The present invention relates to a drug delivery device (1, 100) comprising a drug expelling mechanism and a spring (10, 110) releasable during use of the drug delivery device (1,100) to convey stored energy to the drug expelling mechanism. The spring (10, 110) comprises a first helical portion (11, 111) and a second helical portion (13, 113) surrounding at least a portion of the first helical portion (11, 111).
