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Home / Growing up / Chest changes
Common puberty change

Why is there a lump or tenderness under my nipple?

Temporary breast tissue growth, called pubertal gynecomastia, is common in boys. It can affect one or both sides and often becomes smaller over time.

The 30-second answer

Temporary breast tissue growth, called pubertal gynecomastia, is common in boys. It can affect one or both sides and often becomes smaller over time.

This guide is organized by anatomy. It can apply to anyone with this body question, regardless of gender.

Choose your depth
~50%

About half of teenage boys may notice it.

Estimates vary by source and definition. The important point is that a tender disc or fullness under a nipple during puberty is common and does not mean a boy is becoming female.

What usually happens

  • It may feel tender or firm beneath the nipple.
  • One side may be more noticeable.
  • It often improves over months to a few years.
  • Chest fat and glandular tissue are not the same thing.
Arrange a routine appointment

if the change is very large, painful, persistent, worrying, or associated with medication, supplement, or drug use.

Get prompt medical evaluation

for a hard fixed lump, nipple discharge, skin dimpling, significant redness, fever, or another rapidly changing symptom.

What the short answer leaves out

The fuller answer

A tender, rubbery disc of breast tissue beneath one or both nipples is common during male puberty. Hormone balance shifts during development, and breast tissue can temporarily respond even in an otherwise healthy boy.

One side may start first or remain more noticeable. Pubertal gynecomastia often becomes smaller over one to three years. Chest fat and glandular breast tissue are not the same, and neither says anything about gender identity or masculinity.

A clinician can distinguish common puberty tissue from another lump and review medicines, supplements, cannabis or other drug use, liver or endocrine symptoms, and the timing of puberty. Most evaluations do not lead to surgery.

About halfAAP guidance notes that roughly half of teenage boys notice tender nipple-area tissue.
Usually temporaryMost puberty-related tissue decreases over time without treatment.
Practical, not perfect

What can help today

  • Do not repeatedly squeeze the tissue to “check” it; this increases tenderness and anxiety.
  • A comfortable undershirt, rash guard, or layered shirt can reduce rubbing and self-consciousness.
  • Avoid unregulated bodybuilding or hormone supplements, which can cause or worsen breast growth.
  • Write down medicines, supplements, cannabis, and other substances honestly for a clinician; the goal is safety, not punishment.
  • Report bullying or harassment rather than changing clothes in unsafe isolation.
  • A stable photo in ordinary clothing can help track a rapid visible change, but never send intimate chest photos to strangers.
Remember: Temporary breast tissue does not mean that a boy is “turning into a girl.”
No shame, direct answers

Questions people ask privately

Can it happen on only one side?
Yes. Uneven onset and size are common, although a new hard or fixed lump needs evaluation.
Will exercise remove it?
Exercise can change chest muscle and body fat but cannot selectively erase glandular tissue.
Does touching it make it grow?
No, but frequent pressing can make it sore.
Does it mean low testosterone?
Not by itself. Pubertal gynecomastia is usually part of ordinary hormone changes.
Will I need surgery?
Usually not. Surgery is considered only after careful evaluation for persistent, severe, or very distressing cases.
Can medicine or supplements cause it?
Yes. Some prescriptions, hormones, supplements, and drugs can contribute, so bring a complete list to care.
Ordinary, soon, or urgent

When to get help

Routine appointment

The tissue worries you, persists, is very noticeable, or you want a clinician to confirm what it is.

Make an appointment soon

Growth is rapid, begins before puberty or late after puberty, is very painful, or is associated with medication, supplement, drug, testicle, liver, or hormone symptoms.

Urgent care

There is fever with rapidly spreading redness, severe illness, or a rapidly worsening painful swelling.

You do not need a perfect speech

Words you can use

“I have tender or enlarged tissue under one or both nipples. I know this can happen in puberty, but I want a clinician to confirm it and review possible causes.”

Say it, text it, write it, or show this page. Asking for help is not making a fuss.

Sources and limits: AAP: Breast growth in boys and girls · AAP: Physical development in boys
Evidence and safety language reviewed July 2026. This page has not yet been individually reviewed by a named clinician.
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Related answers

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Editorial statusSubstantially revised July 2026. Sources and limits are shown on complete guides. Named clinician review has not yet been obtained unless a page explicitly says otherwise. Corrections are welcomed through the contact page.