There are three types of nicotine in e-liquids: Freebase nicotine Nicotine salts Hydrid nicotine Freebase nicotine is a common ingredient in many e-juices. It’s the pure form of nicotine and it gives a strong punch when the liquid is heated. Vapers who take a few puffs throughout the day usually go for liquids with freebase nicotine. Nicotine salts are gentler than freebase nicotine; they are smoother and less harsh on the throat. Nicotine salts are regular nicotine, just like freebase, but with a balanced level of pH.  Finally, hybrid nicotine is a blend of freebase and nic slats. With hybrid nicotine liquids, you get a smoother experience and a powerful kick of nicotine.