Reproductive Pituitary gland

Prolactin

Written by the VitaWhat editorial team · Medically reviewed by Steve Davis · Last reviewed 19 July 2026 · Editorial policy

Drives breast-milk production and influences fertility.

What it does

  • Stimulates milk production after birth
  • Influences the menstrual cycle

Too much

  • High prolactin (e.g. a prolactinoma) can cause milk production, irregular periods and low libido

Too little

  • Low prolactin can reduce milk supply
Keeping it balanced: Persistent unexplained milk production or cycle changes should be checked.

Sources & references

  1. You and Your Hormones (Society for Endocrinology)
  2. NHS — Hormonal conditions

Think a hormone may be out of balance?

The symptoms of hormonal excess and deficiency are non-specific — tiredness, weight change, low mood and poor sleep have many everyday causes. No hormone problem can be self-diagnosed from a symptom list.

Diagnosis needs blood tests interpreted alongside your history, sometimes repeated at set times of day because many hormones vary hour to hour. Speak to a GP if symptoms are persistent; seek urgent care for severe symptoms such as confusion, fainting, chest pain or extreme thirst with frequent urination.

Related entries

Follicle-Stimulating Hormone (FSH)Luteinising Hormone (LH)OestrogenOxytocinProgesteroneTestosterone
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