Which Department

Which department should I see for sudden weight gain or loss?

2026-09-17 · Neutral information that names no hospital, doctor or region. No rankings, recommendations or reviews.

Short answer

Family Medicine(가정의학과) is generally the first department to see for sudden or unexplained changes in weight, as it can assess overall health and coordinate referrals. Depending on the suspected underlying cause, you may be referred to Endocrinology(내분비내과), Internal Medicine(내과), or another specialty for further evaluation.

Which department

  1. 1Family Medicine (가정의학과)
    Family Medicine physicians take a broad view of the whole body and are well-positioned to evaluate unexplained weight changes by considering multiple possible causes — including metabolic, hormonal, digestive, and lifestyle factors — in one visit. — First / second line: Starting at a Family Medicine clinic (의원) is generally the most practical first step; the physician can order initial assessments and, if needed, issue a referral to a specialist or a higher-level facility.
  2. 2Endocrinology (내분비내과)
    Endocrinologists specialize in hormonal and metabolic conditions — such as thyroid disorders, diabetes, and adrenal issues — which are among the common medical reasons for significant weight changes. — First / second line: A visit to Endocrinology is typically arranged after a primary care or Family Medicine assessment; a referral letter (요양급여의뢰서) is generally required if you wish to be seen at a university hospital (상급종합병원).
  3. 3Internal Medicine (내과)
    General Internal Medicine covers a wide range of organ systems and can evaluate weight changes that may relate to digestive, cardiac, renal, or other internal conditions, particularly when multiple systems need to be considered. — First / second line: You may go directly to an Internal Medicine clinic as a first step, or be referred there from Family Medicine if a specific internal organ system becomes the focus of concern.
  4. 4Psychiatry / Psychosomatic Medicine (정신건강의학과)
    Weight changes are sometimes associated with mental health conditions such as depression, anxiety, or eating disorders, which fall within the scope of this department. — First / second line: Referral to this department usually follows an initial general medical evaluation; if psychological factors are suspected to be a primary contributor, a Family Medicine physician may suggest this pathway.

Go to the ER / call 119 if

If any of the following applies, do not choose a department — go to an emergency room or call 119 (Korea's emergency number).

  • Sudden, severe shortness of breath accompanied by rapid weight gain (possible fluid accumulation affecting breathing) — go to the emergency room or call 119 immediately.
  • Rapid weight loss combined with altered consciousness, extreme confusion, or inability to stay awake — seek emergency care without delay.
  • Severe chest pain or palpitations occurring alongside sudden weight change — do not wait; go to the emergency room or call 119.
  • Signs suggesting a life-threatening crisis such as unresponsiveness, collapse, or seizure — call 119 immediately regardless of weight-related symptoms.

Before your visit

  • Note when the weight change started, approximately how much weight was gained or lost, and over what period of time.
  • Think about whether the change happened gradually or very suddenly, and whether there were any obvious triggers (diet change, new medication, illness, major stress).
  • Make a list of all medications, supplements, and herbal products you are currently taking, including dosages if you know them — some substances can affect weight.
  • Record any accompanying symptoms such as fatigue, hair loss, increased thirst or urination, swelling, changes in bowel habits, or mood changes.
  • Bring any previous lab results, health checkup reports, or medical records that may be relevant, especially results from the past one to two years.
  • Be ready to describe your recent eating habits, physical activity level, and sleep patterns, as these help the physician form a fuller picture.

General principles

Unexplained weight gain or loss can have a wide variety of causes ranging from hormonal and metabolic conditions to digestive issues, medication effects, and psychological factors. Because the possibilities span multiple organ systems, a generalist such as a Family Medicine physician is typically the starting point, as they can take a comprehensive history and decide which direction further evaluation should take.

In the Korean healthcare system, the general flow often begins at a local clinic (의원) for initial assessment, which may include basic blood or urine tests to screen for common causes. If the findings point toward a specific specialty — such as thyroid or adrenal issues for Endocrinology, or gut-related problems for Gastroenterology(소화기내과) — a referral to that specialty, or to a higher-level hospital if needed, typically follows.

If weight change is accompanied by other symptoms that have been present for several weeks and are not improving, it is generally advisable not to delay seeking medical evaluation, even if the situation does not feel urgent. Early assessment can help identify whether a more thorough workup is warranted and through which specialty pathway.

FAQ

Should I go to a small local clinic or a larger hospital for sudden weight changes?

In general, starting at a local Family Medicine or Internal Medicine clinic (의원) is a practical first step, as the physician can perform an initial evaluation and refer you onward if needed. Visiting a university hospital (상급종합병원) directly usually requires a referral letter from a primary care provider under the general Korean insurance system.

Could my weight change be related to my thyroid, and should I go straight to Endocrinology?

Thyroid conditions are one of several possible causes of weight change, but many other conditions can produce similar symptoms. It is generally more efficient to start with a Family Medicine physician who can assess the full picture first; they can refer you to Endocrinology if thyroid or other hormonal causes are suspected based on initial findings.

Are there specific tests commonly used to investigate unexplained weight changes?

The types of assessments a physician considers will depend on your individual history and accompanying symptoms, so it is not possible to say in advance which tests are appropriate for you. In general terms, physicians evaluating weight changes may consider blood-based screening that looks at metabolic and hormonal markers, but the specific approach is determined through a consultation.

Is the process different for children or older adults experiencing sudden weight changes?

For children, Pediatrics(소아청소년과) is generally the first point of contact, as weight changes in growing children require age-specific evaluation frameworks. For older adults, Family Medicine or Internal Medicine remains a common starting point, though physicians typically consider a broader range of contributing factors including multiple medications and age-related metabolic changes; a consultation with your doctor will guide the appropriate pathway.

Related questions

Find a clinic (external directories)

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This page is general medical information and does not replace diagnosis, treatment or choosing a clinic. Consult a doctor for any symptom. In an emergency, go to the ER or call 119 immediately.