Photograph by Thomas Hannich Avobenzone
Please don't call it butyl methoxydibenzoylmethane. Avobenzone is FDA approved to block UVA and UVB light, both of which can lead to age spots, wrinkles, and skin cancer (only UVB actually burns the skin). Ironically, UVA causes it to degrade, releasing the kind of free radicals that are responsible for skin damage.
Tocopherol
While creepy monikers like butyl methoxydibenzoyl methane are defanged to become avobenzone, humdrum names like vitamin E get chemicalized into tocopherol. This is a powerful biological antioxidant that protects cells from the free radicals caused by sun exposure — and the breakdown of avobenzone.
Dihydroxy Acetone
The star of the show. This carbohydrate reacts with the skin's amino acids, like arginine, in what chefs call the Maillard reaction (it's what makes cooked foods turn brown). Heat this stuff to body temperature and it produces brown polymers known as melanoidins that bind to the outer layer of the skin (and no deeper). A caveat: The natural-looking color doesn't protect you from a burn the way a real tan can.
Propylene Glycol
Automobile antifreeze, sexual lubricants, artificial fog fluid — is there nothing this slippery compound can't do? Here it's used as a moisturizer.
Octocrylene
By itself, this is a perfectly adequate sunscreen that blocks UVB and a few wavelengths in the UVA spectrum. But L'Oréal discovered and patented a process of mixing octocrylene with avobenzone to slow the latter's breakdown, resulting in a much more stable sun block and fewer free radicals.
Oxybenzone
Yet another FDA-approved UVB blocker.
Dimethicone
Silly Putty. There are many different formulations of this silicone oil — some are soft and squishy like breast implants, others are sticky like bathtub caulk. This liquid variant is used in skin moisturizers and, again, sexual lubricants.
Arachidyl Alcohol
The long chain structure of this white, waxy plant derivative makes it a common starting point for producing everything from fragrances and inks to detergent and PVC. It's often used alone as a skin cream and an emulsifier, helping various ingredients mix.
Phenoxyethanol
A preservative specifically tailored to fight the types of bacteria frequently found on skin. Sunburn can leave flesh prone to infection, so it makes sense to add this as a precaution. The downside: It may just speed up the evolution of super-resistant mutant bacteria bent on world domination.
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