[4][5] Physically speaking, gynecomastia is completely benign, but it is associated with significant psychological distress, social stigma, and dysphoria.

[9][22] It may also be accompanied by breast tenderness or nipple sensitivity, which is commonly associated with gynecomastia observed in adolescents, typically early in development.

[21] Gynecomastia that is painful, bothersome, rapidly-growing, associated with masses in other areas of the body, or persistent should be evaluated by a clinician for potential causes.

Gynecomastia has psychosocial implications that may be particularly challenging for adolescents who are experiencing physical maturation and self-identity formation, which includes body image disturbances, negative attitudes towards eating, self-esteem problems, social withdrawal, anxiety, and shame.

[22][27] Known causes can be physiologic (occurring normally) or non-physiologic due to underlying pathologies such as drug use, chronic disease, tumors, or malnutrition.

[32][33] It is self-limited in 75–90% of adolescents and usually resolves spontaneously within 1 to 3 years as pubertal progression increases testosterone levels and cause regression of breast tissue.

[29] Drugs with good evidence for association with gynecomastia include cimetidine, ketoconazole, gonadotropin-releasing hormone analogues, human growth hormone, human chorionic gonadotropin, 5α-reductase inhibitors such as finasteride and dutasteride, certain estrogens used for prostate cancer, and antiandrogens such as bicalutamide, flutamide, and spironolactone.

[7][17][37][38] Drugs with fair evidence for association with gynecomastia include calcium channel blockers such as verapamil, amlodipine, and nifedipine; risperidone, olanzapine, anabolic steroids,[17][39] alcohol, opioids, efavirenz, alkylating agents, and omeprazole.

[17][40] Certain components of personal skin care products such as lavender[41] or tea tree oil have been reported to cause prepubertal gynecomastia due to its estrogenic and anti-androgenic effects.

[44][7] Many kidney failure patients experience a hormonal imbalance due to the suppression of testosterone production and testicular damage from high levels of urea also known as uremia-associated hypogonadism.

Similar to the mechanism behind refeeding gynecomastia, dialysis allows patients with renal failure who were previously malnourished to expand their diets and regain weight.

[44][26] Secondary hypogonadism results when there is damage to the hypothalamus or pituitary (due to radiation, chemotherapy, infection, trauma, etc.

[7][29] The lack of androgen-mediated inhibition of breast tissue proliferation combined with relative estrogen excess result in gynecomastia.

[51] Peutz-Jeghers syndrome is a rare cause of testicular tumors that affect aromatase expression, which results in elevated serum estrogen levels.

[52] Aromatase excess syndrome is a rare genetic disorder that leads to increased conversion of androgens to estrogens in the body.

[55] High levels of prolactin in the blood (which may occur as a result of certain tumors or as a side effect of certain medications) has been associated with gynecomastia.

[27] If β-hCG levels are abnormally high, then ultrasound of the testicles should be performed to check for signs of a hormone-secreting testicular tumor.

[27] Markers of testicular, adrenal, or other tumors such as urinary 17-ketosteroid or serum dehydroepiandrosterone may also be checked if there is evidence of hormonal imbalance on physical examination.

[7][9] If a mass/lump is felt during a physical exam some features of the lump that would point to malignancy would be painless, non moveable (fixed), irregularly shaped, and skin changes.

[24][26] When surgery is performed, the gland is routinely sent to the lab to confirm the presence of gynecomastia and to check for tumors under a microscope.

[60] Testosterone itself may not be suitable to treat gynecomastia as it can be aromatized into estradiol, but nonaromatizable androgens like topical androstanolone (dihydrotestosterone) can be useful.

[60] If chronic gynecomastia does not respond to medical treatment, surgical removal of glandular breast tissue is usually required.

[65] In adolescent males, it is recommended that surgery is postponed until puberty is completed (penile and testicular development should reach Tanner scale Stage V).

[66] In the United States, many insurance companies deny coverage for surgery for gynecomastia treatment or male breast reduction on the basis that it is a cosmetic procedure.

[57][58] Gynecomastia is the most common benign disorder of the male breast tissue and affects 35 percent of men, being most prevalent between the ages of 50 and 69.

[40][70] According to the American Society of Plastic Surgeons, breast reduction surgeries to correct gynecomastia are fairly common but has been a recent decline.

Use of anabolic steroids can result in gynecomastia, and male breasts are sometimes referred to using the pejorative bitch tits in bodybuilding communities.

[74] In the second portion of the bifurcated trial, the plaintiffs sought to prove that the companies knew and deliberately disregarded evidence that Risperidone could lead to gynecomastia in young males, and nonetheless promoted the medication off-label and released the medication into the open market for prescription and use by patients without disclosing the side effects.

The amount was later reduced to $6.8 million by Judge Kenneth Powell Jr.[75] In 2019, a 12-person Philadelphia jury awarded $8 billion in punitive damages to plaintiffs tied to the use of risperidone.

Risperidone is an atypical antipsychotic that was originally approved to treat psychosis, but its use in children, including those with autism, ADHD, and schizophrenia diagnoses, has grown over the last two decades.