A slimming pill is a tablet claimed to help reduce weight, whether by speeding metabolism, suppressing appetite, or blocking the absorption of fat. The category ranges from prescription medicines with proven, modest effects and real side effects, through herbal products with thin evidence, to outright frauds laced with undeclared drugs. History is littered with dangerous slimming pills, from thyroid hormone to amphetamines to sibutramine, withdrawn after harming users. Regulators warn that no pill produces lasting weight loss without diet and activity changes, and that products bought online may contain anything. Anyone considering them should consult a doctor first: the promise is seductive, but the risks are documented and the benefits usually temporary.