The main reason that people smoke is because they are addicted to nicotine. NRT is a medication that provides you with a low level of nicotine, without the tar, carbon monoxide and other poisonous chemicals present in tobacco smoke. It can help reduce unpleasant withdrawal effects, such as bad moods and cravings, which may occur when you stop smoking.
Patches release nicotine slowly. Some are worn all the time and some should be taken off at night. Inhalators, gum and sprays act more quickly and may be better for alleviating cravings. There's no evidence that any single type of NRT is more effective than another. But there is good evidence to show that using a combination of NRT is more effective than using a single product.
Often the best way to use NRT is to combine a patch with a faster acting form such as gum, inhalator or nasal spray. Treatment with NRT usually lasts 8-12 weeks, before you gradually reduce the dose and eventually stop.