# Lithium-Induced Thyroid Dysfunction

URL: https://thethyroidologist.com/conditions/lithium-induced-thyroid-dysfunction/
Section: Conditions
Last medically reviewed: 2025-11-15

> Lithium can cause goitre and an underactive thyroid, and less often overactivity. How thyroid function is monitored and managed on lithium.

Lithium is an effective mood-stabilising medicine, but it affects the thyroid in a significant proportion of people who take it. The most common effects are an enlarged thyroid and an underactive thyroid; overactivity occurs less often.
Because lithium is often essential, the thyroid problem is usually managed alongside it rather than by stopping the drug.

## How lithium affects the thyroid

Lithium is concentrated by the thyroid and can interfere with hormone production and release. It also stimulates the gland to enlarge, which is why goitre is common.
The effects can develop gradually and are often picked up on routine monitoring before symptoms appear.

## Monitoring

Thyroid function is usually checked before starting lithium and then at regular intervals — commonly every six to twelve months, or sooner if symptoms develop. Calcium is sometimes monitored too because lithium can affect the parathyroid glands.
Symptoms such as fatigue, weight gain, cold intolerance, palpitations or neck swelling should prompt earlier testing.

## Management

An underactive thyroid is treated with levothyroxine while lithium continues. The dose is adjusted according to TSH, and monitoring continues at intervals.
Overactive thyroid on lithium is less common and needs specialist assessment; treatment depends on the mechanism and on the psychiatric plan.

## Working with your team

Thyroid changes on lithium are best managed jointly by the prescribing psychiatric team, the thyroid clinician and, where relevant, the GP. Stopping lithium abruptly can destabilise mood, so decisions are made together.

## Frequently asked questions

### Does lithium always affect the thyroid?

No, but thyroid effects are common enough that regular monitoring is recommended for everyone taking lithium.

### Do I have to stop lithium?

Usually not. Thyroid problems can be managed while lithium continues. Any change to lithium should be discussed with your prescribing team.

### Can lithium cause hyperthyroidism?

It can, though less commonly than hypothyroidism. The cause and treatment are assessed in the usual way.

### How often should my thyroid be checked?

Typically before starting and then every six to twelve months, or sooner if you develop symptoms.

## Disclaimer

The content on this website is for general educational purposes only and does not constitute medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional about your specific condition.

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