Prolactin
A pituitary hormone that affects fertility, mood, and libido. Usually tested when something feels off — here's what your number tells you.
Prolactin is produced by your pituitary gland. High levels can cause irregular periods, low libido, and fertility issues. In men, elevated prolactin is one of the most overlooked causes of low testosterone and sexual dysfunction.
What is this test?
Prolactin is a hormone made by the pituitary gland — a pea-sized structure at the base of your brain. Its primary role is stimulating breast milk production, but it also plays a role in metabolism, immune function, and reproductive hormones in both men and women.
You wouldn't normally include prolactin in a routine panel. It's usually tested when you have symptoms like unexplained low libido, irregular periods, difficulty conceiving, or galactorrhoea (unexpected breast discharge).
What your number means
| Prolactin level | What it suggests |
|---|---|
| < 2 ng/mL | Low — rare, may indicate pituitary insufficiency |
| 2–18 ng/mL (men) | Normal range for males |
| 2–29 ng/mL (women) | Normal range for non-pregnant females |
| 30–100 ng/mL | Mildly elevated — most often medication-related or stress |
| 100–200 ng/mL | Significantly elevated — investigate for microprolactinoma |
| > 200 ng/mL | High — strongly suggests macroprolactinoma, needs MRI |
Stress, recent exercise, and nipple stimulation can all transiently elevate prolactin. If your result is mildly elevated (25–50 ng/mL), retest under calm, rested conditions before further workup.
How to lower high prolactin
- Review your medications — antipsychotics, SSRIs, metoclopramide, and domperidone are the most common culprits. Talk to your doctor about alternatives
- Manage stress — chronic stress directly raises prolactin. Sleep, exercise, and meditation help
- Get enough vitamin B6 — B6 supports dopamine synthesis, which naturally suppresses prolactin
- Check your thyroid — hypothyroidism raises TRH, which stimulates prolactin release. Fix the thyroid, fix the prolactin
- Medical treatment — for prolactinomas, cabergoline (a dopamine agonist) is first-line and highly effective
Track your hormone panel over time
eterni connects prolactin, testosterone, thyroid, and more into one dashboard — so you see the full picture, not isolated numbers.
Get early accessFrequently Asked Questions
Can medications raise prolactin?
Yes — this is the most common cause of elevated prolactin. Antipsychotics (risperidone, haloperidol), some antidepressants (SSRIs), anti-nausea drugs (metoclopramide, domperidone), and acid blockers (ranitidine, omeprazole) can all raise prolactin significantly. If your prolactin is high, always review your medication list first.
What is a prolactinoma?
A prolactinoma is a benign (non-cancerous) tumour of the pituitary gland that overproduces prolactin. It is the most common type of pituitary tumour. Prolactin levels above 200 ng/mL strongly suggest a macroprolactinoma. Most respond well to medication (cabergoline or bromocriptine) and rarely need surgery.
Does high prolactin lower testosterone?
Yes. Elevated prolactin suppresses GnRH (gonadotropin-releasing hormone), which in turn reduces LH and FSH, leading to lower testosterone production. In men, this can cause low libido, erectile dysfunction, fatigue, and even gynecomastia. It is an often-overlooked cause of hypogonadism.
How do you lower high prolactin?
First, rule out medication-induced elevation and check for a pituitary tumour with an MRI. If a prolactinoma is found, dopamine agonists (cabergoline is first-line, bromocriptine is the alternative) are very effective. If medication-induced, switching drugs often resolves it. Vitamin B6 and vitex (chasteberry) have mild prolactin-lowering effects but are not substitutes for medical treatment when prolactin is significantly elevated.
Prolactin and male health
Elevated prolactin in men is more common than most people realise, and its effects are significant:
- Testosterone suppression — prolactin directly inhibits GnRH pulsatility, reducing the hormonal signal that drives testosterone production
- Sexual dysfunction — low libido and erectile dysfunction are hallmark symptoms, often preceding measurable testosterone decline
- Gynecomastia — breast tissue enlargement from the combined effect of high prolactin and low testosterone
- Bone loss — chronic hyperprolactinemia leads to hypogonadism, which accelerates bone density loss
If you're a man with low testosterone, always check prolactin before assuming your testosterone issue is primary.
The dopamine connection
Prolactin is one of the few hormones that is primarily under inhibitory control. Dopamine from the hypothalamus constantly suppresses prolactin secretion. Anything that lowers dopamine — medications that block dopamine receptors, pituitary tumours that compress the dopamine pathway, or chronic stress — will raise prolactin.
This is why dopamine agonists (cabergoline, bromocriptine) are so effective at treating high prolactin — they restore the natural brake.
Know what's working. Know what's not.
eterni connects your lab results, supplements, and retests — so you can see the trajectory, not just a snapshot.
Join the waitlist