Prolactin

Prolactin (PRL) is a hormone secreted by the anterior pituitary gland and plays a fundamental role in numerous physiological functions across both females and males. Most widely recognised for its role in promoting lactation and breast development in women, prolactin also has broader implications, including regulation of the immune system, metabolism, and reproductive health. In females, prolactin levels tend to be higher, especially during pregnancy and breastfeeding, where they support milk production. In males, although prolactin is present in smaller amounts, it helps regulate testosterone production and plays a role in sperm quality.

The average prolactin level for women is approximately 20 nanograms per millilitre (ng/mL), whereas in men, normal values range from 5 to 15 ng/mL. These levels can vary depending on age, physiological conditions, medications, and underlying health conditions. Unlike some hormones that remain relatively constant, prolactin levels fluctuate throughout the day and can spike due to stress, physical activity, or sleep.

Understanding prolactin’s function and potential imbalances is crucial. Elevated levels, a condition known as hyperprolactinaemia, can lead to significant health issues like infertility, irregular menstrual cycles, and sexual dysfunction. Conversely, although rare, low levels of prolactin might reflect underlying pituitary dysfunction. This comprehensive guide will explore the role of prolactin, its normal ranges, causes and symptoms of imbalance, diagnostic processes, treatment options, and lifestyle adjustments for hormone balance.

If you're unsure about your hormone levels, a convenient starting point is the Free Testosterone Blood Test, which helps assess your broader hormonal profile alongside prolactin.

What is Prolactin?

Prolactin is a peptide hormone primarily associated with lactation, but its roles extend beyond milk production. It is synthesised and released by lactotroph cells in the anterior pituitary and can also be produced in other tissues including the uterus, immune cells, and brain. The hormone exerts its biological effects by binding to prolactin receptors located in various tissues throughout the body.

In women, prolactin stimulates the mammary glands to produce milk postpartum. This process is triggered by the infant’s suckling, which signals the pituitary gland to increase prolactin secretion. In men, prolactin contributes to reproductive health by influencing testosterone secretion and may impact sperm production and motility.

Beyond its reproductive roles, prolactin influences numerous other processes:

• Regulates immune system function

• Supports neurogenesis and behaviour

• Affects osmoregulation and electrolyte balance

• Contributes to angiogenesis and tissue repair

Prolactin levels are typically suppressed by dopamine, a neurotransmitter that acts as a prolactin-inhibiting factor. When dopamine levels fall or when the hypothalamus is disrupted, prolactin secretion increases. This explains why certain medications or tumours that interfere with dopamine production or signalling can lead to hyperprolactinaemia.

Understanding how prolactin operates across various systems highlights its complexity and relevance in both everyday physiology and specific medical conditions.

Hormone imbalances often affect other systems, including metabolism. A Cholesterol Blood Test may offer additional insight, as prolactin is linked with lipid regulation.

Causes and Effects of Hyperprolactinaemia

Hyperprolactinaemia refers to abnormally high levels of prolactin in the blood and can affect both men and women. This condition disrupts the balance of other sex hormones—primarily oestrogen and testosterone—leading to a cascade of symptoms and health issues.

Common Causes of High Prolactin:

• Pituitary tumours (prolactinomas): These benign growths directly produce prolactin and are among the most frequent causes.

• Medications: Antipsychotics, antidepressants, antihypertensives, and gastrointestinal drugs can inhibit dopamine, increasing prolactin.

• Hypothyroidism: Low thyroid function increases thyrotropin-releasing hormone (TRH), which stimulates prolactin release.

• Chest wall injuries or stimulation: Nerve responses from chest trauma or surgery can trigger prolactin secretion.

• Pregnancy and lactation: Naturally raise prolactin levels.

• Stress: Physical or emotional stress can stimulate a temporary rise in prolactin.

Effects of Elevated Prolactin:

• In women, high prolactin may result in irregular or absent menstrual cycles, infertility, galactorrhoea (milk secretion not associated with childbirth), and decreased libido.

• In men, it can lead to erectile dysfunction, reduced testosterone levels, infertility, and sometimes breast enlargement (gynecomastia).

Chronic hyperprolactinaemia can also contribute to bone density loss, as lowered sex hormones impair calcium absorption and bone metabolism. Identifying the root cause of elevated prolactin is crucial for selecting the appropriate treatment path.

To check for hormone imbalances linked to fertility and menstrual issues, you may consider the Cortisol Blood Test, which can indicate stress-related hormone disruption.

Diagnosis and Testing for Prolactin Levels

Detecting an imbalance in prolactin begins with a thorough medical history, clinical symptoms, and hormonal testing. The most reliable way to measure prolactin is through a serum prolactin blood test. Blood samples are usually collected in the morning after fasting, as prolactin levels naturally fluctuate throughout the day and peak during REM sleep.

Key Steps in Diagnosis:

1. Blood Test: Determines whether prolactin levels are elevated or low. If elevated, further testing may be required.

2. Thyroid Function Test: Checks for hypothyroidism, which could indirectly raise prolactin.

3. MRI of the Brain: Specifically targets the pituitary region to assess for tumours or abnormalities.

4. Visual Field Test: Used when a macroadenoma (large pituitary tumour) is suspected and might be affecting optic nerves.

Additional testing may include luteinising hormone (LH), follicle-stimulating hormone (FSH), oestradiol, or testosterone to assess broader hormonal impact.

It’s important to consider that elevated prolactin may occasionally be transient. Confirmatory tests are often required to verify consistently high levels. For women, tests are usually performed when not pregnant or breastfeeding, unless testing relates to pregnancy complications.

If broader deficiencies are suspected, the Vitamin Deficiency Test may highlight gaps contributing to hormonal imbalance.

Symptoms of High Prolactin in Men and Women

Common Symptoms in Women:

• Irregular or absent menstrual periods

• Difficulty conceiving (infertility)

• Galactorrhoea (milk production not related to breastfeeding)

• Pain or tenderness in breasts

• Decreased libido

Common Symptoms in Men:

• Erectile dysfunction

• Reduced sperm count or motility

• Decreased libido

• Gynecomastia (breast tissue development)

• Fatigue and mood disturbances

Non-Specific Symptoms:

• Headaches

• Visual disturbances (especially if a pituitary tumour is present)

• Low bone density (osteopenia or osteoporosis)

• Anxiety or depression

Because symptoms can often mimic other hormonal disorders, prolactin testing becomes critical in narrowing down the diagnosis. Timely diagnosis not only alleviates symptoms but also prevents long-term complications like infertility or chronic fatigue.

To explore a full range of screening options tailored to individual health needs, browse the All Health Tests Collection.

Treatment Options for High Prolactin

Management of hyperprolactinaemia depends on the underlying cause. Treatment may involve medical therapy, lifestyle modifications, and in some cases, surgery.

Medical Treatments:

• Dopamine agonists: Medications like bromocriptine and cabergoline mimic dopamine’s action, reducing prolactin levels and shrinking prolactinomas.

• Thyroid hormone replacement: For those with hypothyroidism, levothyroxine can normalise prolactin levels.

• Surgical removal: Indicated for prolactinomas that do not respond to medications or cause significant vision problems.

• Radiation therapy: Occasionally used when surgery and medical therapy are ineffective.

Lifestyle and Nutritional Approaches:

• Reduce stress through mindfulness, exercise, and therapy

• Maintain healthy sleep habits, as prolactin peaks during sleep

• Moderate alcohol and caffeine intake

• Avoid medications known to elevate prolactin, unless necessary

Ongoing monitoring is essential, particularly with macroprolactinomas. Periodic blood tests and imaging help ensure that prolactin remains within normal ranges and tumours do not recur or grow.

Additional hormone markers like the Advanced Thyroid Function Blood Test may offer supporting insight in managing prolactin-related issues.

Psychological and Emotional Impact of Hormonal Imbalances

The emotional effects of elevated prolactin are often under-recognised. Hormonal fluctuations can affect mood, energy, motivation, and overall wellbeing. Chronic fatigue, anxiety, and depressive symptoms are commonly reported among individuals with hyperprolactinaemia. These effects can compound the challenges of physical symptoms, especially infertility or sexual dysfunction.

Supportive counselling and, in some cases, hormone-balancing therapies can help patients manage both the mental and physical impact of the condition. Engaging with healthcare professionals, including endocrinologists, mental health experts, and reproductive specialists, creates a holistic approach to care. To explore a broad selection of accessible and accurate tools for testing hormone and health markers, visit the Home Blood Tests.

Risk Factors and Prevention Strategies

Understanding the risk factors for developing high prolactin levels allows for more effective prevention and early detection.

Risk Factors:

• Female gender (especially of reproductive age)

• Use of certain medications

• Presence of thyroid disorders

• Stress or psychological trauma

• Pituitary tumours or head injuries

Preventive Steps:

• Manage thyroid health proactively

• Regular health screenings, particularly if on long-term medication

• Address psychological stress through counselling or stress management

• Seek prompt care for symptoms of hormonal imbalance

Taking a preventive approach ensures better hormonal balance and minimises the likelihood of complications related to prolactin.

Conclusion

Prolactin is a complex and multifunctional hormone vital to reproductive health, emotional stability, and immune regulation. While commonly associated with pregnancy and breastfeeding, its role extends to critical aspects of health for both men and women. Elevated prolactin levels, if left untreated, can lead to substantial disruptions in sexual health, fertility, bone density, and mental wellbeing.

Hyperprolactinaemia may result from a range of causes, from pituitary tumours and hypothyroidism to certain medications or stress. Understanding the symptoms, seeking early diagnosis, and implementing appropriate treatments can prevent long-term complications. Patients are encouraged to maintain open communication with their healthcare providers, undergo regular hormone screenings, and prioritise lifestyle choices that support hormonal balance.

To further investigate any underlying hormonal contributors to prolactin imbalances, the AMH Blood Test can provide additional clarity regarding ovarian reserve and hormone production.

For comprehensive assessments covering everything from nutrition to hormones, the All Nutrition & Intolerance Tests Collection provides targeted solutions for better hormonal clarity.