Perfluorinated Compounds (PFAS) vs Propylene Glycol: which is worse?

What is Perfluorinated Compounds (PFAS)?

Per- and polyfluoroalkyl substances (PFAS) are a large family of synthetic chemicals characterized by extremely strong carbon-fluorine bonds. They are used in food packaging (grease-resistant coatings), non-stick cookware (PTFE/Teflon), food processing equipment, firefighting foam, and many industrial applications. The 'forever chemicals' moniker reflects their extreme environmental persistence.

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.

Documented risks

Perfluorinated Compounds (PFAS): PFAS are among the most extensively studied and harmful groups of synthetic chemicals in the modern environment. Their unique carbon-fluorine bond stability means they do not break down in the environment or in human body tissues — contributing to bioaccumulation over a lifetime. Health effects documented in human epidemiological studies include: - Cancer: PFOA (perfluorooctanoic acid) and PFOS (perfluorooctanesulfonic acid) have been associated with kidney cancer, testicular cancer, thyroid cancer, bladder cancer, and non-Hodgkin lymphoma in occupationally exposed workers and community members with contaminated drinking water. IARC classified PFOA as Group 1 (human carcinogen) in 2023 and PFOS as Group 2B. - Endocrine disruption: PFAS disrupt thyroid hormone signaling and sex hormone balance. Multiple studies find associations between PFAS exposure and hypothyroidism, early puberty in girls, and reduced sperm quality. - Immune suppression: studies have found that PFAS exposure is associated with reduced vaccine response in children and adults, suggesting PFAS may impair immune function. - Developmental effects: prenatal PFAS exposure has been associated with lower birth weight, developmental delays, and reduced immune response in infants. - Cholesterol: PFAS exposure consistently raises LDL cholesterol levels, increasing cardiovascular disease risk. The 2023 EPA MCLG (maximum contaminant level goal) for PFOA and PFOS is zero — reflecting the agency's conclusion that there is no safe level. The EPA set enforceable MCLs in drinking water in 2024. The DuPont/3M PFOA/PFOS contamination of drinking water in communities near Teflon manufacturing facilities led to a $671 million settlement (DuPont/Chemours, 2017) and $10.3 billion 3M settlement (2023) — among the largest environmental contamination settlements in history.

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.