What is oestrogen dominance and how does it affect progesterone use?

Oestrogen dominance describes the adverse symptoms that occur when the ratio of progesterone to oestrogen becomes unbalanced — specifically when oestrogen is disproportionately high relative to progesterone. It is not a disease but a hormonal imbalance, and progesterone therapy is the most effective way to correct it.

When does it occur?

  • When first starting progesterone therapy
  • When using too little progesterone (typically 20–40mg/day)
  • When increasing, decreasing, or stopping progesterone
  • During the days before and during menstruation (progesterone withdrawal)
  • Just before and during ovulation
  • Throughout the luteal phase if insufficient progesterone is produced
  • In early pregnancy, or after birth (contributing to postnatal depression)
  • If you reduce progesterone supplementation too quickly

Common symptoms include:
Bloating, water retention, weight gain, breast tenderness, mood swings, irritability, depression, migraines, heart palpitations, anxiety, panic attacks, hot flushes, fatigue, nausea, skin problems, spotting.

The counterintuitive truth:
When symptoms worsen, many women reduce their progesterone — and this temporarily helps, because the progesterone is no longer stimulating oestrogen receptors. However, this defeats the purpose entirely. The correct response is to increase progesterone, not reduce it, in order to suppress the excess oestrogen causing the symptoms.

To prevent oestrogen dominance when starting out, use higher amounts initially — ideally 100–200mg/day, or 400–500mg/day if symptoms are severe, splitting the dose between morning and evening, The typical 20–40mg/day recommendation is generally insufficient and is a common cause of oestrogen dominance reactions.

Stress plays a significant role — cortisol (the stress hormone) is made from progesterone, so the body diverts available progesterone to produce cortisol during stressful periods, causing levels to drop sharply. Increase your dose during any stressful period.

From saliva testing, the optimal ratio of progesterone to oestrogen for wellbeing has been found to be 600:1 or higher.

Vitamin D is also essential — deficiency reduces the effectiveness of progesterone therapy. Blood levels should ideally be 70–100ng/ml (175–250nmol/L), with a minimum daily intake of 5,000–10,000IU recommended.

For more detailed guidance visit our dedicated page on estrogen dominance.