A medical researcher from the Australian National University describes how early sunscreens emerged in the 1930s, noting that the initial Sun Protection Factor, or SPF, was only two. This level was inadequate for preventing skin cancer or slowing the aging of the skin, underscoring the early limitations of sun protection science.
The early Australian market saw sunscreen products become available during the same decade. A South Australian chemist developed a chemical compound capable of absorbing ultraviolet rays, although the exact composition has not been disclosed. To improve the product’s appeal, perfume was added during preparation. By current standards, the SPF of such formulations would be rated at two, reflecting the modest protection offered at that time.
Historically, tanning was often interpreted as a marker of modern beauty throughout much of the 20th century. Beginning in the 1970s, researchers began to identify UVB radiation as the primary driver of sunburn, a clear signal of the hazard posed by ultraviolet B rays. UVB rays are medium-wavelength ultraviolet light that reaches the earth in varying amounts, and while UVA rays can penetrate deeper into the skin, they are connected with accelerated aging and the potential development of skin cancer, including melanoma.
Sun protection science continued to evolve with sunscreens that mirrored the basic principles of modern products, taking shape in the late 20th and early 21st centuries. At that time, labeling laws did not yet require manufacturers to disclose ingredients on packaging. In 1986, after substantial debate among industry stakeholders and consumers, researchers at the University of Queensland introduced a method to test sunscreen effectiveness, and a standard way to express protective strength—SPF—began to gain traction as a practical measure.
SPF represents the ratio of time before noticeable tanning occurs with the product versus the time required to tan without the product. Put simply, an SPF of 2 roughly doubles the safe time an individual can spend in the sun. Yet the actual effectiveness of sun protection is influenced by multiple factors, including radiation intensity, proximity to the equator, seasonality, altitude, skin type, and how thoroughly the product is applied. These variables help explain why SPF alone isn’t the sole predictor of protection and why daily sun-safety habits remain important for everyone, regardless of SPF value.
Modern sun care guidance emphasizes consistent, broad-spectrum protection that covers both UVA and UVB rays, along with practical sun-safety practices such as seeking shade during peak hours, wearing protective clothing, and reapplying sunscreen regularly. The historical trajectory—from early low-SPF formulations to more scientifically grounded testing methods and standardized labeling—highlights the ongoing effort to improve skin health and reduce UV-related risks over time.
Current research continues to refine our understanding of ultraviolet radiation and its impact on the skin, while regulatory bodies and health professionals advocate for clear labeling and responsible sun exposure habits. The evolution of sunscreen science demonstrates how scientific insight, consumer expectations, and public health priorities intersect to shape safer sun experiences for people everywhere, including Canada and the United States. In clinical practice, practitioners stress preventive measures and informed choices, given the diverse range of skin types and sensitivities across populations. This balanced approach helps minimize sun damage and supports long-term skin health for individuals of all ages and backgrounds.
Health professionals remind individuals to consider individual risk factors and to consult with a dermatologist if there are concerns about sun sensitivity or a history of skin-related conditions. Ongoing education about UV exposure remains essential, as does ongoing innovation to improve product effectiveness, safety, and accessibility for diverse communities.