Just drinking water does not moisturize skin, according to dermatologists. While hydration is absolutely essential for our body to function properly, oral hydration has no direct link to your skin’s hydration.

Dispelling the Myth of ‘Thirsty’ Skin

“It is a complete myth that we should drink a lot of water to maintain hydrated skin,” says Joshua Zeichner, MD, a board-certified dermatologist in New York City. “Water, first and foremost, enters the bloodstream and is then filtered by the kidneys. There is no data to show that drinking more or less water leads to the skin’s quality.” (In fact, there’s even evidence that shows it’s possible to drink too much water.) However, it is true that your skin gets “thirsty.” Much like the rest of our body, skin is made of cells, which are largely made of water. Cells lose water throughout the day through things like physical activity, environmental pollution, and just generally living life. This will result in a flaky and dry texture, making your skin more prone to fine lines, aging, and other skin conditions.

For Better Water Retention, Develop a Skincare Routine

“Your skin’s water retention is a function of TEWL, or transepidermal water loss,” explains skin expert Charlotte Palermino. “If you have dry skin, your barrier is likely weak or impaired. This means that you don’t have enough oil or lipids in your skin to hold on to the water that you have. At that point, no amount of water is going to replenish your skin―you’re going to need a cream for that.” “The solution is topical rather than internal,” agrees Dr. Zeichner. “Rather than drinking water, applying a moisturizer is a far more effective way of addressing dry skin.” Stick to the essential steps of skincare, which dermatologists say are cleansing and moisturizing (brands like Malin+Goetz have made entire lines dedicated to the two-step routine).

Healthy Hydration Practices

When it comes to choosing a moisturizer, the three key ingredients to look for are stearic acid (a type of fatty acid), emollient ceramides, and cholesterol. Yes, cholesterol. “Topically applied, it won’t affect your body’s cholesterol levels,” says Leslie Baumann, MD, a professor of dermatology at the University of Miami in Florida. (In fact, if you’re on a cholesterol-lowering medication, which can cause skin dryness, a cream rich in the ingredient may help.) In order to truly lock in moisture, it’s advised to apply hydrating cream when the skin is slightly wet, especially after a shower. If your skin needs some extra hydration help, you can go beyond moisturizer by employing targeted serums. That being said, your body (and your skin) still needs water to function properly. “Maintaining adequate hydration is important for our general health, as extreme dehydration can have significant impacts on the functioning of our hearts and kidneys,” notes Dr. Zeichner.

Environmental Factors Affecting Your Skin

Minimizing your exposure to depleting elements―low humidity, harsh winds, dry heat, high altitude, sun, alcohol, long baths―and avoiding stripping soaps can also prevent the loss of natural oils. “Diet can play a role in strengthening your skin’s ability to maintain moisture, too,” adds Dr. Baumann. Foods rich in the essential fatty acids found in walnuts, flaxseed, salmon, and olive oil can help skin cells stay hydrated. A study by the Institute of Experimental Dermatology in Germany also revealed that women who took flaxseed—or borage—oil supplements (2.2 grams a day) for 12 weeks experienced a significant increase in skin moisture and a reduction in roughness. A healthy diet with three to five servings a week of fatty acids will suffice for the average person, says Dr. Baumann. In short, dry skin is a result of both genetic and environmental factors that cannot be fixed solely by oral hydration. Perfecting skin’s hydration is dependent on a multitude of factors working together, in addition to drinking water, to make sure that the rest of your body functions well. Katie Rodan, MD, a dermatologist in the San Francisco Bay area and coauthor of Write Your Skin a Prescription for Change, says it best: “Humans aren’t like plants. Our skin doesn’t perk up when we consume water.” A quarter-size dollop of lotion will do much more for your skin than drinking a gallon.