Answer...
Not only does it vary from nation to nation, but from locale to locale within those various nations as well. Here in NYC, the gnerally confirmed epicenter of international heroin use, it used to be almost always lactose and quinine in an 80:20 ration [lactose repsenting the larger number] or lactose, mannitol, and quinine in a 70:10:20 split [again, with lactose represented by the larger number]. Lactoseof course is milk sugar. As it is completely inert, it is used to bulk up the heroin. Mannitol, a substance usually used as a baby laxative, is used to fluff up the heroin and further increase the bulk. It also has the advantage of helping to dispel the related constipation that effects most opiate/opioid users. Quinine, an anti - malarial medication , is usedto helpprovide the illusion of a more chemical odor and taste in the heroin that by now has very little of both. While mannitol is slightly chemical in taste, lactose is sweet. Quinine also is believed to potentiate the "rush" of injected heroin.
Nowadays, since at least the mid 90s, anything under the sun has been used. Part of the problem lies in the nitial maufacture and distribution. While NYC used to enjoy high quality S.E. Asian # 4 white heroin, that was never adulterated/diluted prior to reaching these shores, it now hs been replaced by a lower quality white to brown Colombian product. Although it is also # 4 type, it is almost always less then 85% pure when it is releasedfor distribution. Unlike Mexican heroin it is not the fault of the manufactureing technique, but of a lack of effort with regard to overall purity. Instead of taking the neccessary time and effort to recrystaliize it until it is much more pure, they aim for quantity over quality which of course results in an inferior product. In addition, Colombian manufacturers have taken the unprecedented step of adulterating their product at the point of manufacture. They mosr commonly use lidocaine, a habit that can be blamed on their experiencein manufacturing cocaine.
In other parts of the nation, where Mexican "Tar" is the predominant form of heroin, there are other common adulterants. Aside from lactose, etc. that mostpeople do not even really think are possible adulterants for "Tar," such inert substances as ground coffee and molasses are usedto increase "Tar's" bulk.
Sometimes one finds dangerous substances as the aforementioned scopalmine. One also finds the otc medication Drimen used from time to time in Chicago area heroin...this is usally indicated by the red specs throughout the powedr.
In other nations one finds a different type of heroin predominating depending on the region. Europe is innundated with # 3 heroin which is expressly made for smoking. Becauseof this it is almost always adulterated with up to 40% caffeine which makes it more conducive to smoking. Other times one finds barbitone and even strychnine as well. The barbitone is used to potentiate the heroin and the strychnine is used as a flavoring agent. It is present in such minute concentrations that it does not pose any real health risk, to even the most hardened users. Strychnine is included because of the origin of smoking heroin.
When the practice started in 1920s Shanghai the most commonly sold form was a little red tablet that contained strychnine. After other forms took hold, older users associated the strychnine flavor with quality so that it then became amarketing ploy and has persisted until the present day.
Anyway, hope that bit helped.
