Gynecomastia is a leading cause of man boobs or man breasts. At least 30 percent of guys will grow a set of "man boobs" at some point during their life, according to a study in the Indian Journal of Endocrinology and Metabolism.

Technically called gynecomastia, a full chest on a man comes from benign swelling of breast tissue typically caused by an imbalance in hormones, explains hormone expert Rob Kominiarek, D.O., medical director of ReNue Health in Springboro, Ohio. Guys most often become well-endowed at times when hormones are in natural flux—like during puberty or old age (likelihood for gynecomastia starts going up around 50). But, depending on the cause, man boobs can perk up at any age.

While gynecomastia can be uncomfortable, it doesn’t put your physical health at risk too much. But there is a definite psychological toll it can take, Kominiarek adds. “Many guys with gynecomastia suffer from self-confidence issues and can often isolate themselves because they feel it’s unsightly and embarrassing,” he explains. Depending on the cause there can be problems with depression, anxiety, panic attacks, and social phobias. In fact, even though guys who have man boobs around are more likely to be overweight, they feel more distress over the weight in their chest than their overall lb count, according to a study in Plastic and Reconstructive Surgery.

What causes gynecomastia?

There are four grades of gynecomastia, depending on how much swelling and excess skin you have—so the good news is your blossoming bosom may be on the mild side.

In some cases, man boobs stem from overall obesity, known as pseudogynecomastia, wherein bigger boobs are from fat deposits and not enlargement of the actual breast glands.

But the most common cause of gynecomastia is a hormonal imbalance that leads to your estrogen levels going up and/or testosterone levels going down.

WEIGHT LOSS

Your hormones are regulated by something called the Hypothalamic-Pituitary axis (H-P axis), a complex set of interactions among the three endocrine glands responsible for producing and controlling hormones: the hypothalamus and the pituitary gland in your brain, and the adrenal gland near your kidneys. “The body naturally tries to be in a hormonal homeostatic state of balancing,” Kominiarek explains.

But the H-P axis is responsible for over 30 hormones and their metabolites, and certain factors or events can cause this axis to fail, like radiation, chemotherapy, autoimmune diseases, toxin exposure, alcoholism, illicit drug abuse, genetics, and traumatic brain injury.

Outside of these events, there are a handful of habits you may not realize are throwing your hormones off balance and are encouraging your bazookas to get bigger.

FAT-BURNING WORKOUTS

1. Check with your doc: “For any guy, your first step is to see a physician who regularly manages this kind of issue to understand what the initiating factors are,” Kominiarek advises. Your doc will take a thorough history, do an exam, and likely run a few tests including blood samples and breast imaging to determine what exactly causes your knockers to grow.

There are a handful of other medical conditions to rule out too, including fat necrosis, hematoma, breast cancers, cysts, and metastases from other cancers, he adds. If you do have gynecomastia, surgery and hormone medications may be necessary. But once your doc knows how severe your case is and what the culprit is, he can direct you on what to try before the extreme measures come into play.

2. Hit the gym: According to a study out of the UK, advice on diet and exercise may be sufficient to reduce a mild case of man boobs. While you may think you need to go cardio-crazy, it may be best to focus on building muscle rather than burning fat. Try our 6-Move Man Boob Elimination Workout.

3. Check your meds: Your bigger boobs could be a result of medications you’re taking, Kominiarek says. Opioids, certain antidepressants, benzodiazepines, statins, amphetamines, androgen blockers, even marijuana all have the potential to mess with your hormones in a way that can deliver D-cups.

4. Stop taking steroids: In an ironic twist, taking anabolic steroids may give you boobs instead of bulk since the hormones used to build muscle can stimulate proliferation of male breast tissue glands, according to Brazilian researchers. In fact, steroid abuse is the common link among bodybuilders who develop gynecomastia, says a study out of Surrey. If this is potentially your truth, you need to fess up to your doctor—a lot of the time, steroid abuse causes irreversible damage that’ll require surgery to fix so you won’t nix your knockers without telling him the real root of the problem.

5. Clean up your diet: While it is a myth that eating soy will increase estrogen and puff your chest pillows, food can definitely contribute to fat storage and mess with your hormone balance enough to exacerbate the problem. Nix processed foods, bad fats, and sugar, and increase the amount of healthy fats (like avocados, olive oil, and omega-3s) and lean protein, Kominiarek says.

6. Start gardening green: Certain herbicides and pesticides disrupt your hormones enough to actually cause gynecomastia, Kominiarek says. A few of the worst culprits: endosulfan and atrazine, the second most widely used weed killer in the United States (which is actually under review for safety by the EPA). Switch to chemical-free weed killers—even regular distilled vinegar works—to help both the environment and your endocrine functioning.

7. Purge plastic: “All types of BPA and phthalates can contribute to gynecomastia, Kominiarek says. And indeed, a study in Reproductive Toxicology found that exposure to even low doses of bisphenol-A (BPA), like that found in canned foods and plastics, can promote abnormal breast growth in boys and adult men. One of the worst culprits: water bottles—you know, like the kind you sip from every time you hit the gym. Since even BPA-free plastics can still contain other harmful chemicals, trade it out for stainless steel or glass containers, like Hydro Flask or S'well.

8. Score better sleep: Racking up a solid eight hours is crucial to healthy hormone production. The less you sleep in a night, the less testosterone your body is able to produce, according to Australian research. Plus, inadequate sleep is linked to higher steroid use and obesity—both of which are risk factors for gynecomastia. And it’s not just about squeezing sleep in anywhere: It’s crucial to get adequate sleep during your natural circadian rhythm (nighttime), Kominiarek adds.

9. Consider hormone medications: This is definitely one you want to consult with your doc on, since meds to boost your T levels can actually create gynecomastia if used improperly, Kominiarek points out. But about one-third of guys who use hormone meds responsibly (read: under doctor’s supervision) see benefits on their man boobs, according to a study in The Breast Journal.