I feel like I've been seeing spirulina on menus everywhere these days. In just the last week, I've been offered a spirulina latte, spirulina cream cheese, and even a spirulina doughnut. But I still can't answer the seemingly simple question of what is spirulina. I also know it's often referred to as a superfood, but I don't exactly know any of the benefits of spirulina—except that it's used as an all-natural dye to turn food blue or teal. Turns out that even though spirulina has been trending recently, it's actually a centuries old ingredient that's long been revered for its health benefits. But let's start with the basics, shall we?

Spirulina are a type of blue-green algae. If you want to get specific, spirulina are "multicellular and filamentous blue-green microalgae belonging to two separate genera Spirulina and Arthrospira and consists of about 15 species," according to a report from the Food and Agriculture Organization of the United Nations. This algae is grown in both saltwater and large, freshwater lakes, depending on the species, and it's been a food source for centuries. The Aztecs would collect spirulina from lakes using fine mesh nets and make it into cakes. "Other legends say Aztec messenger runners took spirulina on their marathons," write the experts at the FAO.

The bright blue-green hue of spirulina is part of the reason the ingredient has been trending recently. After all, we're living through peak unicorn toast. But the benefits of spirulina are more than aesthetic. Spirulina has a high protein content; approximately 60 to 70 percent of its mass is protein. It's also a complete protein, meaning it's got all the essential amino acids,and that's rare to find in a plant. Spirulina also has some essential, unsaturated fatty acids, which is the good kind of fat, and includes vitamins B6, B9, B12, C, D, and E, among other nutrients.

It's also true that blue-green algae are very good at absorbing heavy metals like lead from its environment. This is why some people swear by spirulina as part of a so-called heavy metal detox. "This edible blue-green algae draws out heavy metals from your brain, central nervous system, and liver, and soaks up heavy metals extracted by barley grass juice extract powder," writes Anthony William for Goop. The folks at Moon Juice, the LA-based juice shop known for its feud with Father John Misty over an oversized crystal, explain that spirulina "activates your brain, tames inflammation and detoxifies while turning your shake a cosmic blue."

Unfortunately, there's limited evidence to prove that spiriulina can detoxify your body in the ways described by Goop or Moon Juice. In fact, according to the US National Library of Medicine, there just isn't enough evidence to make any concrete statements about the effectiveness of spirulina for most uses—including treating fatigue, aiding with allergies and digesting, even detoxifying from arsenic poisoning—even though that's how the superfood is marketed.

Also, the propensity of spirulina to soak up heavy metals is why it's so important to purchase this ingredient from a reputable source. As researchers at the University of Maryland School of Medicine explain, "Spirulina—like any blue-green algae—can be contaminated with toxic substances called microcystins. It can also absorb heavy metals from the water where it is grown. For these reasons, it is important to buy spirulina from a trusted brand."

So there's just not enough research to say if spirulina is the miracle superfood that some folks claim it to be, but it's certainly a good protein supplement for a smoothie or even a latte, especially in a powder form. It also turns your food blue in an all-natural way, and what's not to love about that?