Nicotine is just as addictive as heroin, cocaine or alcohol. So, it's no surprise if you're having trouble kicking the habit. About 80% to 90% of smokers are addicted to the nicotine in cigarettes. The more you smoke, the more your body comes to rely on nicotine and need it to feel normal. Addiction results in nicotine craving and anxiety and irritability if you can't get it. Younger people are more susceptible to addiction – especially teenagers. Girls appear to become addicted faster than boys.

Smoking can harm every organ in your body including your eyes. Toxic cigarette smoke is linked to many serious eye conditions that can lead to blindness. Cigarette smoking can increase your risk of cataracts or macular degeneration. Damage can also be caused by hot cigarette ash flying into the eye.

Light, ultra-light and low-tar are just as dangerous as ordinary cigarettes – and some research suggests that menthol cigarettes may be more dangerous and harder to give up. This may be because the cooling sensation they cause allows smokers to inhale more deeply.

There are immediate benefits of quitting smoking. Within just 20 minutes, your heart rate and blood pressure return to normal. After 2 days, lungs begin to clear and your sense of taste and smell start returning. After 2 weeks to 3 months, your risk of heart attack begins to fall. By 15 years, your risk of heart attack is the same as someone who's never smoked. After 10 years, your risk of dying of lung cancer is halved compared to a smokers.

According to the British Heart Foundation, quitting smoking is the single best thing you can do for your health. Most smokers try kicking the habit at least once a year. Talk to your GP or pharmacist about quitting and ask friends, family and colleagues for support. Research also shows that people are four times more likely to quit with help from NHS Stop Smoking Services. These are usually offered free locally. They may offer group or one-to-one support. A course usually lasts about 6 weeks.

Passive or second-hand smoke may be even more harmful than actually smoking and it's particularly dangerous for children. Second-hand smoke stays in the air for hours, and breathing it in, for even a short time, can hurt you and your child's body. Research suggests children of parents who smoke are at greater risk of conditons like glue ear, as well as lung and sinus problems including asthma, bronchitis or pneumonia. Don't allow smoking around your child.

Trying to go it alone, or going "cold turkey", can be a difficult prospect if you’re a smoker. Support and encouragement from friends and family can make a significant difference to your success. Research also shows that people do best when they combine either over-the-counter or prescription treatments with counselling. Talk to your GP or pharmacist who can guide you on getting the support you need.

One of the unwanted effects of giving up smoking is some weight gain. However, if you watch what you eat and stay active, it's possible not to gain any weight at all. Studies have found that, on average, people gain between 3 to 4 kilograms (7 to 9 lbs) in weight over the long-term after stopping smoking. To reduce the chance of gaining weight, keep your hands busy, and snack on healthy fruit and veg. Chewing gum may help. Also, brush your teeth often, and don't use food as a reward for giving up.

Quitting smoking has huge benefits but it's not all easy. Lots of people experience nicotine withdrawal symptoms, ranging from  headaches, anxiety and nausea to sadness and depression. Symptoms are usually worst during the first week after quitting and should get less each day. For some people symptoms go on for longer. Your local NHS Stop Smoking Service, GP or pharmacist can help with advice, support and treatment. This may include cutting down smoking gradually, using nicotine replacement therapy (NRT) products, or using medication, to help avoid withdrawal symptoms.

The truth is smoking changes the skin, teeth and hair in ways that can add years to your looks. Smoking deprives the skin of oxygen and studies have shown that smokers are more likely to have: loose skin under the eyes; dry skin which is less elastic; age-spotted or grey skin; and wrinkles around the mouth and eyes – all as early as their 30s.