3 Science-Backed Skincare Ingredients That Actually Work

1. Vitamin C

Free radicals caused by pollution, UV rays and more can lead to wrinkles and dullness. “Vitamin C squelches those free radicals,” says Lisa Kellett, a Toronto-based dermatologist. Because of this superpower, vitamin C is best used in the morning, under sunscreen. Spend more: Skin Authority Super-C Serum, $139, contains a 20 percent concentration—considered an optimal dosage. Spend less: Vichy Liftactiv Vitamin C Brightening Skin Corrector, $45, is a 10-day treatment with 15 percent vitamin C.

2. Retinol

Production of collagen, which gives skin its baby-smooth appearance, slows as we age. Retinol, a vitamin A derivative, speeds it up again. Apply at night, and use SPF 30 or higher in the a.m. Spend more: Neostrata 0.3% Overnight Peel pre-moistened pads, $80, contain 0.3% retinol minus the fillers that can sometimes interfere with the absorption of active ingredients. Spend less: Pixi Beauty Retinol Tonic, $20, is the perfect, gentle introduction to this powerhouse ingredient.

3. Hyaluronic Acid

Hyaluronic acid (HA) keeps skin hydrated, but like collagen, natural stores decrease with age. While a plethora of topical products exist, injectable HA purportedly gets this hero ingredient deeper into skin. Spend more: Kellett injects Restylane Skinboosters (Juvéderm Volite is a competitor) into skin’s superficial layers to address fine lines on cheeks, the upper lip, neck or chest (starting at $500). Two re-ups are required; results last about a year. Spend less: Filorga NCTF-Intensive Supreme Multi-Correction Serum, $123, contains a top secret HA cocktail; religious use allegedly bestows similar benefits to injection.

Plus, do you really need a serum?

Ideally, yes. Beyond a well-balanced acid mantle—the film that acts as a barrier to contaminants—aging skin needs high concentrations of active (not filler) ingredients. More watery in texture than creams, serums can be slightly better at delivering actives to the top layer of skin for faster results, says Kellett. Apply after cleanser and before cream moisturizer. Many serums are also customizable.

Two we love: SkinCeuticals Custom DOSE Precision-Compounded Corrective Serum, from $250, is available through select derms. Your doc-provided skin analysis is fed into a machine, which blends a bespoke formula of actives. And Province Apothecary Custom Face Serum, starting at $48, is a hand-blended mix of plant actives and essential oils. Skin assessments can be done online or in person at its Toronto clinic.