With centella asiatica for added hydration and collagen to improve elasticity, this SPF serum doesn’t just fight against the negative effects of UV rays; it offers unrelated everyday benefits. Sean ZuckerFeel and EffectivenessThe concept of an SPF serum (versus a standard sunscreen or SPF moisturizer) is that it’s thinner and absorbs faster; however, most tend to overlook this notion and present as a standard sunscreen with a cuter name. TimeSavvy is one of the few that actually live up to the original SPF serum billing. Sean ZuckerFinal Verdict: Should You Buy TimeSavvy Hybrid Sheer Serum SPF 50? is a lightweight SPF serum that absorbs in seconds with a weightless, water-like feel that leaves no white cast or greasy residue.