Zhen’s gel: Cesium gel, formulated in Peking by Chinese doctor Zhen Lin, is the best kept skin care secret in the world – at least according to beauty guru Lesley Kenton. It contains caesium salts which stimulate the production of the enzyme acetylcholinesterase. Said to heal cuts and sores, treat acne and related problems, and, the big bonus, rejuvenate the skin.