All about prolactin: what is it and what are the normal values?

The prolactin test is essential for detecting conditions such as hyperprolactinemia, prolactinoma and hormonal imbalances, which can lead to symptoms such as irregular menstruation, milk release, reduced fertility and erectile dysfunction

Prolactin is an important hormone in the human body that performs several functions. In this blog, we explain what prolactin is, what the normal levels are, what increased prolactin levels mean and how stress, lifestyle and medical conditions can affect it.

What is prolactin?

Prolactin is a hormone produced primarily by the pituitary gland, a small gland at the base of the brain. The hormone plays a crucial role in milk production (lactation) in breastfeeding women. In addition, prolactin affects the immune system, metabolism and the reproductive system.

Although prolactin is best known for its role in breastfeeding, it also occurs in men and affects testosterone production and sperm quality in them.

What are the normal values of prolactin?

Normal values of prolactin in the blood can vary depending on gender, age and physiological conditions such as pregnancy. Standard normal values are:

• Women (non-pregnant): 4.8 - 23.3 ng/mL
• Women (pregnant): Up to 400 ng/mL
• Men: 4.0 - 15.2 ng/mL

Abnormal values, such as excessive prolactin levels ("hyperprolactinemia"), may require further investigation.

What does an elevated prolactin level mean?

Elevated prolactin levels, also known as hyperprolactinemia, can have several causes. Some common causes include:

1. Stress: Both physical and mental stress can temporarily increase prolactin production. This is considered a normal response of the body.
2. Pregnancy and lactation: During these periods, high prolactin levels are normal and necessary for milk production.
3. Medication: Certain medications, such as antipsychotics and antidepressants, can increase prolactin production.
4. Medical conditions: A benign tumor in the pituitary gland (prolactinoma) can increase prolactin production. Other conditions, such as hypothyroidism, may also contribute to elevated levels.

When should you continue testing for monomeric prolactin?

Elevated prolactin levels may require further testing for monomeric prolactin. This is the biologically active form of prolactin that actually affects the body. Sometimes elevated total prolactin levels can be caused by the presence of macroprolactin, an inactive form that does not cause symptoms.

Continued testing for monomeric prolactin is especially important in the following situations:

1. Asymptomatic hyperprolactinemia: If you have elevated prolactin levels but no symptoms such as irregular menstruation or milk release.
2. When in doubt about the cause of elevated prolactin levels: To distinguish between macroprolactin and biologically active prolactin.
3. Follow-up examination: If prolactinoma or other pituitary disorders are suspected.

More information about this test can be found here.

Symptoms of excessive prolactin levels in women

In women, elevated prolactin levels can lead to:

• Irregular or absent menstrual periods
• Reduced fertility
• Spontaneous milk release from the breasts (galactorrhea)
• Decreased libido

In men, it can lead to:

• Decreased libido
• Erectile dysfunction
• Reduced sperm production
• Increase in breast tissue (gynecomastia)

Prolactin and stress

Stress is a major factor that can increase prolactin levels. This applies to both acute and chronic stress. Long-term stress can even contribute to hormonal imbalance, causing prolactin levels to remain structurally elevated.

How can you get prolactin levels tested?

You can measure your prolactin levels with a simple blood test. It is important to have this test done sober and preferably in the morning, as prolactin levels can fluctuate throughout the day. With Blood Values Test, you can either perform a blood test at home with a convenient self-collection kit or go to one of the 1,000 lancing stations, where a professional will draw the blood through your vein. This gives you quick and reliable insight into your hormonal levels.

Regular monitoring of your prolactin levels can help detect possible hormonal abnormalities early and target them.