Also called “normal” skin, this type is in fact very rare. It’s even-toned with invisible pores, neither dry nor oily, feels smooth, hydrated and has a glow.

The science: According to Dr. Leslie Baumann, CEO of the Baumann Cosmetic and Research Institute in Miami, and author of “The Skin Type Solution,” optimal skin is skin that functions perfectly.It creates its own moisturizer that keeps the stratum corneum (the outermost layer of skin that is made up of dead skin cells) smooth and hydrated and also receives enough water, vitamins and fatty acids from a balanced diet.Living skin cells manufacture lipids like phospholipids and ceramides; sebaceous glands provide triglycerides, waxes, cholesterol and squalene; sweat glands deliver urea, lactic acid, hyaluronic acid and allantoin. This oily mix creates Natural Moisturizing Factor (NMF), which conditions and nourishes the skin. It also keeps skin at a healthy pH of 4 to 5.5, which protects living skin cells from damage, staves off infection and strengthens its outermost layer.

Causes: “Perfect skin is mainly luck of the draw based on genetics,” insists Omaha dermatologist and founder of Dr. Joel Schlessinger. That said, what your mama gave you will only take you so far: At some point, you don’t just have the skin you were born with but the skin you deserve.“It’s all about prevention,” says New York City dermatologist Francesca Fusco, M.D. “If you always wear sunscreen, don’t smoke, stay hydrated and eat right, your skin will stay great well past your 30s and 40s, which is when damage like wrinkles and hyperpigmentation starts to show.”

Tips for optimal skin:

  • Use a light moisturizer that contains antioxidants like green tea to prevent wrinkles and dark spots.
  • Protect your skin with SPF 30 or higher every day of the year, rain or shine.
  • Skip toner—you don’t need it.
  • Exfoliate once a week with a scrub that contains enzymes to maintain a healthy glow.
  • Stay hydrated by eating water-rich foods like fruit and vegetables. How much water do you really need? Find out here.