Although they're certainly not new — try centuries old, actually — adaptogens are the latest trendy health thing that's supposed to cure us of all the awful effects of our horrible modern lives. Unfortunately, as usual, this one looks like it's running mostly on hype.
Adaptogens are really just herbs — such as ginseng and milk thistle — that can allegedly cure a ton of health problems. Internet health gurus will suggest you use them for everything from reducing the effects of stress to Alzheimer's to asthma to cancer. Even the Bulletproof crew recommends them for relieving stress and improving sex (but you know how we feel about that).
So, as you can see, in many ways "adaptogen" is just a more science-y term used to refer to traditional herbal remedies. But the term does refer to a specific type of remedy: Adaptogens are herbal compounds that purportedly work with your body's stress hormones to prevent and treat pretty much any chronic illness. And that's all possible because these compounds can supposedly "adapt" to whatever your body needs it to do.
However, at this point, no mainstream health organization is ready to classify adaptogens as an actual cure for anything. The FDA regulates herbal remedies as dietary supplements, so they're not required to undergo the clinical testing process that pharmaceutical drugs have to endure.
In a 2008 reflection paper, the European Medicines Agency (EMA) reviewed the available evidence and concluded, "The principle of an adaptogenic action needs further clarification and studies in the pre-clinical and clinical area. As such, the term [adaptogen] is not accepted in pharmacological and clinical terminology that is commonly used in the EU." There are decades of research (mostly not in humans) looking at the potential of adaptogens, and it would take decades to go through them all here. What you need to know is that same EMA paper found that the majority of the existing research has serious methodological issues.
Then there's the fact that just because something is "natural" doesn't mean it's safe. Although most of us could experiment with small amounts of most of these things, there are definitely cases in which herbal remedies can make you sick, cause birth defects, and interfere with medications you're taking on an actual prescription.
So, although we're not saying they're all totally off-limits, we'd suggest checking out more medically-accepted treatments for your ailments first. And, because there may be some adverse effects from your chosen herbal remedy, please do check in with your doctor before taking any adaptogen — and definitely rein in your expectations.