1.) Buy from an authorized reseller. Avoid Amazon and eBay if at all possible, and make sure you have an unconditional guarantee from any online seller.
2.) Insist on buying a jar that it has an engraved Use By date and lot code information. If an engraved code is there, make sure it is not adulterated in any way.
3.) If in doubt, DO NOT PUT IT ON YOUR SKIN! Contact us at firstname.lastname@example.org and we will help you identify whether it is genuine Egyptian Magic.