The hormones of perimenopause and menopause
Understanding the changes and looking after your health
Menopause is usually described as the moment estrogen goes down. The reality is more complex. In the years before the final period, hormones go through significant fluctuations before they settle, and they don’t all change in the same way.
These changes can affect a woman’s physical and emotional wellbeing, and also her metabolism, body composition and long-term health.
Understanding what is happening in our bodies is key to going through this stage informed and getting the right care.
First, the terms
The transition to menopause is divided into stages, mainly according to the changes in the menstrual cycle.
| Stage | What it is |
|---|---|
| Perimenopause | What it isThe transition period when menstrual cycles start to change and symptoms linked to hormonal fluctuations can appear. It includes the first 12 months after the final period. |
| Menopause | What it isThe final menstrual period. It is confirmed in hindsight, after 12 consecutive months without a period, as long as nothing else explains the absence. |
| Postmenopause | What it isThe stage after the final period, during which estrogen levels generally stay low. |
Although it is a natural process, every woman experiences it differently. Some have few symptoms, while others go through changes that significantly affect their quality of life.
Why does it happen?
The brain and the ovaries are in constant communication through hormones that regulate the menstrual cycle.
Over the years, the reserve of ovarian follicles gradually shrinks and the ovaries start to respond differently to hormonal signals.
During perimenopause, this communication becomes more irregular, causing fluctuations in estrogen, progesterone and FSH.
That is why hormonal changes are not linear. There can be large swings before estrogen falls more steadily after menopause.
The main hormones
Communication between the brain and the ovaries is balanced, with stable levels of estrogen and progesterone.
The reserve of ovarian follicles shrinks and the ovaries respond more irregularly. Hormones (estrogen, progesterone and FSH) fluctuate, which can lead to symptoms.
Ovarian function stops, estrogen and progesterone fall in a sustained way, and FSH stays high.
| Hormone | In perimenopause | After menopause |
|---|---|---|
| FSH | In perimenopauseTends to rise, but fluctuates considerably | After menopauseStays high |
| Estradiol | In perimenopauseSteady, rising or falling, irregularly | After menopauseA more sustained fall; estrone takes the lead |
| Progesterone | In perimenopauseFalls and becomes irregular | After menopauseVery low: ovulation stops |
| Testosterone | In perimenopauseDeclines gradually with age | After menopauseNo sharp drop from natural menopause |
| Neurokinin B | In perimenopauseMore active as estrogen falls: hot flashes | After menopauseHot flashes can last several years |
FSH: the brain pushes harder
Follicle-stimulating hormone (FSH) is made by the pituitary gland and stimulates the development of ovarian follicles.
As ovarian function declines, FSH levels tend to rise.
During perimenopause, however, they can fluctuate considerably. That is why a single FSH measurement can’t always confirm or rule out this stage.
Estrogen: ups and downs, then a fall
Estradiol is the main estrogen made by the ovaries during the reproductive years.
During perimenopause, its levels can stay relatively stable, or rise and fall irregularly. Later, with menopause, there is a more sustained decline.
Estrogen is involved in many functions in the body, including regulating body temperature, maintaining bone mass and several metabolic processes.
After menopause, estrone becomes the more prominent circulating estrogen. It is made mainly from hormonal precursors in peripheral tissues, including fat tissue.
Progesterone: tied to ovulation
Progesterone is made mainly after ovulation.
As ovulatory cycles become less frequent during perimenopause, its production falls and becomes more irregular.
These changes can contribute to the shifts in menstrual pattern that are typical of this stage.
After menopause, ovulation stops and progesterone levels stay very low.
Testosterone: not the drop many imagine
Testosterone is also present in women’s bodies and plays a part in several physiological functions.
Its levels tend to decline gradually with age, but natural menopause does not seem to cause a sharp drop on its own.
Surgical removal of both ovaries, on the other hand, can be linked to a more marked reduction.
Testosterone levels, and whether they relate to symptoms, should always be interpreted as part of an individual clinical assessment.
Neurokinin B: the link to hot flashes
Neurokinin B is a substance involved in regulating body temperature in the brain.
Falling estrogen changes the activity of certain neurons involved in this process, which contributes to hot flashes and night sweats.
This understanding has led to new non-hormonal treatments that target these pathways specifically.
Hot flashes can start in perimenopause and continue for several years after the final period. How long they last and how intense they are vary a lot between women.
What about cortisol, thyroid, insulin and melatonin?
During menopause, symptoms are often blamed on changes in other hormones, such as cortisol, thyroid hormones, insulin or melatonin.
It matters, though, to tell apart the effects of the menopause transition itself from those linked to age, lifestyle or other conditions.
| Hormone | What we know |
|---|---|
| Thyroid | What we knowThyroid problems become more common with age and can cause symptoms similar to menopause, such as tiredness, weight changes, sleep problems or irregular periods. So in some situations it may be necessary to check thyroid function. |
| Cortisol | What we knowSome studies have described changes during the menopause transition, but the evidence does not show a consistent rise in cortisol caused directly by menopause. |
| Insulin | What we knowMenopause can come with changes in where the body stores fat and in insulin sensitivity. These changes are also shaped by age, body composition and lifestyle. |
| Melatonin | What we knowSome studies have found lower levels after menopause, though it is hard to separate the effect of the hormonal transition from ageing itself. |
Beyond hormones: what happens to metabolism?
One of the most important things about this stage is that hormonal changes can have effects that go beyond the usual symptoms.
During the menopause transition you may see:
- More fat stored around the abdomen, especially visceral fat.
- Changes in the lipid profile, with a tendency for LDL cholesterol to rise.
- Changes in insulin sensitivity, which can add to metabolic risk.
- Changes in body composition, with more fat mass and a gradual loss of muscle mass linked to ageing.
- Faster bone loss, linked to falling estrogen and a higher risk of osteoporosis.
These changes don’t affect every woman equally and shouldn’t be put down to menopause alone.
Even so, this stage is an important opportunity to check metabolic and cardiovascular health, spot risk factors and put prevention in place.
Do you need a hormone test?
That is because FSH and estradiol can fluctuate considerably during this stage, and a single measurement may not tell you much.
There are, however, situations where further testing may be needed:
| Situation | What may be considered |
|---|---|
| Between 40 and 45 | What may be consideredAn FSH test may be considered when there are compatible symptoms and menstrual changes, depending on the clinical context. |
| Under 40 | What may be consideredMissing or persistently irregular periods need investigating to rule out premature ovarian insufficiency and other causes. |
| Atypical symptoms | What may be consideredIt may be necessary to look into thyroid, metabolic or other endocrine conditions. |
Test results also need to be read in light of hormonal contraception, a history of hysterectomy and other individual circumstances.
Other tests, such as anti-Müllerian hormone (AMH) or saliva hormone tests, are not recommended routinely to diagnose menopause.
What matters is not doing more tests, but identifying which tests each woman actually needs.
How can an endocrinologist help during menopause?
Menopause is much more than the end of periods. The hormonal changes of this stage can affect metabolism, body composition, bone health and cardiovascular risk.
That is why a specialist in Endocrinology and Nutrition can play an important role in women’s health during perimenopause and menopause.
What they can do for you
Their work isn’t limited to checking hormone levels. They can also help identify and treat metabolic changes, such as increased abdominal fat, obesity, insulin resistance or cholesterol changes, and assess the risk of osteoporosis.
An endocrinologist with specific training in menopause can also assess symptoms, rule out other endocrine conditions that can be mistaken for this transition, and offer hormonal or non-hormonal treatment when it is appropriate.
The goal is comprehensive, individual, evidence-based care that not only relieves symptoms but also prevents health problems and improves long-term quality of life.
Collaboration between Endocrinology, Gynecology and other health professionals makes it possible to support each woman according to her needs and circumstances.
Where does treatment fit?
Menopause treatment should be tailored to each woman’s symptoms, medical history, risk factors and preferences.
There are several treatment options that can significantly improve quality of life.
Menopausal hormone therapyThe most effective treatment for hot flashes and night sweats
Hormone therapy is the most effective treatment for hot flashes and night sweats.
For women under 60, or within 10 years of the start of menopause, without contraindications, the balance of benefits and risks is usually favorable for treating vasomotor symptoms.
Even so, it is not right for every woman and needs an individual assessment.
For women with a uterus, systemic estrogen should be combined with a suitable progestogen to protect the endometrium.
Treatments for genitourinary symptomsVaginal dryness and discomfort during sex
Vaginal dryness, discomfort during sex and other genitourinary symptoms can also appear as a result of falling estrogen.
Local treatments, including low-dose vaginal estrogen, can be effective and have different safety considerations from systemic hormone therapy.
Non-hormonal treatmentsFor women who can’t or don’t want to use hormone therapy
There are alternatives for women who can’t or don’t want to use hormone therapy.
They include certain medicines that act on the brain mechanisms behind hot flashes, such as neurokinin 3 receptor antagonists.
These treatments need a medical assessment of their indications, contraindications and possible side effects. Some require liver function monitoring.
What about testosterone?Only in specific situations
The scientific evidence supports testosterone in specific situations, mainly in postmenopausal women with hypoactive sexual desire disorder, after a full clinical assessment.
It is not recommended for general use to treat tiredness, improve body composition or prevent ageing.
Food, exercise and healthy habitsThe foundation for everything else
Managing menopause shouldn’t focus only on medication.
A balanced diet, regular physical activity (especially strength training), good rest and managing cardiovascular risk factors are essential.
These measures help preserve muscle mass, maintain bone health and improve overall wellbeing.
Menopause: a stage to look after your health
Perimenopause and menopause are part of a woman’s natural ageing process, but that doesn’t mean symptoms have to be accepted without seeking help.
Understanding the hormonal changes helps you make informed decisions and recognize when it is worth asking for a medical assessment.
This transition is also an opportunity to pay special attention to metabolic, cardiovascular and bone health, with a preventive, long-term view.
Support from health professionals with specific training in menopause, endocrinologists among them, makes comprehensive, personalized care possible.
Because looking after your health during menopause isn’t only about treating symptoms. It is also about supporting your wellbeing and quality of life in the years that follow.
Key scientific references10 sources
- Harlow SD, et al. Executive summary of the Stages of Reproductive Aging Workshop + 10. Menopause. 2012.
- Santoro N, Randolph JF. Reproductive hormones and the menopause transition. Obstet Gynecol Clin North Am. 2011.
- Randolph JF, et al. Change in follicle-stimulating hormone and estradiol across the menopausal transition. J Clin Endocrinol Metab. 2011.
- Avis NE, et al. Duration of menopausal vasomotor symptoms over the menopause transition. JAMA Intern Med. 2015.
- European Society of Endocrinology. Clinical practice guideline for evaluation and management of menopause and the perimenopause. European Journal of Endocrinology. 2025.
- National Institute for Health and Care Excellence (NICE). Menopause: identification and management. NG23.
- The North American Menopause Society. The 2022 hormone therapy position statement. Menopause. 2022.
- Davis SR, et al. Global consensus position statement on the use of testosterone therapy for women. J Clin Endocrinol Metab. 2019.
- Mintziori G, et al. EMAS position statement: thyroid disease and menopause. Maturitas. 2024.
- Matthews KA, et al. Are changes in cardiovascular disease risk factors in midlife women due to chronological aging or to the menopausal transition? J Am Coll Cardiol. 2009.
Medical note: This article is general information and is not individual medical advice. Talk to your doctor before starting, stopping or changing any treatment.
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