Retinol is considered the gold standard skin care ingredient for anyone who’s looking to improve the look of fine lines, wrinkles, and boost firmness by increasing collagen production. It’s highly lauded by dermatologists and beauty editors because it’s effective and has a ton of scientific research to back it up. However, for all of vitamin A’s benefits, there’s a big catch. The ingredient can be extremely irritating, and you often have to work your way up to nightly use. It also doesn’t play nice with all other actives, like AHAs, for example. That’s why when several of my favorite skin care brands started utilizing peptides in their products, I was instantly on board with the trend. While there are a ton of creams and lotions packed with the ingredient, I’m particularly fond of peptide serums.

Made up of amino acids, peptides are the fundamental building blocks of proteins, including collagen, elastin, and keratin. With age, the production of these vital substances decreases, so topically applying peptides to your skin can provide a needed boost. Aesthetically, this manifests itself as a smoother, plumper, firmer complexion. Unlike retinol, peptides don’t have an adjustment period, so you can use products with them any time of day, and with any ingredient. And that’s exactly why I like slathering on a concentrated serum following my Biologique Recherche P50 liquid exfoliant every night.

Read on for the peptide serums I rely on for plump, firm skin, plus the ones I look forward to trying next.