If you’ve ever looked down at your knees and wondered why they seem darker, rougher, or drier than the rest of your skin, you’re definitely not alone. Knee skin is naturally thicker and regularly exposed to pressure and friction, so ordinary body lotion sometimes isn’t enough to keep it feeling smooth.

Repeated kneeling, crossing your legs, tight clothing, dry weather, and hot showers can contribute to dryness and thickened skin. Dead skin cells may also build up, leaving the knees looking ashy, rough, scaly, or darker than surrounding skin. Previous irritation can sometimes leave lingering discoloration too. One simple routine that may help when dryness and thickened skin are the main problems involves lactic acid lotion followed by a rich moisturizer or petroleum jelly before bed. But getting the benefits without irritating your skin depends on using the routine correctly.