You can waste a lot of money on natural remedies to repel mozzies, so here's some help to choose those most effectively proven (without wasting your money, or using nasty chemicals)
Vitamin B1 (or B5, B6, B12)
While many claim vitamin B1 to be effective, and vitamin B1 products designed for repelling mozzies have been available for years, there is no good clinical evidence to support this view, or to support the use of other B Vitamins.
Check out this trial http://www.ncbi.nlm.nih.gov/pubmed/16033124
These gizmos are sold on the basis that the ultrasonic waves they emit keep mozzies at bay. A clinical trial of even the commercially available ultrasonic devices found no difference in mozzy activity compared to when no devices were used.
Here’s the trial – http://www.ncbi.nlm.nih.gov/pubmed/10890136
Garlic has long been recommended by those who believe in vampires for its repellent activity. Although mozzies also like to feed on blood, there’s no good evidence to support the use of garlic. Here’s another trial – http://www.ncbi.nlm.nih.gov/pubmed/15752181
Citronella Oil & Other Essential Oils (not for consumption)
The repellent activity of Citronella Oil, Lemon Grass Oil and several other oils (including wormwood) has been studied and found to be even more effective than typical D.E.E.T based chemical formulas.
These oils should not be used for consumption and are very toxic, so keep them well out of the reach of children, preferably in a locked medicine cabinet.
My preferred method of repelling mozzies, citronella oil is inexpensive and can be used even for little kids, provided it’s applied as shown in my blog page here http://goo.gl/ESQGpT
Here’s a trial – http://www.ncbi.nlm.nih.gov/pubmed/23998314
A note about D.E.E.T.
D.E.E.T. (N,N-Diethyl-meta-toluamide) is a popular ingredient in strong mozzie repellents. I refuse to use this on my kids due to its toxicity (there have been deaths reported from not only ingestion of this substance, but even from topical use in both adults and children). Check out this report for the details