Sunscreen

Sunscreen emerged in 1928 when conditions aligned: UV radiation's dangers were scientifically documented, beach culture made sun exposure fashionable, and organic chemistry could synthesize molecules that absorbed ultraviolet light. German chemists Hausser and Vahle created the first commercial product, an emulsion containing benzyl salicylate and benzyl cinnamate that absorbed UVB wavelengths (280-320nm) before they penetrated skin. The formula didn't prevent sunburn completely—it reduced damage. That reduction was enough.

What made sunscreen possible wasn't discovering UV radiation caused skin damage—that was known by the early 1900s. What aligned was the collision of scientific knowledge with consumer behavior. Tanned skin shifted from agricultural labor signifier to leisure class marker in the 1920s-30s as Coco Chanel popularized sunbathing. People wanted tans without burns. Sunscreen solved a problem fashion created: how to spend hours in UV radiation without painful consequences. Eugene Schueller, founder of L'Oréal, commercialized this in 1935 with Ambre Solaire, a tanning oil with UV-filtering benzyl salicylate. The marketing was sophisticated: promote the tan, minimize the burn, ignore long-term damage.

Franz Greiter's path to modern sunscreen began with pain. In 1938, the Swiss chemistry student got severely sunburned climbing Mt. Piz Buin. Eight years later, in 1946, he introduced Gletscher Crème (Glacier Cream) with SPF 2—enough protection for gradual tanning without acute burns. Greiter invented the SPF (Sun Protection Factor) rating system in 1962, quantifying protection: SPF 2 means you can stay in sun twice as long before burning compared to unprotected skin. The rating transformed subjective "reduces sunburn" into measurable "blocks X% of UVB." SPF 15 blocks 93% of UVB, SPF 30 blocks 97%, SPF 50 blocks 98%. The diminishing returns above SPF 30 didn't stop marketing from pushing SPF 100+.

The convergent emergence of UV protection proves multiple chemical approaches worked. Para-aminobenzoic acid (PABA), described in 1942 by Rothman and Rubin, became the dominant U.S. sunscreen ingredient for decades. Zinc oxide and titanium dioxide—physical barriers that reflect/scatter UV—served the same function via different mechanism. Chemical absorbers (organic molecules) versus physical blockers (mineral particles) both prevent UV skin penetration, parallel solutions to identical problem. As of 2021, FDA banned PABA due to safety concerns, leaving only zinc oxide and titanium dioxide as GRASE (Generally Recognized As Safe and Effective). The chemicals that dominated for 50 years failed long-term safety standards.

This is path-dependence creating regulatory lag. PABA-based sunscreens entered markets in the 1940s-70s when safety testing was minimal. Manufacturers scaled production, consumers adopted products, beach culture normalized sunscreen use. Only decades later did research reveal allergenicity and potential health risks. Switching required regulatory action, reformulation, and consumer re-education. The modern sunscreen market—$24 billion globally as of 2025—uses zinc oxide, titanium dioxide, and newer organic filters like avobenzone. Broad-spectrum formulas protect against both UVB (burning) and UVA (aging/cancer), addressing what early sunscreens ignored: long-term DNA damage from wavelengths that don't cause immediate burns.

The biological parallel is organisms that evolved UV protection independently. Coral reefs synthesize mycosporine-like amino acids (MAAs) that absorb UV. Microbes produce scytonemin, a UV-blocking pigment. Fish transfer MAAs to their eggs. Humans evolved melanin, but melanin production takes days—too slow for acute exposure. Sunscreen provides instant chemical UV absorption that skin can't produce rapidly enough. Like organisms in high-UV environments, humans needed protection. Unlike organisms with genetic UV defenses, humans engineered chemical surrogates.

As of 2025, sunscreen remains the primary non-clothing UV defense. Reef-safe formulations avoid chemicals harmful to marine ecosystems. Spray sunscreens, sticks, and mineral powders multiply delivery methods. SPF ratings plateau at meaningful protection—SPF 50+ blocks 98%+ of UVB, higher numbers add marginal benefit. The product that emerged to enable fashionable tanning now primarily markets cancer prevention. The niche shifted: from "tan without burning" to "prevent melanoma." Sunscreen succeeded by changing what it protected against. The chemistry stayed similar, the cultural function transformed.