The new range of short acting insulins have not been proven to be safe enough to hand out on a widespread basis to diabetics.
Experts say the drugs should not replace the existing generation until their longer term safety have been established.
Prof Harry Keen, chairman of the British Diabetic Association, says that better designed clinical trials and more experience are needed before the drugs are widely used.
The short acting insulin analogues, such as lispro (Humalog), act very quickly, but this sudden surge of action is contrary to current understanding of treating diabetes, he says.
He said no one wanted a repeat of the problems that occurred when human insulin was introduced. "We want to be absolutely sure there is no repetition of that feeling among patients that they are being submitted to a new insulin which has not been carefully tried in all situations," he said.