The supplement market in the US is expected to grow from $71.81 billion in 2021 to $128.64 billion in 2028—and the variety of products available has exploded. Whether it’s for immune support, cellular aging, microbiome benefits, or even a simple multivitamin, there seems to be a supplement for every health issue. But with so much variety, it can be difficult understanding what’s worth the money, effective, and—most importantly—isn’t dangerous. 

The FDA will only take action against a supplement after it’s already on the market, but third party testing by agencies such as by NSF or the US Pharmacopeia (USP) Dietary Supplement Verification Program—ensures the ingredients and dosage in a supplement have been thoroughly vetted.. Here are the three components of the NSF dietary supplements certification program:

• “Label claim review to certify that what’s on the label is in the bottle”
• “Toxicology review to certify product formulation (we don’t test for efficacy)”
• “Contaminant review to ensure the product contains no undeclared ingredients or unacceptable levels of contaminants”

“Whether in pill, powder or liquid form, the goal of dietary supplements is often the same: to supplement your diet to get enough nutrients and enhance health,” explains Jeffrey Millstein, MD. “In addition to a healthy diet, there is evidence that some supplements can benefit your overall well-being with little to no risk,” says Dr. Millstein. “The most important thing to remember is to be smart when choosing a supplement.” Here is the number one supplement you could take right now, according to experts. Read on—and to ensure your health and the health of others, don’t miss these Sure Signs You’ve Already Had COVID.

Zinc is a trace mineral vital to health, and supplementation can be especially helpful for the elderly, vegetarians and vegans. Zinc deficiency can lead to impaired immune function and affect wound healing. “You don’t need much zinc, but it has so many benefits and can really affect how your body works,” says Rachel Harrison, a registered dietitian and certified nutrition support clinician at Banner – University Medical Center Phoenix. “It plays an important role in several zinc-dependent enzyme systems such as those involved in digestion, wound healing and DNA and RNA production.”

Be careful about which supplements you mix zinc with, Harrison warns. “If you’re supplementing zinc take it without other mineral supplements, such as iron and calcium, to avoid medication interaction. Zinc also works best in an acidic environment, so talk to your doctor if you’re taking proton pump inhibitors or antacids as these can increase the pH or make the environment less acidic.”

Probiotics are made of “friendly” bacteria which support a healthy digestive system and the gut microbiome. “Trillions of bacteria and other microbes live in your gut and make up your individual gut microbiome. These microbes influence many aspects of your health, including your immune system, and they help digest the food you eat,” says Yella Hewings-Martin, PhD.

“Some digestive disease specialists are recommending probiotic supplements for disorders that frustrate conventional medicine, such as irritable bowel syndrome,” says Harvard Health. “Since the mid-1990s, clinical studies suggest that probiotic therapy can help treat several gastrointestinal ills, delay the development of allergies in children, and treat and prevent vaginal and urinary infections in women.”

Vitamin B12 is crucial for brain function and red blood cell production. Vegans especially should ensure they are taking a good quality B12 supplement, as deficiency can cause anemia and nerve damage. “Of all the micronutrients, B12 is the one we’re most concerned about. I’m concerned many people think B12 deficiency is a myth,” says Tom Sanders, emeritus professor of nutrition and dietetics at King’s College London. “It’s something that can be easily avoided, and what concerns me is that many new people becoming vegan are unaware of the need to combine sources of plant proteins. And they’re not aware of the need to ensure they have adequate levels of B12.”

“Vitamin B12 may not be high on your nutritional radar, yet it is essential to some of the body’s most important functions, like forming red blood cells and maintaining nerve function,” says Harvard Health. “Doctors don’t routinely test for vitamin B12 levels, so vitamin B12 deficiency can go unnoticed. But over time, such deficiency may cause anemia, nerve damage, and even problems with memory and reasoning. However, it’s easy to avoid vitamin B12 deficiency by recognizing if you’re at risk and taking measures to avoid developing a deficiency.”

Vitamin D is crucial for healthy bone support, muscle function, immune health, and more. Vitamin D deficiency has been linked to depression, experts say, although the exact relationship is not clear. “It’s true people with depression are more likely to have a vitamin D deficiency,” says Molly Ropte, DO. “But it’s not always true everyone with depression should take a vitamin D supplement. If you struggle with mental illness, talk with your doctor about getting your vitamin D levels tested to determine if supplements are an option.”6254a4d1642c605c54bf1cab17d50f1e

“Vitamin D can have a positive impact,” says rheumatologist Chad Deal, MD. “If you’re healthy and aren’t getting treatment for any medical problems, you don’t have to worry about starting supplements. But if you are now taking supplements, be sure to get your vitamin D levels checked before stopping. If you aren’t sure if you’re at risk for vitamin D deficiency, ask your doctor to check your vitamin D level. They should work with you and repeat the easy blood test required to make sure you’re taking the right amount of supplement.”

The general consensus for the best supplement to take right now is still the humble multivitamin, experts say. There is evidence it can help fill in the nutritional gaps of the standard American diet, and recent studies have linked daily multivitamin use with a lower chance of developing Alzheimer’s disease. “We provide the first evidence in a long-term, randomized controlled trial of older women and men that daily use of a safe, readily accessible, and low-cost multivitamin-mineral can improve cognition,” researchers wrote in Alzheimer’s and Dementia, the Journal of the Alzheimer’s Association.

“So, why do I take a multivitamin? It’s simple. Research shows the risks are low, and there are real benefits for most people,” says food scientist Dr. Taylor Wallace. “Taking a daily multivitamin is a cost-effective way to insure against hidden micronutrient insufficiencies that can sap your immunity, health and long-term vitality. While classic nutrient deficiency diseases like rickets and scurvy are now rare in the US, inadequate levels of certain micronutrients can still impair a wide range of biological functions… While excessive intake of certain nutrients through multivitamins has been documented, it underscores the importance of reading the label and talking with a registered dietitian nutritionist about your supplement regimen. For me, on days I’m eating healthy, I take half of my multivitamin.”