The patch is worn on the skin and your body absorbs nicotine from it continuously, either during the day only (15mg, 16 hr patch) or over 24 hours (21mg, 24 hr patch).
The patch typcially comes in three strengths for weaning off nicotine over 12 or so weeks: Step 1 (21mg), Step 2 (14mg) and Step 3 (7mg). Some smokers benefit from just using Step 1, others from stepping down through all three strengths. Since May 2013, a 25mg (step 1) 16 hr patch has also been available, which goes with a 15mg (step 2) and 10mg (step 3) patch.
There is also an option of a pre-quit patch (21mg, 24 hrs) for use in the two weeks prior to quitting. The pre-quit patch is for smokers who struggle to quit completely the first day they start the patches.
Patches are available at a more affordable subsidised cost on prescription from a GP. Using the patches can help to reduce withdrawal symptoms such as cravings, irritability, and restlessness.
Patches nearly double your chance of quitting.