Repeated platelet donations at short intervals will cause the venipuncture site to scar. While cosmetically it is virtually invisible, the scarring also occurs on the vein itself, making it harder to insert a needle on future occasions. Anecdotal reports have said that rubbing vitamin E oil (or the insides of a vitamin E capsule) on the venipuncture site may reduce scarring. However, a study conducted by the University of Miami Department of Dermatology and Cutaneous Surgery in 1999 demonstrated no positive effect from the application of topical vitamin E.