Yes. 277 FDA-approved labels for Levothyroxine carry a boxed warning, and its subject is not for treatment of obesity or for weight loss. A boxed warning is the most serious warning the FDA requires on a prescription label. It is applied to the drug and to the situations in which it is used, not to any particular person taking it.
What the warning says
Below is how the Levothyroxine warning opens on one specific label, identified underneath it. Of the 25 Levothyroxine labels sampled, 12 carried materially different wordings and this was the most common, used by 5 of them.
WARNING: NOT FOR TREATMENT OF OBESITY OR FOR WEIGHT LOSS Thyroid hormones, including levothyroxine sodium, either alone or with other therapeutic agents, should not be used for the treatment of obesity or for weight loss. In euthyroid patients, doses within the range of daily hormonal requirements are ineffective for weight reduction. Larger doses may produce serious or even life-threatening manifestations of toxicity, particularly when given in association with sympathomimetic amines such as those used for their anorectic effects [see Adverse Reactions (6) , Drug Interactions (7.7) , and Overdosage (10) ].
LEVOTHYROXINE SODIUM, A-S Medication Solutions, label version effective 24 March 2026. Opening of the warning; read the full label on DailyMed.Why the wording differs between manufacturers
There is no single official text of a boxed warning. The FDA sets what a warning must cover, and each manufacturer writes its own label within that. Of the 25 Levothyroxine labels sampled for this page, 12 carried materially different wordings of the same warning, and the version quoted above was used by 5 of them.
The hazard does not change between those 12 versions. Only the sentences do, which is why a refill from a different manufacturer can carry warning text that reads differently without anything about Levothyroxine or its risks having changed.
Levothyroxine is dispensed under 277 current FDA labels despite this warning, which is the point worth holding onto: a boxed warning is a disclosure requirement, not a verdict. What a boxed warning does and does not mean sets out the distinction.
Common questions
Does Levothyroxine have a black box warning?
Yes. 277 FDA-approved labels for Levothyroxine carry a boxed warning, and its subject is not for treatment of obesity or for weight loss. A boxed warning is the strongest warning the FDA requires on a prescription label, and it is applied to the drug, not to any individual taking it.
What does the Levothyroxine boxed warning say?
The wording is set by each manufacturer within FDA requirements, so it varies. In the version quoted on this page, taken from a label effective 24 March 2026, the warning concerns not for treatment of obesity or for weight loss. The full text is linked so the exact version can be read rather than summarised.
Does the Levothyroxine boxed warning mean the drug is unsafe or being withdrawn?
No. It means the FDA requires the risk of not for treatment of obesity or for weight loss to be communicated prominently so prescribers weigh it explicitly. Levothyroxine remains FDA-approved and is dispensed under 277 current labels. A boxed warning is a disclosure requirement, not a judgement that a drug should not be used.
Why do different pharmacies show different warning text for the same drug?
Because each manufacturer writes its own label within the FDA's requirements. Of 25 Levothyroxine labels sampled here, 12 carried materially different wordings of the same warning. The hazard described is the same; the sentences are not. This is a common source of confusion when a prescription is refilled with a different manufacturer's product.
Should I stop taking Levothyroxine because of this warning?
This page does not answer that and cannot. The warning about not for treatment of obesity or for weight loss is written for a prescriber deciding whether Levothyroxine suits a particular patient, and stopping a prescribed medicine carries its own risks that this page knows nothing about. Raise it with the prescriber or a pharmacist, who can see the whole picture.
Where this page's information comes from
The quotation above is from one Levothyroxine label, linked below by its DailyMed set identifier so the exact version can be opened rather than taken on trust. The figure of 277 labels, and the count of 12 distinct wordings among 25 sampled, were computed from the openFDA labelling API on 30 August 2026.
- LEVOTHYROXINE SODIUM prescribing information, A-S Medication Solutions, effective 24 March 2026.
- openFDA drug labelling API, the source of the label counts and variant counts on this page.
Labels are revised over time. The version linked above is the one this page was written against, and a newer revision may differ. Counts reflect the labels present in openFDA on the retrieval date.