We could use double blind studies where some people get the drug and others get a placebo. (wattsupwiththat.com)
Illness: while not scientifically proven through double blind studies in prestigious universities it may be an indication that your dog is missing something in its diet. (ovahosp.com)
In a second double blind study 30 females in the same age range and with similar signs of sun damage were treated with 500 mg / day or placebo for 90 days. (global.vidaglow.com)