Your Side Effects May IncludeSynthroid side effects
levothyroxine
This side effect is printed on the FDA label for Synthroid. It was a question in our daily quiz, where you pick the real side effect from four choices.
A boxed warning against using it to lose weight
Large doses, especially with diet pills, can cause serious or even life-threatening toxicity.
“Thyroid hormones, including SYNTHROID , should not be used for the treatment of obesity or for weight loss.”
Take it exactly as prescribed. Tell your doctor about a racing heart, chest pain or shaking, which can mean the dose is too high.
1,323 reports to the FDA's adverse event system mention an overactive thyroid. A report is not proof the drug caused it. See the query
From quiz No. 12 · October 6, 2026 · Play that quiz →
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Not medical advice. Don't stop or start a medication because of a quiz. Talk to your doctor or pharmacist. Label text and report counts from openFDA. Not affiliated with any drug maker.