Quick answer: Prolactin is a pituitary hormone best known for milk production, but it also affects cycles, libido and immunity. High prolactin can cause irregular or missed periods, milky nipple discharge, low libido and fertility problems. Causes include stress, some medications, hypothyroidism and benign pituitary tumors, so persistent high results need follow-up.
Key takeaways
Prolactin is a pituitary hormone best known for milk production, but it also affects cycles, libido and immunity.
A high level can bring irregular periods, nipple discharge, low libido or fertility challenges.
Stress, certain medications, an underactive thyroid and benign pituitary growths can raise it, so persistent high results need follow-up.
What is Prolactin?
Prolactin is made by the pituitary gland. Dopamine from the brain normally keeps it in check outside of pregnancy and breastfeeding. This marker is part of the Healthspan Assessment panel available to my 1-on-1 patients.
Why Prolactin matters
Prolactin matters for milk production, the menstrual cycle and fertility, libido in men and women, and immune signaling.
Understanding your result
Reference ranges vary by lab, age and sex. Your provider interprets your result against the lab’s range and your overall picture, rather than chasing a single number. Functional labs are optional. They can be helpful in more complex cases, and in my practice they are available only to patients working 1-on-1 with me.
What low Prolactin can mean
Low prolactin is usually not a concern, and it only rarely reflects pituitary underactivity.
What high Prolactin can mean
High prolactin is normal in pregnancy and breastfeeding, and it can also rise with stress, poor sleep or recent exercise. Medications such as some antidepressants and antipsychotics can raise it, as can hypothyroidism and a prolactinoma (a benign pituitary tumor).
What affects Prolactin
Prolactin is affected by stress and time of day, nipple stimulation or exercise before testing, medications, and thyroid function.
Ways to support healthy levels
If prolactin is mildly high, retest under calm, rested conditions, review medications with your doctor, and check thyroid function (see TSH). Persistently high prolactin may need pituitary imaging.
Prolactin and healthy aging
Prolactin is part of the brain-hormone communication network. Chronic stress can raise it, which in turn is linked with disruption of sex hormones that support bone and metabolism.
Related tests and articles: FSH, progesterone.
When to see a naturopathic doctor
It may be time to see a naturopathic doctor if you have missed or irregular periods, or milky nipple discharge. The same is true if you have low libido or erectile problems, or trouble conceiving.
See a medical provider promptly for severe headaches or changes in vision, which can signal a pituitary problem.
Want help making sense of your labs?
A free 15-minute consultation with Dr. Kneessi. No cost, no obligation. In-office in Odenton, MD or by telehealth.
Prolactin at a glance
| Topic | What the article explains |
|---|---|
| Why it matters | Milk production; menstrual cycle and fertility; libido in men and women; and immune signaling |
| What can affect it | Stress and time of day; nipple stimulation or exercise before testing; medications; and thyroid function |
| Supportive habits discussed | Retest under calm, rested conditions if mildly high; review medications with your doctor; check thyroid function; and persistently high prolactin may need pituitary imaging |
Questions to bring to your clinician
These questions can help you get the most out of your next visit.
Could any of my medications or my thyroid be raising my prolactin?
Could any of my current medications or supplements be affecting my Prolactin level?
When would it make sense to recheck Prolactin, and what would we be looking for?
Which daily habits, such as sleep, meals and movement, are most worth focusing on for me right now?
Frequently asked questions
What causes high prolactin?
Stress, medications, hypothyroidism, pregnancy and pituitary tumors.
Can stress raise prolactin?
Yes, often mildly. Retesting under calm conditions helps.
Does prolactin affect men?
Yes. High prolactin can lower testosterone and libido.
Is a prolactinoma cancer?
No. It is a benign pituitary tumor, usually treatable.
Sources
- Melmed S, et al. Diagnosis and treatment of hyperprolactinemia: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab 2011. PMID: 21296991. https://pubmed.ncbi.nlm.nih.gov/21296991/
- MedlinePlus: Prolactin Levels
- MedlinePlus: Pituitary Tumors
This article is for educational purposes only and is not medical advice. It does not replace an individual evaluation. Talk with your healthcare provider before starting supplements or changing medications, especially if you are pregnant, nursing, or managing a health condition.
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