What is oestrogen?

What are the different types of oestrogen?

There are three main types of oestrogens:

• estrone (E1) — the main type of oestrogen your body makes post-menopause
• estradiol (E2) — the primary form of oestrogen during your reproductive years
• estriol (E3) — the main form of oestrogen during pregnancy

Want to improve your hormones knowledge? Learn about testosterone and progesterone.

What’s the normal range for oestrogen?

The normal range for your total oestrogen is 45.4 - 854 pmol/L. 

You can check your oestrogen levels as part of a women's hormones blood test.

What does oestrogen do? 

Oestrogen and puberty 

Oestrogen is an essential hormone responsible for puberty (reproductive development) in females. 

It’s produced in your ovaries and helps your body develop pubic hair, breasts, and a regular menstrual cycle (periods). 

Oestrogen and the menstrual cycle

Oestrogen is the hormone that helps to regulate your menstrual cycle. 

Your oestrogen levels rise steadily before ovulation (when one of your ovaries releases a mature egg) to help thicken your womb lining and prepare it for a mature egg to implant. 

The first day of your period until ovulation is called the follicular phase. This is when your eggs mature in tiny sacs (follicles) that produce oestrogen. 

Just before ovulation, your oestrogen levels are at their highest. The peak in oestrogen causes luteinising hormone (LH) levels to rise, resulting in the release of a mature egg from one ovary. 

Ovulation typically happens around 12 to 16 days before your period starts — but it’s important to remember that every woman is different, so your ovulation days might vary.   It might be helpful to use a tracking app each month so you can get a clear picture of your cycle length. 

During ovulation, you might experience the following symptoms:

• feeling more energised and physically strong
• a higher sex drive (libido)
• wetter, slippery, and clear discharge
• increased body temperature 
• breast tenderness
• cramps — sometimes vigorous exercise can contribute to this

Then, your oestrogen levels generally begin to fall during the second stage of your menstrual cycle — the luteal phase (typically around day 15). 

During the luteal phase, you might experience the following symptoms:

• fatigue
• low libido
• mood swings
• bloating
• tender breasts
• oily or spotty skin

Learn more about PMS and the causes of hormonal imbalances.

If your oestrogen levels are off balance, it can disrupt ovulation. 

Oestrogen and bone health

Oestrogens are essential for keeping your bones healthy as it helps maintain bone density. 

If you’ve reached menopause, you have lower levels of oestrogen. You also have an increased risk of osteoporosis, increasing your risk of fractures. 

Oestrogen and heart health

Oestrogens also play a vital role in protecting you against cardiovascular disease (CVD), reducing your risk of a heart attack. One way it does this is by regulating your cholesterol levels — specifically LDL cholesterol, and reducing the risk of plaque build-up inside your artery walls. It also helps to maintain the healthy function of blood vessels.  

What happens if you have low oestrogen? 

If your oestrogen levels are too low, ovulation doesn't occur, reducing your chances of getting pregnant. Low oestrogen levels also affect how thick your womb lining is — so low levels might cause lighter and irregular periods or stop them altogether. It can also cause fertility difficulties. 

Low oestrogen levels can affect bone mass in young and pre-menopausal women, leading to problems like increased fracture risk and osteoporosis later in life.

But the good news is, there are ways to increase your oestrogen levels if you’re menopausal — like hormone replacement therapy (HRT).

Low oestrogen and menopause 

Oestrogen levels naturally fluctuate and decline when you reach perimenopause and menopause — around age 45 to 55. 

Once you start menopause (1 year after your last period), your oestrogen levels stabilise at a new low level. 

Fluctuating oestrogen levels during menopause contribute to symptoms like:

• irregular periods
• hot flashes 
• fatigue
• brain fog
• vaginal dryness
• sleep issues — studies suggest that magnesium supplements can help improve sleep quality

Other symptoms of low oestrogen include:

• increased risk of urinary tract infections (UTIs) 
• breast tenderness 
• depression 
• trouble concentrating 
• bones that fracture or break more easily 
• weight gain or changes to your body shape 

What can cause low oestrogen?

Increasing age, perimenopause, and menopause are the most common reasons for low oestrogen levels. 

But for younger pre-menopausal women, there are several reasons why oestrogen levels might become too low. For example, some women suffer from functional hypothalamic amenorrhea (FHA). This condition causes your periods to stop and leads to anovulation (not ovulating) and infertility. 

FHA can result from: 

• excessive exercise 
• not eating enough or restricting foods
• emotional or psychological stress
• an eating disorder — like anorexia nervosa or bulimia 
• low body weight or body mass index (BMI)
• low body fat percentage 

Other causes of low oestrogen include: 

• premature ovarian insufficiency (POI) — your ovaries stop functioning as they should before age 40
• Turner syndrome — a genetic disorder that only affects females
• medical treatments that affect your ovaries — like chemotherapy or surgery
• autoimmune diseases

If your oestrogen levels are low and you haven't reached menopause, it's essential to check this with a healthcare professional. 

How to improve your oestrogen levels 

How you improve low oestrogen levels depends on what’s causing them. It’s essential to get treatment quickly too. This is because, over time, low levels can affect bone, fertility, and heart health. 

If you have FHA, you can help improve your oestrogen levels by:

• gaining weight if you’re underweight — your GP can help you do this safely
• increasing your body fat percentage — eating regular meals throughout the day
• reducing exercise intensity and duration  
• managing psychological stress —  seeking help from a professional therapist can help you work through any problems that are contributing to low body weight

Some studies have shown that regularly eating plant oestrogens (phytoestrogens) might lead to mild oestrogen-like effects. But more research is needed to understand phytoestrogens' effects fully. It might be helpful to speak to your GP before increasing your intake. 

Good food sources of phytoestrogens include:

• soya
• milk
• yoghurts
• linseed bread
• edamame beans

Other lifestyle changes can help improve your oestrogen levels, including:

• losing weight if you’re overweight
• stopping smoking
• following a healthy, balanced diet 

What causes high oestrogen levels? 

High oestrogen levels are less common but can sometimes occur naturally or due to certain medications. 

High levels of oestrogen might be caused by the following: 

• HRT
• the contraceptive pill 
• polycystic ovary syndrome (PCOS) 
• your body not breaking it down properly 
• high levels of body fat 

What are the symptoms of high oestrogen?

The most common symptoms of high oestrogen include:

• irregular periods or abnormal vaginal bleeding
• low libido
• breast tenderness
• weight gain

High levels of oestrogen can put you at increased risk of:

• blood clots and stroke 
• ovarian cancer 
• breast cancer

How to reduce your oestrogen levels 

If not caused by medication, then you can reduce your oestrogen levels by following simple lifestyle changes. These include:

• Ensuring you’re getting enough fibre from your diet — fibre supports your gut health, and the gut microbiome plays a key role in regulating oestrogen levels.
• Following a Mediterranean diet — eating lots of fruit and vegetables, whole grains, fibre, fish or plant-based proteins, and healthy fats. Processed foods, sugar, and meat are associated with higher oestrogen levels. 
• Exercise regularly — aim for 75 minutes of vigorous-intensity activity a week or 150 minutes of moderate-intensity activity a week.
• Reduce your alcohol intake — aim for no more than 14 units a week. If you do drink alcohol, try to spread it out over the week and aim for alcohol-free days if you can.