A<unk>  is a structural or functional analog of a controlled substance that has been<unk>  to mimic the pharmacological effects of the original<unk> , while avoiding classification as illegal and/or detection in standard<unk>  tests.<unk> s include psychoactive substances that have been designated by the European Union as new psychoactive substances (NPS) as well as analogs of performance-enhancing<unk> s such as<unk>  steroids. Some of these were originally synthesized by academic or industrial researchers in an effort to discover more potent derivatives with fewer side effects, and shorter duration (and possibly also because it is easier to apply for patents for new molecules) and were later co-opted for recreational use. Other<unk> s were prepared for the first time in clandestine laboratories. Because the efficacy and safety of these substances have not been thoroughly evaluated in animal and human trials, the use of some of these<unk> s may result in unexpected side effects. The development of<unk> s may be considered a subfield of<unk>  design. The exploration of modifications to known active<unk> s—such as their structural analogues, stereoisomers, and derivatives—yields<unk> s that may differ significantly in effects from their "parent"<unk>  (e.g., showing increased potency, or decreased side effects). In some instances,<unk> s have similar effects to other known<unk> s, but have completely dissimilar chemical structures (e.g. JWH-018 vs THC). Despite being a very broad term, applicable to almost every synthetic<unk> , it is often used to connote synthetic recreational<unk> s, sometimes even those which have not been<unk>  at all (e.g. LSD, the psychedelic side effects of which were discovered unintentionally). In some jurisdictions,<unk> s that are highly similar in structure to a prohibited<unk>  are illegal to trade regardless of that<unk> 's legal status (or indeed whether or not the structurally similar analogue has similar pharmacological effects). In other jurisdictions, their trade is a legal grey area, making them grey market goods. Some jurisdictions may have analogue laws which ban<unk> s similar in chemical structure to other prohibited<unk> s, while some<unk> s may be prohibited irrespective of the legal status of structurally similar<unk> s; in both cases, their trade may take place on the black market.
Designer drug
Generic drug
Proprietary drug
Cold medicine
Topological drugs
Botanical drug
Research chemical
Hazardous drugs