Here in Australia Vitamin B patches are sold as a healthy alternative to insect repellant. They really seem to work. I am rarely troubled by biting bugs but I routinely take a Vitamin B complex as a daily supplement. Another suggestion put to us when doing an extended camping trip up through the centre of Aus. was to eat Vegemite each day. This is a yeast extract spread mostly used on toast. This is again high in Vitamin B. However it is also very salty so is an aquired taste, but can be used in gravy and casseroles to enrich the flavour. Those in the UK have a similar spread I believe called Promite and also Marmite.
I would rather rely on natural deterrents rather than more poison which affects us as well as the insects. Good luck with your mossie seaon!!!