Size: 1 oz / 30 ml One of the most effective steps you can add to your nighttime routine. Protocol’s Enzyme-Active Retinol Serum combines 0.1% retinal with aloe, niacinamide, and glycerin to smooth texture, refine tone, and firm skin.  Helps soften the appearance of fine lines and wrinkles Improves the look of dark spots and uneven skin tone Smooths rough-looking texture with consistent use Airless, UV-protective bottle helps maintain potency