Health experts warn of risks from slime ingredients like borax

Health specialists and regulatory bodies are raising alarms regarding the use of chemicals such as borax (sodium borate) and boric acid in homemade slime. While these substances are used to create the toy's characteristic elastic texture, they pose potential health risks to children.

Brazil's National Health Surveillance Agency (Anvisa) recently updated regulation RDC 1.030/2026, adding boric acid, boric oxide, and various borates to the list of prohibited substances in cosmetics and hygiene products. This move aligns Brazil with Mercosul and international regulatory standards based on toxicological evidence concerning reproductive and developmental health.

The Brazilian Society of Pediatrics advises against children having direct contact with boron-derived compounds. While skin absorption through intact skin is relatively low—estimated between 0.21% and 5% during occasional exposure—pediatricians warn that risks increase significantly with prolonged contact, high concentrations, or if the child has skin lesions, fissures, or dermatitis.