People buy nonprescription wrinkle creams and lotions with the hope that these products can reduce wrinkles and prevent or reverse damage caused by the sun. Do they work? That often depends on what’s in the product and how long you use it. Because these types of wrinkle creams aren't classified as medicine, they aren't required to undergo scientific research to prove their effectiveness.

If you're looking for a face-lift in a bottle, you probably won't find it in nonprescription wrinkle creams. The benefits of these products are usually only slight.

Moisturizing alone can improve the appearance of your skin. It temporarily plumps the skin, making lines and wrinkles less visible. Moisturizers are lotions, creams, gels and serums made of water, oils and other ingredients, such as proteins, waxes, glycerin, lactate and urea.

Wrinkle creams often are moisturizers with active ingredients that offer additional benefits. These added ingredients are intended to improve skin tone, texture, fine lines and wrinkles. How well these products work depends in part on your skin type and the active ingredient. Many of them are available in stronger formulations with a prescription from your doctor.

Here are common ingredients of moisturizing serums and creams that might improve the look of your skin. Whatever products you choose, read the label instructions.

• Retinols. This is a product made from vitamin A compounds. It is weaker than a retinoid, which is in many products that require a prescription. Examples are The Ordinary Retinol 0.5% in Squalane and CeraVe Resurfacing Retinol Serum. Retinols and retinoids are not safe to use while pregnant.

• Vitamin C (ascorbic acid). Vitamin C doesn't help much on its own but when added to a wrinkle serum and used regularly, it reduces damage from the sun and pollution and reduces skin discoloration. Vitamin C helps your skin produce collagen too.

  Examples of vitamin C serums are CeraVe Vitamin C Face Serum and La Roche-Posay Vitamin C Anti-Aging Serum. Look for the ingredient L-ascorbic acid. Store your vitamin C product away from air and sunlight to make it last longer.

• Niacinamide (NYE-a-sin-a-mide). This substance is related to vitamin B-3 (niacin). It's used in serums, masks, moisturizers and wrinkle creams. It may reduce signs of aging and skin discoloration. And it can have a calming effect on the skin, making your skin more able to benefit from other ingredients in your cream. Apply it two times a day.
• Bakuchiol (buh-KOO-chee-all). This substance is gentler than retinol and is safe to use while pregnant. It's used in serums and moisturizers. It reduces signs of aging and skin discoloration. Bakuchiol is from the ayurveda medicine tradition. Apply it two times a day.
• Tranexamic (TRAN-ex-AM-ik) acid. This substance is derived from the amino acid lysine. It brightens the skin and reduces discoloration and melasma. Apply it two times a day, with a sunscreen. Examples are La Roche-Posay Glycolic B5 10% Pure Glycolic Acid Serum and Paula's Choice Clinic Discoloration Repair Serum.
• Azelaic (a-zeh-LAY-ik) acid. This is a gentle substance that works well when combined with other ingredients in your wrinkle serum or moisturizer. And it's safe to use while pregnant. Azelaic acid is an antibacterial and skin-lightening agent. Apply it up to two times a day. Examples include The Ordinary Azelaic Acid Serum and The Inkey List Azelaic Acid Serum.

The Food and Drug Administration (FDA) classifies creams and lotions as cosmetics, which are defined as having no medical value. So the FDA regulates them less strictly than it does prescription medicines. And cosmetic products don't get the tests for safety and effectiveness that prescription medicines applied to the skin do. You might hear some of these products called cosmeceutical agents — a term used to capture the idea that these products are part cosmetic and part medicine.

Because the FDA doesn't evaluate cosmetic products or cosmeceuticals for effectiveness, there's no guarantee that any nonprescription product will reduce your wrinkles.

Consider these points when judging the merits of using a wrinkle cream:

• Cost. Cost has no relationship to effectiveness. A wrinkle cream that's more costly may not be more effective than a less costly product.
• Lower doses. Skin products that you can buy without a prescription contain lower concentrations of active ingredients than do prescription creams. So you might not see results, and any change you do see might be short-lived.
• Daily use. You'll likely need to use the wrinkle cream once or twice a day for many weeks before noticing any change in your skin. And once you discontinue using the product, your skin is likely to return to the way it looked before.
• Side effects. Some products may cause skin irritation, rashes, burning or inflammation. And some products cannot be used while pregnant. Be sure to read and follow the product instructions to limit side effects. It may help to select products that don't cause allergic reactions and acne. You might see these labeled hypoallergenic and noncomedogenic. Choose products that offer a consumer help line in case you have questions.
• Individual differences. Just because your friend swears by a product doesn't mean it will work for you. People have different skin types. No one product works the same for everyone.

Anti-wrinkle serums and creams may make tiny wrinkles less noticeable. Your results may depend on how often you use a product, the type and amount of active ingredient in it, and the type of wrinkles you want to treat.

But if you want to take the guesswork out of your skin care routine, try these more reliable ways to care for your skin:

• Protect your skin from the sun. Exposure to UV light speeds up the natural aging process of your skin, causing wrinkles and rough, blotchy skin. In fact, sun exposure is the No. 1 reason for signs of aging in the skin, including uneven pigmentation. Protect your skin by limiting the time you spend in the sun and always wearing protective clothing and a hat. Also, use sunscreen on exposed skin year-round when outdoors.

  Even sunlight that shines through windows can increase signs of skin aging such as wrinkles. So it's also helpful to get in the habit of using daily a product containing sunscreen, even if you aren't planning to be outside on any given day. At least use the product on your face, the V of your chest and your hands.

• Choose products with built-in sunscreen. Use a broad-spectrum sunscreen with an SPF of at least 30, even on cloudy days. Many moisturizers and makeup products have sunscreen built in. So try to pick a morning moisturizer or foundation that already includes sunscreen SPF 30 or higher. And get in the habit of using it every day. Especially when you're outside, apply sunscreen generously. Reapply every two hours, or more often if you're swimming or sweating.

  Products that contain physical blockers such as zinc oxide and titanium oxide provide the most effective protection for sensitive skin. Examples include Eucerin SPF 50, La Roche-Posay SPF 50 and Tizo AM Replenish. Apply it over any other products you're wearing — except insect repellent. Insect repellent goes on last.

• Use moisturizers. Moisturizers can't prevent wrinkles, but they trap water in the skin, temporarily masking tiny lines and creases.
• Don't smoke. Smoking causes narrowing of the blood vessels in the outer layers of the skin. It also damages collagen and elastin. These fibers give your skin its strength and elasticity. As a result, skin begins to sag and wrinkle prematurely. You can improve your skin tone and texture and prevent more wrinkles by quitting smoking.

A dermatologist can help you create a personalized skin care plan by assessing your skin type, evaluating your skin's condition and recommending products likely to be effective.

If you're looking for more dramatic results, a dermatologist can recommend medical treatments for wrinkles. These include prescription creams and serums; injections of medicine such as Botox, Jeuveau, Xeomin, Daxxify, Sculptra, Radiesse; chemical peels; microneedling; and laser treatments.