Three addicts died in 12 hours over the weekend and police fear the death toll will rise unless the source of the batch - thought to be four times the normal strength - is discovered.
Detective Superintendent Kevin Orr, head of Strathclyde Police drugs squad, said: 'We are asking addicts to try a little of the drug before using it and, if it proves to be very concentrated, to get in touch with us to tell us where they got it.
'We must get this scourge off the streets and away from people's veins as soon as we can.
'If some addicts are determined to take the drug come what may, they should make sure they do not inject alone, so that if they lapse into a coma, help is at hand.'
The weekend victims died in the east end of the city. The body of Sara McArthur, 23, from Bridgeton, was discovered in a 'shooting gallery' - a place used by a number of addicts - and Ian Logie, 18, of Shettleston, was found lying in a public lavatory with a syringe by his side. Alexander Muldoon, 42, of Tollcross, was found dead after a drugs 'party' where he is thought to have taken cocaine and heroin.
The other victims were found in the Pollokshaws, Springburn, Gorbals and Paisley districts.
Officers believe they are casualties of a 'cynical marketing ploy' by suppliers, who have introduced the highly-addictive pure heroin in an attempt to increase their share of Glasgow's drugs market.
Det Supt Orr said: 'Drugs are big business and dealers treat heroin as a consumer product, selling it in exactly same way that, say, stall- holders sell food. From time to time suppliers, who compete with one another, introduce pure heroin as a 'loss leader'. In the short term, they know they will lose money because pure heroin is expensive and customers who take too much of the stuff die.
'But in the long term, they know they will make big profits because they will have created new addicts and the word will go round that they have the best, strongest drugs.
'Addicts go to whoever offers the largest 'score bags' and the biggest buzz. It is market forces at their worst.' Scotland has more injecting addicts than any other country in western Europe - about 30,000. Of these about 12,000 live in Glasgow, in particular in the post-war housing schemes that surround the city centre. More than 150 have died in the past two years - prompting calls for a public inquiry.
A fatal accident inquiry into the deaths of four 'typical' addicts in Glasgow last November heard startling evidence of the grip drugs have on young people in the city. Users were said to resort to injecting heroin through their eyes after exhausting other sites on their bodies; and in some areas, streets and estates have been nicknamed after drugs, the inquiry was told.
The results of post-mortem examinations on the seven victims will be released later this week. Detectives are investigating possible links with the deaths of four addicts in similar circumstances in Bristol last month but do not believe there are connections between suppliers in the two cities.