Prolactin is a hormone made by the pituitary gland at the base of your brain, best known for driving breast-milk production after childbirth. On a blood test, a typical (non-pregnant, non-breastfeeding) result falls between about 2 and 40 ng/mL; higher values — a state called hyperprolactinemia — can disrupt periods, fertility and, in men, sexual function. Because levels rise naturally in pregnancy, breastfeeding, stress and even after a poor night's sleep, one raised reading is often repeated before it means anything.
What is the prolactin test?
Prolactin (sometimes written PRL) is produced by specialised cells in the anterior pituitary. Its main job is to prepare the breasts for milk production and to sustain lactation, but it also influences the reproductive hormones that govern ovulation and the menstrual cycle. When prolactin is too high, it suppresses those reproductive signals — which is why the test sits at the heart of many fertility and menstrual investigations.
A doctor typically orders a prolactin test when a woman has irregular or absent periods, difficulty conceiving, or milky nipple discharge that is not related to breastfeeding (called galactorrhea). In men, it is checked for reduced sex drive, erectile difficulty, infertility or, less commonly, breast enlargement. It is also part of the work-up for unexplained headaches with vision changes, which can point to a pituitary growth. In India, prolactin is a routine part of women's hormone and fertility panels, especially in the assessment of irregular cycles and conditions such as PCOS.
The test is a simple blood draw. Because prolactin rises with stress, exertion, breast stimulation and sleep, samples are usually taken a few hours after waking and after resting quietly for a short while — your doctor will advise on timing.
Prolactin normal range
Prolactin is reported in ng/mL (nanograms per millilitre). In a non-pregnant, non-breastfeeding adult, a result in the range below is generally considered normal, and higher values are graded by how far above the usual range they sit. The bands below reflect standard laboratory reference ranges used by clinical laboratories; the exact cut-offs vary slightly between labs and assays.
| Prolactin (ng/mL) | Interpretation |
|---|---|
| 2–40 | Normal range for non-pregnant adults |
| 40.1–60 | Borderline high — often needs a repeat test |
| 60.1–100 | Moderately high |
| 100.1–200 | Markedly high |
| Above 200 | Very high — warrants prompt specialist review |
| Below 2 | Low — rarely clinically significant on its own |
Two practical points matter here. First, always read your result against the reference range printed on your own report, because laboratories differ. Second, the degree of elevation is a useful clue: mildly raised prolactin often reflects stress, medication or an underactive thyroid, while very high values are more suggestive of a pituitary tumour that produces prolactin. That is why your doctor cares not just whether the result is high, but how high.
Normal range by age, sex and condition
Prolactin is one of the hormones where physiological state — far more than a fixed number — decides what "normal" means. The laboratory cut-off is not adjusted for most groups; instead, certain situations are expected to raise prolactin, and results must be read in that light. The table below is qualitative: it does not assign separate numeric cut-offs, because standard ranges do not define per-group values here.
| Group or situation | Why prolactin interpretation differs |
|---|---|
| Pregnancy | Prolactin rises steadily through pregnancy to prepare for milk production, reaching many times the non-pregnant level. A high result is expected and normal. |
| Breastfeeding | Suckling triggers prolactin surges to maintain milk supply, so raised levels are physiological, not a disorder. |
| Women (reproductive age) | Because high prolactin suppresses ovulation, it is a common and important cause of irregular periods and infertility, so the test is used frequently in this group. |
| Men | Prolactin is normally low; a raised result more often points to a medication effect or a pituitary cause, and can lower testosterone and sex drive. |
| People on certain medications | Some drugs raise prolactin as a side effect, so the medication list is reviewed before assuming a glandular cause (see below). |
| Underactive thyroid (hypothyroidism) | Low thyroid hormone can drive prolactin up; treating the thyroid often normalises it, so thyroid function is usually checked alongside. |
| Recent stress, exertion or breast exam | Prolactin rises transiently, so a mildly high reading is often repeated under calmer, standardised conditions before it is acted on. |
Because these differences are about physiological context rather than different numbers, a prolactin result is always interpreted alongside your history, your medications, a thyroid check and — where relevant — your menstrual and fertility picture.
What high prolactin means
A result above the normal range (above roughly 40 ng/mL on repeat testing) is called hyperprolactinemia. Once pregnancy and breastfeeding are excluded, the common causes include:
- Prolactinoma — a benign (non-cancerous) growth of the pituitary gland that produces prolactin. This is the classic cause of markedly or very high levels, and larger tumours can press on nearby structures to cause headaches or visual changes.
- Medications — several drugs raise prolactin, including some antipsychotics, certain anti-nausea and gut-motility medicines, some antidepressants, and a few blood-pressure drugs. This is one of the most frequent explanations for a mildly raised result.
- Underactive thyroid (hypothyroidism) — a common and easily checked cause; correcting the thyroid often brings prolactin back down.
- Other causes — chronic kidney disease, chest-wall irritation, significant stress, and, in some assays, a harmless large form of prolactin called macroprolactin that can falsely elevate the reading.
Symptoms of high prolactin come mainly from its effect on reproductive hormones. In women, that means irregular or absent periods, difficulty conceiving, and galactorrhea (milky discharge unrelated to breastfeeding). In men, it can cause low sex drive, erectile difficulty, infertility and sometimes breast tenderness or enlargement. Very high levels from a large pituitary tumour can additionally cause headaches and vision problems. Because high prolactin is closely tied to fertility, it is often uncovered during the same work-up that assesses other hormones such as testosterone.
What low prolactin means
Low prolactin (below the usual range) is uncommon and rarely a problem on its own. The main situation where it matters is hypopituitarism — a state in which the pituitary gland under-produces several of its hormones, usually because of injury, surgery, radiation or a larger pituitary problem. In that setting, low prolactin appears alongside deficiencies of other pituitary hormones and is picked up as part of that broader assessment. After childbirth, notably low prolactin can also contribute to difficulty producing enough breast milk. For most people, though, a low reading needs no action.
How to manage a high prolactin result
The right response to a raised prolactin depends entirely on the cause, which is why the first steps are diagnostic rather than dietary. Sensible, evidence-aligned points include:
- Repeat the test properly first. A single mildly high value is often confirmed on a second, calm, well-timed sample before anything else is done — because stress, exertion and breast stimulation can inflate the result.
- Review your medicines with your doctor. If a drug is the cause, never stop it yourself; your doctor may adjust or switch it where it is safe to do so.
- Check the thyroid. Because an underactive thyroid can raise prolactin, treating it often resolves the elevation without any prolactin-specific therapy.
- Ask about macroprolactin. If you have no symptoms but a raised level, the lab can test for macroprolactin, a harmless large form that can cause a falsely high reading.
- Follow specialist advice for a prolactinoma. Confirmed pituitary tumours are usually managed with medication under an endocrinologist, and imaging of the pituitary may be arranged.
There is no proven food or supplement that reliably lowers prolactin, and lifestyle changes are not a substitute for finding the cause. That said, managing stress and getting adequate sleep can reduce the transient spikes that muddy the picture. When to see a doctor: if you have irregular or missing periods, trouble conceiving, milky nipple discharge, reduced sex drive or erectile difficulty, or headaches with vision changes. If you are tracking your hormones over time — for a PCOS or fertility work-up, for instance — keeping every report in one place with ExaHealth makes it easier to see how prolactin and related markers move across the months.
Guidelines and references
The bands above reflect standard laboratory reference ranges rather than a single named guideline. For interpretation, rely on:
- Your own laboratory's printed reference range, which is the definitive cut-off for your result.
- Endocrine Society — general clinical guidance on hyperprolactinemia and pituitary hormone disorders.
For how prolactin fits alongside the other hormones behind cycles and fertility, read our guide to women's hormones, fertility and menopause, and browse more explainers in the lab tests library.
Frequently asked questions
What is a normal prolactin level?
For a non-pregnant, non-breastfeeding adult, a normal prolactin result is generally between about 2 and 40 ng/mL. The exact cut-off varies slightly by laboratory, so check the range printed on your own report.
What does a high prolactin level mean?
High prolactin (hyperprolactinemia) can disrupt periods and fertility and cause milky nipple discharge. Common causes include certain medications, an underactive thyroid, and a benign pituitary growth called a prolactinoma — but pregnancy, breastfeeding and stress raise it naturally too.
Can high prolactin affect fertility?
Yes. Raised prolactin suppresses the hormones that control ovulation, which can cause irregular or absent periods and difficulty conceiving in women, and reduced sex drive or infertility in men. It is a routine check in fertility and PCOS work-ups.
Why does prolactin need to be tested at a particular time?
Prolactin rises with stress, exertion, sleep and breast stimulation, so a single reading can be misleadingly high. Samples are usually taken a few hours after waking and after resting quietly, and borderline results are often repeated.
Can medications raise prolactin?
Yes. Some antipsychotics, anti-nausea and gut-motility medicines, certain antidepressants and a few blood-pressure drugs can raise prolactin. Tell your doctor about all your medicines, and never stop a prescribed drug without advice.
Does high prolactin always mean a tumour?
No. Many raised results come from medications, an underactive thyroid, stress or a harmless large form of prolactin called macroprolactin. A prolactinoma is more likely with very high levels, which is why the degree of elevation guides the next steps.