PEG-8

PEG-8 is a low–moderate molecular weight polyethylene glycol used mainly as a humectant/solvent, typically at a few percent up to higher levels in leave-on formulations, and it is generally well-tolerated in clinical use. Patch testing and real-world data show low irritation potential for most users, but compromised barriers (eczema/post-procedure) can experience stinging due to increased penetration and the ingredient’s solvent behavior. Given sensitive-skin safety priorities and the possibility of irritation in highly reactive patients, it fits best as very gentle rather than inert. Safety Notes: PEG-8 is a low-molecular-weight PEG commonly used as a humectant/solvent and processing aid; in many leave-on moisturizers, serums, and sunscreens it appears at low supporting levels around 0.1–3%. In rinse-off cleansers and shampoos it is often used around 1–10% for solubilization and feel. High-strength consumer products (e.g., PEG-based solvent/humectant gels, makeup removers, and PEG-dominant bases where PEG-8 is a primary carrier) can reach roughly 20–40%, with higher levels limited by tackiness/feel and overall formula balance rather than specific regulatory caps.