As Dermatologist Dr. Adam Geyer says:
“As people have become savvier about their skin-care routines, layering has become increasingly prevalent. By using a serum, people are able to intensify the strength of their regimen or round out the ingredients they are applying to their skin to provide a more comprehensive approach to anti-aging and hydration,” Geyer says. “Serums are usually formulated with a higher concentration of active ingredients so that a few drops are sufficient to cover the entire face.”