Retinol is considered "one of the best-known skin care ingredients on the market," and when applied, these tiny molecules "go deep beneath the epidermis (outer layer of skin) to your dermis" where it "helps neutralize free radicals," and "boost the production of elastin and collagen, which creates a "plumping" effect," per Healthline. Honestly, there is no correct age at which to start using retinol. "The production of collagen fibers starts to decline in our 20s," Dr. Allison Arthur, MD, FAAD, at Sand Lake Dermatology Center, told MarthaStewart.com. They recommend adding retinol into your skincare routine in your early 20s. 

We know retinol is quite impressive, so how do we find the best of the best? Peter Thomas Roth Retinol Fusion PM Night Serum was voted Byrdie's "best overall" retinol serum because it has "1.5% concentration of encapsulated, time-released retinol (making it gentler than most) and brightening antioxidant," with the editor reporting that her skin had "an overall more refreshed appearance" without any "irritation or redness." 

This serum is a bit pricey, but it may be worth it. Honest Brand Reviews loves how this serum also has vitamins C and E, "which provide a healthy dose of antioxidants," and considers the brand "well worth the money."