Last month, a Reddit user and former Sunday Riley employee started a thread on Reddit titled PSA Sunday Riley Employee: We Write Fake Sephora Reviews. “A lot of the really great reviews you read are fake,” the user explained. “We were forced to write fake reviews for our products on an ongoing basis…I saved one of those emails to share here.”

The following screenshot of an internal email had Twitter rumbling. There it was: proof that the one of the biggest resources beauty shoppers use to solicit authentic and unbiased opinions was no longer such. The email detailed directives employees were given to hype up the brand’s products in reviews, including talking points like, “please address how cooling it felt, the green color, the non-drying mask effect, radiance boosting, got rid of your acne after a couple uses,” as well as instructions on how to set up a VPN, or virtual private network, to hide employees’ identities.

The news came as a shock to loyal fans of the brand; many of whom wondered why it needed to take such measures given that the company’s products are revered for their ability to transform your skin. (Good Genes is often cited as one of the best exfoliating serums out there.) A lone nugget of honesty in the memo seemed to point to a rationale: “The power of reviews is mighty, people look to what others are saying to persuade them,” one line read.

That’s exactly the problem—and not only in the beauty industry. Fake reviews are rampant within e-commerce, since online shopping eliminates the option of touching, testing, or swatching a product for yourself. Studies have shown that just having a lot of reviews can actually boost a shopper’s interest in a product—even if a comparable one with fewer reviews is of higher quality. (The reasoning behind this: The more reviews a product receives, the more popular and therefore more desirable it must be.)

And the beauty industry, in which brands face stiff competition and need to find ways to set themselves apart from the crowd, is ripe for all sorts of fakery. (Influencer reviews, which are a whole different beast, also recently came into question over shady practices.) It’s no wonder Estée Laundry, an Instagram account that dubs itself an Anonymous #BeautyCollective, has recently appointed itself a watchdog, calling out fake reviews, copycats, and company scandals. It already boasts 30,500 followers.

The repercussions for these behaviors go way beyond a public shaming. (Not to mention fake reviews could pose legal issues, though they’re usually too small-scale for the FTC, which has strict rules regarding endorsements, to pursue.) Online beauty reviews require some level of trust—namely, that the reviewer actually used the product and is sharing their genuine opinion. The breakdown of that trust can have lasting effects. “Trust and authenticity are keys to buyers today, particularly millennials,” says Russell Winer, Ph.D., a professor and the deputy chair of the marketing department at NYU Stern School of Business. “If that is destroyed, a company can be seriously hurt.”

Sunday Riley, for its part, owned up to it. A few days after the Reddit thread was posted, the brand took to Instagram. “First, you can be assured that the only way that our brand will communicate on all channels, including ‪sephora.com‬, is with our official brand badge,” the brand said in the caption. “Second, we are going to have our business practices and company culture audited by a third-party and will publicly release the results. Lastly, we are actively listening and would love your constructive feedback on what you would like to see from us.” They followed it up with a post tagged with #TransparencyxSundayRiley.

The issue poses a unique challenge to big-box retailers and e-commerce sites, some which get thousands of shopper reviews a week. Sephora was quick to address the matter with the brand, according to a statement given to Glamour. “Sephora has very strict brand rules regarding our Ratings and Reviews, which we know are an important decision tool for our clients,” the retailer says. “Additionally, we have teams dedicated to protecting the integrity of our Ratings and Reviews, ensuring through detailed moderation that it’s a constant trusted, unbiased, authentic source for all.”

In some cases, retailers enlist third-party companies to sift through reviews. “There’s software that companies can use to spot fakes with high accuracy,” says Winer. Ulta Beauty partners with a third-party agency, PowerReviews, to help them manage their review process and covers both product reviews and product Q&As, according to a representative. It also takes steps to identify “Verified Buyers” with a badge attached to the review. That indicates it’s been written by someone who purchased the product directly from Ulta Beauty—thus minimizing the chances that it’s inauthentic.

While Amazon declined to comment for this story, the site has made headlines for issues with fake reviews in the past. It’s inevitable, really, with that amount of inventory. “Anything that has a really high margin, is highly competitive, and has a low cost of goods—like, I imagine, beauty products—has a problem with inauthentic reviews on Amazon,” says Tommy Noonan, the founder of ReviewMeta.com, a website that analyzes the trustworthiness of Amazon reviews.

An elephant in the room is the retailers themselves. After all, they don’t always have a lot of incentive to take down fake reviews—especially if they’re positive. “The conflict of interest is glaring,” says Noonan. “The higher the rating of the product, the more it’s going to sell.” Sift through the foundations on Sephora and you’d be hard press to find a formula that falls below three stars. (Although, there are products in other categories with 2.5 stars or less, they’re often found buried on page six or seven of options.) Ulrike Gretzel, Ph.D., a senior fellow at USC’s Annenberg School of Communication & Journalism and the director of research at market research company Netnografica, agrees. “Retail platforms often display products based on rating scores, and the average rating score is often the only thing consumers see right under the product name,” she explains. “This means that consumers will not even look at products that receive low average ratings.” And if they’re not looking at them, they’re probably not buying.

That leaves a lot of the sleuthing up to us. Aside from looking for vetted reviews, like those that stem from verified purchases, you can take matters into your own hands by looking for the hallmarks of a fake review. “The main one is a lack of detail about the product implying that the reviewer hasn’t actually used it,” says Winer. “Sometimes, a bunch of fake reviews show up at once if the competitor’s employees have been told to do this; check the timestamps on the reviews.” Fake reviews will also often be shorter—since posters may not put as much time or effort into it if they have a ton of them to write.

He also recommends that you focus on the reviews that fall in the middle of the range—so, if the rating is one to five stars, look at the reviews that give two to four stars. “The fives are generally uniformly enthusiastic, [while] the ones are the opposite,” Winer explains. “You get more information from the middle group, as they usually list pluses and minuses, which help more.”

It’s far from a perfect system and it’s disappointing that there aren’t more ways to deter fake reviews. Not only do they undermine truly good quality brands, but they also hurt and mislead customers who spend money on products that work—or so they think. While verifying purchases and, yes, maybe calling it out when it happens will help, in the long-run, brands and retailers alike need to continue to hold themselves to a higher standard. After all, if a product isn’t getting rave reviews, maybe the solution is to re-work the formula instead of simply duping fans.