Perimenopause
Perimenopause Symptoms UK: The NHS List, and When a Blood Test Adds Anything
Reviewed by a qualified clinician · analysed at UKAS-accredited UK labs (ISO 15189)
Last reviewed September 20265 min read
Every Helvy guide is written by our health editors, then checked by a qualified clinician before it goes live and re-checked as the science moves. We name clinical roles, not individuals, until each reviewer has agreed to be credited publicly. This is wellness guidance to help you understand your own data, not a diagnosis.
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Perimenopause is the run-up to your last period. The NHS lists changes to your periods, hot flushes, night sweats, broken sleep, mood changes, brain fog, weight gain and vaginal dryness. If you are 45 or over, NICE says those symptoms identify it without any laboratory test.
Not sure which markers you need? Build your test →You are 46. Your periods have gone odd, you wake at 3am for no reason, and last week you could not remember a colleague's name mid-sentence. Somebody said perimenopause. You wanted a blood test to prove it.
Here is the part nobody leads with. At your age, the symptoms are the evidence. A test is not what settles it, and knowing that saves you arguing for one you do not need.
1. What are the symptoms of perimenopause?
The NHS says a change to your periods is usually the first sign. They may come more often or less often, and the bleeding may get heavier or lighter. Everything else sits around that.
- Hot flushes and night sweats.
- Trouble getting to sleep or staying asleep.
- Mood swings, low mood, anxiety.
- Problems with memory or concentration, often called brain fog.
- Weight gain, often around the stomach and upper body.
- Vaginal dryness, and sex that has become painful.
- More urinary infections, or needing to pee more often.
- Joint and muscle aches, headaches, hair thinning, dry skin, lower sex drive.
Two things about that list. It is long, and almost nobody gets all of it. The NHS also notes that a faster or more noticeable heartbeat can be part of it, which is worth mentioning to a GP rather than filing under hormones.
2. How long do perimenopause symptoms last?
Longer than most people are told. The NHS puts it at 7 to 9 years, sometimes longer, and says the symptoms can change during that time.
Perimenopause ends at menopause, which is the point when you have gone 12 months without a period. After that it is called post menopause. So perimenopause is only ever named looking backwards, which is part of why a single blood test struggles with it.
3. Do you need a blood test to confirm perimenopause?
If you are 45 or over, no. The national guideline is direct about it.
“Identify the following, without laboratory tests ... aged 45 or over and have menopause-associated symptoms: perimenopause, if they have vasomotor symptoms that have recently started and any changes in their menstrual cycle.”
NICE guideline NG23, recommendation 1.3.1 (vasomotor means hot flushes and night sweats)
NG23 goes further. Over 45, it tells clinicians not to use anti- Mullerian hormone, inhibin A or B, oestradiol, antral follicle count or ovarian volume to identify perimenopause. Those tests move too much month to month to settle the question.
So if a GP declines to test your hormones at 47, that is the guideline working, not a fob-off.
4. When does a blood test add something?
NG23 names two situations. It says to consider a serum FSH level only in people aged 40 to 45 with menopause-associated symptoms including a change in the cycle, and in people under 40 where menopause is suspected.
FSH is follicle-stimulating hormone, the pituitary signal that tells the ovaries to get going. It climbs as the ovaries respond less, which is why it is the marker used here. Our guide to a high FSH result covers how it is read.
One important exclusion. NG23 says not to use an FSH test in people taking combined oestrogen and progestogen contraception, or high-dose progestogen. The result will not mean what you think it means.
Under 40 is a different conversation entirely, and it belongs with a GP. Our guide to early menopause testing explains why.
5. What else feels exactly like this?
This is where testing earns its place even at 48. Several common things produce the same tiredness, low mood, brain fog and weight change, and they are all measurable.
An underactive thyroid is the classic look-alike. So is low iron, which is easy to build up to if your periods have got heavier. Low vitamin B12 and low vitamin D both do tiredness and low mood well. Our guide on telling menopause from a thyroid problem takes that pair apart.
Two things worth saying plainly. A blood test measures markers and gives you something concrete to take to a GP. It does not diagnose any condition, and one marker outside its range does not on its own mean something is medically wrong.
See a GP if your bleeding has got heavier rather than lighter, or if you have gone 12 months with no period and then bleed. The NHS names both as reasons to get checked.
6. Which blood test should you consider?
Helvy's Hormone Balance panel measures FSH, LH, SHBG, total testosterone and the free androgen index, from a home finger-prick kit processed by a UKAS-accredited UK lab. It is the set behind the NG23 conversation above.
Three honest limits, because they matter more than the sales pitch. It does not include oestradiol or progesterone. FSH and LH move with your cycle, so the kit tells you which days to sample. And over 45 the result is not what identifies perimenopause, whatever it says.
If the look-alikes are your real question, a wider baseline suits you better. General Energy & Wellness carries thyroid TSH, free T4, vitamin B12, vitamin D, cortisol and cholesterol. Vitamins & Minerals carries iron, ferritin, B12, folate, vitamin D and magnesium.
If you are not sure which fits, the build-my-test tool walks you through it in about a minute. The menopause hub collects the rest of these guides, and our perimenopause blood test guide goes deeper on the markers themselves.
READY TO TEST?
Rule out the look-alikes before you settle on hormones
Helvy's home kits measure thyroid, iron, B12 and vitamin D, or the cycle hormones themselves, read against your own lab ranges, so a flagged number never sits there unexplained. Ask your blood.
Frequently asked questions
What is usually the first sign of perimenopause?
A change to your periods. The NHS says they may come more often or less often, and the bleeding may get heavier or lighter. Eventually they stop altogether.
At what age does perimenopause start?
Most often in the forties, but there is no fixed age. NICE also notes that people from some ethnic minority backgrounds, and people with some lifelong conditions, may reach menopause younger.
Can a blood test confirm perimenopause?
Not after 45. NICE says to identify perimenopause without laboratory tests in people aged 45 or over with recent hot flushes and cycle changes. Testing is for those aged 40 to 45, and for anyone under 40.
How long do perimenopause symptoms last?
The NHS says symptoms usually last 7 to 9 years, sometimes longer, and they can change during that time. Perimenopause ends once you have gone 12 months without a period.
Is it perimenopause or my thyroid?
Both produce tiredness, low mood, brain fog and weight change, so symptoms alone will not separate them. Thyroid markers are measurable, which is the practical reason to check them.
Does Helvy test oestrogen?
No. Hormone Balance measures FSH, LH, SHBG, total testosterone and the free androgen index. Oestradiol and progesterone are not part of this test. If your clinician wants oestrogen tracked directly, that is a conversation with them.
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