Thyroid Function
How well your thyroid gland produces metabolism-regulating hormones — an underactive thyroid can cause weight gain.
Plain English
Patient-Friendly Explanation
Your thyroid is a small butterfly-shaped gland in your neck that produces hormones controlling how fast your body burns energy — your metabolism. When the thyroid is underactive (hypothyroidism), your metabolism slows down, which can lead to weight gain, fatigue, and difficulty losing weight. A simple blood test can check if your thyroid is working properly.
Medical
Clinical Definition
Thyroid function refers to the hypothalamic-pituitary-thyroid axis regulating circulating levels of thyroxine (T4) and triiodothyronine (T3), the primary hormones governing basal metabolic rate, thermogenesis, and macronutrient metabolism. Primary hypothyroidism (elevated TSH, low free T4) affects approximately 4.6% of the population and reduces resting energy expenditure by 15–30%. Even subclinical hypothyroidism (TSH 4.5–10 mIU/L with normal free T4) is associated with modest weight gain and reduced efficacy of weight-loss interventions.
Key Insight
Why It Matters
Unexplained weight gain or difficulty losing weight despite diet and exercise may signal an underlying thyroid disorder. At Accord Medical, Dr Joseph Wang routinely evaluates thyroid function as part of a thorough weight management workup, ensuring hormonal causes are identified and treated appropriately.
Sources
Reviewed against standard medical references.
Medically reviewed by
Family Physician & Registered Acupuncturist, Accord Medical Clinic. MBBS (NUS), Graduate Diploma in Family Medicine (NUS), Graduate Diploma in Acupuncture (Singapore College of TCM).
Last reviewed: August 2026
This page is general health education, not medical advice. Whether any treatment is appropriate for you is a decision made in consultation after assessment.