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Loss of Muscle Mass

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Last updated March 26, 2021

Muscle loss questionnaire

Use our free symptom checker to find out what's causing your muscle loss.

Losing muscle mass is a normal condition when getting older, however abnormal muscle loss can be caused by malnutrition, an eating disorder, or an autoimmune disease like HIV/AIDs. Muscle deterioration can also be a sign of a serious chronic disease or mental health issue. Read below for more information on causes and how to seek treatment.

Muscle loss questionnaire

Use our free symptom checker to find out what's causing your muscle loss.

Muscle loss symptom checker

Loss of muscle mass symptoms

Muscles are vital to everyday function, and if you noticeably lose muscle mass — especially without knowing why — it can be frightening. Losing some muscle mass is expected as you age. However, losing muscle mass rapidly, or atrophy, especially in the context of other symptoms, can indicate an underlying condition.

Common accompanying symptoms of loss of muscle mass

If you experience a loss of muscle mass, you may also experience:

8 causes of loss of muscle mass

Most people lose muscle mass as they age, which tends to happen slowly. Additionally, muscle mass can be lost if you switch to a more sedentary lifestyle. However, if muscle mass is rapidly lost, this can be a symptom of severe disease.

Lifestyle-related causes

Certain habits or aging can result in a loss of muscle mass.

  • Aging: Aging is characterized by replacement of some muscle mass with fatty tissue.
  • Sedentary lifestyle: "Use it or lose it," as some say. Use your muscles to ensure they stay strong.
  • Exercise: Exercise may lead to the strengthening of certain muscle groups at the expense of others. Running a marathon, for instance, may lead to some muscle breakdown in the unused muscles, even as the legs become stronger.

Systemic causes

Systemic causes of a loss of muscle mass are related to disease or illness.

  • Cancer: Advanced cancers use a lot of energy and may break down muscle as a source of body fuel. Also called cancer wasting or cancer cachexia, this is characterized by a progressive loss of not only muscle but also body fat and overall weight. This phenomenon accounts for 20-30% of cancer deaths.
  • Chronic disease: Advanced diseases of the lungs, heart, or kidneys can lead to loss of muscle mass.
  • Neurologic deficits: Altered cognition and movement difficulties associated with the neurologic disease can lead to malnutrition and weight loss.
  • Medication side effects: Some medications may cause loss of muscle mass.
  • Genetic: Rare genetic diseases can result in loss of muscle mass.

Metabolic causes

A loss of muscle mass related to metabolic processes include the following.

  • Malnutrition: Extremely poor diet can lead to loss of muscle mass as your body breaks down the muscles for energy.
  • Endocrine disease: Imbalance of various hormones caused by damage to hormone-producing glands can lead to unintentional weight loss. Examples include diabetes or an over-active thyroid (hyperthyroidism).

Inflammatory causes

Inflammatory causes of a loss of muscle mass include the following.

  • Autoimmune disease: Autoimmune disease, when your immune system becomes confused and attacks your own tissues, can lead to weight loss due to the associated high energy use.
  • Infectious disease: Chronic infection can cause weight loss and loss of muscle mass as your body breaks down tissues for energy.

Muscle loss questionnaire

Use our free symptom checker to find out what's causing your muscle loss.

Muscle loss symptom checker

Gastrointestinal causes

Gastrointestinal causes of a loss of muscle mass may include the following.

  • Malabsorption: Some diseases of your gastrointestinal tract make it less efficient at absorbing nutrients, leading to loss of muscle mass.
  • Inflammatory: Inflammation of your stomach or intestines can cause poor nutrient uptake.

Psychiatric causes

Psychiatric causes relate to your feelings, emotions, behaviors, and cognitive processes.

  • Mood disorder: Certain mood disorders, especially depression, can lead to a loss of appetite.
  • Eating disorder: People may lose muscle mass if they have an eating disorder that alters their nutritional intake.
  • Drug use: Overuse of certain substances can lead to weight loss and loss of muscle mass. Examples include methamphetamines ("meth").

This list does not constitute medical advice and may not accurately represent what you have.

Brachial plexopathy (shoulder nerve issue)

The brachial plexus is a web of nerves between the neck and shoulder, connecting the spinal cord nerves to the arm. There is one web on each side of the neck. Any injury that forces the shoulder to stretch down, and the neck to stretch up and away, can damage these nerves and cause brachial plexopathy.

Sports injuries and car accidents are often involved. Inflammation, tumors, and radiation treatment can also damage the brachial plexus.

Milder symptoms include numbness and weakness in the arm, with a shocklike stinging or burning sensation. A more severe injury can cause paralysis and loss of feeling in the arm, with pain in some parts of the arm, hand, and shoulder.

These symptoms should be seen by a medical provider since permanent damage can result if the injuries are not treated.

Diagnosis is made through electromyography (EMG) testing, CT scan, MRI, and sometimes angiogram.

Treatment usually involves rest and physical therapy. Surgery may be necessary to remove scar tissue or repair the damaged nerves.

Rarity: Uncommon

Top Symptoms: pain in one arm, shoulder pain that shoots to the arm, arm weakness, numbness in one arm, shoulder pain

Symptoms that never occur with brachial plexopathy (shoulder nerve issue): pain in the front middle part of the neck

Urgency: Primary care doctor

Cushing syndrome

Cushing Syndrome is a hormonal disorder. The cause is long-term exposure to too much cortisol, a hormone that the adrenal gland makes. Sometimes, taking synthetic hormone medicine like corticosteroids to treat an inflammatory disease leads to Cushing's syndrome.

Rarity: Rare

Top Symptoms: fatigue, headache, depressed mood, weight gain, back pain

Urgency: Primary care doctor


HIV (human immunodeficiency virus) refers to a virus that kills or damages the body's immune system cells and spreads through unprotected sex with an infected person, sharing drug needles or through contact with the blood of an infected person. AIDS (acquired immunodeficiency syndrome) occurs when the body's immune system has become very weak and has a difficult time fighting off other infections.

Rarity: Rare

Top Symptoms: fatigue, headache, cough, fever, distal numbness

Urgency: Primary care doctor

Idiopathic inflammatory myopathy

Idiopathic inflammatory myopathy refers to a closely related group of conditions that cause inflammation of muscle tissue.

Rarity: Ultra rare

Top Symptoms: fatigue, muscle aches, fever, rash, unintentional weight loss

Urgency: Primary care doctor


Anorexia nervosa is a type of eating disorder. Anorexia usually affects adolescents or adults. While weight loss is the primary feature of anorexia, this condition can affect many organ systems throughout the body

Amyotrophic lateral sclerosis (als)

Amyotrophic lateral sclerosis is also called ALS or Lou Gehrig's Disease named after the Hall of Fame baseball player whose career ended when he developed ALS. It is a degenerative disease that destroys nerve cells, which eventually ..

Mitochondrial myopathy

Mitochondrial myopathies are a set of disorders involving abnormalities in mitochondria, which are structures within cells that are responsible for using oxygen to produce energy — often described as the powerhouses of the cells. Therefore, mitochondrial myopathies most ..

Overactive thyroid

The thyroid is a small, bow-tie shaped gland in your neck. Its main job is to produce thyroid hormone (known as T3 or T4), which serves a wide array of functions throughout the body.

When too much thyroid hormone is released, the body’s metabolism gets ramped up, causing symptoms ..

Muscle loss questionnaire

Use our free symptom checker to find out what's causing your muscle loss.

Muscle loss symptom checker

Loss of muscle mass treatments and relief

Most of the time, when people lose muscle mass, it is due to a change to a more sedentary lifestyle or aging. Loss of muscle mass or significant weight loss in other contexts, however, can indicate a condition that merits full medical evaluation. Unfortunately, in this case, muscle loss is harder to combat. If you have rapidly and unintentionally lost weight and muscle mass, see a physician.

At-home treatments

You can try the following treatments at home to address your symptoms.

  • Exercise: The most effective way to build your muscles is to use them. Go on a run, hit up the gym, or be more active around your home.
  • Diet alteration: You can lose muscle mass if you don't eat enough, as your body will break down muscle for energy.

When to see a doctor

If at-home treatments are not enough, you can consult your physician about the following. Once you learn more about the cause of your loss of muscle mass, you can determine the best treatment plan together.

  • Blood and urine testing: Lab tests can check your nutrition and other metrics.
  • Imaging: X-rays or other imaging can figure out the cause of your loss of muscle mass symptoms.
  • Muscle testing: Strength and testing of the nerves feeding muscles can help with diagnosis.
  • Physical or occupational therapy: In some cases, therapies can help build strength or function.
  • Medication: Some medical conditions that cause muscle loss require medication.
  • Surgery: Rarely, loss of muscle mass may be caused by a disease requiring an operation.

When it is an emergency

You should seek help without delay if you have:

  • Fever, chills, or signs of infection
  • Difficulty breathing
  • Any new bumps or masses
  • Sudden-onset confusion
  • Frequent falls or imbalance


Preventing a loss of muscle mass can be achieved by exercising regularly (such as strength training) in conjunction with a balanced diet of lean meats and proteins, fruits and vegetables, healthy fats, and whole grains. Of course, if this loss is due to an underlying illness, this must also be addressed and mindfully managed.

Questions your doctor may ask about loss of muscle mass

  • Have you ever been diagnosed with diabetes?
  • Did you just suffer from a high impact injury (e.g., a fall, collision, accident or sports trauma)?
  • Did your symptoms start after getting sick?
  • Have you ever been diagnosed with cancer?

Self-diagnose with our free Buoy Assistant if you answer yes on any of these questions.

Share your story
Dr. Rothschild has been a faculty member at Brigham and Women’s Hospital where he is an Associate Professor of Medicine at Harvard Medical School. He currently practices as a hospitalist at Newton Wellesley Hospital. In 1978, Dr. Rothschild received his MD at the Medical College of Wisconsin and trained in internal medicine followed by a fellowship in critical care medicine. He also received an MP...
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