Radium!

From Barbara Goldsmith's Obsessive Genius: The Inner World of Marie Curie:

Minute dilutions of radium were added to tea, health tonics, ice creams, lipsticks, bath salts, costumes that glowed in the dark, and so forth. La Crème Activa, purported to contain radium was guaranteed to keep skin looking young. Curie Hair Tonic guaranteed no loss of hair. A bag containing radium worn near the scrotum was said to restore virility; a Cosmos Bag was strapped to the waist for arthritis. Radium toothpaste was said to preserve and whiten teeth, a radium inhaler to increase the vigor and enrich the blood. A doctor calling himself "Alfred Curie" marketed Crème Tho-Radia. His advertisement showed a beautiful blonde woman with flawless skin bathed in blue light. [...]

One could buy a Revigorator -- a flask lined with radium to be filled with water each night to drink the following morning. Radithor, a drink containing one part radium salts to 60,000 parts zinc sulfide, was said to cure stomach cancer, mental illness, and restore sexual vigor and vitality. An American industrialist, Eben Byers, drank a bottle each day for four years, at the end of which he died in excruciating pain from cancer of the jaw as his facial bones disintegrated. The famous American Follies Bergère dancer Loie Fuller became infatuated with Marie and her discovery and wrote requesting some radium to create a costume. When Marie refused, Loie came to the Curies' house and performed a dance, her body lit by electric lights colored by blue cellophane filters -- the nearest she could come to a radium effect. Soon, in Paris, New York and San Francisco, theater and nightclub reviews featured women invisible but for the glowing radium paint on their costumes.