The only difference in nicotine action between traditional cigarettes and E-cigarette is the duration of the effect
The seller notes that the engines were rebuilt many years ago
doi:10.1186/s12987-015-0022-x
With regard to the current decision before the FDA, Wang said, The standards that the FDA has to apply to approve e-cigarettes as consumer products or therapeutic devices are fundamentally different. Funding: The work was supported by National Heart, Lung, and Blood Institute (F32HL144063, K12HL143961, T32HL007185, and cooperative agreement U54HL147127 from the National Heart, Lung, and Blood Institute and the Food and Drug Administration Center for Tobacco Products
Choosing between salts and freebase at 20mg comes down to your personal preference, how quickly you want relief, and whether you value smoothness or a pronounced throat hit