Perimenopause can feel like your body has started behaving in ways you don't recognise. Irregular periods, fatigue that doesn't shift with sleep, mood changes that seem to come from nowhere, brain fog, weight gain, poor sleep, low libido — the list of symptoms is long, and for many women, the experience of trying to get answers through the NHS is frustrating and slow.
One of the most valuable things you can do if you suspect you're perimenopausal is get the right blood tests. Not a generic health check — the right panels, interpreted in the right context. Here's what I recommend, and why.
First — why blood tests for perimenopause?
Perimenopause is the transitional phase before menopause, typically beginning in a woman's 40s but sometimes earlier. During this time, hormone levels — particularly oestrogen and progesterone — begin to fluctuate unpredictably. These fluctuations are behind most of the symptoms women experience, but they can also affect other systems in the body, including thyroid function, iron levels, and vitamin status.
A blood test won't definitively diagnose perimenopause — hormone levels vary so much day to day that a single result rarely tells the whole story. But the right panel gives you a baseline, helps rule out other causes of your symptoms, and gives your clinician the information needed to support you properly.
The key blood tests for perimenopause
FSH (Follicle Stimulating Hormone)
FSH is the most commonly used marker for perimenopause. As your ovaries become less responsive, your pituitary gland produces more FSH to try to stimulate them. A raised FSH level — particularly above 10 IU/L — can indicate that your ovaries are beginning to change, though levels fluctuate significantly during perimenopause, which is why a single test isn't always conclusive.
Oestradiol (Oestrogen)
Oestradiol is the primary form of oestrogen in women of reproductive age. During perimenopause, levels begin to decline and become more erratic. Low oestradiol can contribute to hot flushes, vaginal dryness, poor sleep, mood changes, and bone density loss. Testing oestradiol alongside FSH gives a much more complete picture.
LH (Luteinising Hormone)
LH works alongside FSH in the menstrual cycle. Tracking LH alongside FSH helps build a clearer understanding of where you are in the hormonal transition and whether ovulation is still occurring regularly.
Progesterone
Progesterone is often the first hormone to decline in perimenopause, even before oestrogen. Low progesterone is closely linked to irregular periods, anxiety, poor sleep, and heavy bleeding. It's frequently overlooked in standard hormone panels but is an important piece of the picture.
Testosterone
Often thought of as a male hormone, testosterone plays a significant role in women's health — affecting libido, energy, muscle tone, mood, and cognitive function. Levels naturally decline with age and can drop significantly during perimenopause. If you're experiencing low motivation, reduced sex drive, or persistent fatigue, testing testosterone is worthwhile.
Thyroid function (TSH, Free T3, Free T4)
Thyroid problems and perimenopause share many symptoms — fatigue, weight changes, mood disturbances, brain fog, and poor sleep. An underactive or overactive thyroid can be mistaken for perimenopause, or the two can occur simultaneously. A full thyroid panel should be included in any perimenopausal assessment.
Vitamin D
Vitamin D deficiency is extremely common in the UK and becomes increasingly important during perimenopause. Low vitamin D is linked to low mood, fatigue, poor bone density, and immune dysfunction — all of which overlap with perimenopausal symptoms. Many women are deficient without knowing it.
Ferritin and iron studies
Heavy or irregular periods during perimenopause can deplete iron levels over time. Ferritin — your body's iron store — is the most sensitive marker and is often missed on standard NHS tests. Low ferritin causes fatigue, hair loss, brain fog, and breathlessness, and is frequently misattributed to perimenopause itself.
B12 and folate
B12 deficiency is more common than most people realise, particularly in women over 40. Symptoms — fatigue, mood changes, cognitive difficulties — overlap significantly with perimenopause. Testing B12 alongside your hormone panel ensures nothing is missed.
What about the NHS?
GPs in England are advised not to routinely test FSH for women over 45 with typical perimenopausal symptoms — they're expected to diagnose based on symptoms alone. This means many women never get the blood tests they want, leaving them without the data to make informed decisions about HRT or other support.
Private blood testing puts that data in your hands. At Boost & Glow, Lucy carries out venous blood draws — the same method used in hospitals and GP surgeries — either at our clinic in Epping or at your home across Essex, Hertfordshire, and London. Results are returned promptly with clear guidance on what they mean for you.
What happens after your results?
Getting your results is just the beginning. Understanding them in the context of your symptoms, your cycle history, and your overall health is where the real value lies. At Boost & Glow, Lucy will talk you through your results and help you understand your next steps — whether that's a conversation with your GP about HRT, targeted nutritional support, or lifestyle changes backed by your data.
Ready to get tested?
If you're experiencing symptoms that might be perimenopause and want answers backed by actual data, book a private blood test with Boost & Glow. We offer a dedicated hormone panel designed specifically for perimenopausal assessment, carried out by Lucy with a venous draw at home or in clinic.
0 comments