Sorbitol vs Avobenzone: which is worse?

What is Sorbitol?

Sorbitol is a sugar alcohol (polyol) naturally found in some fruits, including apples, pears, and prunes. Commercially, it is produced by hydrogenation of glucose. It has approximately 60% of the sweetness of sucrose but provides fewer calories (2.6 kcal/g vs 4 kcal/g for sugar) and does not cause a significant immediate insulin response.

What is Avobenzone?

Avobenzone (INCI: Butyl Methoxydibenzoylmethane) is a chemical UV filter that is the only FDA-approved broad-spectrum UVA-absorbing active sunscreen ingredient in the US that covers the full UVA spectrum (320–400 nm). It is inherently photounstable and must be combined with photostabilizers.

Documented risks

Sorbitol: At doses above 20–50 g/day, sorbitol can cause osmotic diarrhea because it is incompletely absorbed in the small intestine and is fermented by colonic bacteria. EU regulations require products containing more than 10% added polyols to carry the label 'excessive consumption may produce laxative effects.' This is well-known and predictable. Sorbitol is not carcinogenic and does not raise blood glucose significantly, making it suitable for diabetics in controlled amounts.

Avobenzone: Avobenzone is effective and considered safe at approved concentrations (up to 3% in US OTC sunscreens). A 2019 FDA study found that several sunscreen actives including avobenzone were systemically absorbed above the 0.5 ng/mL threshold after repeated use, triggering a call for additional safety data. This does not indicate harm, but the FDA requested more studies under its proposed sunscreen monograph. Current evidence supports its continued safe use. No clear endocrine disruption or carcinogenicity at human exposure levels is established.