The Nursing Hormone (and Fertility Suppressor)
Prolactin stimulates breast milk production—that's its day job. But it has a powerful side effect: it suppresses reproductive hormones. This is nature's birth spacing (breastfeeding prevents ovulation). Abnormally high prolactin from medications or pituitary tumors creates the same reproductive shutdown.
What is Prolactin?
Prolactin is from the anterior pituitary, normally inhibited by dopamine. Anything that blocks dopamine raises prolactin. Stress, sleep, and nipple stimulation transiently elevate it. Persistent elevation requires investigation.
↑ What High Prolactin Means
Prolactin is suppressing your reproductive axis. If not breastfeeding/pregnant: causes missed periods, infertility, low libido, erectile dysfunction. #1 causes: medications (antipsychotics, SSRIs) and prolactinoma (benign pituitary tumor).
Common symptoms:
Women: missed periods, infertility, galactorrhea, low libido · Men: low libido, erectile dysfunction, gynecomastia, infertility · Both: headache, vision changes if large tumor
↓ What Low Prolactin Means
Usually not significant. Can indicate pituitary damage.
Common symptoms:
Usually asymptomatic · Inability to breastfeed (postpartum)
Why It Matters
When normal:
Essential for lactation
Screens for prolactinoma
Helps explain menstrual irregularity and male hypogonadism
Risks if abnormal:
High: suppresses GnRH→LH/FSH→sex hormones→infertility
Prolactinoma: can compress optic chiasm
Medication-induced elevation very common
What Can Cause Abnormal Levels?
Medications (high)
50% likelyAntipsychotics, SSRIs, metoclopramide block dopamine, removing prolactin's brake.
Prolactinoma (high)
35% likelyBenign pituitary adenoma. Most common pituitary tumor. Usually responds to medication.
Hypothyroidism
High TRH directly stimulates prolactin. Always check TSH.
Stress
Transiently raises prolactin. Recheck fasting morning draw.
Pregnancy/Nursing
Normal 10-20x elevation.
What You Can Do
Recheck fasting, morning, rested (stress/timing affect results)
Impact: Confirms true vs transient elevation \u00B7 Timeline: 1-2 weeks
Check TSH (hypothyroidism raises prolactin)
Impact: Treating thyroid normalizes prolactin \u00B7 Timeline: 6-8 weeks
If lifestyle changes aren't enough:
Review medications
Impact: Switching medication may normalize prolactin \u00B7 Timeline: 2-4 weeks
Vitex (chasteberry): 20-40mg daily
Impact: Dopaminergic herb for mild elevation \u00B7 Timeline: 4-8 weeks
Recommended retest: 4-8 weeks after intervention; 6-12 months for monitoring
Related Markers
Got your blood test report?
Upload your PDF and understand ALL your markers in 2 minutes. Plain language. Traffic light status. No medical jargon.
Analyze My Report — FreeFirst report is free. No credit card needed.