I'm Thin: Could I Still Be Hypothyroid?

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Many people are aware that weight gain, or difficulty losing weight, can be symptoms of hypothyroidism. This leads to some people— including doctors—assuming that being slender or at a normal weight means that someone can't be hypothyroid.

This situation can even be an obstacle to getting diagnosed. The typical story? A woman has many symptoms of an underactive thyroid, but there's one major exception: she's slender and hasn't gained a pound.

In some cases, she may have even lost weight. Yet, she has other symptoms that point to an underactive thyroid. But she questions her own judgment, thinking that weight gain must be present with hypothyroidism, and assumes that her symptoms are caused by something else other than a thyroid problem. She may not even pursue an evaluation and diagnosis with her doctor. 

Or, a thin woman pursues evaluation and treatment, and the doctor becomes the obstacle. The doctor doesn't suspect thyroid problems, or when the issue is rasied, dismisses concerns with some variation of: "Well, if you had an underactive thyroid, you'd be overweight, so I see no point in testing you." 

Weight gain is a common symptom of an underactive thyroid, one frequently covered here at Verywell. There is an important fact to keep in mind, however. Weight gain—or an inability to lose weight—is not a symptom in everyone with hypothyroidism.

A subset of patients don't gain any weight when they hypothyroid and haven't been treated with medication. There are even some people who paradoxically lose weight when they are hypothyroid.

If You're Thin, Can You Still Be Hypothyroid?

As noted, while weight gain, or the inability to lose weight despite diet and exercise, are frequent complaints of people with undiagnosed or improperly treated hypothyroidism, there is a subset of patients with an underactive thyroid who do not gain weight.

These thyroid sufferers may have a number of other common but debilitating hypothyroidism symptoms, including the following:

  • fatigue and exhaustion
  • feeling run down and sluggish
  • depression, moodiness
  • anxiety, inability to cope with stress
  • difficulty concentrating, memory issues, brain fog
  • dry, coarse and/or itchy skin
  • dry, coarse and/or thinning hair
  • loss of hair from the head or body
  • loss of hair from in the outer edge of eyebrows
  • feeling cold, especially in the extremities
  • constipation
  • muscle cramps, aches/pain
  • menstrual problems, including increased menstrual flow, and more frequent periods
  • infertility/miscarriage
  • low blood pressure
  • frequent infections
  • bloating/puffiness/swelling in hands, feet, eye area, face
  • carpal tunnel syndrome / tarsal tunnel syndrome
  • foot and heel pain

You are also more likely to have a thyroid condition if you have a personal or family history of thyroid issues, or autoimmune disease. 

Other Clinical Signs

Weight gain, or an inability to lose weight, is just one of the possible clinical signs of hypothyroidism. But even in the absence of this common symptom, there are other clinical signs your doctor may be able to observe in an examination. These include: 

  • Slowed reflexes
  • Slow heart rate
  • Unusually low blood pressure
  • Puffiness around eyes, and in hands and feet
  • Loss of hair from the outer edge of the eyebrows
  • Neck enlargement
  • The sound of blood flow in the thyroid, known as bruit

In addition to evaluating you for these measurable and observable clinical signs, your doctor should also run, at minimum, a thyroid stimulating hormone (TSH) test, as well as free T4 and free T3 tests, to evaluate thyroid function and aide in a diagnosis of hypothyroidism. 

A Word from Verywell 

What is the key message you should take away? Being slender, and even losing weight does not mean that you aren't hypothyroid.

 

If you don't have a weight problem, but do have signs and symptoms of hypothyroidism, see your physician for a complete evaluation of your thyroid. That should include a clinical exam, medical history, and blood tests to evaluate your thyroid function. 

If your doctor refuses to consider the possibility that your thyroid is underactive or conduct testing for hypothyroidism because you are slender, what is your next step? Find a new doctor who will consider the full range of symptoms, and conduct the clinical exam and order the tests needed to determine whether you do have a thyroid problem.

Sources:

​Bahn, R., Burch, H, Cooper, D, et al. Hyperthyroidism and Other Causes of Thyrotoxicosis: Management Guidelines of the American Thyroid Association and American Association of Clinical Endocrinologists. Endocrine Practice. Vol 17 No. 3 May/June 2011.

Braverman, L, Cooper D. Werner & Ingbar's The Thyroid, 10th Edition. WLL/Wolters Kluwer; 2012.

Garber, J, Cobin, R, Gharib, H, et. al.  "Clinical Practice Guidelines for Hypothyroidism in Adults: Cosponsored by the American Association of Clinical Endocrinologists and the American Thyroid Association." Endocrine Practice. Vol 18 No. 6 November/December 2012.

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