Muscle Aches and Weakness
Muscle aches, cramps and weakness are recognised features of thyroid disease. In an underactive thyroid they tend to build slowly; in an overactive thyroid they can appear with wasting and fatigue.
Because muscle symptoms are so common in everyday life, thyroid disease is easily missed unless other clues are present.
Last medically reviewed: 15 November 2025
How hypothyroidism affects muscles
In hypothyroidism, muscles may ache, feel stiff and cramp, and the reflexes slow. Some people notice weakness, particularly in the shoulders and hips, and muscle enzymes can be mildly raised on blood tests.
These symptoms generally improve with adequate thyroid hormone replacement.
How hyperthyroidism affects muscles
An overactive thyroid can cause muscle weakness and wasting, sometimes with difficulty climbing stairs or lifting the arms. This reflects the increased metabolic rate breaking down muscle.
The changes are usually reversible once thyroid function is controlled.
Other causes
Muscle aches are far more often due to strain, medication side effects, vitamin D deficiency, or other conditions. Blood tests — including thyroid function, vitamin D, and muscle enzymes — help sort out the cause.
A clinician can distinguish thyroid-related muscle symptoms from other causes.
Frequently asked questions
Can thyroid disease cause muscle pain?
Yes — both hypothyroidism and hyperthyroidism can cause muscle aches, cramps and weakness, which usually improve when thyroid function is treated.
Is the weakness permanent?
In most cases it is reversible once thyroid levels are corrected, though recovery can take time.
What tests might I need?
Thyroid function tests are the starting point. Depending on the picture, vitamin D, calcium and muscle enzyme tests may also be checked.
References & further reading
This page is based on established medical knowledge and guidelines from authoritative sources. Always consult a qualified clinician for personal medical advice.
Ready to discuss your thyroid health?
Book a specialist consultation — in person or by teleconsultation.