Possible Dangers and SPF Misconceptions of Sunscreens for Sunbathing Investigated by Scientist, Dr. Win L. Chiou

BURR RIDGE, Ill., March 2, 2023 /PRNewswire/ — For many years, sunscreens with sun protection factors (SPFs) ranging from 15 to 100 have commonly been promoted to help reduce sunburns, the risks of premature skin aging (photoaging) and skin cancer. Yet, skin cancers continue to rise, so are sunscreens effective and safe as thought to be? 

Dr. Win L. Chiou, a renowned retired professor from University of Illinois at Chicago (1971-2005) with 200+ publications and 6 patents, and a former consultant to the Food and Drug Administration (FDA), has published a series of critical articles on these topics and would like to warn of the potential serious risks and misconceptions in the use of sunscreens during sunbathing with hopes to reduce sunburns, save millions of dollars in medical costs and spare our environments from potential serious sunscreen pollutions. 

Use of SPF sunscreen often results in inconsistent and missed areas on exposed skin, resulting in sunburn (1). For example, in a European study titled “A Sun Holiday is a Sunburn Holiday”, all 25 sunbathers got sunburned after one week of vacation at a resort. In another well-controlled study, a mean of 20% of exposed skin was missing with sunscreen application. Chiou hypothesized that contrary to conventional expectations, the increasing use of sunscreen may be mainly responsible for the exponential increase of most skin cancer incidences in recent decades (2). The false feeling of protection in not considering missing areas may mainly explain the likely futility of increasing SPF value to overcome the reported increase of incidences of sunburn and skin cancer in past decades. We may need to reexamine the notion that the higher the SPF, the better the sunscreen. Label instruction like ‘Apply liberally’ is subjective and arbitrary and cannot assure no missing applications. Consequently, overreliance on sunscreen use during intense sunbathing may likely result in sunburn and increase the risks of premature skin aging and skin cancer. Avoiding peak sun-hours for tanning without sunburn, wearing proper clothing and seeking shelter are good alternatives (3). 

Chiou said although sunscreens have been marketed as over-the-counter drugs for decades, their efficacies in preventing sunburn and skin cancer, especially for intense intermittent sun exposure have not been fully established. It seems that the current FDA guidance for sunscreen approval was mainly based on a 2011 study from Australia that was later found to have serious flaws in experimental design (4). Furthermore, user patterns between Australia and the USA are quite different. Therefore, their results may not be directly applied to the USA. 

Since Chiou recently presented evidence indicating severe sunburn as the root cause of most skin cancers and severe sunburn is predominantly caused by ultraviolet (UV) B rays, therefore the need to use broad-spectrum sunscreens containing UVA filters may need to be reevaluated (3). 

Effects of sunlight on skin are known to vary greatly with skin types. It appears illogical to use a one-for-all SPF product for all populations. Chiou was the first one to perform a pharmacodynamic modeling study of sunscreens (1). He suggested that for general use, an SPF of 2 to 6 and 8 may be adequate for people with colored, non-sensitive skin and white sensitive skin, respectively.

Dr. Chiou was promoted to full professor in 1976 and was a fellow in 4 organizations. He was the inventor of Gris-pegĀ®, an ultrafine griseofulvin used to treat fungal diseases since the 1970s. He correctly pointed out in 2012 that numerous oral tetracyclines, widely used by dermatologists throughout the world to treat acne for about half a century, surprisingly act like placebos, and vehicles alone may account for up to 90% of the total anti-acne activity of topical anti-acne drugs on the market. 

Chiou’s group was the first one to demystify a century-old misconception that ‘blood is blood’ no matter where in the body the blood is sampled for analysis (5). His 1971 review article on solid-dispersion/nanotechnology in the Journal of Pharmaceutical Sciences has received about 2,700 citations per Google. His group first discovered that the commonly available rat is the best animal model to study oral absorption and body clearance, thus greatly facilitating drug research and development.

Win Chiou, President of Chiou Consulting Inc, can be reached at 630-789-9081 or at

SOURCE Win L Chiou