Superior White Raffard's Decoction is the highest form of the potion. The in-game description of the effect is rather misleading; instead of granting full immunity from damage, the potion actually nulls a threshold of health loss for a limited time. If Geralt takes large enough amount of damage before the duration ends, the immunity effect will be cancelled.
Three of these can be crafted at any one time and placed in the consumables slot.
See also Edit