Sunscreen is a common but complex sun safety product regulated in the US as a non-prescription drug. Recently, contributors on social media such as YouTube and Pinterest have advocated for making your own sunscreen at home. Such online tutorials likely represent misinformation in that they present an untested product as a safe replacement for a regulated drug. Purpose of the Study: To describe Do-It-Yourself sunscreen tutorials on YouTube, to determine whether viewers are making sunscreen, and whether specific misinformation is crowd-corrected in the online environment. This study demonstrates the use of online comments to identify behavioral outcomes of misinformation on social media. Method: We searched YouTube (March 2019) using search terms DIY sunscreen and Do-It-yourself sunscreen and selected the top 15 English-language videos sorted by relevance and views (N = 30). We double-coded the recipes for inclusion of FDA-approved photofilters, ingredient measurements and product claims (e.g., SPF level). We collected and coded all viewer comments (N = 2,477) for valence, presence of comments suggesting use on children is safe, crowd-correction by the online community, and indication of past or planned behavior change. Results: Most videos (67%) included SPF claims that were not accompanied by testing. Zinc oxide was the only photofilter used (present in 83%) and 17% of recipes contained no FDA-approved photofilters. Ingredient quantity was imprecise or absent in 23% of recipes. A notable fraction of videos (33%) had all supportive and no critical comments. Many videos (47%) had comments indicating a plan to use the recipe on babies, toddlers or children. Response to comments about use on children did not correct this misinformation. Comments indicated viewers had made or planned to make the recipe in 63% of videos. Discussion: Sunscreen is a drug intended to prevent sunburn and cancer, yet recipes for DIY sunscreen mischaracterize resulting product properties, thus misinforming the public. Further, viewers of DIY sunscreen videos frequently post positive comments regarding homemade sunscreen and do not correct false statements regarding their safety for use on infants and children. Making sunscreen, especially for use on children, may lead to skin damage.

The following are the 17 highest scoring abstracts of those submitted for presentation at the 44th Annual ASPO meeting held March 22–24, 2020, in Tucson, AZ.