Please be wary of purchasing skincare on Amazon or eBay: orders fulfilled by Amazon mean that the seller has a deal with Amazon to store the items in an Amazon warehouse, which can translate to varying temperatures (and time spent on the shelf unmonitored), affecting the product. Additionally, because the product isn’t coming directly from the manufacturer, there’s a high possibility it could be fake, or expired—there’s very little regulation on sites that allow third-party sellers.

We get it: everyone loves a good deal, which makes incredible beauty discounts online hard to resist. But consider this before price shopping your beauty and skincare routine from an unauthorized dealer (most likely on Amazon): Counterfeit beauty products have become increasingly common and can cause serious harm. They’re being manufactured and sold at such a rapid pace these days that it’s now considered a global epidemic. And unlike that Chanel “replica”—which might only cause you a little embarrassment if it doesn’t simply fall apart—fake beauty products could end up sending you straight to your professional esthetician.

The Ugly Truth About Counterfeit Beauty Products

Sometimes the difference between buying authentic beauty products and buying counterfeit ones could mean not having to deal with permanent skin damage and long-term diseases like Alzheimer’s and cancer. The Police Intellectual Property Crime Unit (PIPCU), found fake cosmetics and skincare to contain toxic levels of chemicals and unpleasant substances, such as arsenic, mercury and even urine. Back in 2012, Inside Edition tested counterfeit cosmetics bought on the street and the results were surprising. The tests found high levels of aluminum (linked to Alzheimer’s disease), beryllium (a known carcinogen) and bacteria in the products.

With more and more people shopping online, it has become easier for counterfeiters to distribute their products anywhere in the world. Even giant online retailers can have a hard time controlling the authenticity of beauty products sold by third parties. In the U.K. alone consumers spend $140 million on fake beauty products, and most of them probably didn’t even know it until they noticed the side effects.

Here’s the rub: Counterfeiters don’t have any standards to uphold. They infringe intellectual property rights (yes, it is illegal). They use the cheapest ingredients to turn the biggest possible profit. They take shortcuts. And importantly for skincare, they don’t abide by the FDA’s sanitation guidelines, and their products don’t undergo rigorous tests required by law before they’re released to the public.

How to Spot a Counterfeit Beauty Product Online

It’s easy to identify a fake designer handbag when the item in question is something that normally retails for thousands of dollars and it’s available for less than $100. Beauty products, however, are trickier to spot and the sad truth is that counterfeiters are becoming better at making and imitating product packages. So good, in fact, that it can be nearly impossible to tell a fake from the real thing, especially when it’s being sold at a comparable price on Amazon or eBay.

The single easiest way you can be sure you’re getting the real deal is to buy your products straight from the brand or its authorized dealers and retailers. Some brands like SkinMedica do a great job of actually listing the bogus websites that sell their products. Aside from compromised ingredients, in skincare the shelf life of a product is also very important. Buying cosmeceutical products from offline retailers may result in old product inventory that is past it’s prime. To make sure your getting the real deal, check for authorized dealers listed on the brand’s official website. You might not get the lowest price, but your health, safety and well-being won’t be compromised.