Simply put, nicotine salts infused e liquids refers directly to the nicotine type that's there in Propylene Glycol (PG) as well as Vegetable Glycerin (VG). Together, they contribute towards a bulk portion of the eliquid.
In essence, nicotine salt juice is naturally extracted from tobacco leaves and retains a similar feel like that of traditional cigarettes. This is why when you vape nic salts, you tend to feel a lot less harsh hit coming from the puff.
Typically, nicotine vape carries a higher degree of nicotine concentration and are all the way “bioavailable”. In other words, it facilitates quick absorption to offer the rush you desire.