Prolactin Levels Explained: What's Normal, What's Not, and What to Do

Maybe your doctor mentioned a prolactin test and you nodded along like you knew what that meant (we've all been there). Or maybe you've been TTC and the term keeps coming up. Either way, if you want the full lowdown on prolactin levels, you're in the right place.

This hormone doesn't get nearly as much airtime as estrogen or progesterone, but it plays a surprisingly big role in your reproductive health — and beyond.

So, what does prolactin do, what do your levels actually mean, and when should you be worried? Let's get into it.

In this article: 📝

What is prolactin?

Prolactin is a hormone produced mainly by the pituitary gland — a tiny but mighty gland at the base of your brain. It's also made in smaller amounts by other tissues around the body, including the uterus, breasts, and immune cells. [1]

Its most famous job? Triggering and sustaining breastmilk production — which is exactly how it got its name. You might also see it referred to as PRL, luteotropic hormone (LTH), or simply the "milk hormone."

But prolactin is way more than a one-trick pony. More on that in a sec.

What does prolactin do in females?

Prolactin has been linked to at least 300 functions in the body — yes, really. In women specifically, its roles include:

• Breast development and milk production: Prolactin stimulates the growth of mammary glands during pregnancy and kickstarts milk production after birth. (If your boobs are leaking during pregnancy, prolactin is the reason.)
• Regulating the menstrual cycle: Prolactin interacts closely with other reproductive hormones like estrogen and progesterone, so when levels are off, your cycle can be too.
• Supporting your immune system: Prolactin plays a role in immune regulation, which is part of why it shifts so much during pregnancy.
• Metabolism: It influences how your cells use energy.
• Fluid balance: It helps regulate fluid levels in the body.
• Stress response: Research suggests prolactin plays a role in coping with stress, and changing levels are linked to postpartum anxiety. [2]

What is a normal prolactin level by age?

Prolactin levels naturally vary throughout the day (they tend to be highest in the morning, FYI — which is why that's a great time for breastfeeding moms to pump). They also shift depending on where you are in your menstrual cycle, your stress levels, whether you've just exercised, and of course, whether you're pregnant or breastfeeding.

Labs can differ slightly on what counts as "normal," so always check the reference range on your own results. But as a general guide:

It's also worth knowing that prolactin levels can be temporarily elevated by things like stress, intense exercise, eating, or sexual activity — so a single elevated result doesn't automatically mean something is wrong. Your doctor may suggest retesting before drawing any conclusions.

What does a high prolactin level mean?

When prolactin levels are persistently elevated in someone who isn't pregnant or breastfeeding, it's called hyperprolactinemia. It's more common than you might think — around 1 in 25 women of reproductive age are affected.

High prolactin can interfere with the normal production of estrogen and progesterone, which disrupts ovulation and the menstrual cycle. It can also make it harder to conceive.

There are several possible causes, including:

• Prolactinoma: A benign (non-cancerous) tumor of the pituitary gland, and the most common cause of persistently high prolactin. Prolactinomas account for up to 40% of pituitary tumors. [3]
• Hypothyroidism: When your thyroid isn't making enough thyroid hormone, it can trigger the release of more prolactin (more on this below). [4]
• Certain medications: Including opioid painkillers, some antidepressants, antipsychotics, blood pressure drugs, anti-nausea medications, and some heartburn treatments.
• PCOS: The relationship is complicated, but elevated prolactin can occur alongside PCOS (more on this below too). [5]
• Kidney or liver disease: These conditions can reduce the body's ability to clear prolactin. [6]
• Problems with the hypothalamus: The part of the brain that regulates the pituitary gland. [7]
• Idiopathic hyperprolactinemia: In about a third of cases, no clear cause is found. This often resolves on its own. [8]

Does high prolactin mean PCOS?

Not necessarily — but the two can overlap, and it's worth understanding why.

Prolactin levels are usually normal in women with PCOS (generally less than 25 ng/mL). However, it's important to check for high prolactin in order to rule out other problems — such as a pituitary tumor — that might be causing PCOS-like symptoms. Some women with PCOS do have mildly elevated prolactin, typically in the 25–40 ng/mL range. [9]

The tricky part: both conditions can cause irregular periods, anovulation, and fertility issues, so they can look similar on the surface. In order to determine whether someone has PCOS in addition to hyperprolactinemia, prolactin levels need to be normalized before a PCOS diagnosis can be confirmed. [10]

Bottom line: if you have PCOS symptoms, getting your prolactin checked is part of the standard workup — and if your levels are elevated, that needs to be investigated on its own terms first.

Is high prolactin related to thyroid issues?

Yes — and this is a connection that often flies under the radar. Hypothyroidism can cause hyperprolactinemia. When thyroid hormone is low, the negative feedback on thyrotropin-releasing hormone (TRH) is removed, allowing for excessive prolactin release. [1]

Some research suggests that around 20-40% of people with an underactive thyroid have at least mildly elevated prolactin levels. This is one reason thyroid function tests are usually ordered alongside a prolactin test. [11]

The good news: if hypothyroidism turns out to be the cause of your high prolactin, treating the thyroid issue should bring prolactin back to normal on its own.

What are the main symptoms of high prolactin levels?

There are actually quite a few possible symptoms of high prolactin in women — but two of the most common and noticeable are:

1. Irregular or absent periods

High prolactin suppresses the hormones needed for ovulation, which can throw your cycle completely off. Periods may become irregular, very light, or stop altogether — even before the age of 40.

2. Galactorrhea (unexpected nipple discharge)

This is when your breasts start producing a milky discharge even though you're not pregnant or breastfeeding. It can happen spontaneously or when the nipple is touched. It sounds alarming, but it's one of the most recognizable signs that prolactin is elevated.

Other symptoms can include:

• Tender breasts
• Vaginal dryness
• Difficulty getting pregnant
• Low sex drive
• Unexplained headaches
• Changes in vision

For women who have already been through menopause, symptoms might not appear until the condition is more advanced — which is why it can go undetected for longer in this group.

Does high prolactin cause weight gain?

Research does suggest a link. High levels of prolactin (hyperprolactinemia) can cause infertility in women, and many people with the condition are also overweight. One older study from 1998 found that treating hyperprolactinemia led to weight loss in 70% of patients — suggesting the hormone plays a real role in metabolism and weight regulation. [12]

Can I get pregnant with high prolactin?

High prolactin can make it harder to conceive, for a couple of reasons.

First, it can interfere with ovulation. Prolactin suppresses the hormones that trigger egg release from the ovaries, making it harder to time conception — and in some cases, stopping ovulation entirely.

Second, it can reduce progesterone levels. Progesterone is needed to prepare the lining of the uterus for implantation. Without enough of it, even if ovulation does happen, implantation may be less likely to succeed.

The reassuring news: high prolactin is one of the more treatable causes of fertility issues. With the right treatment, many women go on to conceive.

What not to do when prolactin is high?

If you've been told your prolactin is elevated (or you're about to get it tested), a few things are worth knowing:

• Don't stop any prescription medications without talking to your doctor first: If a drug is contributing to your high prolactin, your doctor will help you weigh the risks and alternatives — abruptly stopping medication can cause more harm than good.
• Avoid nipple stimulation: It can temporarily raise prolactin levels. This is especially relevant before a blood test; you should avoid nipple stimulation for 24 hours before a prolactin test.
• Skip tight or restrictive clothing around your chest: Irritation of the chest wall — even from a too-tight bra — can be a contributing factor to elevated prolactin. [13]
• Avoid intense exercise and significant stress right before a blood draw: Both can cause a temporary spike in prolactin that doesn't reflect your true baseline.
• Don't self-diagnose or self-treat: There are many possible causes of high prolactin, and some — like a prolactinoma — need proper investigation. If your results are elevated, a follow-up is almost always needed.

Can you fix high prolactin levels?

Yes — and the good news is that high prolactin is usually very treatable.

Medical treatment

For most people with a prolactinoma, medication is the first line of treatment. Drugs that mimic dopamine (the "feel-good" hormone that naturally inhibits prolactin) are highly effective at lowering prolactin levels and shrinking tumors. The most commonly used is cabergoline, followed by bromocriptine. Surgery is reserved for larger tumors that don't respond well to medication. [14,15]

If hypothyroidism is the culprit, treating the thyroid issue with thyroid hormone replacement should normalize prolactin levels without any additional treatment.

If medication is raising your prolactin, your doctor may adjust your dose or switch you to an alternative that doesn't have the same effect.

Natural approaches

The evidence here is more limited, but some things may help:

• Managing stress: Chronic stress raises cortisol, which can disrupt hormone balance — including prolactin. Yoga, meditation, adequate sleep, and gentle movement are all reasonable options.
• Healthy eating: A balanced diet supports hormonal health in general.
• Vitamin B6: One 2021 study found that high-dose vitamin B6 successfully reduced prolactin levels by an average of 68% in a group of men with drug-induced hyperprolactinemia. The research in women is more limited, but it's promising. [16]
• Vitamin E: A small 1992 study found vitamin E reduced prolactin in dialysis patients, though the sample size was only 12 people. [17]

Worth noting: natural approaches should complement medical care, not replace it — especially if a prolactinoma or other underlying condition is involved.

What foods are high in prolactin?

If you're breastfeeding and want to support milk supply, certain foods may help. Asparagus, apricots, and dates are high in tryptophan, which stimulates prolactin production. New moms looking for tips on how to increase prolactin are often directed toward these. [11]

On the flip side, if your prolactin is already too high, some herbs — including fenugreek, fennel seeds, and red clover — are thought to raise prolactin levels, so they're worth being aware of. [13]

When to worry about prolactin

A mildly elevated result on a one-off test doesn't always mean there's a problem. Stress, exercise, eating, and even the timing of your blood draw can all cause a temporary blip.

But you should follow up with your doctor if:

• Your periods have become irregular or have stopped, and you're not pregnant
• You're experiencing unexplained nipple discharge
• You've been struggling to conceive
• You're having persistent headaches or changes in your vision (these can sometimes indicate a larger pituitary tumor pressing on nearby structures)
• Your prolactin levels remain elevated on repeat testing

If prolactin levels are very high — up to 1,000 times the upper limit of normal — this could be a sign of a prolactinoma, and your doctor will likely refer you for an MRI to get a clearer picture of what's going on. The vast majority of prolactinomas are benign and respond well to treatment.

Prolactin levels don’t have to be a mystery

Prolactin is one of those hormones that most people don't think about until something prompts them to — whether that's a fertility investigation, an unusual symptom, or a routine blood test. But understanding your prolactin levels is actually a really useful piece of the puzzle when it comes to your reproductive and overall health.

If your levels come back elevated, try not to panic. High prolactin is common, it's manageable, and there are effective treatments available. Talk to your doctor about next steps — and in the meantime, the Peanut community is full of women who've navigated exactly this, ready to share their experiences and support.

You're not alone in this.