Prolactin might not make headlines like testosterone or estrogen, but it’s one of the most fascinating—and misunderstood—hormones in the body. Known primarily for its role in lactation, prolactin also acts as a stress signal, an immune modulator, and a key player in reproductive balance. Both men and women produce it, and when levels drift out of range, the effects ripple across metabolism, fertility, mood, and energy. By the end of this guide, you’ll understand what prolactin really measures, what high and low values mean, and how this quiet hormone fits into your bigger health picture.
What Prolactin Actually Measures
A prolactin test measures the concentration of the hormone prolactin in your blood, typically reported in nanograms per milliliter (ng/mL). It’s produced by the pituitary gland, the master regulator at the base of your brain. Its primary function is to stimulate breast development and milk production in women after childbirth, but that’s only part of its story. Prolactin also influences immune function, reproductive hormones, and even mood regulation through its effects on dopamine and serotonin pathways.
In both sexes, prolactin is closely tied to the hypothalamic–pituitary axis—the same hormonal system that controls stress, thyroid, and reproductive signaling. That means it often rises or falls in tandem with life stress, sleep quality, and metabolic state.
The Science, Made Simple
Think of prolactin as a multitasking messenger. It’s like your body’s “pause button” hormone—temporarily reducing reproductive drive and energy expenditure during times of stress, illness, or recovery. Under normal conditions, dopamine from the brain keeps prolactin in check. But when stress, inflammation, or pituitary stimulation occurs, dopamine’s inhibition lifts, and prolactin levels climb.
That’s why prolactin levels can spike after intense workouts, during emotional stress, or with disrupted sleep. In women, it rises naturally during pregnancy and breastfeeding. In men, it helps regulate testosterone balance and sperm quality, though too much can suppress libido and energy.
Normal Versus Optimal
Typical reference ranges vary slightly by lab, but general guidelines are:
• Women: 4–23 ng/mL
• Men: 3–15 ng/mL
Optimal levels usually sit comfortably in the midrange, though transient increases can occur from exercise, sex, or mild stress. For women, levels are naturally higher during pregnancy and breastfeeding. For men, levels toward the lower end tend to support stable testosterone and libido.
Consistently elevated prolactin—especially above 25 ng/mL—warrants further evaluation, as it can disrupt the delicate feedback loops between the brain, pituitary, and gonads.
Interpreting High and Low Levels
When Levels Run High
High prolactin (hyperprolactinemia) can result from multiple causes: pituitary overactivity (often benign microadenomas), stress, certain medications (like antipsychotics or antidepressants), thyroid disorders, or excessive estrogen. Even lifestyle stressors—poor sleep, overtraining, or fasting—can transiently elevate prolactin.
Symptoms vary: women may experience irregular cycles, infertility, or breast tenderness; men may notice low libido, fatigue, or erectile dysfunction. Because prolactin suppresses gonadotropins (LH and FSH), it can quietly reduce sex hormone production across time. If levels remain elevated, clinicians often assess pituitary function and screen for secondary causes such as hypothyroidism or medication effects.
When Levels Run Low
Low prolactin is uncommon and usually not concerning on its own. It may reflect stress-related suppression, dopamine overactivity, or pituitary underfunctioning (as seen in rare hypopituitarism cases). Unless accompanied by other hormone deficiencies or symptoms like fatigue, low libido, or abnormal thyroid markers, mildly low prolactin usually has little clinical impact.
Longevity and Whole-Body Health
Prolactin sits at the crossroads of metabolism, reproduction, and immunity. Chronically elevated levels—especially in the context of stress or inflammation—can accelerate metabolic dysfunction by lowering sex hormones and raising insulin resistance. In contrast, balanced prolactin supports mitochondrial energy production, cognitive function, and immune stability.
From a longevity perspective, prolactin acts as a marker of adaptability. Stable levels indicate a body in sync—responding to stress when needed, then resetting. Persistently high levels, however, signal that your internal “pause button” is stuck, often due to unresolved stress, inflammation, or hormonal imbalance.
How to Improve or Optimize Your Levels
Nutrition
Diet influences prolactin through its effects on dopamine and thyroid function. Foods rich in tyrosine—like eggs, fish, legumes, and nuts—support dopamine synthesis, which naturally inhibits excess prolactin. Ensuring adequate iodine and selenium helps optimize thyroid hormone production, since hypothyroidism can raise prolactin levels. Antioxidant-rich foods like berries, leafy greens, and olive oil help reduce the oxidative stress that drives pituitary stimulation.
Limiting alcohol, refined sugar, and excessive caffeine can also help steady prolactin, especially in individuals with stress-related elevations.
Exercise
Moderate, consistent exercise lowers stress hormones and improves dopamine tone—two direct levers for regulating prolactin. However, extreme endurance training or overtraining can have the opposite effect, temporarily elevating prolactin due to chronic stress signaling. Balance is key: movement that energizes, not exhausts, supports hormonal harmony.
Sleep and Stress
Prolactin follows a circadian rhythm, peaking during deep sleep. Chronic sleep deprivation or irregular sleep timing can disrupt that rhythm and cause higher daytime levels. Stress management—through mindfulness, recovery time, or even laughter—helps restore the natural dopamine-prolactin balance. Think of sleep and rest as hormonal “resets” that bring prolactin back into its proper rhythm.
Micronutrients and Supports
Magnesium, vitamin B6, and zinc all help regulate dopamine and pituitary function, indirectly influencing prolactin levels. Adaptogenic herbs like ashwagandha and rhodiola have been studied for their stress-modulating effects, which may help normalize prolactin indirectly through the hypothalamic–pituitary–adrenal (HPA) axis. Always test before supplementing—hormonal balance depends on precision, not excess.
Medical Considerations
If prolactin is persistently elevated, your clinician may investigate with pituitary imaging (to rule out microadenomas), thyroid testing, or medication review. Dopamine agonists like cabergoline or bromocriptine are sometimes prescribed to lower prolactin and restore hormonal balance, though treatment depends entirely on the cause. For stress- or lifestyle-related elevations, addressing sleep, nutrition, and recovery often normalizes levels naturally.
Connecting the Dots with Related Biomarkers
Prolactin interacts closely with estrogen, testosterone, and thyroid hormones. High estrogen can raise prolactin, while low thyroid function (high TSH) can signal pituitary overstimulation. Measuring prolactin alongside LH, FSH, cortisol, and TSH offers a full map of pituitary–adrenal–gonadal communication. In men, pairing prolactin with testosterone helps distinguish pituitary-related hypogonadism from primary testicular causes.
Why Testing Is Worth It
Prolactin testing is a small window into a big system. It helps explain symptoms that don’t fit neatly into one category—low libido, fatigue, menstrual irregularity, or unexplained infertility. Because it reflects both brain and endocrine function, prolactin bridges physical and emotional health, showing how stress and physiology intertwine. Tracking it alongside other hormones helps identify when your system is stuck in “pause” mode—and how to gently press play again.
How Superpower Can Help
Superpower’s comprehensive biomarker panel measures prolactin alongside thyroid, cortisol, estrogen, and testosterone markers—mapping how your pituitary, adrenal, and gonadal systems communicate. With clear interpretation and trend tracking, Superpower helps you spot hormonal imbalances early, understand their roots, and build a personalized plan to restore rhythm, resilience, and vitality—without guesswork.