.ncbi.nlm.nih.gov/pubmed/19004414 hup://www.ncbi.nlm.nih.gov/pubmed/17297639?ordinalpos=l&itool=EntrezSvstem2.PEntrez.Pu knied.Pubmed_RestiltsPanel.Putimed SingleltemSupl.Pubmed Discovery RA&Iinkpos=4&log$= relatedreviews&loudbfrom -pubnicsi In my mind, other substances are much safer Good review: http://en,wikipedi