Can Men Lactate? What Science Says About Male Lactation

Can men produce breast milk? It’s a question people ask out of curiosity, after noticing a milky drop on their own nipple, or because a family is exploring ways to share feeding. The honest answer is that the biology allows it in some situations, but it’s rare, it usually signals a medical issue, and it isn’t a practical way for cisgender men to feed a baby.

This guide explains the hormones involved, what can cause milky discharge in men (and why it needs a doctor), and what the medical literature says about induced lactation.

The biology: men have breast tissue too

Male bodies have breast tissue, and how much of it develops depends mostly on hormones. MedlinePlus explains that breast growth in males (gynecomastia) is usually caused by an imbalance between estrogen and testosterone, and that hormone shifts in newborns, during puberty and with aging can all lead to it.

Even babies can leak milk. MedlinePlus notes that some newborns, boys included, have breast swelling with a milky discharge, caused by estrogen from the mother. It usually lasts a couple of weeks to months.

The key milk-making hormone is prolactin. The NIDDK says prolactin signals a woman’s breasts to produce milk during pregnancy and breastfeeding. Prolactin isn’t only a “female” hormone: men can have high prolactin levels too, for example from a pituitary tumor or certain medicines. That’s why milky discharge can occasionally appear in men (more on that below).

Making a real milk supply takes more than prolactin. Medical protocols for induced lactation try to copy pregnancy: high estrogen and progesterone first, then a drop in those hormones to mimic birth, plus something to raise prolactin and regular breast pumping (Reisman and Goldstein, 2018). Our guide to when breast milk comes in explains how this works after a birth. Men don’t go through these changes, which is one reason male milk production is so unusual.

Milky nipple discharge in men (galactorrhea)

Milk or milky fluid coming from the nipple when you’re not breastfeeding is called galactorrhea. A review in American Family Physician notes it can occur in women who have never been pregnant, after menopause, “and even in men” (Huang and Molitch, 2012).

It isn’t something to ignore. MedlinePlus advises having any nipple discharge checked by a health care provider.

Common causes

Many causes work by raising prolactin. Based on MedlinePlus, the NIDDK and the American Family Physician review, they include:

Cause	Examples
Medicines	Some antipsychotics, some blood pressure medicines (including verapamil), anti-nausea and gut-motility drugs such as metoclopramide, opioid pain relievers, some antidepressants
Pituitary tumor	A prolactinoma, a noncancerous tumor that makes prolactin
Thyroid problems	An underactive thyroid (hypothyroidism)
Kidney disease	Chronic kidney disease or kidney failure
Chest wall irritation	Burns, shingles affecting the chest, injury, spinal cord injury, frequent rubbing or stimulation
Drugs and herbs	Cocaine, opioids and marijuana; some herbs such as fennel, anise and blessed thistle

Sometimes no cause is found.

Prolactinoma in men

A prolactinoma is the most common type of pituitary tumor, making up about 40% of them, according to the NIDDK. It’s noncancerous, and it’s more common in women than men.

In men, it often shows up differently. The NIDDK lists loss of interest in sex (linked to low testosterone) and erectile dysfunction as common symptoms. MedlinePlus adds breast enlargement, infertility, headaches and vision changes, especially reduced side vision. MedlinePlus also notes that larger tumors are more common in men, that they tend to appear at an older age, and that a tumor can grow quite large before symptoms appear.

The good news: prolactinomas usually respond well to treatment. The NIDDK says medicines called dopamine agonists (cabergoline is preferred) control prolactin and shrink the tumor very effectively, with surgery or radiation as options if medicine isn’t enough.

How doctors check it

Your doctor will usually start with your medicines and health history. According to MedlinePlus and the American Family Physician review, tests may include:

• a prolactin blood test (sometimes repeated, avoiding exercise and nipple stimulation beforehand)
• thyroid blood tests and a kidney function test (creatinine)
• reproductive hormones such as testosterone, if low sex hormone levels are suspected
• an MRI of the pituitary gland if prolactin is high without another clear cause
• breast imaging if a lump or unusual discharge needs checking

MedlinePlus also points out that squeezing the nipple to check for discharge can make it worse.

When to see a doctor

See a doctor about any nipple discharge. Get checked promptly if:

• the discharge is bloody
• it comes from one nipple only, or appears on its own without touching
• you feel a hard or firm lump, or notice a sore on the skin of the breast
• you have headaches, vision changes, low sex drive or erection problems
• you’ve started a new medicine and noticed breast swelling or discharge (don’t stop a prescribed medicine without talking to your doctor)

MedlinePlus lists bloody discharge, discharge from one nipple and discharge that comes out on its own as signs that discharge isn’t normal. Rarely, nipple discharge can be a sign of cancer, which is another reason not to wait.

Induced lactation: what the case reports show

Some people want to make milk to feed a baby they didn’t give birth to. For adoptive mothers and nongestational partners, this is called induced lactation. A small but growing number of case reports describe transgender women doing it.

A 2018 case report (Reisman and Goldstein), which its authors believe was the first formal one in the medical literature, described a 30-year-old transgender woman who had taken feminizing hormones for 6 years. She:

• followed a regimen of estradiol, progesterone, domperidone and regular breast pumping, under medical supervision
• was producing about 8 oz (240 ml) of milk a day after about 3 months
• fed her baby only her milk for the first 6 weeks, with the pediatrician reporting normal growth, feeding and bowel habits
• then added formula because of concerns about milk volume, while continuing to breastfeed

A 2024 scoping review included 21 articles published between 2018 and 2023, six of them case reports. Lactation was achieved in all six case reports, but the authors called the evidence “fragile” and recent, and said more robust studies are needed.

Important caveats:

• This is medical treatment, not a home project. It involves prescription hormones and monitoring.
• Domperidone isn’t approved in the US. The FDA says it is not FDA-approved for any use in humans, is not approved in any country to increase milk supply, has been linked to serious heart rhythm problems, and passes into breast milk. The 2018 case obtained it outside the US.
• No method exists for cisgender men. We found no clinical studies showing that cisgender men can induce enough lactation to feed a baby. Hormone treatment carries its own risks and should only happen under medical care.

If you’re a transgender or nonbinary parent hoping to breastfeed or chestfeed, look for an endocrinologist and an IBCLC with experience in induced lactation. Our breastfeeding support page explains how to find lactation help.

Ways partners can be part of feeding

If the real question is “how can I share feeding?”, there are well-proven ways that don’t involve making milk:

• Give bottles of pumped milk. Our guide to paced bottle feeding shows how to give a bottle in a way that supports breastfeeding.
• Take over the jobs around feeds: burping, diaper changes, settling, washing pump parts and bringing water and snacks.
• Do skin-to-skin contact, which any parent can offer.

For more on how breastfeeding works and how to get started, visit our breastfeeding basics hub.