elixir
noun [ C usually singular ] literary uk/iˈlɪk.sər/ us/iˈlɪk.sɚ/
（通常为液体的）万灵药，灵丹妙药，长生不老药
a substance, usually a liquid, with a magical power to cure, improve, or preserve something
It's yet another health product claiming to be the elixir of life/youth (= something to make you live longer/stay young). 这又是一种号称灵丹妙药的保健产品，据说有延年益寿／永葆青春之奇效。