The short explanation
Swelling of breast tissue on both sides in a man is called gynaecomastia. It is common and is usually caused by a change in the balance between hormones. In adult men, causes include weight gain, some medicines, alcohol, use of anabolic steroids or certain supplements, cannabis, and less commonly problems with the liver, kidneys, thyroid or testicles. Gynaecomastia on both sides that is tender is usually benign, but a doctor should check it to look for a cause, particularly if it appeared recently.
What depends on your situation
The parts of this that change from woman to woman. Uncertainty is stated, not hidden.
- A doctor will ask about medicines, supplements, gym products, alcohol and drug use, examine the chest and testicles, and may order blood tests.
- Treating the cause often helps the tissue reduce. Some men consider other treatments if it persists and bothers them.
- A firm lump on one side, especially under the nipple, nipple discharge or skin changes are more worrying signs and should be checked promptly.
- Men often feel embarrassed. Reassure him that this is a common problem that doctors see regularly.
What this answer cannot determine
The boundary of online education. These need a clinician who can see you.
- This cannot tell you what is causing his breast swelling. Examination and sometimes blood tests are needed.
Questions for your clinician
Take these with you. You can add any of them to an appointment card.
- What might be causing this swelling?
- Could any medicines or supplements be involved?
- Does he need blood tests?
- If it does not go away, what are the options?
When to seek help
Clinician-approved guidance for this topic. When in doubt, being seen is never the wrong choice.
Book an appointment soon
- Encourage him to see a clinician within a couple of weeks, sooner if there is a firm lump on one side or nipple discharge.
Raise it at a routine appointment
- Bring a list of any medicines, supplements or gym products to the appointment.
Sources
The evidence this explanation is built on.
- Breast diseases MedlinePlus (NIH)
- Breast cancer MedlinePlus (NIH)
Who wrote and reviewed this
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- Author
- AskHer Editorial (AI-assisted draft) AskHer's editorial team — not an individual clinician Works in English, தமிழ், हिन्दी
- Clinical reviewer
- Nobody yet No clinician has signed this answer off, and no person on the editorial team has read it yet. That is what the “Written with AI assistance” label means. It is queued for an editor to read, and then for a clinician who works in this area. The sources it was drafted against are listed above.
- Review status
- Written with AI assistance — not yet reviewed by a person
- Last reviewed
- Not yet reviewed by a person
- Version
- 1
Correction history
Substantive changes are listed, not quietly edited away.
No corrections have been made since this answer was first published.
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