Not really, they’re two competing design criteria. Concealable means small and low profile. But for protection you need it to be strong to distribute the impact across your head and also cushioning to absorb energy of the impact and spread the impact event out over a longer duration (like an airbag). As a result you need a relatively tough material suspended away from the surface of your head e.g. with webbing or foam etc. so good helmets are military ones (obviously) or mountaineering helmets, ski sports, full face mountain biking, construction helmets etc.