Propylene Glycol vs Butylated Hydroxytoluene: which is worse?
Quick answer: Butylated Hydroxytoluene carries the heavier risk profile. Propylene Glycol is — in the EU and — in the US; Butylated Hydroxytoluene is — in the EU and — in the US.
| Property | Propylene Glycol | Butylated Hydroxytoluene |
|---|---|---|
| EU status | — | — |
| US status | — | — |
| Risk level | — | — |
| Banned in | — | Japan (banned for food use) |
| Restricted in | European Union (not permitted as a direct food additive in most food applications; only permitted as a carrier solvent for specific additives at low levels) | European Union (ADI-based restrictions), United Kingdom, Australia |
| Category | additive | additive |
| Where it hides | — | — |
What is Propylene Glycol?
Propylene glycol is a synthetic organic compound used as a humectant, solvent, and emulsifier in food, pharmaceuticals, cosmetics, and industrial applications. It is produced from propylene oxide (derived from petroleum). Its chemical formula is C3H8O2.
What is Butylated Hydroxytoluene?
Butylated hydroxytoluene (BHT) is a synthetic phenolic antioxidant preservative derived from petroleum. A white crystalline solid with formula C15H24O, it prevents fat oxidation in processed foods, cosmetics, and industrial applications. Often used synergistically with BHA.
Documented risks
Propylene Glycol: Propylene glycol is generally considered safe by the FDA and is metabolized by the liver to lactic acid and pyruvate (normal metabolites). However, at high doses — particularly from intravenous pharmaceutical formulations — propylene glycol can accumulate and cause lactic acidosis, kidney toxicity, and CNS effects. These effects are seen in critically ill patients receiving high-dose PG-containing intravenous medications, not from food consumption. In children and people with impaired liver or kidney function, PG accumulation may occur at lower doses than in healthy adults. Animal studies have found reproductive and developmental effects at high doses. EFSA's 2018 re-evaluation found no concerns at typical food use levels but noted the EU limits PG use as a direct food additive, using it only as a carrier solvent for permitted additives.
Butylated Hydroxytoluene: BHT has complex, bidirectional carcinogenicity data — some NTP bioassays found liver tumors in female mice at high doses, while other studies suggested BHT might inhibit cancer initiation. IARC has not formally classified BHT due to conflicting evidence. A 2017 study linked BHT to thyroid hormone disruption in female rats. The American Academy of Pediatrics (2018) recommended reducing synthetic preservative exposure including BHT in children. Kellogg's uses vitamin E in European versions of cereals that contain BHT in US versions — a commercially meaningful substitution.
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