Drug profile

The FDA adverse-event record for Thyroid Supplement

129 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Thyroid Supplement. See the species affected, top reactions, and outcomes below.

129
adverse-event reports
14.7%
death-coded share
Dog
most-reported species
20
Weight loss - top reaction
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Important: Adverse event reports do not establish that a drug caused or contributed to the event. Consult your veterinarian before making treatment decisions.
129
Total Reports
19
Deaths Reported
14.7%
Death Rate

Active Ingredients

Thyroid Supplement

Administration Routes

OralUnknown

Species Affected

Dog 128
Cat 1

Most Affected Breeds

Retriever - Labrador 16
Retriever - Golden 12
Crossbred Canine/dog 8
Boxer (German Boxer) 7
Beagle 6
Terrier (unspecified) 5
Shepherd Dog - German 4
Dog (unknown) 4
Pug 3
Rottweiler 3

Most Reported Reactions

Weight loss 20
Diarrhoea 17
Death by euthanasia 16
Lack of efficacy - NOS 16
Vomiting 15
Lethargy (see also Central nervous system depression in 'Neurological') 13
Decreased appetite 13
Elevated alanine aminotransferase (ALT) 11
INEFFECTIVE, LOSS OF EFFECT 11
Elevated serum alkaline phosphatase (SAP) 10
Decreased urine concentration 10
Polydipsia 9

Outcome Breakdown

Ongoing
49 (38.0%)
Outcome Unknown
37 (28.7%)
Recovered/Normal
24 (18.6%)
Euthanized
16 (12.4%)
Died
3 (2.3%)

Thyroid Supplement Adverse Event Insights

129 reports name Thyroid Supplement; 19 recorded a death outcome (14.7% of reported events, not a population-level mortality rate). Active ingredient: Thyroid Supplement. Administration routes: Oral, Unknown.

By species: Dog (128 reports), Cat (1 reports). By breed: Retriever - Labrador (16), Retriever - Golden (12), Crossbred Canine/dog (8).

Leading clinical signs: Weight loss (20), Diarrhoea (17), Death by euthanasia (16), Lack of efficacy - NOS (16). Outcome, 129 coded reports: Ongoing leads at 38.0%.

Read these counts as reporting volume, not risk: per our methodology, a widely-prescribed drug will rack up more raw FDA reports in a given year than a rarely-used one at an identical true rate, so we recommend comparing within similar-exposure products rather than across the full 2025 catalog.

Source: FDA Center for Veterinary Medicine openFDA Animal & Veterinary Adverse Events (CVM AER) · 2025

Every figure on PlainBreed is rendered directly from FDA openFDA adverse event data, no number is typed in by an editor. This page draws directly on FDA openFDA data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.