The Lifeforce Potion is a buff potion that grants the Lifeforcebuff when consumed, which increases the player's health capacity by 20%. This lasts for 8 minutes, but can be canceled at any time by right-clicking the icon (), by selecting the icon and canceling it in the equipment menu (), by double-tapping the buff icon (), or by canceling the buff from the buffs screen ().
If the player has used a total of 15 Life Crystals and 20 Life Fruits to upgrade their health capacity to the 500 point maximum, Lifeforce Potion will temporarily boost the player's health capacity by +100, to a total of 600, the highest amount of health one can legitimately reach.
As the player's natural health regeneration rate is related to the maximum health, it will also slightly increase player's regeneration rate.
Possibly due to how the game handles rounding, it actually gives 20 maximum health per 100 maximum health total. (for example, player with 280 maximum health will get 320 maximum health rather than 336)
The Prismite can only be acquired by fishing in the Hallow. Though it can be caught at any depth, the player will have a greater chance to catch the Prismite if they fish on the surface, because only two special fish can be caught within the surface Hallow (the Prismite and the Princess Fish).
Despite the Prismite being available on the 3DS version and having 'Material' listed in its tooltip, the Lifeforce Potion cannot be crafted due to a lack of Shiverthorn in the game. However, it can still be found in Chests in the Underworld.
Using the Lifeforce Potion can greatly increase a player's chances of winning any major boss battle, especially in Expert Mode and Master Mode, since the player needs all the buffs and health they can get.