Do you drink a glass of OJ every morning? Add peppers to your salad at lunch? If so, your skin thanks you—not only for the healthy diet but for making sure that vitamin C is a part of it. Your body needs a variety of nutrients to look and function its best, of course, but C is a particularly important player. It offers much more than the immune-boosting properties you probably already know it for; because a lot of C is stored in your skin, it helps rejuvenate and protect your complexion whether you get it from food or apply it topically. Simply put, vitamin C should be part of your skincare regimen—as important as washing your face or applying sunscreen.

Here’s what happens when you feed your body vitamin C:

It Helps Prevent Sun Damage

When skin is exposed to UV light, damaging molecules called free radicals attack cells and collagen, your skin’s support structure. This can trigger inflammation and lead to wrinkles, sunspots, and even skin cancer. A potent antioxidant, vitamin C acts like an army protecting its territory: It neutralizes free radicals before they wreak havoc and reduces inflammation, minimizing its effects. Research has shown that women with the highest dietary intake of vitamin C had fewer noticeable wrinkles and less dryness.

It Helps Keep Skin Strong And Firm

Along with minimizing the appearance of fine lines, vitamin C also helps the surface of your skin appear smoother and firmer by activating cells called fibroblasts that make new collagen.

It Helps Heal Skin

Cuts, burns, and other injuries that lead to scar tissue need the help of vitamin C to repair damaged skin. The vitamin may also play a role in the formation of keratinocytes—cells needed to close up a wound on the skin’s surface. While increasing your vitamin C intake does not appear to speed up the repair process, not getting enough may delay healing.

How Much Should You Get?

The recommended daily amount of vitamin C for men is 90 mg; it’s 75 mg for women. Green peppers, broccoli, oranges (and orange juice), papaya, strawberries, and cantaloupe are all excellent sources. Consider eating C-containing fruits and vegetables in combination with foods high in vitamin E, such as almonds, sunflower seeds, and peanut butter. Research suggests that the two antioxidants provide more effective protection against UV damage when consumed together.

Here’s what happens when you apply vitamin C topically:

It Provides Antioxidant Protection

As with dietary vitamin C, applying the nutrient topically also feeds your skin protective antioxidants that fight free radical damage and inflammation caused by the sun, pollution, and other factors. The key is using a product that has the L-ascorbic acid form of vitamin C—the only one that can penetrate the deep layers of your skin. While using sunscreen is still the best way to prevent burns and the aging effects of UV light, rubbing in a vitamin C-containing serum or lotion underneath delivers extra insurance by counteracting the small percentage of UV rays that can sneak through sunblock.

It Helps Improve Signs Of Aging

Topical vitamin C triggers collagen production by turning on fibroblasts (the same way eating broccoli and strawberries does), which helps improve the appearance of fine lines. What’s more, the vitamin may also help slow the breakdown of collagen, preserving the skin’s structure. Researchers have been able to show the effects of using vitamin C externally: When participants in a 12-week study applied a vitamin C product to half of their face and the same product without the nutrient to the other half the researchers found a significant visible improvement on the side given the vitamin, including a decrease in wrinkles.

It Can Even Out Skin Tone

The L-ascorbic acid form of vitamin C has also been shown to interrupt the overproduction of pigment, called melanin; over time that can help lighten brown spots, what’s known as hyperpigmentation. Although C is less effective than some other skin-lightening agents you’ll find, like hydroquinone, it’s milder—ideal for sensitive skin. For best results in smoothing out blotchiness or discoloration, look for vitamin C in combination with other gentle ingredients, such as licorice extract and soy.

When choosing vitamin C skincare products, look on the ingredient list for L-ascorbic acid. And, because vitamins C and E are more effective as a team, look for products that list E’s active form, alpha-tocopherol.

Remember that the closer an ingredient is to the top of the list on a product label, the higher its concentration. Whether you choose a serum, lotion, or cream, ascorbic acid can degrade quickly when exposed to sunlight, so choose products in dark or opaque jars and store them safely away from sunlight.