Baby Safety / Compounds / Cyproterone acetate

Is Cyproterone acetate safe for babies and kids?

Very high risk for kids

Infants are more vulnerable to Cyproterone acetate than children or adults due to immature hepatic/renal clearance, higher intake-to-body-weight ratio, rapid organ development, and increased gastrointestinal absorption.

What is cyproterone acetate?

CAS number
427-51-0
Molecular formula
C24H29ClO4
Molecular weight
416.94 g/mol
SMILES
CC(=O)OC1(CCC2C1(CC(C3C2CCC4=CC(=O)C=CC34C)Cl)C)C(=O)C
PubChem CID
9880

Risk for babies

Very high risk

Infants are more vulnerable to Cyproterone acetate than children or adults due to immature hepatic/renal clearance, higher intake-to-body-weight ratio, rapid organ development, and increased gastrointestinal absorption.

Neonates and infants up to 12 months have incomplete blood-brain barrier development, immature Phase I/II metabolic enzymes (particularly CYP3A4, UGT1A1), and higher gastrointestinal permeability. Equivalent doses produce higher internal concentrations and longer residence times.

What to do: Minimize infant exposure through source control. For breastfeeding mothers: reduce maternal exposure. For formula-fed infants: use certified low-migration bottles and verified water sources. Consult pediatrician regarding any concerns.

Risk for pregnant and nursing people

Very high risk

ABSOLUTELY CONTRAINDICATED. Feminization of male fetus. Category X.

Regulatory consensus

2 regulatory and scientific bodies have classified Cyproterone acetate. The classifications differ — that's the data.

AgencyYearClassificationNotes
EU/EMA2020Authorized — restricted to high-dose indications due to meningioma risk (2020)
FDA2020Not FDA-approved in US (available in most other countries)

Regulators apply different standards of evidence — animal-data weighting, exposure-pattern assumptions, epidemiological power thresholds — which is why two scientific bodies can review the same data and reach different conclusions. The disagreement is the data.

Where kids encounter cyproterone acetate

  • Pharmaceutical
  • Environmental Contaminant

Safer alternatives

Lower-risk approaches that achieve a similar outcome to Cyproterone acetate:

  • Spironolactone (anti-androgen, fewer hepatic concerns)
    Trade-offs: Removes 95-99% of dissolved contaminants including metals, PFAS, nitrates; wastes 2-4 gallons per gallon produced (improving with newer systems); removes beneficial minerals; $0.05-0.25/gallon; requires pre-treatment for longevity.
    Relative cost: 1.2-2×
  • Bicalutamide (non-steroidal AR antagonist)
    Trade-offs: Removes 95-99% of dissolved contaminants including metals, PFAS, nitrates; wastes 2-4 gallons per gallon produced (improving with newer systems); removes beneficial minerals; $0.05-0.25/gallon; requires pre-treatment for longevity.
    Relative cost: 1.2-2×

Frequently asked questions

Is cyproterone acetate safe for kids?

Infants are more vulnerable to Cyproterone acetate than children or adults due to immature hepatic/renal clearance, higher intake-to-body-weight ratio, rapid organ development, and increased gastrointestinal absorption.

What should I do if my child is exposed to cyproterone acetate?

Minimize infant exposure through source control. For breastfeeding mothers: reduce maternal exposure. For formula-fed infants: use certified low-migration bottles and verified water sources. Consult pediatrician regarding any concerns.

See Cyproterone acetate in the baby app

Look up products containing cyproterone acetate, compare to alternatives, and explore the full data record.

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Sources (1)

Reference data, not professional advice. Aggregates publicly available regulatory and scientific data; not a substitute for veterinary, medical, legal, or regulatory advice. Why we built ALETHEIA →