Baby Safety / Compounds / Estriol

Is Estriol safe for babies and kids?

Context-dependent for kids

Infants have immature drug-metabolizing enzymes (CYP450 ontogeny), reduced renal clearance, and different volume of distribution. Accidental exposure or breast milk transfer of Estriol poses heightened risk.

What is estriol?

Also known as: Oestriol, Trihydroxyestrin, Aacifemine, Estratriol.

CAS number
50-27-1
Molecular formula
C18H24O3
Molecular weight
288.4 g/mol
SMILES
CC12CCC3C(C1CC(C2O)O)CCC4=C3C=CC(=C4)O
PubChem CID
5756

Risk for babies

Context-dependent

Infants have immature drug-metabolizing enzymes (CYP450 ontogeny), reduced renal clearance, and different volume of distribution. Accidental exposure or breast milk transfer of Estriol poses heightened risk.

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

Context-dependent

Regulatory consensus

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

AgencyYearClassificationNotes
EDC Assessment—Confirmed endocrine disruptor
Regulatory Framework—Regulated as pharmaceutical (FDA/EMA); not typically classified under industrial chemical regulations

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 estriol

  • Consumer Products — topical HRT creams

Safer alternatives

Lower-risk approaches that achieve a similar outcome to Estriol:

  • Alternative drug class; Non-pharmacological therapy; Lowest effective dose
    Trade-offs: Direct chemical substitution requires verification that the replacement does not introduce new hazards (regrettable substitution). Conduct full hazard assessment of proposed alternative before adoption.
    Relative cost: 1.2-2×

Frequently asked questions

Is estriol safe for kids?

Infants have immature drug-metabolizing enzymes (CYP450 ontogeny), reduced renal clearance, and different volume of distribution. Accidental exposure or breast milk transfer of Estriol poses heightened risk.

What products contain estriol?

Estriol appears in: topical HRT creams (Consumer products).

What should I do if my child is exposed to estriol?

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 Estriol in the baby app

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

Open in baby View raw API data

Sources (1)
  1. PubChem (2026) — database

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 →