Cigarettes contain many harmful toxins that damage the body. The nicotine in cigarettes can cause you to have high blood pressure and damages the lungs. Even if you stop smoking, the effect of nicotine will last for years.
Just 10 seconds after a cigarette smoker inhales, nicotine is absorbed through the skin and the mucosal linings in the nose, mouth and lungs, and travels through the bloodstream to the brain.
Nicotine can also lead to insulin sensitivity and insulin resistance, as well as an increased risk of developing metabolic syndrome, type 2 diabetes and cardiovascular disease.
It affects thyroid hormones, pituitary hormones, sex hormones and adrenal hormones.