Pet Drug Reports

Ingredients

Active ingredient · pooled across combinations

Testosterone: adverse event reports, pooled

4 ingredient sets in reports · 1 FDA-approved application in the Green Book

80reports naming the ingredient, 1987–20250% of all reports · about 2 a year
3reports, 12 months to March 20262 in the 12 months before
57.1%classed serious, as reportedall reports: 38.6%
55%of reports concern cattledog 12.5%

80 adverse event reports received by FDA list a drug containing testosterone, alone or in combination, from July 1987 to November 2025. This page pools every ingredient set that includes it; 4 such sets appear in reports.

The Green Book lists 1 FDA-approved application containing it. openFDA masks brand and manufacturer names in adverse event records, so the reports counted here cannot be attributed to a particular brand.

3 reports arrived in the 12 months to March 2026, up 50% from 2 in the 12 months before. FDA posts reports quarterly with a delay of three to six months, so the newest months are incomplete and usually grow in later releases. That is about 2 reports a year over its reporting history and 0% of all reports.

Pooled across every set, the terms listed most often are death (27.5%), vaginal prolapse (16.3%) and implant, Abnormal (15%). Many drugs combine several ingredients, and many reports list several drugs, so a term on this page may relate to any of them or to none.

Of reports that state seriousness, 57.1% were classed as serious (38.6% across the whole database); 27.5% record a death or euthanasia (6.4% overall). Ingredients used in older or sicker animals, or in anaesthesia and cancer care, carry higher shares for that reason alone.

Ingredient sets that include testosterone

Active ingredients recorded for the drugReportsShare of this page's reportsLatest 12 months
Estradiol + Testosterone4758.8%0
Estradiol + Testosterone + Tylosin1620%0
Testosterone1215%3
Estradiol Benzoate + Testosterone + Tylosin Tartrate56.3%0

Ordered by report count. FDA states that these data "cannot be used to estimate the risk associated with the product or compare one drug or device product with another"; counts follow sales volume and years on the market. A report can list more than one set, so shares can add to more than 100%.

Signs listed in reports, pooled

share of testosterone reports listing the termall reports in the database

  1. Death27.5%22
  2. Vaginal prolapse16.3%13
  3. Underfilling, Package[a product quality report, not a sign in an animal]12.5%10
  4. Hypersalivation[drooling]7.5%6
  5. Dispenser, Abnormal[a product quality report, not a sign in an animal]5%4
  6. Facial oedema[swollen face]5%4
  7. Anaphylaxis[sudden severe allergic-type reaction]3.8%3
  8. Death by euthanasia[the animal was euthanized]3.8%3
  9. Dyspnoea[difficulty breathing]3.8%3
  10. Lethargy[unusually tired or inactive]3.8%3
  11. Mammary gland disorder NOS[NOS: not otherwise specified]3.8%3
  12. Product Defect, General[a product quality report, not a sign in an animal]3.8%3
  13. Anorexia[not eating]2.5%2
  14. Diarrhoea[diarrhea]2.5%2
  15. Infertility NOS[NOS: not otherwise specified]2.5%2
  16. Injection site swelling[swelling where the injection was given]2.5%2
  17. Lack of efficacy - NOS[the product did not have the expected effect]2.5%2
  18. No sign[no clinical sign was reported]2.5%2
  19. Other abnormal test result NOS[abnormal laboratory result, type not specified]2.5%2
  20. Tachypnoea[fast breathing]2.5%2

Pooled across every ingredient set and every report that names the ingredient. One report can list several terms and several drugs; a term here may relate to any of them or to none.

Monthly reports by species, five years

Dog4 · peak 1
Aug 2021: 1Feb 2025: 1Jul 2025: 1Nov 2025: 12022202320242025
Cat0 · peak 1
2022202320242025
Horse0 · peak 1
2022202320242025
Other4 · peak 1
Apr 2022: 1Jan 2023: 1Apr 2024: 1Oct 2025: 12022202320242025

By month of receipt; each panel has its own scale. The newest months are incomplete because FDA posts reports with a delay of three to six months.

0471987: 119871988: 11989: 41990: 219901994: 11997: 11998: 319981999: 62000: 52001: 520012002: 52003: 22004: 320042005: 22006: 12007: 220072009: 52010: 62011: 720112012: 12013: 32015: 220152016: 12017: 12018: 120182020: 12021: 12022: 120222023: 12024: 12025: 42025

Outcomes, report types and ages

Outcome recorded in the report

Recovered/Normal3.8%3
Recovered with Sequela1.3%1
Ongoing5%4
Died27.5%22
Euthanized0%0
Outcome Unknown10%8

What kind of report it was

Safety issue63.8%51
Lack of expected effectiveness5%4
Both safety and lack of expected effectiveness1.3%1
Manufacturing or product defect30%24
Other0%0

Species

Cattle55%44
Dog12.5%10
Human exposure2.5%2

Age of the animal

Under 1 year20%16
1 to 3 years8.8%7
4 to 7 years0%0
8 to 11 years5%4
12 years and over6.3%5
Age not given60%48

Coloured bar: reports naming testosterone. Grey bar: all 1,357,245 reports. Outcomes are as stated by the reporter; FDA has not necessarily determined whether any product played a part.

In context

MeasureTestosteroneAll reports
Reports801,357,245
Latest 12 months against the 12 before+50%-5%
Classed serious, of reports stating it57.1%38.6%
Death or euthanasia recorded, per 1,000 reports27563.8
Filed as lack of expected effectiveness (wholly or partly)6.3%23%

Shares of reports, not of animals treated: how many animals receive the ingredient is not public. Ingredients used in anaesthesia, cancer care or in old animals carry more serious outcomes in their reports for that reason alone.

FDA-approved products containing testosterone (Green Book)

Reference information, not report statistics. openFDA masks brand and manufacturer names in adverse event records, so the reports counted here cannot be attributed to a particular brand. The list below is the FDA Green Book as of 1 Oct 2026; nothing on this page says which of these products, if any, a report concerned.

Trade nameActive ingredientsSponsorApproved forApplication
Component E-H with TylanEstradiol, Testosterone, TylosinElanco US Inc.CattleNADA 135-906

Species are the major species the Green Book search lists for the application ("—" where it lists another species or none). Approval dates are not part of the Green Book listing files and are not shown. Pioneer applications (NADA) come first, then generics (ANADA).

Questions about testosterone reports

How many FDA adverse event reports mention testosterone?

80 reports through March 2026, 3 of them in the latest 12 months, counting testosterone alone and in combinations.

Which brands do these reports concern?

That cannot be known from the public data. openFDA masks brand and manufacturer names in adverse event records, so the reports counted here cannot be attributed to a particular brand. The Green Book reference list on this page names approved products containing testosterone without any counts.

In which combinations is testosterone reported?

Estradiol + Testosterone (58.8% of these reports), Estradiol + Testosterone + Tylosin (20% of these reports), Testosterone (15% of these reports) and Estradiol Benzoate + Testosterone + Tylosin Tartrate (6.3% of these reports).

What reactions are reported for testosterone?

death (27.5%), vaginal prolapse (16.3%), implant, Abnormal (15%), underfilling, Package (12.5%) and rectal prolapse (10%). Shares are of reports naming the ingredient; one report can list several terms.

Which animals are these reports about?

cattle (55%), dog (12.5%) and human exposure (2.5%).

Does a high count mean testosterone is a problem ingredient?

A count cannot show that. FDA states that "there is no certainty that the reported drug or device caused the adverse event" and that the event "may have been related to an underlying disease, other drugs used at the same time or other non-drug related sources." Widely used ingredients collect more reports because more animals receive them.

How do I report a problem?

Call the drug company using the number on the label, or send Form FDA 1932a to FDA. See the guide on how to report.

Where this comes from. Counts are built from the openFDA Animal & Veterinary adverse event bulk files released 28 Sep 2026, which hold reports FDA's Center for Veterinary Medicine received through 31 Mar 2026. openFDA masks brand and manufacturer names in these files, so drugs are counted by the active ingredients each record discloses and no figure is attributed to a brand, application or company. Ingredient names, and the separate reference lists of approved products, follow the FDA Green Book as of 1 Oct 2026. Ingredient names follow the Green Book; salts and forms are kept as FDA lists them. Drug entries are matched by the active ingredients their unmasked ingredient field discloses. No report text, lot numbers or reporter details are published. See the methodology and sources; FDA's record is authoritative, and corrections are handled within five working days.