Zeranol
Zeranol is a synthetic non-steroidal estrogen primarily used as a growth promoter in cattle and other food-producing animals. It promotes weight gain and improved feed efficiency in livestock. While it has estrogenic properties, it is not approved for human therapeutic use in most countries.
Zeranol is a veterinary growth promoter with estrogenic activity used in food-producing animals, not approved for human medical use.
Key facts at a glance
- RxNorm
- 1368476
- Generic
- Zeranol
- Class
- unclassified
- Brands
- Ralgro
- Availability
- rx
- Lactation
- unknown
- Routes
- —
- Forms
- —
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Dosage and administration
- Usual dose
- 36mg as a single implant
- Maximum
- consult physician
- Frequency
- single administration
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- Not applicable - veterinary use only
- Maximum
- consult physician
- Frequency
- N/A
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- Not applicable - veterinary use only
- Maximum
- consult physician
- Frequency
- N/A
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
Overdose information
Special Populations
8 groupspregnancy
first trimesteravoid completely
contraindicated during pregnancy due to risk of fetal harm and virilization
regular fetal ultrasound monitoring
Use of this medication in this population requires careful consideration of risks and benefits.
pregnancy
second trimesteravoid completely
contraindicated throughout pregnancy
fetal monitoring recommended if exposure occurred
Use of this medication in this population requires careful consideration of risks and benefits.
pregnancy
third trimesteravoid completely
contraindicated during pregnancy
fetal monitoring
Use of this medication in this population requires careful consideration of risks and benefits.
lactation
breastfeedingavoid completely
not recommended during breastfeeding; transfer to breast milk likely
monitor infant for hormonal effects
Use of this medication in this population requires careful consideration of risks and benefits.
pediatric_age
adolescentsavoid in children and adolescents
not recommended for pediatric patients due to effects on growth plates and development
monitor growth and development parameters
Use of this medication in this population requires careful consideration of risks and benefits.
geriatric
elderlyuse with caution; consider reduced dose
increased risk of cardiovascular events and prostate issues in elderly males
regular cardiovascular monitoring and PSA testing
Use with caution and monitor for adverse effects.
renal_impairment
moderate to severereduce dose or avoid
use with caution; may worsen renal function
monitor renal function tests regularly
Use with caution and monitor for adverse effects.
hepatic_impairment
anyavoid
contraindicated in patients with hepatic impairment due to hepatotoxic potential
liver function tests required if used
Use of this medication in this population requires careful consideration of risks and benefits.
Statistics and clinical data
First FDA approval year
Initial FDA approval for veterinary use
Drug class
Pharmacological classification
Primary use
Therapeutic indication
Regulatory status in EU
International regulatory status
Zeranol is used in veterinary medicine as a growth-promoting implant for beef cattle to improve weight gain and feed conversion efficiency.
Zeranol acts as a non-steroidal estrogen agonist, binding to estrogen receptors and mimicking the effects of natural estrogen, which promotes anabolic effects including increased protein synthesis and weight gain.
Zeranol is prohibited for use in food-producing animals in the EU and other regions due to concerns about hormonal disruption in humans who consume treated meat. It is not approved for therapeutic use in humans.
Contraindications
Conditions and patient states where this medication should be avoided or used with caution.
Do not use (1)
Known allergy to this medication or its components
Use caution (1)
Consult healthcare provider for benefits vs risks assessment
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 24, 2026. · Read our editorial policy