Prolactin

On this page

What is prolactin?
Where is prolactin produced?
Function of prolactin
Normal prolactin levels
Causes of high prolactin (hyperprolactinaemia)
Symptoms of high prolactin
Causes of low prolactin
Prolactin and fertility
When and how to test prolactin
Prolactin in traditional Chinese medicine
Acupuncture and prolactin
Chinese herbal medicine and prolactin
Diet, supplements and lifestyle
Related pages

1. What is prolactin?

Prolactin is a peptide hormone produced by the anterior pituitary gland. Its primary role is to stimulate breast development in pregnancy and to produce milk during lactation — hence the name (lactin = lactation). Prolactin also has more than 300 other documented biological effects, including roles in immune function, behaviour, metabolism and the menstrual cycle. After childbirth, high prolactin levels temporarily stop the menstrual cycle for the first few months, preventing another pregnancy.

Reference ranges vary from country to country and between laboratories. Always interpret your own result against the reference range provided by the laboratory that performed your test.

2. Where is prolactin produced?

Prolactin is produced by lactotroph cells in the anterior pituitary gland. Its release is unusual among pituitary hormones because it is primarily under tonic inhibition by dopamine from the hypothalamus, rather than being released in response to a stimulating hormone. When the dopamine signal is reduced (for example by stress, by certain medications or by a pituitary tumour), prolactin rises.

3. Function of prolactin

The main functions of prolactin are:

Stimulating the growth and development of the breasts during pregnancy.
Maintaining milk production during breastfeeding.
Suppressing the menstrual cycle and ovulation in the early postpartum period to prevent rapid successive pregnancies.
Modulating the immune system.
Influencing maternal bonding behaviour.

4. Normal prolactin levels

The normal range of prolactin is approximately 2–29 ng/mL on day 3 of the menstrual cycle in women who are not pregnant or breastfeeding. During pregnancy, prolactin rises sharply, reaching 200–500 ng/mL at term. Reference ranges vary from country to country and between laboratories.

5. Causes of high prolactin (hyperprolactinaemia)

Hyperprolactinaemia — chronically elevated prolactin levels in a woman who is not pregnant or breastfeeding — is a common cause of infertility. Causes include:

Stress — stress stimulates the pituitary to increase prolactin production. This is the most common cause of mildly elevated prolactin.
Hypothyroidism — the high TRH that drives compensatory TSH release also stimulates prolactin.
Polycystic ovary syndrome (PCOS) — a proportion of women with PCOS have elevated prolactin.
Pituitary adenomas (prolactinomas) — small benign tumours of the pituitary that secrete prolactin.
Medications — including some antidepressants, antipsychotics, anti-emetics, opioids and oestrogens.
Chest wall stimulation — including nipple stimulation, surgery and chest trauma.
Renal failure — reduced clearance of prolactin from the blood.

6. Symptoms of high prolactin

Symptoms of hyperprolactinaemia in non-pregnant women include:

Irregular or absent menstrual cycles.
Anovulation and infertility.
Galactorrhoea (milky nipple discharge in a woman who is not breastfeeding).
Reduced libido.
Vaginal dryness.
Headaches and visual disturbance — particularly with larger pituitary tumours.

In men, hyperprolactinaemia causes reduced libido, erectile dysfunction, low sperm count and infertility.

7. Causes of low prolactin

Low prolactin is much less common and is rarely a clinical problem outside the postpartum period, where it can cause inadequate milk supply. It can occur with:

Pituitary disease (Sheehan's syndrome).
Use of dopamine agonist medications.
Some forms of pituitary surgery or radiation.

8. Prolactin and fertility

Even modestly elevated prolactin can disrupt the menstrual cycle by suppressing GnRH release from the hypothalamus, which in turn reduces FSH and LH and prevents ovulation. Hyperprolactinaemia is one of the most easily corrected causes of female infertility — once treated, fertility usually returns rapidly.

9. When and how to test prolactin

Prolactin is usually measured as part of a baseline fertility hormone panel on day 2 or 3 of the menstrual cycle, alongside FSH, LH, oestradiol and TSH. Because prolactin is sensitive to stress, the test should ideally be performed in the morning after a relaxed start to the day; nipple stimulation, recent intercourse and physical exam of the breasts can all transiently elevate prolactin. A markedly elevated prolactin should always be confirmed with a repeat test, and very high levels warrant pituitary MRI to exclude a prolactinoma.

Reference ranges vary from country to country. Always interpret your own result against the laboratory's own reference range and discuss it with your doctor.

10. Prolactin in traditional Chinese medicine

In traditional Chinese medicine, mildly elevated prolactin from stress is most commonly seen as a pattern of Liver Qi stagnation, often with underlying Spleen Qi or Blood deficiency. Where elevated prolactin occurs alongside an underactive thyroid, the pattern typically also includes Kidney Yang deficiency. Symptoms of breast tenderness, irregular cycles, irritability and tension headaches are very characteristic.

11. Acupuncture and prolactin

Acupuncture is highly effective at reducing stress-related elevations in prolactin. By regulating the hypothalamic-pituitary axis and reducing cortisol, acupuncture allows dopamine inhibition of prolactin to be restored, and prolactin levels frequently normalise within two to three menstrual cycles. Acupuncture should be combined with medical treatment if a prolactinoma is present.

12. Chinese herbal medicine and prolactin

The most commonly used Chinese herbal formula for stress-related hyperprolactinaemia is Xiao Yao San (Free and Easy Wanderer) or its modified versions Jia Wei Xiao Yao San and Dan Zhi Xiao Yao San. These formulae harmonise the Liver, support the Spleen and gently nourish the Blood, addressing the underlying patterns that drive prolactin elevation.

13. Diet, supplements and lifestyle

To support healthy prolactin levels:

Reduce psychological stress through mindfulness, meditation, yoga, counselling or whatever works for you.
Sleep before 10 p.m. — late nights and poor sleep raise prolactin.
Avoid excessive nipple stimulation outside of intentional breastfeeding contexts.
Have your thyroid function checked — treating subclinical hypothyroidism often normalises prolactin.
Vitex agnus castus (chasteberry) has been shown to reduce mildly elevated prolactin and is widely used in herbal practice.
Avoid medications known to raise prolactin where alternatives are available — discuss with your doctor.