Hypothyroidism vs Hyperthyroidism: Differences, Symptoms, TSH Levels & Treatment Explained

The thyroid is a small gland located in the neck that is responsible for producing T3 and T4 hormones, which are crucial for maintaining normal thyroid hormone levels. These hormones manage how your body manages energy. The thyroid hormone affects weight, metabolism, heart rate, mood, body temperature, and energy levels. The pituitary gland is responsible for releasing and stimulating thyroid-stimulating hormone (TSH).

The conditions of hyperthyroidism and hypothyroidism significantly affect various body functions. Hypothyroidism slows down the body processes, while hyperthyroidism speeds up. In both cases, some symptoms may appear similar, such as weight fluctuations, fatigue, and stress. Understanding the difference between the two can help you identify the warning signs and get appropriate testing and treatments done.

Studies suggest that thyroid imbalances, often related to autoimmune thyroid disease, have significantly increased in recent decades. Thyroid disorders can affect various bodily processes, causing a high risk of complications if left undetected or untreated.

T3 (Triiodothyronine) is categorized as the active form of thyroid hormone and is considered stronger than T4. It primarily manages digestion, metabolism, brain function, body temperature, and heart rate.

T4 (Thyroxine) is considered the inactive form of thyroid that is later converted into T3. It helps control metabolism and energy levels in the body by ensuring an adequate availability of thyroid hormone.

TSH (Thyroid Stimulating Hormone) is formed by the pituitary gland in the brain, and it signals the thyroid to produce T3 and T4 hormones need to be produced. High TSH suggests an underactive thyroid, while low TSH indicates an overactive thyroid.

Hypothyroidism, also called underactive thyroid, occurs when your body processes slows down because the thyroid is unable to produce sufficient amounts of T3 and T4 hormones. Typically, high TSH and low T4 indicate hypothyroidism.

• Weight gain

• Low energy and lethargy

• Slow heart rate

• Dry hair and skin

• Feeling of cold

• Constipation

• Stress or low mood

• Autoimmune harm to the thyroid (Hashimoto’s thyroiditis)

• Iodine deficiency

• Genetic factors

• Aging

• Certain medications

• Thyroid surgery

• Women are at higher risk

• People above 40 years of age

• Family history of thyroid disorders

• Autoimmune diseases such as celiac and rheumatoid arthritis

• Excess or deficiency of iodine

• Radiation treatment at the neck

• Thyroid surgery

• Pregnancy

• Obesity

• Chronic stress

• TSH levels are high in hypothyroidism

• T4 levels are low

• T3 levels are low or normal

Hyperthyroidism or an overactive thyroid makes the bodily functions faster than usual because the thyroid gland produces excessive amounts of T3 and T4.

• Sudden weight loss

• Irregular or very fast heartbeat

• Heat intolerance or feeling too hot

• Excessive sweating

• Sleep disturbances

• Nervousness, anxiety, or irritability

• Thyroid inflammation

• Graves' disease

• Thyroid nodules producing excess hormone

• Excessive exposure or intake of iodine

• Thyroid medication overdose

• Family history of thyroid disorders (Graves’ disease)

• Females between 20-50 years of age

• Autoimmune diseases

• Excessive iodine consumption

• Goitre (thyroid nodules)

• Pregnancy

• Improper use of thyroid medications

• TSH levels are low in hyperthyroidism

• T4 levels are high that indicating excessive thyroid production

• T3 levels are high or very high

Here’s the symptom-based comparison table of Hypothyroidism vs hyperthyroidism, which can help maintain normal thyroid hormone levels :

Here’s how hypothyroidism and hyperthyroidism affect TSH, T3, and T4 levels:

Underactive thyroid, due to which T3 and T4 are not produced in adequate amounts. The pituitary gland increases TSH levels to force the thyroid to put more effort into producing high levels of TSH.

Overactive thyroid due to too much production of T3 and T4. The pituitary gland senses overproduction of hormones and decreases TSH production.

The most asked question about thyroid is, regarding primary hypothyroidism vs hyperthyroidism, which is worse? Let's understand the worst-case scenarios of both conditions.

Hypothyroidism gradually progresses, which may go unnoticed sometimes. It causes slow metabolism, fatigue, and weight gain. Usually, an underactive thyroid can be easily treated with hormone replacement therapy. If left untreated for a long time, it may lead to heart problems, high cholesterol levels.

Hyperthyroidism involves symptoms such as anxiety, faster heartbeat, heat intolerance, and weight loss. Usually, these symptoms are very intense and can not be ignored. Treatment involves medication, radiation, and surgery. Untreated or severe cases may lead to severe heart issues, bone loss, and thyroid storm.

In conclusion, hyperthyroidism is considered worse, which may lead to serious heart concerns; on the other hand, hypothyroidism leads to metabolic and cardiovascular concerns if it goes unnoticed and untreated.

Underactive thyroid (hypothyroidism) is more common, while overactive thyroid (hyperthyroidism) is less common. Hypothyroidism affects a larger population of women and older adults worldwide. Hyperthyroidism is quite uncommon and is usually associated with autoimmune conditions (Graves' disease).

• Around 5-10% population is affected by hypothyroidism.

• Around 1-2% population is affected by hyperthyroidism.

• Women are approximately 5 to 8 times more prone to developing thyroid problems than men.

• Thyroid hormone replacement (Levothyroxine)

• Typically taken daily on an empty stomach in the morning

• Periodic TSH screening is used for dosage adjustment

• Usually, lifelong treatment is required

• Anti-thyroid medications (carbimazole and methimazole)

• Beta blockers (propranolol) for symptom relief

• Radioactive iodine therapy

• Thyroidectomy (surgical procedure) in rare cases

• Regular monitoring of T3, T4 and TSH levels

Thyroid problems are quite common during and post-pregnancy. During pregnancy, the thyroid is controlled by the hCG hormone, which can reduce TSH production. The woman’s body requires more T3 and T4 to support her body and the fetus, thus thyroid function increases. Sometimes women are diagnosed with pregnancy-related thyroid disorders, including gestational thyrotoxicosis or postpartum thyroiditis.

If thyroid-related problems are left undetected during pregnancy, they may pose a risk to the mother and the fetus as well.

Risks to Mother: anemia, miscarriage, gestational hypertension, preeclampsia, placental issues, heart problems, depression, severe fatigue, and risk of preterm delivery.

Risks to Baby: Preterm birth, low birth weight, cognitive delays, improper brain development, neonatal thyroid issues, impaired growth, and developmental delays.

• Take your medications as recommended by your healthcare provider

• Regular thyroid monitoring throughout the pregnancy

• Thyroid-friendly diet and lifestyle habits

• Get adequate sleep and manage your stress

You should consider a thyroid check-up if you have symptoms, including:

• Unexplained weight fluctuations

• Fatigue and weakness

• Unusual cold and hot feeling

• Irregular menstrual cycle

• Stress, anxiety, and or depression

• Swelling around the neck

• Slow heart rate or palpitations

• Pregnancy

• Had thyroid surgery

In simple words, hypothyroidism means slow body processes, and hyperthyroidism means faster body processes than normal. Hypothyroidism is an underactive thyroid that causes high TSH and low T4 levels in the body, leading to fatigue, weight gain, and slower metabolism. Hyperthyroidism is an overactive thyroid that causes low TSH and high T4, leading to faster metabolism, rapid heart rate, anxiety, and weight loss.

Early testing can help plan the right treatment and prevent complications. Detecting thyroid imbalances early helps reduce the risk of fertility issues, cholesterol problems, and heart-related conditions. Regular thyroid monitoring during pregnancy helps prevent miscarriages, preterm birth, and the risk of developmental delays in the baby. Make sure you keep checking your thyroid levels regularly to avoid health complications in the future. Book your test with MyDiagnostics at a reasonable price.

***Medical Disclaimer - The following information is for educational purposes only. No information provided on this website, including text, graphics, and images, is intended as a substitute for professional medical advice. Please consult with your doctor about specific medical advice about your condition(s).