Women's hormones
FSH Levels by Age: What’s Normal at 35, 40, 45 and Beyond
Reviewed by a qualified clinician · analysed at UKAS-accredited UK labs (ISO 15189)
Last reviewed August 20267 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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There is no official FSH-by-age chart in the UK. Labs set FSH ranges by cycle phase, not by age. FSH does climb as you get older, and it starts rising about six years before your last period. NICE advises against testing FSH after 45, because levels swing week to week.
Not sure which markers you need? Build your test →Your cycle has gone strange. The gaps are longer, or shorter, and you are 43. Somebody mentions FSH, so you go looking for the chart that says what your number should be at your age. That chart does not exist, and this guide explains why the real answer is more useful than one.
1. Is there an FSH chart by age in the UK?
No. FSH stands for follicle-stimulating hormone. It is the signal your pituitary gland sends to your ovaries. UK labs report it against where you are in your cycle, not against your birthday.
Look at how three NHS laboratories publish the same marker. The ranges do not match, and neither do the menopausal cut-offs.
| Lab | Follicular | Mid-cycle | Luteal | Menopausal |
|---|---|---|---|---|
| North Bristol | 3.9 to 8.8 | 4.5 to 22.5 | 1.8 to 5.1 | above 16 |
| Oxford | 3.0 to 8.1 | 2.6 to 16.7 | 1.4 to 5.5 | 26.7 to 133.4 |
| NW London | 1.5 to 10 | 7 to 20 | 1.5 to 8 | above 20 |
2. What does FSH actually do as you get older?
It rises. As the ovaries respond less readily, the pituitary sends a louder signal, and FSH is that signal. The timing has been mapped properly, and it is the useful part.
The Study of Women’s Health Across the Nation followed 3,302 women and modelled 1,215 of them through a natural last period. FSH began climbing 6.1 years before that final period. It accelerated 2.05 years before, then settled 2 years after.
Two details from the same paper are worth holding on to. The pattern held whatever age a woman reached her last period. And carrying more weight flattened the rise, delaying its start to 5.45 years before.
Turn that into ages and the problem is obvious. The NHS says menopause usually happens between 45 and 55. Someone finishing at 55 would start climbing near 49. Someone finishing at 45 would start near 39. Same curve, ten years apart.
So FSH tracks your transition, not your age. Two women of 47 can sit years apart on that curve. This is exactly why an age chart misleads and why the same number reads differently in different people.
3. Why NICE says not to test FSH after 45
This surprises people, so it is worth stating plainly. UK guidance is that menopause after 45 is identified from symptoms, without blood tests. FSH swings too much through the transition to settle the question.
“Consider using the person’s serum FSH level to confirm menopause only: in people aged 40 to 45 with menopause-associated symptoms, including a change in their menstrual cycle; in people under 40 in whom menopause is suspected.”
— NICE NG23, recommendation 1.3.6
Notice what that leaves in place. Under 45, with a cycle that has changed, FSH is one of the markers guidance points to. Over 45, the symptoms are the evidence. The NHS menopause page says the same thing in fewer words.
4. When is an FSH test worth doing?
These are the situations where the number earns its place:
- You are 40 to 45 and your cycle has changed noticeably.
- You are under 40 and your periods have become infrequent or stopped.
- You want FSH read next to LH, because the pattern between the two carries more information than either alone.
- You want a baseline now, to compare against in a few years.
One caution for the under-40 case. NICE is explicit that a single blood test settles nothing there, and asks for two samples taken four to six weeks apart. Our early menopause guide covers that conversation.
It is also worth ruling the ordinary things in or out. Thyroid trouble and low iron produce the same tiredness and the same unpredictable cycles. A full blood count and a thyroid check often answer more than FSH does. The menopause hub sets out the wider marker list.
5. What makes a single FSH reading misleading?
- The day you sampled. Labs expect days 2 to 5 of your cycle. See when to take a hormone blood test.
- Hormonal contraception. NICE says not to use FSH at all on the combined pill or high-dose progestogen.
- The swing itself. Through perimenopause, FSH can read high one month and normal the next.
- Body weight. The SWAN data found a flatter, later FSH rise in women carrying more weight.
None of that makes the marker useless. It means one reading is a snapshot, and a qualified clinician reads it against your cycle, your age and your symptoms.
Men have an FSH range too, and it does not split by cycle phase for obvious reasons. North Bristol NHS Trust reports 1.3 to 19.3 IU/L for adult men. FSH there is usually read next to LH and testosterone, which is the pattern our men’s blood test guide walks through.
6. Which blood test measures FSH
Helvy’s Hormone Balance panel (£99) measures FSH, LH, SHBG, total testosterone and the free androgen index. It is a home finger-prick kit, processed by UKAS-accredited UK labs, and the kit tells you which days to sample.
Two honest limits. It does not include oestradiol or progesterone, so it will not track your oestrogen directly. And it measures biomarkers rather than identifying menopause, which is a clinical judgement your GP makes.
To choose your own marker list, the build-my-test tool walks you through it.
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See the hormones behind the change
Helvy’s home blood tests report FSH and LH with plain context, read against the day you sampled. Samples are processed by UKAS-accredited UK labs.
Frequently asked questions
What is a normal FSH level by age in the UK?
UK labs do not publish FSH ranges by age. They publish them by cycle phase. A typical follicular range runs from about 3 to 9 IU/L, and menopausal cut-offs differ by lab, from above 16 to above 26.7 IU/L. Read your result against your own lab’s range.
What FSH level means perimenopause?
No single number marks it. FSH rises and falls week to week through perimenopause, which is why NICE advises against using the test after 45. A high reading is consistent with the transition, but it does not confirm it on its own.
At what age does FSH start rising?
It tracks your transition rather than your age. In the SWAN study, FSH began climbing 6.1 years before the final period and accelerated 2.05 years before it. For a woman whose periods stop at 51, that puts the start somewhere near 45.
Can an FSH test tell me if I am in menopause?
Not on its own, and not after 45. UK guidance identifies menopause from symptoms in that age group. Under 40, NICE asks for two raised FSH samples taken four to six weeks apart before anyone draws a conclusion.
When in my cycle should FSH be tested?
Days 2 to 5, counting the first day of proper bleeding as day 1. That is the window UK labs build their follicular range around. If your cycles are irregular, test when you can and note the day, so the result can be read properly.
Does the pill affect FSH results?
Yes. NICE advises against using an FSH test to identify menopause in anyone taking combined oestrogen and progestogen contraception, or high-dose progestogen. Those treatments suppress the signal the test measures.
Related guides
LH & FSH Blood Test UK
What the two pituitary signals mean read together, and the ratio that matters.
Perimenopause Blood Test UK
Why FSH alone cannot settle it, and the markers that genuinely help.
When to Take a Hormone Blood Test
Day 2 to 5 testing, plus the rules for irregular cycles and contraception.
AMH Blood Test UK
The ovarian reserve marker, its ranges by age, and what it cannot tell you.
Early Menopause & POI Blood Test
Under 40 with menopausal symptoms? The two-sample rule explained.
Menopause Hub
Every Helvy guide on perimenopause, menopause and HRT in one place.