The substance is often described as a cocktail of various ingredients, and these may vary, but the principal active ingredient of the drug is heroin, often smoked with cannabis.
The drug is sometimes said to contain antiretroviral drugs particularly efavirenz of the type prescribed to treat HIV, but analysis of samples shows no such content, and police have remarked that dealers are known to add "all sorts of stuff" to a drug to bulk it out. Effects of wunga may last two to four hours.