“I can’t stop crying,” Rachell “Valkyrae” Hofstetter, YouTube’s most popular female streamer, wrote in a now-deleted tweet this week after announcing her new skin care line. The collection, RFLCT, promised to mitigate “blue light pollution” from computer and phone screens. “This has been a long journey with my team,” she added. “This is just the beginning.” Almost immediately, however, viewers and other streamers expressed skepticism: Blue light pollution, they said, is not a real problem and could be used to “scam” impressionable young viewers into buying products that don’t work as advertised. Experts appear to agree: At the very least, there’s not enough credible research on the subject to warrant product lines.