These are FDA-regulated drugs like retinols, which are used in anti-aging formulas, salicylic acid, a common acne treatment, and avobenzone, which protects against UVA/UVB rays. Many have a max capacity in topical treatments for consumer safety.
This describes the "delivery system" of the active ingredients (most often water or oil-based).
Ingredients are always listed in order of concentration, from most to least. “The exception to the rule,” Shourie says, “is that any ingredient under one percent concentration can be listed in any order, so brands will often put more exotic ingredients first to draw customers in.
These dates are usually determined by heating a sample in a lab oven to simulate the decay process. The actual expirations vary, but no product should be kept on the shelf more than one-and-a-half years. Shourie says, “Products with natural ingredients generally last a shorter amount time because their molecules are less stable.”
“All-natural” labels vary widely but the USDA Organic seal is stiffly regulated—95 percent of the product’s ingredients must be from a USDA organic farm. “It means quite a lot to see this on a product,” says Shourie.
Most preservatives are slight irritants because of their bacteria-killing powers but products without them have a shorter shelf-life.