Smoking is one of the strongest modifiable risk factors for improved erection health. Tobacco smoke damages the endothelium (the inner lining of blood vessels), reduces nitric oxide availability, and accelerates atherosclerosis (plaque built up in the arteries) - all of which impair penile blood flow. Research shows men who smoke are about twice as likely to develop ED as non-smokers, and the risk increases with duration and intensity of smoking. Nicotine itself is a vasoconstrictor, narrowing arteries and counteracting the relaxation needed for erections. Even e-cigarettes and nicotine replacement therapies may have negative vascular effects. The good news: stopping smoking leads to significant improvement in erectile function, especially in younger men without established cardiovascular disease.