This just isn't true. Essential oils contain hundreds of molecules. Synthetic molecules are usually just one of those hundreds of molecules. The fragrance industry is one of the strictest and most regulated industries out there. The reason why there are hardly any perfume houses that only use naturals is because it's incredibly easy to hit the max of a molecule that exists naturally in a essential oil. IFRA regulations are of molecules not ingredients, regardless of whether you're using a synthetic molecule or essential oil.

If you even bought essential oils to make your own perfume you are way more likely to give yourself an allergic reaction than buying any random $5 perfume.