Tender nipples are most often caused by hormonal shifts tied to your menstrual cycle, but they can also signal pregnancy, friction irritation, medication side effects, or (less commonly) an infection or skin condition that needs medical attention. The sensation ranges from mild sensitivity to sharp pain, and the cause usually becomes clear once you consider the timing and any other symptoms.
Hormonal Changes Before Your Period
Hormonal fluctuations are the single most common reason for nipple and breast tenderness. A rise in estrogen and progesterone in the second half of your menstrual cycle causes breast tissue to swell and retain fluid, which puts pressure on nerve endings. This typically starts three to five days before your period begins and resolves once bleeding starts.
If you notice the tenderness follows a predictable monthly pattern, hormones are almost certainly the explanation. The soreness often affects both sides and may extend across the entire breast, not just the nipple. Some cycles feel worse than others depending on how much your hormone levels fluctuate that month.
Early Pregnancy
Nipple tenderness is one of the earliest signs of pregnancy, sometimes showing up before a missed period. The sensation feels similar to premenstrual soreness but tends to be more intense and persistent. Rising levels of pregnancy hormones cause increased blood flow to the breasts and rapid changes in the milk ducts, which makes the nipples especially sensitive.
If your period is late and the tenderness hasn’t gone away on its schedule, a home pregnancy test is a reasonable next step. In pregnancy, the soreness usually peaks during the first trimester and gradually eases as your body adjusts to the new hormone levels.
Friction and Irritation
Physical rubbing from clothing is a surprisingly common cause of nipple pain, especially during exercise. Runners know this as “jogger’s nipple.” Each stride shifts your shirt slightly across your chest, and over the course of a long run, that repetitive motion can chafe the skin raw or even cause small cracks. Sweat-soaked shirts that cling to your body make it worse because the wet fabric increases friction. Cotton shirts are particularly notorious for this, especially once they get heavy with moisture. Cold weather also plays a role because it makes nipples more erect and therefore more exposed to rubbing.
Tight bras, rough fabrics, and even seatbelts can produce the same kind of irritation outside of exercise. If the tenderness appeared after a new activity or a change in clothing, friction is the likely culprit. Switching to moisture-wicking synthetic fabrics, wearing a well-fitted sports bra, or applying a barrier like petroleum jelly before workouts usually solves the problem.
Medications That Cause Breast Tenderness
Several common medications list breast or nipple pain as a side effect. Oral contraceptives and hormone replacement therapy are frequent offenders because they directly change your estrogen levels. Certain antidepressants in the SSRI class (like fluoxetine) can also trigger tenderness, as can some antipsychotic medications, certain blood pressure drugs, and diuretics (water pills). If your nipple sensitivity started or worsened after beginning a new medication, that connection is worth discussing with your prescriber. Stopping or switching the drug often resolves it.
Breastfeeding-Related Causes
If you’re nursing, tender nipples are extremely common in the first few weeks as your body adjusts. A poor latch is the most frequent cause. When a baby doesn’t take enough of the breast into their mouth, the nipple bears the brunt of the suction and can become cracked, blistered, or raw. Adjusting your baby’s positioning so they latch onto the areola (not just the nipple tip) makes a significant difference. Breaking a painful latch by sliding a clean finger into the corner of your baby’s mouth and then re-latching is better than pushing through the pain.
Two infections can also cause nipple tenderness during breastfeeding, and they feel quite different from each other:
- Thrush (yeast infection): Causes pink, flaky, shiny, or itchy nipples. You may notice shooting pains deep in the breast during or after feedings. Your baby might have white patches on the inside of their cheeks, tongue, or gums.
- Mastitis (bacterial infection): Comes with flu-like symptoms including fever, chills, body aches, and fatigue. The affected breast feels warm or hot to the touch, looks red or pink, and may produce a yellowish discharge. Mastitis needs prompt treatment.
For general breastfeeding soreness, avoid harsh soaps or products with astringents on your nipples. Rinsing with clean water is enough. Warm washcloth compresses can also ease discomfort. If you’re pumping, an incorrectly sized flange (the cone-shaped piece that fits over the nipple) is a common and overlooked source of pain.
Skin Conditions and Allergies
Contact dermatitis from a new laundry detergent, body wash, lotion, or fabric can make nipples red, itchy, and tender. Eczema can also affect the nipple area. These causes are usually easy to identify because the skin looks visibly irritated, and the tenderness corresponds with a product change. Switching back to a fragrance-free product typically resolves it within a few days.
When Tenderness May Signal Something Serious
Nipple tenderness by itself is rarely a sign of cancer. However, a rare condition called Paget disease of the breast can mimic common skin problems while actually indicating an underlying malignancy. The warning signs include flaking, crusty, or thickened skin on or around the nipple, a nipple that becomes flattened or inverted, and discharge that is bloody or yellowish. You may also feel a lump in the same breast. Paget disease can look very similar to eczema or dermatitis, which is why skin changes around the nipple that don’t improve with basic treatment deserve a closer look.
In general, nipple tenderness that follows a cyclical pattern, responds to simple measures, and doesn’t come with visible skin changes or lumps is almost always benign. The signs that warrant a medical visit are tenderness that doesn’t follow your menstrual cycle, any lump or thickening in the breast, spontaneous nipple discharge (especially if bloody or one-sided), and persistent skin changes that don’t heal within a couple of weeks.