Chances are you’re one of the many Americans who takes a daily multivitamin. According to the Council for Responsible Nutrition, approximately 75 percent of adults in the U.S. take daily dietary supplements for a variety of reasons, from boosting overall wellness and supporting immunity, to promoting hair, skin, and nail health. And, of all the supplements Americans take, a multivitamin is the most popular, according to The National Institutes of Health (NIH).

“Even with a balanced diet, you may not meet 100 percent of your nutrient needs every single day, and a multivitamin helps to fill in the gaps,” explains dietitian Erin Palinski-Wade, R.D., C.D.C.E.S., author of Belly Fat Diet for Dummies. “A multivitamin is not a substitute for a balanced diet but an insurance policy that helps ensure you won’t fall short on key nutrients.”

With countless options available, though, trying to decide which multivitamin to purchase can be a daunting task. Here are four factors Palinski-Wade recommends taking into account when shopping for a multi.

1. Your Profile

The first step in narrowing down your multivitamin options is to consider your gender and age, since numerous companies have created supplements specifically for men or women across multiple generations. After all, males and females require different vitamins and minerals during various stages of life.

For example, the Office on Women’s Health (OWH) recommends a prenatal supplement for females who are pregnant or could become pregnant that contains at least 400 micrograms of folic acid. Meanwhile, a supplement for menopausal women should contain calcium and vitamin D to help ward off osteoporosis.

Check your labels to see if a multi is specifically designed for your age and gender. Vthrive The Vitamin Shoppe brand, for example, has Bioactive Multivitamins specific to men and women both over and under 45 years of age.

2. Your Diet

Next, Palinski-Wade suggests assessing your eating patterns and identifying any nutrients you’re at most risk for falling short on. Individuals who follow a vegan diet, for example, may consume less-than-adequate amounts of vitamin B2 (riboflavin), vitamin B12, and vitamin D, which are mostly found in animal sources, per the OWH.

On the flip side, do you get enough fruits and veggies in your diet? According to the Centers for Disease Control and Prevention (CDC), only about 13 percent of adults eat the recommended daily fruit intake, while only nine percent consume enough vegetables. This can potentially lead to insufficient levels of essential vitamins A, C, and E and minerals calcium and magnesium.

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If you’re concerned about your nutrient status, your healthcare provider can conduct a blood test to detect nutritional deficiencies. Palinski-Wade advises against taking more than the Recommended Dietary Allowance (RDA), Adequate Intake (AI), or Tolerable Upper Intake Level (UL) of a nutrient unless instructed to do so by your doctor or registered dietitian, as fat-soluble vitamins A, D, E, and K can build up to harmful levels in the body over time. Additionally, certain water-soluble vitamins, like vitamin C, can cause undesirable side effects like gastrointestinal issues when taken in excess.

Also worth noting: The NIH advises consulting with your physician if you take blood-thinners since most multivitamins contain vitamin K, which can impact their effectiveness.

3. Verifications

“Since supplements are not regulated in the same way as medications, it is important to do your research and make sure the supplements you select actually do what they claim,” stresses Palinski-Wade. “Generally, you want to look for a credible company that has third-party testing or has clinical studies to support their statements.”

The USP (U.S. Pharmacopeia) Verified Mark on a supplement label indicates the product has been verified for purity and potency. Another third-party “seal of approval” may come from the NSF (National Science Foundation). And some companies may have their own unique certifications from a medical advisory team and clinical research involved throughout product development. The Vitamin Shoppe brand, for example, uses its Quality Promise seal to capture the rigorous quality assurance steps and third-party testing of ingredient purity and potency its products must pass.

Another certification to search for on a supplement label is the USDA Organic seal and/or the Non-GMO Project Verified seal.

4. Added Ingredients

Finally, you may choose to opt for a multivitamin that contains plant- or animal-based ingredients, instead of synthetic ones. These options are usually referred to as food-based supplements.

“Food-based vitamins typically include additional antioxidants and adaptogens, which may offer additional health benefits,” says Palinski-Wade.

Read More: Pair Your Supplements With These Foods For Better Absorption

Also, while supplements come in multiple forms—capsules, tablets, liquid, powder, and gummies—Palinski-Wade recommends avoiding gummies if you’re watching your sugar intake.

And, finally, forego supplements made with other fillers, such as preservatives (including parabens and sulfites), as well as artificial colorings, flavors, and sweeteners. “Although artificial ingredients won’t typically impact the quality of nutrients in the product, they’re usually not necessary in a high-quality supplement,” says Palinski-Wade.