Types of Nipples

4 Main Categories and 7 Variations in Size, Color, Texture and Number

Nipples are as varied in shape, size, and color as the breasts themselves. Broadly speaking, nipples can be categorized in one of four ways:

  • Protruding (raised)
  • Flat (flush with the skin)
  • Inverted (sunken)
  • Unclassified (various characteristics)

The majority of nipples, roughly 75%, are protruding.

Beyond these baseline characteristics, there are other morphological (structural) features that describe a nipple. These include the size, color, and texture of a nipple, as well as uncommon variations like bifurcated nipples (two nipples next to each other), supernumerary nipples (an extra nipple elsewhere on the body), and athelia (missing nipples).

This article will describe the four types of nipples a person can have as well as common and uncommon variations in nipple morphology.

nipple variations

Verywell / JR Bee

For the purpose of this article, "female" refers to people born with vaginas and "male" refers to people born with penises irrespective of their gender identity.

Nipple Anatomy

The nipple is the typically raised area of skin at the center of a pigmented, circular area of tissue called the areola. In females, the nipple is the structure through which breastmilk leaves the breast via lactiferous ducts ("milk ducts").

Protruding Nipples

Although protruding nipples are the most common type, their shape can vary from person to person. One study found that the average height of a nipple is 0.9 centimeters (roughly one-third of an inch). For many people, protruding nipples are raised above the areola all the time.

In response to cold, physical stimulation, or sexual arousal, the nipples can harden and stick out even further. Although this is perfectly normal, it can be a cause of embarrassment for some people if the nipples are suddenly and prominently seen beneath a top or blouse.

This can be overcome by wearing thicker fabrics, tops with colorful prints or darker colors, or a bra with a cup insert.

Flat Nipples

Flat nipples are the second most common type of nipples, occurring in roughly 23% of people. Some flat nipples will always remain flat, while others may become erect with cold temperatures, physical stimulation, or sexual arousal.

People with flat nipples who intend to breastfeed may experience some difficulty. Gently pulling the nipple forward and rolling it between the fingers can help engorge the tissues with blood. Using a breast pump for a few seconds before breastfeeding can also help.

Inverted Nipples

Instead of protruding, inverted nipples are tucked below the skin's surface. As a result, they can appear dented or sucked in. Nipple inversion is usually a congenital condition (meaning something you are born with).

Studies suggest that roughly 2% of nipples are inverted.

Inverted nipples, also known as invaginated or retracted nipples, can result from shortened milk ducts that pull the nipple tissue inward. Although harmless, inverted nipples can make breastfeeding difficult.

Inverted nipples can often protrude when gently stimulated. Some inverted nipples, however, will never protrude even with stimulation.

Unclassified Nipples

Unclassified nipples are those that don't fit neatly into the abovelisted categories. It can mean that there are unilateral (one-sided) variations in your nipples. For example, one side may be raised and the other side may be inverted.

Variations like these may be due to a past injury or simply be something you were born with. However, in they could also be a sign of a serious medical condition. Unilateral puckering, for instance, could be a sign of breast cancer.

Nipple anomalies (uncommon variations) also fall under the category of unclassified nipples, These are almost always due to genetics and are rarely a cause of medical concern. Even so, some people may seek surgical correction for cosmetic reasons.

These include:

  • Supernumerary nipples: This is an extra nipple or nipples. Also known as polythelia, a supernumerary nipple can appear anywhere along the two parallel "milk lines" which start in each armpit, run through the "typical" nipple, and end at the groin.
  • Bifurcated nipples: Also known as double nipples, this is when there are two nipples on one areola. The condition may be unilateral or bilateral (two-sided).
  • Athelia: This is the absence of a nipple. In most cases, the condition is bilateral but can be unilateral if caused by genetic disorders such as Poland syndrome (in which a child is born with missing or underdeveloped chest muscles).

Other Nipple Variations

Beyond how raised or flat a nipple may be (or how many nipple you might have), there are other variations that characterize nipples:

Nipple Size

Nipple sizes can vary not only from person to person but also by biological sex. Due to evolutionary biology, female nipples are typically larger because they are functional and are needed to facilitate breastfeeding. They can also change in size under the influence of estrogen and progesteone.

Studies suggest that female nipples are around 36% larger than nipples in males. While the size of nipples in males is relatively uniform, there can be a wide variation in size among females.

Nipple Color

The color of a nipple can vary by genetics and race, ranging from light pink to dark brown. The color usually matches that of the areola. Nipple color is not generally indicative of a health concern and can change with age or during menstruation, pregnancy, or menopause.

While suntanning can cause nipples to darken, there are other conditions that can cause transient or permanent changes in nipple color.

One of these is hyperkeratosis in which the outer layer of skin (known as the stratum corneum) starts to thicken and harden, causing the skin to darken. Hyperkeratosis can occur for no known reason but can sometimes be the result of hormonal birth control or medications like spironolactone.

Nipple Texture

Nipples can also vary and change in texture. Gentle stimulation can engorge nipples with blood and make them harder. Tissue damage caused by breastfeeding, nipple piercing, or excessive sun exposure can cause nipples to become firmer, larger, dry, and flaky. By contrast, the aging-related loss of collagen can cause nipples to soften and sag.

It is also not uncommon to have pimple-like bumps on your nipples. These are due to glands called Montgomery tubercles located on the nipple and areola. During pregnancy, the glands can swell and turn milky white as they produce more oils to lubricate the nipple during breastfeeding.

Hairy Nipples

Hair follicles surround the nipples, so it's normal to have a few strands there. While the hairs may be thin and virtually transparent, with age, nipple hairs tend to become thicker and coarser.

In most cases, hairy nipples aren’t a cause for concern; they’re simply a part of the normal aging process. However, if you consider them unsightly, plucking, tweezing, or shaving them can cause ingrown hairs and infection. Cutting the hair with nail scissors is a far better option.

What Your Nipples Say About Your Health

If you are born with flat or inverted nipples, they are not "abnormal" but are simply variations influenced by genetics. The same applies if your nipples change with age due to the loss of collagen and change in hormones.

You should be concerned, however, if you experienced sudden changes in your nipples, especially if you are younger, the changes are significant, or one nipple is affected but not the other.

Here are some examples of changes to contact your healthcare provider about:

  • Nipple puckering: The unilateral (one-sided) inversion or puckering of a protruding or flat nipple should never be ignored. It may be due to duct ectasia (when milk ducts become swollen and clogged) but may also be a sign of breast cancer (including Paget's disease of the nipple).
  • Changes in texture or color: Scaly, flaky, or itchy nipples may be due to eczema or a fungal or bacterial infection. Redness, warmth, and pain may be a sign of an infection, the risk of which increases if ever nipples are dried or cracked.
  • Swollen, enlarged pores: Peau d'orange is a term used to describe an orange-peel-like texture of skin that suddenly thickens and has enlarged pores. A nipple infection can cause this, but it is also a classic sign of inflammatory breast cancer.
  • Excessive hair growth: The abnormal growth of hair, called hirsutism, may be a sign of a hormonal disorder like polycystic ovary syndrome (PCOS) or Cushing's syndrome as well as ovarian or testicular cancer which can affect the balance of estrogen and testosterone.
  • Abnormal discharge: Nipple discharge that is bloody, comes from only one nipple, or comes out on its own without squeezing or touching the nipple may be a cause for concern. This may be a sign of an infection, a benign growth on a milk duct, or breast cancer.

Summary

Although most people have protruding nipples, they can vary in appearance. Flat and inverted nipples are variations that people are born with or that can develop due to aging. During puberty, pregnancy, and menopause, hormonal fluctuations can affect nipple appearance and sensitivity.

A few hair strands around the nipple are normal, but excessive hair growth can be caused by certain medical conditions. Notify your healthcare provider of any nipple changes, especially if they occur suddenly or on only one side.

A Word From Verywell

Becoming familiar with how your nipples look and feel is important as it allows you to report any changes to your healthcare provider as soon as you notice them. Doing a monthly breast self-exam is one way to do this.

If you notice any changes, it doesn't necessarily mean that you have cancer or any health condition. But, on the off chance that cancer is diagnosed, early detection almost variably leads to better outcomes.

Frequently Asked Questions

  • Why are my nipples so big suddenly?

    In females, it is not uncommon for nipples to get bigger during periods or pregnancy. Both estrogen and progesterone draw fluid into the breasts, making nipples feel swollen and tender. In older males, the nipple and breasts may get larger due to a common aging-related condition called gynecomastia.

  • What type of nipples are best for breastfeeding?

    Having protruding nipples may help the baby latch onto the breast more easily, but with the support of a lactation consultant, successful breastfeeding is possible with any nipple type.

9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Del Riego J, Pitarch M, Codina C, et al. Multimodality approach to the nipple-areolar complex: a pictorial review and diagnostic algorithm, Insights Imaging. 2020 Dec;1:89. doi:10.1186/s13244-020-00896-1

  2. Sanuki J ichi, Fukuma E, Uchida Y. Morphologic study of nipple-areola complex in 600 breasts. Aesth Plast Surg. 2009;33(3):295-297. doi: 10.1007/s00266=088-9194-y.

  3. Karaçam Z, Sağlık M. Breastfeeding problems and interventions performed on problems: systematic review based on studies made in Turkey. Turk Pediatri Ars. 2018;53(3):134-148. doi:10.5152/TurkPediatriArs.2018.6350

  4. Zucca-Matthes G, Urban C, Vallejo A. Anatomy of the nipple and breast ducts. Gland Surg. 2016;5(1):32-6. doi:10.3978/j.issn.2227-684X.2015.05.10

  5. Nagaraja Rao D, Winters R. Inverted nipple. StatPearls.

  6. Caouette-Laberge L, Borsuk D. Congenital anomalies of the breast. Semin Plast Surg. 2013 Feb; 27(1): 36–41. doi:10.1055/s-0033-1343995

  7. Kelly AJ, Dubbs SL, Barlow FK, et al. Male and female nipples as a test case for the assumption that functional features vary less than nonfunctional byproductsAdaptive Human Behavior Physiol. 2018;4:344-53. doi:10.1007/s40750-018-0096-1

  8. Wei J, Li Q, Wu H, Yin X, Ren G. Severe bilateral hyperkeratosis of the nipples and areolae: a case report and literature review. Front Med (Lausanne). 2022;9:781693. doi:10.3389/fmed.2022.781693

  9. Kanakis GA, Nordkap L, Bang AK, et al. EAA clinical practice guidelines—gynecomastia evaluation and managementAndrology. 2019;7(6):778-93.

By Serenity Mirabito RN, OCN
Serenity Mirabito, MSN, RN, OCN, advocates for well-being, even in the midst of illness. She believes in arming her readers with the most current and trustworthy information leading to fully informed decision making.

Originally written by
Pam Stephan
Pam Stephan is a breast cancer survivor.
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