Here’s the thing: Though probiotic supplements show a lot of promise, “we’re really pretty early in the research,” Jampolis says, and there are a lot of factors that influence whether or not a specific probiotic supplement will be beneficial for you. “I think it’s really important to be smart about them,” she says.

Specifically, pay attention to which strain, or strains, a probiotic contains to make sure it’s appropriate for the issue you’re trying to solve. For example, the right strain or strains of probiotics for someone dealing with immune health issues is different from the one that’s most effective for a woman facing recurrent urinary tract infections.

It can be confusing for the average shopper to know which strains are a good match for which health conditions, which is why Jampolis suggests talking to a medical specialist to get personalized recommendations. For example, “if you’re looking for something for a specific gut condition, talk to your gastroenterologist,” she says. Wanting help with a vaginal concern? Consult an OB-GYN. “Since it’s their field, they are more likely following the research and can advise you on which products actually have the right strains and in the right doses,” Jampolis explains. (Also important: It’s wise to first chat with your healthcare provider before starting a probiotic, just to ensure it doesn’t interfere with any medications or supplements you’re already taking, Ehsani says.)

Beyond that, look for supplements that have been produced under GMP, or Good Manufacturing Practice (a system that ensures products are made consistently and adhere to quality standards), Jampolis says, and that are third-party tested for transparency, adds Gilberg-Lenz.

To that end, take note of any certifications on the label. Those from independent organizations, like the United States Pharmacopeia (USP), NSF International, or ConsumerLab.com, are a good sign, as they can reassure you of a product’s quality and adherence to rigorous standards, Johnson says. Pay attention to what else is on the label, too. “A trustworthy brand will provide clear and transparent labeling, including the list of ingredients, potency, expiration date, and any other relevant information,” Johnson adds. She suggests steering clear of products with vague or misleading labels and instead recommends brands that prioritize research, create evidence-based formulations, and give detailed, science-backed information on their products. “Reputable brands often publish their research findings in peer-reviewed journals or make them accessible on their website,” Johnson says.

Try to buy directly from a company where possible, Gilberg-Lenz says, instead of unauthorized third-party retailers. And pay attention to a product’s potency, or the number of live bacteria or colony-forming units (CFUs) per dose, Johnson explains. If you’re looking to generally maintain gut health and overall well-being, a supplement with 1-10 billion CFUs per dose “may be sufficient for most individuals,” she says. Bonus points if the label specifies how many CFUs are active at the time of the product’s expiration, says Jampolis, since that confirms how much bacteria will be alive the whole time you’re taking the product.

To that end, many probiotic supplements still need refrigeration (i.e. they are not shelf-stable), unless the company has a unique manufacturing process, Jampolis says. “So if they’re not, that’s probably a red flag,” she says.

Lastly, consider cost. While Jampolis doesn’t believe you need to spend a fortune on probiotic supplements, if you want quality products that have been rigorously researched and tested, you’ll likely need to accept a higher price point. “The companies who are investing in the research are probably the ones that are going to be charging a little bit more,” Jampolis says.