I'd like to use natural malaria prevention. Insect repellent patch seems to be very promising. One patch contains 75 mg of B1 and covers 36 hours. However, it's not very cheap. Many other travellers recommend doses of B1 vitamin.
If you want a natural solution, try lemon eucalyptus oil.
Considering that B1 does not deter mosquitos, any dose you like will be comparable to 75mg (zero effect). However, if we wish to assume it works, you'll want the patch. Eating B1 won't help much. Since B1 is principally excreted in your urine, eating a lot of it would only really help if you bathed in your urine afterwards.
New England Journal of medicine
Most alternatives to topically applied repellents have proved to be ineffective. No ingested compound, including garlic and thiamine (vitamin B1), has been found to be capable of repelling
http://www.entomology.wisc.edu/mosquitosite/homeremedy.html
Studies of garlic and vitamin B did not find evidence that these substances could reduce mosquito attraction.
http://www.webmd.com/allergies/features/are-you-mosquito-magnet?page=2
In the last few years, nonchemical repellents worn as skin patches and containing thiamine (vitamin B1) have arrived in some big-box stores under the name Don’t Bite Me! The science behind this repellent comes from a study done in the 1960s. It showed that thiamine (B1) produces a skin odor female mosquitoes don't like. But no other studies have confirmed thiamine's effectiveness as a mosquito repellent when worn on the skin. Chari Kauffmann, president of the company that sells skin patch called Don’t Bite Me!, says studies on the product are ongoing, though the company has no conclusions to report.
Generally if a study can't be confirmed within 50 years, including by a company trying to profit from it, it's a sign that there was a flaw in that study. In addition multiple studies (My apologies for some of the studies not being public access) have found the counter, which is that is is not effective.
You should also be aware that everything is a poison at some point. In the case of B1, long term dosing (like say, frequently to ward off mosquitoes) of 3g or more could cause harm.
I traveled in Cambodia with a doctor who has decades of experience in tropical medicine. On his recommendation, our group:
Are there "natural" preventatives? I don't know. However, consider this:
I sympathize with your desire not to expose yourself to more chemicals than necessary. But in this matter, please be careful. Use whatever works best to avoid malaria.
I appreciate the preference to use natural protection, however, I think it is important to point out that using insect repellent should not be the only method of defence against malaria that you employ. Insect repellent is not 100% effective (*) and does not directly prevent malaria - the mosquito acts as the host to transmit the Plasmodium parasite, which causes malaria. If you are traveling in the Malaria Belt, I would strongly recommend seeking professional medical advice on the use of prophylactic anti-malarial drugs.
Just for fun, historically the natural anti-malarial prophylactic was quinine (occuring naturally in the bark of the cinchona tree) and used to flavour tonic water. Anecdotally, it was consumed with gusto during the reign of the British Empire when gin and tonics were the drink of choice in British colonies in tropical areas to protect against malaria due to the quinine in the tonic water. There are now many more effective anti-malarial drugs.
(*) The product you link only describes its protection as an "almost impenetrable shield" (emphasis mine).
Vicks Vaporub works for me. I used this method in Iraq when nothing else would work.
Those B1 patches work great for Deterring mosquito, fleas, flys and ticks. I am a naturalist, wild crafter and herbalist, when we do plant identification, scout and harvest we use them and they do work. We have field tested them in the woods of North Carolina, in the rain as well. Bugs stay away and ticks will not attach. they will try, but we have never had one attach. I personally, usually get bit by mosquitoes, they love me, but when I use these patches they don't. All I can say is try them. I personally will not use anything that is not natural and safe. DEET IS NOT SAFE. I lived in Africa for 3 years in the 70s and as long as you take the anti-malaria pills, you should be okay. Wouldn't hurt to try the patches as well. Each Don't Bite Me Patch contains less than 10mg of Vitamin B1. From our experience, we find that they work very well.
