Baby Safety / Compounds / Melengestrol acetate (MGA)

Is Melengestrol acetate (MGA) safe for babies and kids?

Very high risk for kids

Infants are more vulnerable to Melengestrol acetate (MGA) 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 melengestrol acetate (mga)?

CAS number: 2919-66-6
Molecular formula: C25H32O4
Molecular weight: 396.52 g/mol
SMILES: CC(=O)OC1(CCC2C1(CC(=C3C2CCC4(C3CC(C4OC(=O)C)C=C)C)C)C)C(C)=O
PubChem CID: 11647

Risk for babies

Very high 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

High risk

Progestogenic — potential effects on fetal sexual development. Not studied in human pregnancy.

Regulatory consensus

3 regulatory and scientific bodies have classified Melengestrol acetate (MGA). The classifications differ — that's the data.

Agency	Year	Classification
FDA	1968	Approved veterinary feed additive (NADA 034-254) — heifers
EU	1989	Banned in livestock — Directive 96/22/EC
Codex Alimentarius	2004	ADI 0-0.03 ug/kg bw/day — MRLs established

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 melengestrol acetate (mga)

Veterinary Medicine
Environmental Contaminant

Safer alternatives

Lower-risk approaches that achieve a similar outcome to Melengestrol acetate (MGA):

Non-hormonal management
Trade-offs: Alternative approach; specific tradeoffs depend on application context, scale, and regulatory requirements. Full hazard assessment of alternative recommended before adoption to avoid regrettable substitution.

Relative cost: 1.2-2×
GnRH-based protocols
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 melengestrol acetate (mga) safe for kids?

What should I do if my child is exposed to melengestrol acetate (mga)?

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.

Why do regulators disagree about melengestrol acetate (mga)?

Melengestrol acetate (MGA) has been classified by 3 agencies including FDA, EU, Codex Alimentarius, with differing conclusions. 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. See the regulatory consensus table on this page for the full picture.

See Melengestrol acetate (MGA) in the baby app

Look up products containing melengestrol acetate (mga), 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 →