Sulfur
Description
A yellowish element that smells of rotten eggs and it might be familiar to you from the periodic table (has the symbol S in there).  It has a long history...
Function
Properties
Regulatory Status
Elemental sulfur is permitted in the EU under Regulation 1223/2009 with no specific concentration limits and approved as FDA GRAS for OTC acne (3-10%) and dandruff treatment (2-5%). Primary hazard is skin irritation (Category 2); dermal absorption is low (1.8-10%) with no systemic absorption through intact skin, and no sensitization potential.
FDA GRAS OTC drug: acne treatment 3-10% standalone (21 CFR 333.310(e)) or 3-8% with resorcinol 2%; dandruff/seborrheic dermatitis 2-5% (OTC Monograph M032). Permitted combinations: resorcinol 2%, resorcinol monoacetate 3%, salicylic acid 1.8-3%. CIR Expert Panel deferred evaluation to FDA OTC drug assessment.