Forget the tonics and surgery. This is physics based. And not that silly quantum woo either.
We all know time is affected by gravity. In fact low earth orbital satellites. Have to compensate for the fact time goes faster up there than down here. Now if the moderate gravity of earth is enough to slow time enough that your instruments can detect it.
Imagine how much slower times goes in the center of Jupiter.
So for the low low price of 500 trillion I'll send you to the center of Jupiter. This is guaranteed by Einstein himself to slow your ageing.
But if this entry level deal isn't good enough for you. I'll send you into orbit around a black hole. We're you'll only age seconds while we in earth age decades or even centuries.
Now this is a special offer only good for the next 20 minutes or until stock runs out. The price is $9,999,999,999,999,999,999,999,999,999,999,999,999,999,999,999,999,999,999,999,999,999.48 USD
Only a few left in stock.