Letters from the March 4, 2006, issue of Science News

Impure thoughts

Epidemiologist Scott Davis warns, “Melatonin supplements are not regulated” the way drugs are. … “There may be all kinds of impurities and contaminants” (“Bright Lights, Big Cancer: Melatonin-depleted blood spurs tumor growth,” SN: 1/7/06, p. 8). Are you really going to tell me that you aren’t going to take melatonin—if you’re convinced that it might lower your chance of getting cancer by as much as 50 percent—because you are afraid of impurities?

James Street
Oakland, Calif.