Before you work too hard or pay too much for “the real thing”, be aware that the effects of absinthe have been greatly exaggerated. Absinthe sold in the US must be “thujone-free”. Thujone is found in a number of plant species (such as wormwood, Artemisia absinthium), and is the component that was largely blamed for the alcohol’s hallucinogenic properties. However, it seems that no one really believes any longer that the tiny amounts of thujone found in “real” absinthe actually caused hallucinations at all. And so, absinthe sold in the US is categorized as thujone-free, because these levels are so low anyway. It’s not like anything is being removed, or kept from being added.
So, the stuff you’re buying in the US won’t give you hallucinations, but apparently the stuff that Oscar Wilde and other artists drank didn’t give them hallucinations, either. And most of the absinthe sold in the US is “real” absinthe, with wormwood as a primary ingredient.
Here is some further information from The Wormwood Society.
And @gailcalled, apparently making your own absinthe at home is illegal. :/