High Prolactin: The Hormone That Can Curb Your Ovulation, Libido, and Hormonal Balance

Hello, I am Dr. Isabel Viña Bas, a physician and Scientific Director of IVB Wellness Lab. In my practice, there is one hormone that almost everyone reduces to a single function: producing milk during breastfeeding.That hormone is prolactin.

Prolactin is much more than just the milk hormone. Much more. If it remains elevated outside of pregnancy and breastfeeding, it can curb ovulation. Furthermore, it can reduce libido, alter testosterone, weaken bones, and worsen metabolic control.High prolactin affects many systems at once.

And there is more. A second, equally important idea: having high prolactin in a blood test does not always mean there is a disease. It can be a real elevation, a passing effect of stress, or even the consequence of a medication; or perhaps a laboratory mirage called macroprolactinemia.Before treating a number, you have to understand where it comes from.

What is prolactin and why does dopamine keep it in check?

Prolactin is a huge peptide hormone, formed by between 190 and 199 amino acids. It was discovered in 1970, quite a while ago; but for years it was confused with growth hormone. Why, you might ask? Both share a very similar structure and come from the same embryonic cells.In the blood, its levels should almost always remain below 20 micrograms per liter.

Unlike many other hormones, prolactin does not need the brain to stimulate it constantly. In fact, the exact opposite happens: the body must keep it inhibited most of the time.The one in charge of doing this is dopamine.

I like to imagine dopamine as the handbrake of a car. Prolactin is ready to start, but dopamine keeps the brake on. If that signal drops due to stress, certain drugs, or an illness, said brake loosens andprolactin rises.Furthermore, it is not released continuously: it has about nine pulses throughout the day, which are more intense during the night hours.

There are only two situations in which we need an elevation that is both sustained and physiological: during pregnancy and breastfeeding. With pregnancy, your body's estrogens and progesterone develop the breasts, but they temporarily block the action of prolactin. Then, after childbirth, both plummet andleave the way clear for prolactin so it can activate milk production.

High prolactin and fertility: why the body slows down reproduction

When prolactin rises outside of that context, the body interprets that it is not a good time to reproduce. It is a survival mechanism: if there is stress, illness, or high energy demand, the organism prioritizes staying safe and parks functions it considers secondary.This is where high prolactin begins to interfere withfertility.

Elevated prolactin also inhibits GnRH, the master hormone produced in the hypothalamus. By lowering GnRH, the pituitary gland releases less FSH and, above all, less LH. In us women, without the LH surge, ovulation does not occur properly.This can shorten the luteal phase, space out periods, make them disappear for months, or make trying to conceive difficult.

In men, on the other hand, that drop in LH causes the testicles to generate less testosterone. The result can be an intense drop in libido, erectile dysfunction, and less facial hair growth.I have patients who go from shaving daily to doing it twice a week: a detail that may seem small, but is sometimes the first hormonal clue.

Symptoms of high prolactin beyond the period

Menstrualdisturbancesand difficulty ovulating are the best-known signs, buthyperprolactinemia does not stop at the reproductive system.One of its most striking manifestations is galactorrhea: the leakage of milk from the nipple outside of pregnancy and breastfeeding. It can appear in women and men, because both have breast tissue.

It also affects the bone. By lowering estrogens and testosterone,high prolactin weakens cortical boneand, if it persists, it favors the loss of bone mass and osteoporosis. And yes: men also need a small amount of estrogen to have strong bones.

Metabolically, prolactin favors a certain insulin resistance. During breastfeeding, it makes sense because it helps reserve glucose to produce milk. Outside of that context, it can worsen blood sugar control.In some women, acne and hair loss also appear, because as ovarian hormones drop, adrenal androgens gain relative weight.

Prolactin also stimulates the immune system. When it remains elevated, it can worsen autoimmune diseases such as lupus, multiple sclerosis, rheumatoid arthritis, or autoimmune hypothyroidism.That is why you should never read this hormone in isolation: it is part of a network.

Why does prolactin rise? Stress, drugs, thyroid, and PCOS

Stress is one of the causes that generates the most confusion. A specific upset, intense training, or even sexual intercourse can raise prolactin for a few hours, and that is not pathological.The problem arrives with chronic stress: dopamine remains low and high prolactin can become installed.

Many medications act through the same pathway. Antipsychotics, some antidepressants, metoclopramide for nausea, verapamil, opioids, alprazolam, or certain contraceptives with estrogens can raise it because they reduce or block the dopamine signal.Alcohol and marijuana also have an influence.

This does not mean you should stop a treatment on your own. If prolactin has risen after starting a medication, you must review it with the person who prescribed it and assess whether there is an alternative, a dose adjustment, or if the benefit of the drug compensates for that effect.Never stop anything without talking to your doctor first.

There are also diseases that should be ruled out. Inpolycystic ovary syndrome, excess testosterone can be converted into estradiol and curb dopamine. In untreated hypothyroidism, the brain releases more TRH to try to wake up the thyroid, and that same TRH stimulates prolactin. Chronic kidney disease can prevent it from being eliminated properly and, in other cases, the origin is in a pituitary adenoma, such as a prolactinoma, or in a lesion that compresses the pituitary stalk.Each cause completely changes the approach.

Macroprolactin: when the blood test scares you but the hormone does not act

Here is one of the keys to the episode. More than 25% of the prolactin elevations we see in a blood test can correspond tomacroprolactinemia.It is not really active prolactin, but several prolactin molecules stuck to an IgG antibody, forming a huge complex.

The laboratory machine sees that complex and counts it as if there were a lot of prolactin circulating. But because it is so large, it can barely act on the tissues.That is why there are people with very high values on paper who do not have menstrual disturbances, galactorrhea, or loss of libido.

Treating that number without first checking for macroprolactinwould be like setting off the fire alarm because the detector confused water vapor with smoke. The number is scary, but it is the context that says if there is a real fire.

How to measure prolactin well so as not to treat a false positive

Prolactin is very, very sensitive to the time and the way the blood is drawn. The simple fear of the needle could trigger this hormone. In the podcast episode, I tell the case of a patient of mine who went from 20 to 147 micrograms per liter just from the stress of an operation.That is why, for me, these measurement rules must be non-negotiable:

Choose the day of the cycle well.In women, the extraction is done in the first five days of the cycle, ideally on day 2 or 3, to reduce the influence of estrogens.

Respect the schedule and rest.The blood test must be done while fasting, between 8:00 and 10:00, after at least ten minutes of sitting quietly.

Avoid what raises it.During the 48 hours prior, no intense exercise or sexual intercourse, because they falsify the result.

Ask for the two-sample method.An IV is placed, a first sample is taken, and you wait twenty minutes without being pricked again. The second measurement is much more reliable because the initial shock of the needle has already passed.

Request macroprolactin.The laboratory can precipitate with PEG. If more than 40% of the initial prolactin is recovered, the elevation is real. However, if less is recovered, it is most likely that almost everything was macroprolactin.

How to lower prolactin: first the cause, then the treatment

There is no single treatment forhigh prolactin, because there is no single cause. An elevation due to stress is not approached the same way as hypothyroidism, a medication, or a prolactinoma. The first step is not to chase the number: it is to confirm that it is real and locate the origin.

When there is a prolactinoma or another medical indication, the drugs used are cabergoline and bromocriptine. They act on the dopamine pathway andmust always be prescribed and monitored by a doctor, especially if there is a lesion in the pituitary gland.

In elevations linked to stress, PCOS, or certain medications, and not to treat tumors, the natural active ingredient with the most interest is Vitex agnus-castus or chasteberry. In the episode, I recommend looking for extracts between 150 and 250 mg, standardized to provide about 1 mg of agnusides, which are the compounds that act on dopamine regulation.It is the same active ingredient we work with for femalehormonal balance.

At IVB, we incorporate it intoFemmeBalance, ourfood supplementfor supporting female hormonal balance. It can fit when the cause of the elevation is compatible with that mechanism, but it does not replace a well-done blood test, endocrinological assessment, or the treatment of a prolactinoma. In hormones, more than in almost anything else, order matters.

What to do if your blood test shows high prolactin?

The first thing is not to panic over an isolated figure. Repeat the blood test with the correct protocol and ask for macroprolactin. Then, review the medication you take with your doctor and assess frequent causes such as hypothyroidism, PCOS, or a kidney problem.If the elevation is confirmed, is persistent, or is accompanied by symptoms, the pituitary gland will have to be studied and the treatment decided.

And remember the exception: in pregnancy and breastfeeding, high prolactin fulfills a physiological and necessary function. Outside of those stages, ask yourself two questions before "how do I lower it": why has it risen and how do you know the measurement is real.That difference avoids both ignoring an important signal and treating something that was never altered.

Transforming your health is a matter of applying science with order and consistency, day by day.You have in your hands the knowledge to better interpret your hormones, ask the right questions, and choose the next step with less fear.

Author:Dr. Isabel Viña Bas 

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