Some women do report symptoms feeling more intense in the first days as levels shift, before settling as they reach a steady state. It is unsettling but usually short-lived.
Is patch, gel or tablet better?
For symptom relief they work on broadly similar timelines. For safety they are not equivalent: transdermal oestrogen avoids the small increase in clot and stroke risk that comes with tablets, which is why it is preferred where there is any raised clot risk.
Will HRT help brain fog and fatigue?
Often yes, though usually more slowly than hot flushes and partly indirectly, through better sleep. If fatigue and poor concentration persist once symptoms are otherwise controlled, thyroid function, ferritin, B12 and vitamin D are worth checking – HRT will not correct a deficiency.
How often will I be reviewed?
The standard pattern is a review three months after starting, or after any change of preparation, then annually once things are stable. More often than that if we are still fine-tuning, and always sooner if something is troubling you.