Coenzyme Q10 is also called ubiquinone (the "ubiquitous quinone"), because it is present in plants and animals, including the human skin. This is a crucial molecule in respiration. Its topical application restores mitochondrial activity, increasing energy production as ATP, plus reducing power needed to make new collagen.
Coenzyme Q10 should not cause allergic reactions, but idebenone, a synthetic version of CoQ10, has been known to do so.
Coenzyme Q10 is NOT hype. Mitochondrial function can be limited by insufficient CoQ10, and topical application of the quinone can help older mitochondria work better because electron transport is a crucial part of respiration and energy production.