Hyaluronic acid is easily one of the most popular skin care ingredients of the moment. It's a gentle, sensitive skin-safe humectant moisturizer that helps attract moisture to your skin like a magnet. It's particularly well-loved for its ability to hold 1,000 times its weight in moisture, thus providing more resilience and firmness to the complexion.

Try:

L'Oreal Paris Revitalift Derm Intensives 1.5% Pure Hyaluronic Acid Serum, $23.99

Drunk Elephant B-Hydra Intensive Hydration Serum, $52

The Ordinary Hyaluronic Acid 2% + B5, $6.80

Linoleic acid is an omega-6 rich essential fatty acid. As British aesthetician Kimberly Sayer explained in New Beauty, "Linoleic acid is as an excellent carrier oil that can get below the surface of the skin, facilitating the penetration of other active ingredients such as antioxidants." It has hydrating properties that help improve the skin's moisture barrier for a supple and glowing complexion.

Try:

Alpha H Essential Hydration Cream, $49

L'Occitane Almond Supple Skin Oil, $50

Perricone MD Essential FX Acyl-Glutathione Intensive Overnight Moisturizer, $179

If you're not using retinol yet, it's time to start: It's great for basically all ages and skin types (yes, even sensitive skin) and it does pretty much everything you could possibly think of. It promotes cell turnover and collagen production, leading to a brighter, firmer and smoother complexion. Certain varieties of the stuff are also amazing acne fighters, helping with pore control as well.

Try:

La Roche-Posay Redermic R Retinol Cream, $56.99

Neutrogena Ageless Intensives Anti-Wrinkle Deep Wrinkle Night Moisturizer, $15.96

SkinMedica Retinol Complex 0.5, $66.30