Synthetic marijuana, more commonly known as “spice” or K2, is consumed just like real cannabis flower, but the two substances are actually very different drugs. Synthetic marijuana is not FDA approved, and the label actually reads “Not for human consumption,” though the drug is easily found in smoke shops under brand names. Producers bypass the law by using new chemicals that are changing faster than the lawmakers prohibiting them, so they are sprayed on dried plant matter to create a psychoactive marijuana effect. This experience is very different than marijuana though, because the amount of chemicals sprayed and the specific chemicals sprayed vary, so spice can be anywhere from 1 to 800 times more potent than real cannabis flower and THC.
The chemicals sprayed on the spice change frequently, creating different high experiences that can be harmful, with a number of side effects that are both psychological and physical. Even though the two substances are not to be compared for these reasons and more, K2 is a chemical analog of cannabis with a similar structure that binds to the same system of receptors as real cannabis flower, which means that spice technically is marijuana, because it mimics THC.