Swallowed or snorted (also called bumping) meth give the user an intense high. Injections create a quick but strong intense high, called a rush or a flash.
People who abuse methamphetamines feel high and full of energy. They think the drug will allow their bodies to keep going and going. But meth is very damaging to the body and brain, especially with repeated use.
Side effects include rapid breathing, an irregular heart rate, and increased blood pressure. Users also complain of sweating, headaches, blurred vision, dry mouth, hot flashes, and dizziness. Because the drug often decreases or even eliminates appetite, it has been used as a dangerous dieting strategy for people trying to lose weight quickly.
"Meth mouth" is another risk. This severe tooth decay and gum disease often causes teeth to break or fall out.
Long-term use can bring on brain damage that causes problems with memory and body movements, and can cause mood swings and violent behavior.
When used in larger doses, meth can cause dangerously high body temperature, confusion, convulsions (uncontrollable jerking body movements), and even death.