S.W.
Please read what the CDC says about insect repellent effectiveness:
http://www.cdc.gov/ncidod/dvbid/westnile/qa/insect_repell...
There are only three ingredients that have been shown to work and to be safe by scientific tests:
1) DEET is N,N-diethyl-m-toluamide
2) Picaridin is KBR 3023, sometimes known as “Bayrepel” outside the US
3) The active ingredient in oil of lemon eucalyptus is p-menthane 3,8-diol (PMD)