Avobenzone vs Erythritol: which is worse?

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.

What is Erythritol?

Erythritol is a four-carbon sugar alcohol naturally occurring in small amounts in fruits, fermented foods, and mushrooms. Commercially produced via fermentation of glucose by yeasts such as Moniliella pollinis, it has approximately 70% of sucrose's sweetness, provides 0.24 kcal/g, and has a glycemic index of 0. It is nearly completely absorbed in the small intestine and excreted unchanged in urine, which explains its unusually low laxative effect compared to other polyols.

Documented risks

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.

Erythritol: A 2023 observational study published in Nature Medicine (Hazen et al., Cleveland Clinic) found that elevated blood erythritol levels were associated with increased risk of major adverse cardiovascular events (MACE), including heart attack and stroke. Additionally, erythritol was found to enhance platelet aggregation in vitro. This study was widely reported and has generated significant scientific debate; critics note that it was observational (not causational), and that the study population had pre-existing cardiovascular risk factors. Regulatory agencies have not changed their approval status. The long-term cardiovascular implications require further research.