If you're looking for long-lasting adult protection against mosquitos while hiking or camping, scientific studies say you can't do better than formulations containing DEET, a form of diethyl methybenzamide. However, DEET is not recommended for children and many people would rather use a compound based on natural ingredients. With a little experimentation, you can make mosquito repellent in your own kitchen.
In a small, airtight container, mix the essential oil with the soybean oil.
Try a few drops on a small area of your skin. Essential oils can be potent and allergenic.
If there is no reaction after a few minutes, apply liberally in exposed areas, keeping away from nose, mouth and eyes.
Keep solution air tight and reapply after 20 minutes.
Try different oils and different combinations until you find what works for you. Some people are naturally less attractive to mosquitoes than others and do not require much protection.