Oestrogen and Progesterone - Get to know your hormones

Oestrogen and Progesterone - Get to know your hormones

Oestrogen and progesterone are known as sex hormones because they are essential for women's reproductive function. But don't be fooled by the name, these hormones are important for more than just reproduction, essential for many activities in the brain and body. During menopause, progesterone and oestrogen decline. If you are thinking about taking hormone replacement therapy, these are the hormones that are most commonly replaced. You can read more about hormone replacement therapy here.


Oestrogen is one of the essential hormones in your body. There are three major types of oestrogen:

  1. Oestrone: the only type produced after menopause by fatty tissues and the adrenal glands (a small organ above each kidney),
  2. Oestradiol: produced mostly by your ovaries during your reproductive years stopping after menopause,
  3. Oestriol: produced during pregnancy.

Don't worry, remembering the different types isn't that important. It's just worth understanding that each is produced at different times in your life. Oestradiol is the most potent and common type of oestrogen, produced by your ovaries until menopause. Following menopause, the primary type of oestrogen switches to oestrone. Compared to oestradiol, oestrone is far less potent, and the benefits are therefore limited.

So, what does oestrogen do? Oestrogen is a hormone that has far-reaching actions affecting all parts of the body. It regulates your menstrual cycle, lifts your mood, protects your bones, maintains your heart health, and even keeps your skin elastic and supple. Before menopause, levels of oestrogen naturally change according to where you are in your menstrual cycle.

Here are some bodily functions that are coordinated by oestrogen:

  • short term memory and temperature regulation in an area of the brain called the hypothalamus,
  • mood and sleep-regulating hormones such as serotonin, dopamine and noradrenaline,
  • bone health and protection,
  • collagen production maintaining skin, hair and nail health,
  • timing of menstrual cycles,
  • joint and muscle health,
  • vaginal, bladder and bowel strength,
  • metabolism regulation and weight distribution.

After menopause, your ovaries – the primary source of oestrogen production – stop ovulation and stop producing oestrogen. This leads to low levels of oestrogen in the body, manifesting as menopause symptoms.


Progesterone is another hormone produced by your ovaries during the 2nd half of the menstrual cycle. Its principal function is to prepare the body for pregnancy, including changes to our breasts and womb lining creating a suitable environment for implantation of a fertilised egg. If implantation doesn't occur, progesterone levels will eventually fall, which is what causes our period each month.

Progesterone also has a role in the brain affecting mood and sleep. It is responsible for lifting our mood while also giving us a sense of calm or relaxation, explaining why some women in their last months of pregnancy can report a high sense of wellbeing. It's drop at the end of pregnancy is associated with postnatal depression. Additional scientific research has shown that when progesterone is administered; it can make the person feel sleepier. During menopause, lower progesterone levels therefore cause unwanted effects on our mood and sleep.

To read more in this series, visit:

  1. An introduction to hormones
  2. Testosterone
  3. Thyroid Hormone
  4. Cortisol


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