I'm Thin: Could I Still Be Hypothyroid?

slender woman with a thyroid condition

I occasionally hear from a reader wondering if she could be hypothyroid, but she's running into an obstacle to getting properly diagnosed and treated. The typical story? She 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 frequently assuming 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. 

In some cases, a thin woman with no weight issues pursues evaluation and treatment, and a doctor becomes the obstacle. A few women have told me that they had risk factors and symptoms of thyroid disease, and went to see a doctor to have them evaluated. They got nowhere. The doctor dismissed the issue, without testing or further evaluation. The reason? The patient was thin. Doctors dismissed their concerns about thyroid disease 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 I frequently cover here at the Verywell site, and in my advocacy work and books.

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 hypothyroid, and some people even lose weight after treatment.

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, exhaustion
  • feeling run down and sluggish
  • depression, moodiness
  • difficulty concentrating, 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 in hands, feet, eye area, face
  • carpal tunnel syndrome / tarsal tunnel syndrome
  • foot and heel pain

The Takeaway Message

The key message you should take away? Being slender, and even losing weight does not exclude you from having an underactive thyroid.

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 evaluate you for hypothyroidism only 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.

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