'Research Chemical' is a term used to refer to any chemical that has not been well researched and does not have an established long-term safety profile.
'Research chemical' is a term used to indicate a chemical which has not had a history of research or human use, and is therefore considered to be at a 'research stage.' There is no official body which determines a research chemical, or when a research chemical has accrued enough history of use to cease its classification as one. Some have suggested that these chemicals should be called "unresearched chemicals" or another term "Experimental Chemicals". Some are new, while others have been around for years; and little is known about most of them besides first-hand accounts of their use. There are research chemicals of many different types of drugs: while many drugs are qualified as research chemicals, the term itself is more of a flag than a category.
The expression can be considered somewhat of a misnomer, as drugs in this category have often not actually been researched, or at least have almost no history of human use. Many research chemicals in use today were originally discovered and published by Alexander Shulgin in PiHKAL and TiHKAL, and a lot more have been found based on these works. The term partially came from the fact that substances in the recreational markets were drugs that had been discovered in labs and only examined in-vitro or low-level animal studies. However, the 'research' more readily applies to the fact that these drugs were usually found through a process of research - such as through exploring analogues of existing psychoactive substances. Very little to no research has been used to establish the toxicology or human pharmacology of these drugs.
'Legal highs' commonly sold on a grey-area market are usually one or more research chemicals made to mimic the effects of other illicit drugs. There is currently a very large market for the production, sale and use of research chemicals, driven by their implicit legality; vendors and users alike pursue research chemicals to avoid legal troubles encountered from being involved with the more traditional chemicals. Governments tend to ban research chemicals a short while after they become popular, and this, in turn, leads to more being discovered and sold. Some legal systems, such as that of the USA, have moved against research chemicals with acts of law implicitly banning analogues of drugs which are already banned.
As many of these drugs are very new and may not have a well-established safety profile, there are a variety of stronger risk factors in using them. It is likely that many research chemicals have undocumented side-effects, interactions or contraindications.
Remember, just because it is an analogue of something, does not mean it will behave the same way.
An example of this can be seen in the following comparison of two structurally related chemicals MDAI and MDMA. MDMA has been documented since the late 60's. MDAI is an analogue of MDMA, and while it produces some similar effects to MDMA it differs in that it's non-neurotoxic.
Or we can take 2C-B and its analogues such as BK-2C-B, 25B-NBXXX, TCB-2, DOB, Bromo-Dragon-Fly, 2C-B-FLY. The parent drug in this example is much safer than the rest. There is no record of a death from 2C-B alone, with 25B-NBOMeN-Benzyl-Ortho-Methoxy derivatives of psychedelic phenethylamines. there have been reports of multiple deaths during its short history of release.
While there is a certain element of risk involved in all experimentation/use of research chemicals. There are some basic precautions one can take in an effort to make an inherently risky behaviour less dangerous than otherwise.
While most readily available anecdotal information on research chemicals cannot be entirely trusted (due to the nature of research chemicals most data available on RC's is just that, a series of anecdotes), even for very new drugs there is usually a fair amount of information available which can give a good idea of what to expect. It is important that you do your own research and carefully make your own informed decisions; don't take people's word for what a drug can/will do to/for you at face value as the same drug can affect people differently.
When experimenting with any new drug a little forethought can go a long way, especially when it comes to drugs about which very little is actually known.
Usually, if you're experimenting with a new drug (or even just a drug that is new to you) it's best practice to have a sober sitter with you, just in case something goes wrong. Some types of drugs produce effects that are more risky to go into alone than others but if you're using something new and you are unaware of how it will affect you, it's never a bad idea to be accompanied by a trustworthy person, such as a close friend, to help guide you through a difficult experience or just someone to keep an eye on how your body reacts to something.
As these chemicals are generally very new, and little information exists as to their effect on humans, there is also a lack of information about recommended doses. Often, speculative doses can be found on the Internet. When a new research chemical is released, the first results can often be found on forums such as Bluelight or drugs-forum. These consist of anecdotal trip reports, and cannot be trusted very much since in the early days of a drug's release, vendors will often sell other drugs under the newer name. After a time, and once some verifiable reports about the drug have been collected, tiered summaries are compiled by resources such as TripSit Factsheets and Erowid, which can provide more conclusive dosage guidelines. However, even when speculative doses are published, they should not be fully trusted due to the lack of long-term testing a drug has received at this point. Drugs which do not have much reliable information pertaining to their dose will generally be tagged.
With a chemical that has never been tested in vivo (animal subjects) for most substances, you would want to start around 25ug's and titrate your dosage up to 50ug's in increments of 25ug's Leaving a week minimum between the 25ug test and 50ug, and work your way up. But this isn't needed for every chemical, such as BK-2C-I. You can use BK-2C-B as a "reference" of sorts, of it being 10x weaker than the parent compound(BK-2C-B). It is much safer to start at a lower dose than what would be an active dose to see if your body can handle the drug.Some might say that you can gauge an activity with just SAR's (Structure-Activity relationship) which in the most part true, yet in cases such as Lophophine and IRIS, there is a very good reason why it should be active, yet it isn't. That can also go the other way, as IRIS is one of the "Ten Classic Ladies" or the ten possible homologues of DOM. While DOM is active around 3mg's, yet IRIS is inactive.
Therefore, because of the importance of using sub-threshold tester-doses, and since many of these new chemicals are highly potent anyways it is imperative that one has a reliable way to accurately measure chemicals in low doses.
It is not safe to assume any consumer-grade scale will be reliably accurate <50mg, however, there is a way to measure accurately low doses of chemicals using a method known as 'volumetric dosing', Quick guide to volumetric dosing. While this technique is not particularly difficult it does require some planning and precision.
If you intend to employ volumetric measuring techniques, or when working with new chemicals (or any chemicals for that matter) it is important to be sure to use the most accurate scale available on a consumer level. Unfortunately, there are no scales that are reliably accurate for weights under approximately 25 mg that are readily available to the average consumer. That being said, there are some scales for sale for under $100, which if used correctly, can be safely used to prepare a solution for volumetric dosing of a substance. For more information on how to correctly use a scale, and sources for reasonably reliable scales to buy, check Scales.