ProlactinmU/L
Pituitary prolactin secretion
Typical optimal range
86–324 mU/L
Female
A typical reference range is around 86–324 mU/L, though exact boundaries differ between laboratories and analysers, so your result should always be interpreted against your own lab's reference interval. These figures are indicative — the range printed on your own lab report is the definitive one for your results.
Interpretation of prolactin results follows NHS and Society for Endocrinology guidance, with NICE pathways informing GP referral for suspected pituitary conditions.
What is Prolactin?
Prolactin is a hormone produced by the pituitary gland, a small gland at the base of the brain. It is best known for stimulating milk production after childbirth, but it is present in everyone and plays a role in reproductive health, immune function, and metabolism. Measuring prolactin in the blood is useful because chronically raised levels can disrupt the hormonal axis that governs reproductive function in both women and men, and can be an early sign of an underlying pituitary condition.
What a high Prolactin means
A raised prolactin result is a signal worth investigating further rather than a diagnosis in itself — many causes are benign or reversible, and a single elevated reading does not confirm a problem. Your GP will usually want to repeat the test under standardised conditions before drawing any conclusions.
- Prolactinoma. A prolactinoma is a benign tumour of the pituitary gland that secretes excess prolactin. It is the most common type of pituitary tumour and is highly treatable, usually with medication rather than surgery. Your GP may refer you to an endocrinologist if a prolactinoma is suspected.
- Medications. A wide range of prescribed medicines can raise prolactin, including certain antipsychotics, antidepressants (particularly older tricyclics), metoclopramide, domperidone, and some antihypertensives. Always tell your GP every medicine and supplement you take when discussing this result.
- Hypothyroidism. An underactive thyroid raises levels of thyrotropin-releasing hormone (TRH), which can also stimulate prolactin release. Treating hypothyroidism typically normalises prolactin, so your GP may check thyroid function (TSH and free T4) alongside a raised prolactin result.
Prolactin is highly sensitive to acute stress, strenuous exercise, recent sexual activity, breast stimulation, a recent meal, and even the stress of the blood draw itself — all of which can temporarily push levels above the reference range. This is why repeat testing under calm, fasting conditions is standard practice before further investigation.
What a low Prolactin means
A low prolactin level is rarely clinically significant for most people and is not usually a cause for concern on its own. It can occasionally reflect pituitary damage or the effect of certain medicines.
- Dopaminergic medications. Drugs that increase dopamine activity — such as cabergoline or bromocriptine used to treat prolactinomas — intentionally suppress prolactin. A low result in this context is expected and therapeutic.
- Hypopituitarism. Damage to the pituitary gland from trauma, surgery, or other causes (hypopituitarism) can reduce prolactin alongside other pituitary hormones. This would typically be investigated as part of a broader assessment of pituitary function.
In clinical practice, a low prolactin level in someone not on dopamine-active medication rarely requires action on its own; interpretation depends on the full clinical picture.
Should I be worried?
A single raised prolactin result is common and very often turns out to be a transient or benign finding once the test is repeated under proper conditions. If a repeat test — taken in a relaxed state, ideally in the morning with no prior exercise or breast stimulation — also comes back elevated, your GP can explore the cause systematically. They will usually check thyroid function, review your medications, and may arrange an MRI of the pituitary if there is no obvious explanation. In men, persistently raised prolactin may suppress testosterone, which can cause reduced libido, erectile difficulties, or reduced fertility, so it is worth raising these symptoms too. The reassuring news is that the most common underlying cause — a prolactinoma — is typically small, slow-growing, and responds very well to medication.
What actually helps
Where a raised prolactin is driven by a reversible cause, addressing that cause is the primary lever — but general wellbeing strategies can also support a healthy hormonal environment.
- Manage stress. Acute psychological stress and anxiety can temporarily elevate prolactin via the hypothalamic-pituitary axis. Regular relaxation practices — such as mindfulness, gentle exercise, or improved sleep — may help keep baseline stress hormones, and therefore prolactin, lower.
- Review your medications with your GP. If a prescribed medicine is driving raised prolactin, your GP may be able to adjust the dose or switch to an alternative that has less effect on prolactin secretion. Never stop prescribed medication without medical advice.
- Support thyroid health. If hypothyroidism is contributing, following your GP's treatment plan (usually levothyroxine) is the most direct way to bring prolactin back into range. Ensuring adequate iodine, selenium, and iron through diet supports thyroid function more broadly.
- Prioritise sleep. Prolactin follows a circadian pattern and peaks during sleep. Chronic poor sleep disrupts the hypothalamic-pituitary axis more broadly; aiming for seven to nine hours of quality sleep per night helps maintain healthy hormonal rhythms.
There is no specific diet proven to lower prolactin directly, but a balanced, nutrient-rich diet supports pituitary and thyroid function and may help indirectly.
Oily fish (salmon, mackerel, sardines)
Rich in omega-3 fatty acids and vitamin D, both of which support general neuroendocrine health and reduce systemic inflammation that can stress the pituitary axis.
Iodine-rich foods (seaweed, dairy, white fish)
Adequate iodine is essential for thyroid hormone synthesis; supporting thyroid function helps avoid the TRH-driven rise in prolactin associated with hypothyroidism.
Brazil nuts
One of the richest dietary sources of selenium, a mineral required for thyroid hormone conversion and shown to support thyroid health in population studies.
Wholegrains and legumes
Provide B vitamins including B6, which plays a role in dopamine synthesis — the primary inhibitory signal that keeps prolactin in check under normal circumstances.
Leafy green vegetables (spinach, kale, broccoli)
Good sources of magnesium and folate, which support neurotransmitter balance and overall hormonal regulation, with consistent evidence for cardiovascular and metabolic benefit.
Low-fat dairy or fortified alternatives
Provide calcium and often vitamin D, supporting bone health which can be compromised if chronically elevated prolactin suppresses sex hormones over time.
Track your own Prolactin
Upload a lab PDF and Better Days trends Prolactin over time, flags it when it drifts, and suggests foods that help.
More in Hormones
Sources & further reading
These are reputable UK health resources for further reading. This page is written to be consistent with their guidance but is not a substitute for them.
For information only — not medical advice, and not individually reviewed by a clinician. Reference ranges vary by lab and individual. Discuss any results with a qualified clinician before making changes.