Guar Gum vs Propylene Glycol: which is worse?

What is Guar Gum?

Guar gum is a galactomannan polysaccharide extracted from guar beans (Cyamopsis tetragonoloba), grown primarily in India and Pakistan. It is a highly effective thickener — approximately 8 times more powerful than cornstarch — and functions as a dietary fiber. It is used extensively in food, pharmaceutical, and industrial applications.

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

Guar Gum: Generally recognized as safe. At high doses (e.g., dietary supplement doses of 10–20 g/day), guar gum can cause flatulence, bloating, and diarrhea. Historically, concentrated guar gum dietary supplements were associated with esophageal obstruction, prompting the FDA to ban such supplements in 1992. At typical food additive use levels, no significant safety concerns have been identified. EFSA confirmed its safety as a food additive in 2017.

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.