Key Hormones – Oestrogen

Avatar for Hadyn Luke Hadyn Luke posted this on Tuesday 19th of December 2017 Hadyn Luke 19/12/2017


Key Hormones – Oestrogen

In a recent blog, we discussed the Key HormonesInsulinGlucagonTestosterone, Oestrogen and Human Growth Hormone (HGH).

Now, in today’s blog, we’re focusing on oestrogen. Like testosterone, oestrogen is an androgen – a type of steroid hormone – but where testosterone is largely associated with male characteristics, oestrogen is the dominant female sex hormone.


Secreted by the Ovaries (see our blog on The Endocrine System), Adrenal Glands and fat cells in women, oestrogen is also found in a range of foods in the form of phytoestrogens. These include:

  • Dark green leafy vegetables
  • Lentils, pulses and beans
  • Wholegrains
  • Nuts and seeds

Men can produce oestrogen in the testes and fat cells. As men get older, the aromatase in fat cells starts to convert testosterone to oestrogen; this aromatase reaction is higher in men with a large amount of body fat.


The production of oestrogen increases as girls reach puberty, helping the development of secondary sex characteristics, strengthening various parts of the sexual organs, producing vaginal mucus and triggering ovulation.

Oestrogen regulates several processes in women’s bodies, including:

  • Promoting the development of female characteristics
  • Controlling the reproductive cycle, stopping the production of the hormone FSH to ensure that only one egg matures in each menstrual cycle
  • Stimulating the pituitary gland so that it releases the hormone LH
  • Pregnancy, childbirth and lactation
  • Stimulating and controlling body temperature
  • Helping to improve collagen, skin and hair; strengthening bones and aiding healthy heart and liver function

Oestrogen can be artificially produced for oral contraceptives and also for the treatment of menopausal and menstrual issues.


Increases and decreases in oestrogen are all a natural part of the female body’s cycle.

However, as women reach the menopause, they can be affected by lower levels of oestrogen, which can cause mood swings and stress as well as affecting the joints and bones, before the body adapts to these changes. Some women will take Hormone Replacement Therapy during the menopause, which includes oestrogen; however, there have been concerns about the effects of HRT and women should consult a medical expert if they are considering this route.

Oestrogen levels can also become low if a woman has polycystic ovarian syndrome or anorexia, or carries out extreme levels of exercise.

Low oestrogen levels have been linked with:

  • Cardiovascular disease
  • Alzheimer’s
  • Parkinson’s
  • Osteoporosis

High oestrogen levels have been linked with:

  • Breast cancer
  • Endometriosis
  • Type 1 diabetes
  • Rheumatoid arthritis

As mentioned, men may produce oestrogen as they age; the effects of increased levels of oestrogen on a man can include:

  • Tiredness, lack of libido and erectile dysfunction
  • Reduced muscle mass
  • Gynecomastia (enlarged breasts)
  • Prostate cancer and heart disease


While oestrogen levels may rise and fall naturally, women may need to consult their doctor for irregular periods or problematic symptoms of the menopause. Overweight men should be aware of the dangers of high oestrogen production in their body.

Subscribe to the blog

Interested in becoming a personal trainer
or sports massage therapist?

Leave your details below and a member of the
CMS team will contact you shortly.