The causes of gynecomastia have always been somewhat of a mystery for the medical community and since it is a benign condition, not much effort was put into finding what causes gynecomastia on a fundamental level. But before delving deep into the causes of gynecomastia, let’s be clear and on the same page about what is gynecomastia and what it is not. Breast enlargement in men can be caused by breast tissue growth and this is genuine gynecomastia.

Breast enlargement in men can also be caused by fat being built up behind and around the areola and this is called pseudogynecomastia. Now this being said, the very strict classification of breast enlargement in men into gynecomastia and pseudogynecomastia is mainly for the purpose of clarity. In most cases except in body builders and those who are very lean, there will be some fat as well along with excess breast tissue growth. Finding the cause of gynecomastia in your particular case is where the challenge lies.

Anatomy Of Gynecomastia

An illustration showing breast tissue growth as one of the causes of gynecomastia.

Causes Of Gynecomastia: The Main Culprit Is Excess Estrogen

Almost all causes of gynecomastia can be in one way or other traced back to excess production of the female hormone estrogen causing abnormal growth of breast tissue. All men have some level of the female hormone in their body and that is perfectly normal but it becomes problematic when it goes overboard. There can be different reasons but all of these reasons finally causes excess estrogen production.

causes of gynecomastia in men can be different

If we take a look at men who have gynecomastia, we can classify them broadly into men from the general population, men who take steroids without precaution, men who are under a medication regiment for an existing condition and men who are into substance abuse drugs like marijuana.  The pathway that we see from the surface can be different for each of these different sub-sects of men but, the root cause and culprit can almost always be traced back to excess estrogen.

Causes Of Gynecomastia In Teenagers

approximately 48-64% of teenagers develop some excess breast tissue in their adolescence

You did not come here to read that excess breast tissue growth among adolescents is normal, right ?. That is the truth and let me tell you why + a really good news. Breast tissue growth happens in men during three stages in the life span of an individual and they are infancy, adolescence and old age. When teenagers go through puberty and becomes sexually mature, there are a lot of hormonal changes including estrogen dominance for some time and this can cause development of breast tissue. Not all boys going through puberty will experience this but it is estimated that between 48-64% of all adolescents will have some form of breast tissue growth. This is called pubertal gynecomastia.

Now the good news is that this is quite natural and this excess breast tissue will flatten out as you enter adulthood and their will not be any abnormality for your chest in appearance or when touched. So if you are thinking about that little breast tissue you have now as a teen is an exception, know that 6 out of 10 of your peers will have the same. There is one very crucial advise that you need to take to heart if this should go away naturally. In normal circumstances, you do not need any treatment. Avoid marijuana and drugs like the plague, be active, do not put a lot of weight and you should be fine by the time you enter adulthood.

Causes Of Gynecomastia Among Male Adults

using recreation drugs like marijuana can be one of the causes of gynecomastia

We are talking about the typical male in the 21-50 age range who is medium built and is not currently on medication regiment for a major medical condition. If you can relate to being in this group and have gynecomastia, there are a few things that you need to look into. One of the causes for your gynecomastia may be because you had developed breast tissue during your teenage years (pubertal gynecomastia) and rather than it subsiding and flattening out as you entered adulthood, it might have stayed.

Another cause can be that you will be having disproportionate levels of estrogen in your body at the moment that is silently working underneath towards breast tissue growth. There are also a few genetic and medical conditions that can cause gynecomastia and you might have but you do not know. The first step for you is to see a doctor who specializes in the treatment of gynecomastia and they will do a thorough look at your hormone levels and what is the current state of hormonal balance. A detailed history taking and physical examination by a doctor specializing in gynecomastia can go a long way in determining what all can be the causes of gynecomastia in your case.

Marijuana Can Cause Gynecomastia

There used to be a time when the relationship between marijuana as one of the causes of gynecomastia was not well established but these days, physicians are starting to see a direct and definite relationship between smoking marijuana and gynecomastia. Doctors are also seeing a pattern where a majority of their patients coming in have continuously used marijuana. Smoking marijuana is also one of the reasons why gynecomastia in teenagers which must be gone as enter adulthood persists and become permanent. Elements in marijuana alters the hormonal mechanism in the body leading to estrogen conversion and gynecomastia.

How What You Eat Can Become One Of The Causes Of Gynecomastia

eating foods that are rich in estrogen can also be one of the secondary causes of gynecomastia

Unbeknownst to us until now, a number of the food items that we eat on a daily basis and see on the menu are full of estrogens and drives up the estrogen levels in the body. This is very true in the case of genetically modified meat and milk. Some food items like soy and tofu are also rich in estrogen. However, having these food items once in a while will not cause gynecomastia. But that being said, if you already have high levels of estrogen in your body, having these foods act like a double whammy and aid other causes of gynecomastia.

List Of Food Items That Contain Estrogen

No: Description
1 Dried fruits
2 Flax seed
3 Peas
4 Beans
5 Peas
6 Sesame seeds
7 Chickpeas
8 Bran cereals
9 Soybean
10 Tempeh
11 Tofu
12 Alfalfa sprouts

Medical Conditions That Can Cause Gynecomastia

pre-existing medical conditions can also be one of the causes of gynecomastia

In some men, the causes of gynecomastia can be one of the many medical conditions contributes to breast tissue growth. Medication or a combination of medications that they have been following can also be causing breast tissue growth. From time to time, researchers are also finding out about new medications that have the potential to cause gynecomastia as evident from the recent controversy and lawsuit around the drug Risperdal.

Klinefelter Syndrome

One of the classic examples of a medical condition that can cause gynecomastia is Klinefelter Syndrome. This syndrome is characterised by a chromosomal anomaly with men having an additional X chromosome. Studies have showed that men with this medical condition have gynecomastia as a common symptom.


The thyroid gland is responsible for the production of thyroid hormones and hyperthyroidism occurs when this gland becomes over-active. Hyperthyroidism is gender neutral and can happen to both men and women but in men, it is considered as one of the causes of gynecomastia. Early recognition of this condition and timely intervention have been found to successfully reverse gynecomastia.

Kidney Failure

Kidney failure is one of the medical conditions that can cause gynecomastia. When our kidneys are unable to do their normal filtering process, it triggers a series of bodily reactions and hormonal dysfunction is one of them. The end result is a suppression of the production of Testosterone. In this scenario, estrogen levels tip the hormonal balance causing gynecomastia.


Malnutrition is one of the often misunderstood and underrated medical conditions that can cause gynecomastia. When our body is devoid of the amount of nutrition that it requires, it reduces the production of testosterone but at the same time, there is no change in the level of estrogen. In this way, malnutrition becomes one of the causes of gynecomastia.

Medications That  Could Cause Gynecomastia

an image showing that some medication can also cause gynecomastia

Known or unknown medications can be one of the causes of gynecomastia and this is why a detailed history collection by your doctor specializing in the treatment of gynecomastia is important. There is a real dearth of knowledge among the common folks about the side effects of medication. The most common categories of medications that can cause gynecomastia includes anti-retrovirals, medication regiments that are part of prostate cancer therapies and anti-psychotics. The following list of medication that could cause gynecomastia has been compiled by Gretchen Dickson, MD and published at the Association of American Family Physician website.


No: Description Of Medication
1 Alkylating agents
2 Bicalutamide (Casodex)
3 Cimetidine (Tagamet)
4 Cisplatin
5 Flutamide
6 Isoniazid
7 Ketoconazole
8 Methotrexate
9 Metronidazole (Flagyl)
10 Omeprazole (Prilosec)
11 Penicillamine (Cuprimine)
12 Ranitidine (Zantac)
13 Spironolactone (Aldactone)
14 Anabolic steroids
15 Diazepam (Valium)
16 Digoxin
17 Estrogen agonists
18 Gonadotropin-releasing hormone agonists
19 Human chorionic gonadotropins
20 Phenytoin (Dilantin)
21 Phytoestrogens
22 Diazepam
23 Phenytoin
24 Haloperidol
25 Metoclopramide (Reglan)
26 Phenothiazines
No Medications Whose Mechanism Of Action Causing Gynecomastia Is Unknown 
1 Amiodarone
2 Amlodipine (Norvasc)
3 Angiotensin-converting enzyme inhibitors
4 Antiretroviral agents
5 Atorvastatin (Lipitor)
6 Didanosine (Videx)
7 Diltiazem
8 Etomidate (Amidate)
9 Fenofibrate (Tricor)
10 Finasteride
11 Fluoxetine (Prozac)
12 Heroin
13 Methadone
14 Methyldopa
15 Minocycline (Minocin)
16 Minoxidil
17 Mirtazapine (Remeron)
18 Nifedipine (Procardia)
19 Nilutamide (Nilandron)
20 Paroxetine (Paxil)
21 Reserpine
22 Risperidone (Risperdal)
23 Rosuvastatin (Crestor)
24 Sulindac (Clinoril)
25 Theophylline
26 Tricyclic antidepressants
27 Venlafaxine (Effexor)
28 Verapamil

Causes Of Gynecomastia In Steroid Users

steroid use without properly flushing it out is also one of the causes of gynecomastia

Steroid users are one of the sub groups among men who have gynecomastia. I want to make it clear that the use of steroid in itself is not one of the causes of gynecomastia rather, the un-systematic use of it is what causes gynecomastia. If you scout the various body-building forums online, you can thread after thread of horror stories by steroid users who have developed gynecomastia. They cycle on with anabolic steroids for continuous periods of time and does not cycle of periodically and flush out the excess estrogens through post cycle therapy. Some steroid users does not cycle off at all, inviting breast tissue growth. Users of anabolic steroid users must take precautions to control the excess estrogen, cycle off and flush out excess estrogens to prevent water retention, gynecomastia and a whole lot of other issues.

How Does Gynecomastia Occur In Steroid Users

an illustration showing a steroid user with gynecomastia

When a steroid user starts his cycle, the natural hormonal balance in his body is altered by suppression of the production of the male hormone testosterone. So the testosterone (male hormone) estrogen (female hormone) balance is tilted and estrogen dominance happens in the body. This triggers a series of chain reaction culminating in the development of gynecomastia. If you are taking anabolic steroids, you should use Omega-3 fatty acids, circumin, digestive enzymes, vitamin C as well as liver protection supplements to reverse the side effects followed by post cycle therapy to restart testosterone production to optimum levels and to keep the gained muscles. Not providing your body with necessary supplements during cycling and not executing a well balanced PCT are the major causes of gynecomastia among body builders. If you want to learn more, read the post cycle therapy to prevent gynecomastia page.

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Still Couldn’t Find The Information ?

If you still have more questions than answers or if the information above did not include your specific question, there are a few more places on this websites you can look for that. We have THE most comprehensive knowledge-base about gynecomastia, pseudogynecomastia and breast enlargement in men in general. Take a look at our knowledge-base and if that does not provide you with the answer, head over to our community forums about gynecomastia and post your question there. Chances are most probably, your question already has been asked and answered there. You can also contact us through the below contact form and we will get back to you.

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