Nipples are one of the most fascinating oddities of the body—they can change color and size or become sore and produce discharge without apparent reason. Suffice it to say: There’s a lot of facts to know about nipples, giving rise to plenty of questions about this piece of human anatomy. So, if you’ve ever wondered why your nipples are sensitive or why you keep getting sad when touching your nipples, you’re not alone—these are fairly common nipple concerns.

To “nip” any confusion in the bud about their idiosyncrasies, board-certified OB/GYNs Heather Irobunda, MD, and Christine Greves, MD, answer common questions about the dots on our chest and sort out the facts from the myths.

10 facts about nipples

1. Is my nipple color normal?

The short answer is yes. From pale pink to deep brown, nipples come in different colors based on the person and their unique skin tone, which is often dictated by the amount of melanin, or natural pigment, present in the skin. “The more melanin that you have, the darker [nipples] will be,” says Dr. Irobunda.

Your nipples can change color over the course of your life, too. “They typically get darker as you grow older, and pigment can also be affected by hormones,” says Dr. Irobunda. For example, a person’s nipple color—and not to mention size—can change when they’re expecting a baby. In some instances, the shift in shade can be permanent—or it can take time for them to return to their previous hue. Either way is perfectly normal. “The only time that I would be concerned about the change in nipple color is if it is associated with any pain,” she says—in which case, it’s worthwhile to talk to an OB/GYN.

2. Is it normal for my nipples to change size?

Just as the color of nipples can vary, so can their size—which, again, is normal. However, the nipples and areolas (the area of pigmented skin surrounding the nipple) become larger when a person is pregnant due to increased amounts of the hormones estrogen and progesterone. In a 2022 study of over 50 women, researchers found that nipples increased in length and width during pregnancy. Dr. Irobunda also theorizes that the change in size naturally occurs to help support breastfeeding. “It’s thought that the nipples grow to make it easier for a baby to locate the nipple for breastfeeding,” she says.

3. Why does one of my nipples look different from the other?

If your nipples look different from one another, there’s usually no reason to fret. “If your breasts are not symmetrical, and that’s how it’s always been, then don’t worry about it,” says Dr. Greves. As mentioned, nipple size and color can also change due to hormonal fluctuations, like during puberty, pregnancy, breastfeeding, and menopause—which is all within normal range.

Still, it’s worth speaking to an OB/GYN about it, especially if there’s a sudden change in their appearance, she says.

4. Why is there hair around my nipples?

Those rogue hairs around your nipples are usually no cause for concern, though some people are more likely to develop hair around their nipples than others. “It’s more prevalent when there’s more male testosterone present,” says Dr. Greves. As such, when your hormones fluctuate, like during pregnancy or menopause, it can also increase your likelihood of growing hair around your nipples, according to Cedars Sinai.

However, excessive hair growth on your nipples and the rest of your body can also indicate a hormone problem like polycystic ovary syndrome (or PCOS), which often comes with other symptoms like irregular or missed periods, acne, and weight gain. If you’re noticing hair sprouting up in new places, it’s a good idea to talk to an OB/GYN. Otherwise, you can chalk it up to genetics.

There’s no harm in leaving your hair intact, but there are a myriad of ways to remove nipple hair if you choose, including methods like waxing and shaving, or if you have sensitive skin, laser hair removal, or plucking.

5. What’s the deal with these bumps on my nipples?

There are two distinct types of bumps that naturally occur on nipples—and they both serve a pretty interesting purpose. The first are the bumps on the nipples themselves, which are milk duct openings. They release milk and colostrum, a nutritious precursor to breast milk produced in the first few days after a baby’s birth. The second are the small raised bumps on the areolas, aka Montgomery glands. These glands contain fluid to provide lubrication during breastfeeding, says Dr. Irobunda. She adds, “Sometimes, these bumps may get larger if they get blocked, but if they do, there’s no need to be concerned.”

6. Is it normal that my nipples point inward instead of out (or vice versa)?

If you have inverted nipples that point inward instead of outward, know that you’re not alone. As per one 2013 study that categorizes nipples into three main types—protruding, flat, and inverted—approximately two percent of people fall under the last category, and just like the other types, they’re normal.

“Many women are born with nipples like this, and there is nothing concerning about them,” says Dr. Irobunda. “The reason why these nipples point inward is because nipples have muscles that make them poke out, and some people are not born with those muscles.” Very rarely, some people may notice their nipples suddenly turn inward. “This change in the nipple can be associated with inflammation, surgery performed on the breast, or even cancer,” she says.

Keep in mind that regardless of what your nipples look like and whether or not they fall under the above categories, it’s all normal. That said, it’s important to note any changes in your nipples or your breasts, especially if they’re sudden.

7. Is it possible to have more than two nipples or one or no nipples at all?

The short answer is yes—and, according to Dr. Greves, having extra or supernumerary nipples is normal. “It’s usually not a cause for concern, and up to six percent of people born in the US have it,” she says. As to why they occur? The reason is unknown, though supernumerary nipples form in the womb, per the Cleveland Clinic, and as mentioned by Dr. Greves, it is rarely associated with underlying medical conditions. While normal, look out for “pain, itching, hardness, or discharge,” she says—any of which could indicate a problem.

On the other hand, it’s possible, albeit rare, for a person to have one or no nipples at all, which is a condition typically known as athelia. According to one 2013 study, it is common in those born with Poland syndrome and ectodermal defects—and though athelia is usually of no concern in itself, Poland syndrome and ectodermal defects can pose health issues.

8. Why are my nipples sore?

If your nipples are sore or sensitive, it can be just as confusing as it is uncomfortable—and there are different reasons that might be behind the discomfort. For one, you can experience tenderness during breastfeeding. “If a woman decides to breastfeed, she may notice that her nipples may become irritated when she initially starts,” says Dr. Irobunda. “This is due to the friction that is caused initially when a baby starts to breastfeed.”

According to Standard Medicine Children’s Health, mild nipple soreness or sensitivity is normal for the first week or two of breastfeeding. However, if your nipples become red, raw, blistered, or cracked, it can be due to a shallow latch (when your baby isn’t opening their mouth widely enough to nurse without causing you pain) or an allergic reaction or infection if you suddenly experience sore or sensitive nipples after months of pain-free breastfeeding. If the symptoms are severe, talk to a doctor or a lactation consultant, says Dr. Irobunda.

Outside breastfeeding, a person can have sore nipples during their menstrual cycle—or, more specifically, during the premenstrual phase, which is a condition known as cyclical mastalgia. The discomfort can range from a mild sensitivity to stabbing pain, according to the Cleveland Clinic. Why nipple soreness occurs is likely due to hormones, and it’s also fairly common during the beginning of puberty or menopause. Usually, sore nipples aren’t a cause for concern unless the pain is persistent, accompanied by discharge, lumps in your breasts, or a general feeling of malaise.

According to board-certified OB/GYN Mary Jane Minkin, MD, in a previous interview with Well+Good, sensitive nipples can also be caused by a “superficial skin irritation, like eczema.” Nipple eczema can be characterized by symptoms ranging from mild (like redness and itchy skin) to severe, such as a burning sensation and discharge. If you suspect this might be the case, speak to a doctor or dermatologist.

9. Why are my nipples hard?

You might wonder why your nipples become hard and, at times, without provocation. Perhaps you’re going braless, and all of a sudden, your nipples poke out from underneath your T-shirt, or they rise up with little to no warning. According to Dr. Greves, there might be a few reasons why.

For one, it might be due to cold temperatures. Exposure to cold weather can stimulate the muscles underneath the nipples and areolas, causing the skin to pucker inward and the nipples to stick out. Physical stimulation, whether nonsexual (e.g., the fabric of your T-shirt brushing up against your breasts) or sexual (e.g., breast play), can also trigger this response.

One of the more interesting, albeit lesser-known, facts about nipples is that they are one of the body’s extragenital erogenous zones. When touched, it can make them stand erect and induce bodily pleasure—and, sometimes, with enough stimulation, people can experience a breast orgasm (or, in this instance, a nipplegasm).

Nipples needn’t require any external stimulus to become hard or erect, though—and, in this instance, hormones are usually to blame. Nipple erections can occur during ovulation due to a surge of estrogen levels, says Dr. Greves, as well as during the postmenstrual phase (or after your period has ended). Nipples are also more pronounced during pregnancy and breastfeeding.

10. Is nipple discharge normal?

It’s common for your nipples to leak when you are pregnant or breastfeeding, says Dr. Greves. (“Lactating increases the hormone prolactin,” she says—which, in turn, causes breast leakage in preparation for or to feed your baby).

However, you can also experience nipple discharge outside the above scenarios, says Dr. Greves. It can occur during nipple stimulation, she says. According to the Cleveland Clinic, nipple discharge can occur during hormonal fluctuations when taking certain medications or if you have an injury—all of which are totally normal. The color of the discharge can range from clear to milky white to yellow to green to red, and though color isn’t a primary factor for determining its cause, it’s worth bringing up to your OB/GYN if the discharge is “bloody or pink or greenish brown, or if it’s ever painful” says Dr. Greves.

Frequently asked questions: more facts about nipples

At what age do nipples pop out?

Nipples are present as soon as we are born, per Stanford Medicine Children’s Health, but they can further change and develop throughout puberty. Generally speaking, nipples first begin to protrude during the preteen years of an assigned female at birth (AFAB).

Do nipples flatten as you age?

As an AFAB approaches menopause, the milk ducts under the areola shorten, leading to an age-related condition known as duct ectasia. As a result of duct ectasia, the nipples might lay flat or turn inward, according to the Cleveland Clinic.