High Prolactin And Low Testosterone In Men: What It Means

Written by the UPGUYS Editorial Team

Published on September 02, 2026

High prolactin can affect more than reproductive health. In men, persistently elevated prolactin can interfere with the hormonal signals involved in testosterone production and may contribute to low testosterone, reduced libido, sexual difficulties and fertility problems.

This is important because a low testosterone result does not always mean the testes themselves are the source of the problem. In some men, elevated prolactin can suppress signalling from the brain and pituitary gland, creating a pattern consistent with secondary hypogonadism.

For men considering testosterone replacement therapy (TRT) in Canada, understanding why testosterone is low is an important part of the assessment. An elevated prolactin result may need further investigation before deciding whether TRT is appropriate.

A single abnormal prolactin result should also not be interpreted in isolation. The level may need to be repeated and considered alongside testosterone, LH, FSH, symptoms, medications and medical history.

Topics covered in this article:

What Is Prolactin?

Prolactin is a hormone produced primarily by the pituitary gland, a small gland located at the base of the brain.

It is best known for its role in breast development and milk production in women, but men also naturally produce prolactin in much smaller amounts.

In men, prolactin interacts with the hormonal system that regulates testosterone production and reproductive function. This system is known as the hypothalamic-pituitary-gonadal axis, or HPG axis.

Under normal circumstances, prolactin remains within a relatively low range. When levels become persistently elevated, a condition known as hyperprolactinemia, prolactin can interfere with hormonal signalling between the hypothalamus, pituitary gland and testes.

This disruption may affect LH and FSH signalling and, in some men, contribute to lower testosterone, changes in sexual function or fertility problems.

The significance of an elevated prolactin result depends on how high the level is, whether it remains elevated on repeat testing and what other symptoms or hormone abnormalities are present.

Can High Prolactin Lower Testosterone?

Yes. Persistently high prolactin can lower testosterone by suppressing hormonal signals from the hypothalamus and pituitary that normally stimulate the testes.

A simplified version of the pathway looks like this:

high prolactin → reduced reproductive hormone signalling → lower LH/FSH stimulation → potentially lower testosterone

High prolactin can interfere with the release of gonadotropin-releasing hormone (GnRH) from the hypothalamus. This can reduce the pituitary gland’s release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH).

When LH signalling falls, the testes may receive less stimulation to produce testosterone. If this suppression is significant or persistent, testosterone levels can decrease.

This is one reason elevated prolactin is considered a possible cause of secondary hypogonadism in men.

However, not every mildly elevated prolactin result will cause low testosterone. The effect depends on factors such as how high the prolactin level is, whether the elevation persists and what other hormonal abnormalities are present.

How Does High Prolactin Affect LH and FSH?

High prolactin can suppress the hormonal pathway that controls LH and FSH, causing these hormones to become low or inappropriately normal.

The process begins at the hypothalamus. Elevated prolactin can reduce normal GnRH signalling, which then decreases stimulation of the pituitary gland.

As a result:

1. LH may become low or inappropriately normal
2. FSH may also decrease
3. The testes receive less hormonal stimulation
4. Testosterone production may fall
5. Sperm production may also be affected

This pattern can resemble secondary hypogonadism, where the main problem is reduced signalling from the hypothalamus or pituitary rather than a primary problem within the testes.

The combination of low testosterone with low or low-normal LH is particularly important because it may prompt a healthcare provider to check prolactin and investigate other possible causes of reduced pituitary signalling.

This is why LH, FSH, prolactin and testosterone are often more useful when interpreted together rather than as separate lab results.

What Are the Symptoms of High Prolactin in Men?

High prolactin in men can affect sexual function, testosterone levels and fertility, although some men may have few or no obvious symptoms.

Possible symptoms include:

1. Low libido
2. Erectile difficulties
3. Symptoms associated with low testosterone
4. Reduced fertility
5. Breast enlargement or tenderness
6. Rare nipple discharge
7. Headaches
8. Visual changes

Sexual symptoms are often among the most noticeable. Elevated prolactin can interfere with reproductive hormone signalling, which may contribute to lower testosterone and reduced sexual function.

Breast enlargement or tenderness can occur in some men, while nipple discharge is much less common.

Headaches or visual symptoms are more concerning because they can occur when a pituitary mass is affecting nearby structures. However, these symptoms do not automatically mean a pituitary tumour is present.

The severity of symptoms does not always match the prolactin level. Some men with elevated prolactin may have significant hormonal changes with relatively few symptoms, which is why the full clinical picture matters.

Can High Prolactin Cause Low Libido?

Yes. Elevated prolactin can reduce sexual desire directly and may also lower testosterone, which can further affect libido.

Prolactin influences the hormonal pathways involved in sexual function. When levels remain elevated, it can suppress GnRH signalling and reduce LH stimulation, which may lower testosterone production.

This means low libido can develop through more than one pathway:

1. A direct effect of elevated prolactin on sexual desire
2. Reduced testosterone caused by suppressed reproductive hormone signalling
3. Other symptoms associated with the underlying cause of high prolactin

The European Association of Urology notes that prolactin can negatively affect sexual desire and recommends considering prolactin testing in appropriate men with low sexual desire, particularly when low testosterone or secondary hypogonadism is suspected.

However, low libido has many possible causes, including stress, poor sleep, medications, relationship factors and other health conditions. High prolactin should therefore be considered as one possible contributor rather than assumed to be the cause based on symptoms alone.

Can High Prolactin Cause Erectile Dysfunction?

Yes. High prolactin can contribute to erectile dysfunction, but it is usually one possible factor rather than the only explanation.

Elevated prolactin may affect erections indirectly by reducing sexual desire and suppressing the hormonal signals that support testosterone production. If testosterone also falls, sexual function may be affected further.

However, erectile dysfunction is multifactorial. Other common contributors include:

1. Diabetes
2. Cardiovascular disease
3. High blood pressure
4. Certain medications
5. Stress or anxiety
6. Poor sleep
7. Neurological conditions
8. Other hormonal problems

For that reason, an elevated prolactin result should not automatically be assumed to explain ED. A proper assessment should consider sexual symptoms, testosterone levels, cardiovascular and metabolic health, medications and other possible causes.

Why Would a Man Have High Prolactin?

High prolactin in men can have several causes, ranging from temporary physiological changes to medications or pituitary conditions.

Possible causes include:

1. Certain medications
2. A prolactinoma or other pituitary adenoma
3. Hypothyroidism
4. Other pituitary or hypothalamic conditions
5. Kidney disease
6. Liver disease
7. Physical or emotional stress
8. Strenuous exercise
9. Temporary physiological fluctuations
10. Laboratory variation
11. Macroprolactin

A prolactinoma is a usually benign pituitary tumour that produces prolactin, but it is only one possible cause of an elevated result.

Some medication classes can also increase prolactin by interfering with dopamine signalling, which normally helps keep prolactin levels under control.

Hypothyroidism can raise prolactin in some cases, while reduced clearance in kidney or liver disease may also contribute.

Prolactin can sometimes rise temporarily because of stress, exercise or the circumstances around the blood draw. Laboratory variation is another reason an unexpected elevation may need to be repeated before conclusions are drawn.

Another possibility is macroprolactin, a form of prolactin that can register as elevated on testing but may have less biological activity.

The important point is that one elevated prolactin result does not automatically mean a man has a pituitary tumour. The result should be interpreted in context and, when appropriate, confirmed with repeat testing and further evaluation.

Can Medications Raise Prolactin?

Yes. Certain medications can raise prolactin levels, especially those that interfere with dopamine signalling.

Dopamine normally helps suppress prolactin release from the pituitary gland. When a medication reduces dopamine activity or blocks its effects, prolactin levels may increase.

Medication-related prolactin elevation can occur with certain classes used for:

1. Mental health conditions
2. Nausea or digestive symptoms
3. Pain management
4. Blood pressure or cardiovascular conditions
5. Other neurological or hormonal conditions

The degree of elevation varies depending on the medication, dose and individual response.

If a medication may be contributing to high prolactin, it should be reviewed with a healthcare provider. Do not stop or change a prescribed medication on your own, since doing so may create other health risks.

A clinician can determine whether the medication is a likely contributor and whether repeat testing, an adjustment or further evaluation is appropriate.

Does High Prolactin Always Mean a Pituitary Tumour?

No. High prolactin does not automatically mean a man has a pituitary tumour.

A prolactinoma is one possible cause of elevated prolactin, but there are many others, including medications, hypothyroidism, other health conditions and temporary physiological changes.

When prolactin is elevated, the next steps may include:

1. Repeating the prolactin test
2. Reviewing current medications
3. Checking thyroid function
4. Considering whether macroprolactin is contributing
5. Looking at testosterone, LH and FSH
6. Assessing symptoms and medical history

The degree of prolactin elevation also matters. A mild elevation may have a different explanation from a markedly elevated and persistent result.

Symptoms provide additional context. Headaches, visual changes, very low testosterone or abnormalities involving other pituitary hormones may increase the need for further pituitary evaluation.

The key point is that an elevated prolactin result is a finding that needs context, not a diagnosis of a pituitary tumour by itself.

What Is a Prolactinoma?

A prolactinoma is a usually benign pituitary tumour that produces excess prolactin.

Because the pituitary gland helps regulate reproductive hormones, a prolactinoma can raise prolactin enough to interfere with normal hormonal signalling.

In men, this may contribute to:

1. Lower LH and FSH signalling
2. Lower testosterone
3. Reduced libido
4. Erectile difficulties
5. Fertility problems

Larger prolactinomas can also cause symptoms from pressure on nearby structures, including headaches or visual changes.

Not every man with elevated prolactin has a prolactinoma. Diagnosis depends on the prolactin level, repeat testing, symptoms and, when appropriate, pituitary imaging.

What Does High Prolactin With Low LH and Low Testosterone Mean?

High prolactin together with low testosterone and low or low-normal LH can point toward secondary hypogonadism caused by suppressed pituitary-hypothalamic signalling.

In this pattern, the testes may not be the primary source of the problem. Instead, elevated prolactin may be interfering with the hormonal signals that normally stimulate testosterone production.

The pattern can look like this:

high prolactin → reduced GnRH signalling → low or inappropriately normal LH → less testicular stimulation → lower testosterone

This is why prolactin is particularly relevant when testosterone is low but LH is not appropriately elevated.

The American Urological Association recommends measuring prolactin in men with low testosterone and low or low-normal LH because this combination can suggest a central or secondary cause of testosterone deficiency.

However, high prolactin does not identify the underlying cause by itself. A clinician may need to consider medications, thyroid function, repeat prolactin testing, pituitary symptoms and other hormone results.

The important point is that this pattern should prompt further evaluation rather than an automatic move to TRT. If elevated prolactin is contributing to low testosterone, addressing the underlying cause may affect the treatment approach.

Should Prolactin Be Checked Before TRT?

Prolactin is not necessarily required for every man, but it is particularly important when low testosterone is accompanied by low or low-normal LH or when symptoms suggest hyperprolactinemia.

The decision to check prolactin depends on the overall hormone pattern and clinical picture.

Prolactin testing may be especially useful when there is:

1. Low testosterone with low or low-normal LH
2. Persistent low libido
3. Erectile difficulties without a clear explanation
4. Fertility concerns
5. Headaches or visual symptoms
6. Other signs that may suggest pituitary dysfunction

When testosterone is low but LH is not appropriately elevated, a secondary or central cause may be contributing. Elevated prolactin is one possible explanation because it can suppress normal reproductive hormone signalling.

Current AUA and EAU guidance supports checking prolactin in men with low testosterone and low or low-normal LH.

The goal is to understand why testosterone is low before treatment is started. If elevated prolactin is contributing to the hormonal pattern, that underlying issue may need to be addressed before deciding whether TRT is appropriate.

What Happens If Prolactin Is High on a Blood Test?

An elevated prolactin result usually needs to be interpreted in context and may be repeated before further conclusions are made.

A healthcare provider may consider:

1. Repeating the prolactin measurement
2. Looking for temporary or stress-related elevation
3. Reviewing medications
4. Checking thyroid function
5. Considering macroprolactin
6. Reviewing testosterone, LH and FSH
7. Assessing symptoms and medical history

A repeat test can be important because prolactin may rise temporarily due to stress, exercise, the blood draw itself or other short-term factors.

If prolactin remains elevated, the next step depends on how high the level is and what other findings are present. Persistent elevation may lead to further endocrine evaluation, especially when there is low testosterone, low or low-normal LH, fertility problems, headaches, visual symptoms or other pituitary hormone abnormalities.

The American Urological Association recommends repeating an elevated prolactin result before moving forward with additional evaluation.

The key point is that one high prolactin result is not enough to determine the cause. The pattern should be confirmed and interpreted alongside the rest of the hormonal and clinical picture.

When Is Pituitary MRI Considered for High Prolactin?

A pituitary MRI is not needed for every man with high prolactin. It is generally considered when the prolactin elevation is persistent and the overall pattern raises concern about a pituitary or hypothalamic cause.

MRI may be considered when there is:

1. Persistently elevated prolactin
2. Secondary hypogonadism
3. Headaches
4. Visual changes
5. Other pituitary hormone abnormalities
6. Very low testosterone with low or inappropriately normal LH and FSH

The reason imaging may be useful is that a pituitary condition, including a prolactinoma, can sometimes explain both elevated prolactin and reduced reproductive hormone signalling.

Current EAU guidance supports pituitary imaging when confirmed hyperprolactinemia occurs with secondary hypogonadism, symptoms suggesting a pituitary mass or other pituitary hormone abnormalities.

The decision should be individualized. An elevated prolactin result by itself does not automatically mean an MRI is required. Repeat testing, medication review and other laboratory findings often help determine whether imaging is appropriate.

Can Treating High Prolactin Raise Testosterone?

Yes, in some men. If elevated prolactin is suppressing the reproductive hormone system, treating the underlying cause may allow testosterone signalling to recover.

When prolactin falls, normal hypothalamic and pituitary signalling may improve. This can allow LH and FSH stimulation to recover and, in some men, testosterone production may increase.

How much testosterone improves depends on the cause of the high prolactin and whether there are other factors affecting testosterone production.

For example, recovery may be different when elevated prolactin is related to a reversible medication effect compared with a pituitary condition or another endocrine disorder.

Improvement is not guaranteed, so testosterone should be reassessed after the underlying cause of elevated prolactin has been addressed.

This is an important reason not to assume that low testosterone automatically means TRT is required. If high prolactin is contributing to the hormonal suppression, treating that cause may change the testosterone picture and the treatment decision.

Does TRT Fix High Prolactin?

No. TRT does not fix high prolactin.

Testosterone replacement therapy replaces testosterone when a man has appropriately diagnosed testosterone deficiency, but it does not treat the underlying reason prolactin is elevated.

If high prolactin is contributing to low testosterone, the prolactin abnormality may still need its own evaluation and treatment. Depending on the cause, this could involve reviewing medications, checking thyroid function, investigating pituitary causes or addressing another underlying condition.

Starting TRT without first understanding a pattern of secondary hypogonadism may also make the original hormone picture harder to interpret because external testosterone suppresses LH and FSH.

For that reason, persistent high prolactin should generally be assessed on its own rather than assuming TRT will correct it.

Can You Use TRT If Prolactin Is High?

Possibly, but it depends on why prolactin is elevated and whether testosterone deficiency remains present after appropriate evaluation.

Persistent high prolactin should usually be investigated before TRT is started. The underlying cause may be reversible or may require separate treatment.

A healthcare provider may consider:

1. How high the prolactin level is
2. Whether the elevation persists on repeat testing
3. Testosterone, LH and FSH results
4. The cause of the prolactin elevation
5. Symptoms of testosterone deficiency
6. Pituitary or other endocrine findings
7. Current and future fertility goals

In some men, treating the cause of high prolactin may allow testosterone levels to recover. In others, testosterone deficiency may persist and TRT may still be considered after the underlying problem has been addressed.

Fertility is especially important because TRT can suppress LH, FSH and sperm production.

The decision should therefore be individualized. High prolactin does not automatically rule out TRT, but it should not be ignored before treatment either.

How Does High Prolactin Affect Fertility in Men?

High prolactin can affect male fertility by reducing the hormonal signals needed for normal testicular function and sperm production.

Persistently elevated prolactin can suppress GnRH signalling from the hypothalamus. This may reduce LH and FSH release from the pituitary gland.

As a result:

1. LH stimulation of the testes may decrease
2. Intratesticular testosterone may fall
3. FSH support for sperm production may be reduced
4. Sperm production may decline
5. Fertility may be affected

High prolactin can also contribute to low libido and erectile difficulties, which may make conception more difficult even when sperm production is not severely impaired.

Fertility goals are especially important before TRT is considered because external testosterone can further suppress LH, FSH and sperm production.

Men who are trying to conceive or want to preserve future fertility should discuss this before starting TRT. Depending on the situation, additional fertility assessment such as semen analysis may also be appropriate.

What Other Tests May Be Checked With Prolactin?

Prolactin is usually interpreted alongside other hormone and baseline tests rather than on its own.

Depending on the clinical picture, testing may include:

1. Repeat prolactin to confirm that the elevation is persistent
2. Total testosterone
3. Free testosterone and SHBG when indicated
4. LH
5. FSH
6. Thyroid testing
7. Other pituitary hormones when pituitary dysfunction is suspected
8. CBC and hematocrit when TRT is being considered
9. Other appropriate pre-TRT tests based on age, symptoms and medical history

Looking at prolactin together with testosterone, LH and FSH can help show whether the pattern is consistent with secondary hypogonadism.

Thyroid testing may also be useful because hypothyroidism can sometimes contribute to elevated prolactin.

If there are signs of broader pituitary dysfunction, a healthcare provider may order additional hormone tests before deciding whether imaging or specialist assessment is needed.

The goal is to determine why prolactin is elevated, whether it is affecting testosterone production and whether any underlying condition should be addressed before TRT is considered.

When Should You Speak to a Healthcare Provider?

Consider speaking to a healthcare provider if you have an elevated prolactin result, low testosterone or symptoms that could suggest a hormonal problem.

This is especially important if you have:

1. Persistently elevated prolactin
2. Low testosterone
3. Ongoing low libido
4. Erectile difficulties
5. Fertility problems
6. Headaches
7. Visual changes
8. Low testosterone with low or low-normal LH

A healthcare provider can review prolactin together with testosterone, LH, FSH, medications, symptoms and medical history to determine whether repeat testing or further investigation is needed.

Headaches or visual changes deserve particular attention because they can sometimes occur with pituitary conditions, although they do not automatically mean a pituitary tumour is present.

Men should not self-start TRT or try to lower prolactin on their own based on one blood test. The cause of the abnormal result should be understood first so that treatment is directed at the right problem.

Key Takeaways

1. High prolactin can suppress reproductive hormone signalling and contribute to low testosterone.
2. Elevated prolactin may also affect libido, erections and fertility.
3. Several conditions, medications and temporary factors can raise prolactin.
4. A high prolactin result does not automatically mean a pituitary tumour.
5. Low testosterone with low or low-normal LH is an important pattern in which prolactin testing may be appropriate.
6. Persistent hyperprolactinemia should be investigated to determine the underlying cause.
7. Treating the cause of high prolactin may allow testosterone levels to improve in some men.
8. TRT replaces testosterone when appropriate, but it does not treat high prolactin itself.

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