Unfortunately the answer is no. The ingredient used in the scientific studies and recommended by the CDC is “Oil of lemon eucalyptus”, which is made from lemon eucalyptus oil but isn’t the same thing.
Lemon eucalyptus oil contains small amounts (less than 2%) of a substance called p-methane-3,8-diol (PMD), which is a very effective and long lasting mosquito repellent. Oil of lemon eucalyptus is lemon eucalyptus oil that has been processed to increase the level of PMD to around 71%. That’s a big difference. You can read about the process here.
So does lemon eucalyptus repel mosquitoes? Yes it does, but not as effectively as oil of lemon eucalyptus and not for anywhere near as long. I still like to use it and I find it effective but it needs to be re-applied every hour or so. And if I’m going anywhere that’s really heavily infested with mosquitoes or that has disease carrying mosquitoes, I always use a spray like Cutter Lemon Eucalyptus Insect Repellent that contains oil of lemon eucalyptus.
The Cutter spray was found to be effective against disease carrying mosquitoes in 2 different studies. This study compared 8 different mosquito repellents and found that the Cutter brand was around as effective as products containing DEET. This study compared 11 different spray on and wearable repellents and also found the Cutter brand to be very effective.
If you’d like to try making your own diy lemon eucalyptus mosquito repellent, here is the recipe.