What is Prolactin (PRL)?

Prolactin is a hormone synthesized mostly by the pituitary gland in the brain. In women, it is primarily known for its role in regulating milk production after childbirth (lactation) and plays a role in the menstrual cycle. It also affects male reproductive health by regulating testosterone production, impacting libido, erectile function, and fertility. In both men and women, prolactin is released in response to stress, sleep, and other factors, and can have interactions with other hormones like cortisol and thyroid hormones.

Why is it measured?

PRL is critical for the analysis of a variety of issues, and abnormal levels may indicate pituitary gland irregularities, including tumors.

In men:

  • Low PRL is correlated with negative metabolic, psychological, and sexual characteristics
  • High PRL can lead to erectile dysfunction, decreased libido, and low sperm production
  • High PRL can inhibit testosterone production and cause decreased energy, muscle mass, and blood count (anemia)

In women:

  • Low PRL can impede breast milk production
  • High PRL can cause menstrual cycle and ovulation irregularities
  • High PRL levels can cause a milky discharge from the nipples when not pregnant (galactorrhea) and vaginal dryness
  • Females of reproductive age with both abnormally low and abnormally high PRL may be more prone to cardiovascular and metabolic complications

How can I better understand my results?

For men:

Men should ideally be on the lower end of the 5-20 ng/mL normal range. The average man has a prolactin level of 5 ng/mL.

For women:

Women who are not pregnant or breastfeeding should ideally fall in the low to middle end of the 5-30 ng/mL normal range. The average woman has a prolactin level of 13 ng/mL. Pregnant or breastfeeding women can expect much higher levels between 80-400 ng/mL.

If your PRL levels are slightly low, many women try pharmacologic or natural galactagogues (milk boosters) such as fenugreek to raise PRL levels and promote lactation.

In both men and women, certain medications (antipsychotic, cardiovascular, opiates, etc.), health conditions (infections, autoimmune disease, Sheehan syndrome, etc.), and pituitary gland disorders (prolactinomas or pituitary gland tumors) can all cause abnormally high or low levels of prolactin, which is why it is important to consult with your physician if you are concerned about any of your results. It is important to remember that prolactin levels follow a circadian rhythm associated with the onset of sleep and can appear higher or lower depending on a multitude of factors, with the optimal timing for blood tests being 2-3 hours after waking and while fasting.

If your PRL levels are slightly elevated, you can try:

  • Since dopamine suppresses prolactin, consume a diet rich in tyrosine (dopamine precursor) and vitamin C (sustains dopamine's inhibitory effect)
  • Limit gluten (may stimulate PRL release) from your diet
  • Limit alcohol (increases PRL, decreases testosterone levels) consumption
  • Consume or supplement vitamin B6 (wild salmon, chicken, spinach, etc.)
  • Consume or supplement vitamin E (nuts, seeds, greens, etc.)
  • Consume or supplement zinc (shellfish, beef, turkey, beans, etc.)
  • Consume or supplement ashwagandha (testosterone boosting effect may suppress PRL)
  • Try to reduce stressors

Where can I learn more?

Cleveland Clinic - Prolactin

NIH - Physiology, Prolactin

Longdom - The Role of Prolactin in Men

NIH - Hyperprolactinemia

Wolters Kluwer - Patient education: High prolactin levels and prolactinomas

Synlab - Drugs Causing Hyperprolactinaemia

Science Direct - Low prolactin is associated with sexual dysfunction and psychological or metabolic disturbances in middle-aged and elderly men

Springer Link - Cardiometabolic profile of young women with hypoprolactinemia