Everything you need to know about hormones

From oestrogen to progesterone, here’s the scoop on female hormones

Sleep, metabolism, sex drive… you name it, your hormones will probably affect it.

What's a hormone?

Hormones are chemical messengers that travel in the bloodstream to tissues and organs. They influence cognitive function, mood, libido, development, growth and more. Hormones in women include:


AKA the major female sex hormone. Not only does oestrogen play a huge role in regulating a woman’s reproductive function and monthly menstrual cycle, it also helps maintain bone density and helps regulate mood. It’s the ultimate multi-tasker!


As well as serving a very important role in fertility and early pregnancy, progesterone helps regulate mood and promote the growth of new bone tissue.


Libido, sex drive, sexual desire… whatever you want to call it, testosterone plays a role in it. Although testosterone is a male sex hormone, women produce a small amount of it in their ovaries. It plays an important part in helping the body produce oestrogen and contributing to muscle and bone mass.

Luteinising hormone

Made in the pituitary gland, luteinising hormone (LH) helps stimulate ovulation.

Follicle stimulating hormone

Made in the pituitary gland (alongside LH), follicle stimulating hormone (FSH) help the ovaries work as they should.

How do hormones change during the menstrual cycle?

The menstrual cycle can be broken down into three main phases – follicular (before the egg is released), ovulatory (as the egg is released) and luteal (after the egg is released).

The follicular phase begins on the first day of menstrual bleeding. At this stage, levels of oestrogen and progesterone are low, meaning the top layers of the uterus are shed and menstrual bleeding occurs. This bleeding lasts for an average of five days.

Around this time, FSH levels increase slightly, kick-starting the growth of several follicles in the ovaries. Later in the phase, as the FSH level decreases, one of these follicles will continue to grow and produce oestrogen, preparing the uterus for the next phase.

Next up is the ovulatory phase, which usually lasts between 16 and 32 hours. This phase begins with an increase in LH and FSH levels and ends with the release of an egg, which can be fertilised for up to 12 hours after its release. During this phase, some women experience pain in their abdomen.

And last (but by no means least) comes the luteal phase, which tends to last around 14 days (unless fertilisation occurs). During this phase, progesterone and oestrogen levels are high, which can sometimes cause breast swelling and tenderness (ergh!). If the egg is not fertilized, levels of oestrogen and progesterone will decrease and a new menstrual cycle will begin.

Changes in your body's hormone levels before your period can cause a whole bunch of physical and emotional changes, including feeling bloated, breast tenderness, mood swings, feeling irritable, getting spotty skin or greasy hair and losing your sex drive. This is most commonly known as premenstrual syndrome (PMS) and symptoms tend to improve once bleeding begins.

Getting to know the pattern that your hormones are following can help you understand why you’re feeling a certain way.

What happens if your hormones aren't behaving?

Excessive exercise, stress, birth control pills, poor diet – these are just a few things that can result in a hormonal imbalance. As the name suggests, when you have a hormone imbalance, you have too much or too little of a certain hormone.

Women can experience hormonal imbalances as they enter perimenopause (the transition towards menopause) and menopause (when a woman’s ovaries stop producing as much oestrogen and no longer release an egg each month). The reduced level of oestrogen can result in a lowered sex drive, hot flushes, night sweats and vaginal dryness. Find out more about ‘the change’ here.

Certain medical conditions, such as polycystic ovary syndrome (PCOS), can also affect a woman’s hormone levels. Women with PCOS often have higher levels of testosterone which can cause irregular periods or loss of periods, difficulty getting pregnant, excessive hair growth – usually on the face, chest or back – and acne.

A shift in hormones, whether it’s due to a hormone imbalance or your menstrual cycle, can wreak havoc with a whole range of bodily functions. Stay in tune with your body to help understand what’s going on, and always seek professional medical advice if you’re worried.