Man boobs, 'moobs' or enlarged male mammary glands

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The medical term for 'man boobs' is gynecomastia which comes from the Greek meaning 'woman' + 'breasts'.

Although the cause is often deemed idiopathic (meaning it's not known), the majority of cases are caused by an imbalance of sex hormones. About 25% of cases fall into the idiopathic category.

The physical manifestation is breast enlargement, it normally occurs in both breasts but can sometimes be in one only, known as asymmetrical or unilateral gynecosmastia. Occasionally a secretion of milk can be present too. Man boobs can affect up to 60% of men, including infants and adolescents.

The breast can increase in size due to stimulation of the breast tissue and an increase in adipose (fat) cells. Man boobs can be tender or painful, the medical term is mastodynia, mastalgia or mammalgia.

The following is a list of terms in use denoting different aspects of gynecosmastia or man boobs:

  • Infants Over 50% of male infants are born with enlarged breasts, which normally resolves about three weeks from birth. When pregnant the mother's oestrogen and progesterone levels increase considerably. If an excess of oestrogen is present this affects the male infants. Oral contraceptives taken by a breast feeding mother can cause gynecomastia.
  • Adolescent Studies have found gynecomastia varies from as low as 4% to over 60% in boys. The enlarged breasts are due to the fluctuating levels of oestrogen and testosterone in puberty. 90% resolve within three years if the cause is an hormonal imbalance.
  • Adult This occurs chiefly between the ages of fifty to eighty years, with at least 25% of men affected. Dropping testosterone levels, and rising oestrogen levels, are a significant factor.
  • Puffy Nipples The enlargement is confined to the area under the areola. It is more common in adolescents and many have self esteem issues and depression because of their appearance.
  • Bodybuilders The use of anabolic steroids causes stimulation of the breast tissue, and can lead to man boobs.
  • Pseudogynecomastia This is a term some use for a fatty male breast. It's a poor term, as oestrogen stimulates mitosis in any hormonally sensitive tissue, including adipose cells. Mitosis causes cells to divide and multiply.
  • Obesity and over weight Man boobs are often present in overweight individuals. Oestrogen stimulates mitosis in adipose cells, these cells also produce oestrogen, so a vicious cycle ensues. Farmers take advantage of this fact by giving oestrogen to their livestock. Eat only organic meat, chicken and eggs.

Causes of man boobs

  • Oestrogen This female sex hormone is mitogenic, meaning it causes cells to divide and multiply. Man boobs result when the levels of oestrogen rise, as a consequence the ratio of testosterone to oestrogen becomes unbalanced. Oestrogen and testosterone cause the secondary sexual characteristics to develop at puberty. Both sexes make both hormones, men making principally testosterone, women oestrogen. Testosterone causes muscle mass to increase, deepening of the voice and body hair to grow in men. Oestrogen stimulates the breasts and ovaries to develop and the fatty layer covering humans to thicken in women, emphasizing the hips. An excess of oestrogen will increase these feminizing traits in men. Excess oestrogen can arise from numerous causes: pesticides and industrial chemicals which mimic the action of oestrogen, also called xeno-oestrogens, are now found in food, water, air and skin care products, particularly sunscreens. Other causes of excess oestrogen are drugs, tumours, malnutrition and foods containing phytosterols like soy which have an oestrogenic affect.
  • Androgen antagonists or antiandrogens can cause man boobs, i.e., the drugs spironolactone, finasteride, flutamide and cyproterone. These drugs are given to suppress testosterone in prostate cancer, BHP etc. But by suppressing testosterone, oestrogen begins to rise.
  • HIV medications, in particular efavirenz, used in HAART treatment
  • Anti-anxiety drugs eg. valium
  • Antidepressants particularly the older tricyclic antidepressants
  • Corticosteroids
  • Cimetidine an ulcer medication which enhances oestrogen activity
  • Chemotherapy
  • Heart medications
  • Alcohol
  • Amphetamines
  • Marijuana
  • Heroin
  • Antipsychotics These are known to cause high levels of prolactin (hyperprolactinemia), leading to a milky discharge (galactorrhoea). Risperidone increases prolactin to a greater extent than other atypical antipsychotics. High prolactin levels can be caused by factors other than antipsychotic drugs. A lack of protein in the diet, leading to a deficiency in the amino acid tyrosine can cause it. Tyrosine is the precursor to dopamine, a drop in dopamine levels stimulates prolactin release. Dopamine is the neurotransmitter responsible for sexual arousal, prolactin counters the effect of dopamine. Hyperprolactinemia is thought to be a cause of impotence and loss of libido. In a pregnant woman, high levels of progesterone prevent the release of prolactin, the same would apply in men using supplemental progesterone. The drop in progesterone levels at childbirth signals the release of prolactin. It's at this point the foetus can absorb prolactin from the mother, leading to both male and female babies sometimes secreting milk from their nipples. Commonly known as Witch's milk, this affect is generally short lived. Stress can drop dopamine levels thereby increasing prolactin levels. Tyrosine is not only the precursor to dopamine, but to the stress hormones adrenaline and noradrenaline which are released when stressed. Supplemental tyrosine affectively counters the release of prolactin, increases dopamine levels and by the same token increases libido if the drop is caused by excess prolactin. Progesterone also causes an increase in dopamine by suppressing prolactin. Progesterone is a mono amine oxidase inhibitor. Mono amine oxidase is an enzyme that breaks down dopamine and serotonin to name two. Due to this action progesterone is helpful in depression. Oestrogen causes prolactin to rise by suppressing progesterone.

See under 'More Information' below for further drugs that can cause man boobs.

Other causes of man boobs...

  • Tumours in the pituitary, adrenals and testes
  • Hypogonadism, which results in low levels of testosterone
  • Excess thyroxine caused by an over active thyroid
  • Kidney failure which affects the testicles
  • Androgen resistance syndrome where cells fail to respond to androgens in the blood stream
  • Chronic liver disease, liver failure, and cirrhosis
  • Adrenal malfunction
  • Malnutrition, including feeding after malnutrition, which increases substances for aromatase production
  • Herbs containing phytosterols, which bind to oestrogen receptors
  • Foods containing phytosterols, particularly soy, have oestrogenic affects. Soy reduces the sperm count in men, avoid eating it
  • Congenital testicular regression, where the testes regress back to a less developed state
  • Herpes zoster
  • Cystic fibrosis
  • Myotonic dystrophy
  • Mental stress
  • Spinal cord injury
  • Leukaemia
  • Hemophilia
  • Leprosy
  • Genetic disorders such as Klinefelter's syndrome and Gilbert's syndrome

Treatment of man boobs


If all other factors which cause man boobs, as outlined above, have been eliminated, in all probability it's been caused by excess oestrogen.

The safest route is to suppress this is with progesterone.

Progesterone is not a sex hormone, it plays no part in the secondary sexual characteristics which develop at puberty. It is secreted primarily by the testes in men and the ovaries in females. Smaller amounts are produced by the adrenal glands, the brain and glial cells.

There are no great quantitative differences between men and women (at least outside the woman's luteal phase).

Progesterone is the precursor to the sex hormones oestrogen and testosterone, and to cortisol and aldosterone.

Progesterone has several other advantages:

  • unlike oestrogen which can exacerbate brain injury, especially in animal models of ischaemic stroke, progesterone can be given to both males and females without affecting gender and sexual functions
  • it's use in TBI (via IV transfusion) yielded extremely promising results and found no adverse events attributable to progesterone
  • inhibits the mitogenic action of oestrogen
  • protects against breast cancer which is increasing in men
  • helps correct the hormonal imbalance commonly found in men with erectile dysfunction as it increases the production of nitric oxide. In much the same way as Viagra does, but with no adverse side affects
  • as an anti-inflammatory agent, progesterone has been shown to reduce the response of natural killer cells as well as other known initiators of inflammation. Hence it's benefit for mastalgia (breast pain/inflammation)
  • influences spermiogenesis, sperm capacitation/acrosome reaction and testosterone biosynthesis in the Leydig cells in men
  • is used in the treatment of benign prostate hyperplasia (BPH) in men via a transscrotal delivery system
  • is used to lower dihydrotestosterone levels in men. The progesterone metabolite 17-0H-progesterone was found to have the highest inhibitory effect on the enzyme 5-alpha reductase which converts testosterone into DHT
  • is rapidly absorbed transdermally and its patterns of distribution and metabolism are comparable to those previously reported for intravascularly administered progesterone
  • the progesterone metabolite allopregnanolone reduces the brain's response to stress
  • progesterone regulates the secretion of catecholamines during stress
  • prevents lipid peroxidation
  • acutely inhibits cholesteryl ester formation which is associated with atherosclerosis
  • confers coronary vascular protection
  • improves sleep
  • promotes regeneration and myelination of axons
  • enhances remyelination in degenerative disorders
  • has a neuroprotective and antioxidant effect in an injured nervous system
  • has multiple effects on glial cells, it influences growth, differentiation and increases the expression of myelin-specific proteins in oligodendrocytes, and potentiates the formation of new myelin sheaths by Schwann cells in vivo
  • it reduces programmed cell death and the synthesis of inflammatory factors that can kill neurons hours to days after traumatic brain injury
  • systemic injections of the neurosteroid progesterone given after traumatic brain injury (TBI) have been shown to improve cognitive, sensory and motor recovery, enhancing both short and long term recovery
  • readily crosses the blood brain barrier (BBB) reducing oedema to barely measurable levels in TBI
  • reduces lipid peroxidation and the generation of isoprostanes, which contribute to post-injury ischaemic conditions
  • produces metabolites which decrease pro-apoptotic and increases anti-apoptotic enzymes (in TBI)
  • reduces the expression of pro-inflammatory genes and their protein products (in TBI)
  • reduces the area of necrotic cell death and improves behavioural outcomes (in TBI)
  • protects neurons distal to the site of injury which would normally die after TBI
  • produces significant sparing of cognitive, sensory and spatial learning performance after bilateral brain injury

There are several routes used to deliver progesterone, injections, suppositories, IV transfusion (for brain trauma), transdermal creams, buccal drops and oral pills. It is rapidly absorbed transdermally and its patterns of distribution and metabolism are comparable to those previously reported for intravascularly administered progesterone. For this reason alone it is preferable to the other routes. Another advantage is that it can be applied anywhere. Although progesterone is circulated rapidly throughout the body, applying it to the afflicted part brings quicker relief.

Between 10-100mg per day progesterone should be used, dependant on symptoms. Rubbing it directly on the breast/s is more effective. For more information see How to use progesterone cream.

Before using progesterone it's essential to read the page on Oestrogen Dominance first.


Oestrogen suppressing drugs are commonly used to treat man boobs. Tamoxifen, clomiphene, androgens (testosterone) and aromatase inhibitors such as letrozole and anastrozole. The enzyme aromatase converts androgens into oestrogen, which then bind to the oestrogen receptor, causing the cells to divide. Although officially these drugs are used for women, off-label prescribing is increasing in men with excess oestrogen (particularly oestradiol, the most active oestrogen). Some men who use steroids for increased performance or body building, take aromatase inhibitors to prevent symptoms of excess oestrogen, eg. man boobs, BHP, water retention and hypogonadism.


An alternative to drugs is surgery, either removing the gland or liposuction. Medical insurance companies often regard surgery for male breast removal as cosmetic, so don't cover it. Male breast reduction surgery is the fastest growing procedure in plastic surgery in England. The British Association of Plastic Surgeons reported 581 men with man boobs had breast reductions in 2009, an increase of 80% over the previous year. The American Society of Plastic Surgeons estimate 18,000 men in the States had the surgery in 2008. It is in the top five cosmetic surgery procedures performed on males. Of these men, 14,203 were between the ages of thirteen to nineteen, a 79% increase in adolescent surgery since 2003.

Risks for the surgical removal of man boobs...

  • Scarring
  • Bleeding
  • Clots
  • Infection
  • Poor wound healing
  • Nipple of breast sensation changes may be temporary or permanent
  • Liposuction could result in unevenness, loose skin, fluid loss or accumulation
  • Discolouration of skin and pigmentation changes
  • Swelling
  • Bruising
  • Deeper damage can occur to nerves, blood vessels muscles and lungs
  • Asymmetrical breasts
  • Necrosis (death) of fatty tissue might occur
  • Complications can occur such DVT, cardiac and pulmonary problems
  • Persistent pain
  • A further operation might be necessary

Diet and man boobs

All meat and vegetables should be organic. The diet should contain no oxidised and refined oils and fats, but be high in the essential fatty acids (EFA's) found in oily fish, omega 3 fish oils and flax. Omega 3 found in oily fish is so vital to health no one should be without it. It is an essential fatty acid, which means we cannot make it so we have to obtain it from food, unfortunately the diet we eat has virtually none left, due to the processing and refining of foods. Include fibre, in particular that found in green leafy vegetables. Additional soluble fibre can be added, as in ground flax seeds, pectin, guar gum, xanthum gum and psyllium.

The following herbs and spices help the liver to detox the body or have anti-cancer properties: milk thistle, turmeric, cayenne pepper, ginger, astragalus, echinacea, sutherlandia, green tea and olive leaf extract. Calcium D-glucarate has been shown to inhibit beta glucuronidase, which prevents glucuronidation. Glucuronidation is responsible for removing excess levels of oestradiol and testosterone.

As a substitute for sugar use xylitol, erythritol or stevia. Stevia is a natural extract from the plant Stevia rebaudiana, a member of the daisy family, native to Paraguay. The extract is 200-300 times sweeter than sugar, but has none of the drawbacks and does not affect blood sugar in any way. The fresh or dried leaves are easier to use and taste better. Xylitol and erythritol are sugar alcohols, which look and taste like sugar, but are metabolized by the body at a much slower rate, they have respectively 2.4 and 0.0 calories per gram. They cannot be used by oral bacteria, so do not contribute to tooth decay. A drawback is their high cost. If used in large quantities xylitol can cause flatulence and have a laxative affect, unlike erythritol which is absorbed into the blood stream before reaching the large intestine.

Drink only filtered water. As water is now contaminated with oestrogen from HRT and The Pill, plus the oestrogen mimics generated by industry, men and women are increasingly subject to an excess, and with this comes an increase in the oestrogen related cancers, breast, prostate, testicular, ovarian and cervical and of course an increased incidence of man boobs.

The following are some eating plans recommended when reducing the effects of man boobs:


Along with a good diet, exercise too is always beneficial in establishing, maintaining and enhancing body fitness and well-being.

More information on man boobs...

Mayo Clinic

American Society of Plastic Surgeons

List of drugs that can cause man boobs


A Board Certified Plastic Surgeon

Our Stolen Future - Endocrine disruptors

Sunscreen dangers

EWG - Skin care


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