Prolactin
Quick answer
What is Prolactin?
Prolactin is a pituitary hormone. In men, persistently elevated prolactin (hyperprolactinaemia) suppresses GnRH, lowering LH and ultimately testosterone. It's the marker that catches a prolactinoma — a benign pituitary tumour that's the most common pituitary cause of secondary hypogonadism.
- Units:
- mIU/L
- Reference range:
- <350 mIU/L (men)
- Sample:
- Venous blood (serum)
- Category
- Hormones
- Units
- mIU/L
- Reference range
- <350 mIU/L (men)
What does a high Prolactin result mean?
Prolactinoma, certain medications (antipsychotics, opioids), hypothyroidism, chronic stress, recent nipple stimulation. Mild elevations are often non-pathological; significant elevations warrant pituitary MRI.
What does a low Prolactin result mean?
Generally not clinically significant in men.
Why does Prolactin matter?
A prolactin reading is the cheapest way to rule out a treatable pituitary cause of low T. Skip it and you miss it.
FAQs
- What level of prolactin warrants further investigation?
- Sustained levels above ~500 mIU/L in men, especially with low T or visual symptoms, warrant repeat testing and possibly pituitary MRI.
References
- [1]Testosterone Therapy in Men with Hypogonadism: Endocrine Society Clinical Practice GuidelineEndocrine Society / JCEM (2018)
- [2]Diagnosis and Management of Male Late-Onset HypogonadismPubMed / J Clin Endocrinol Metab
Want Prolactin interpreted in the context of your full panel? Every FORM bloodwork tier covers it, with an MD walking you through the result.
Message on WhatsApp