"What’s worse, says Blaha, many e-cigarette users get even more nicotine than they would from a combustible tobacco product: Users can buy extra-strength cartridges, which have a higher concentration of nicotine, or increase the e-cigarette’s voltage to get a greater hit of the substance."
https://www.hopkinsmedicine.org/health/wellness-and-preventi...
"What’s worse, says Blaha, many e-cigarette users get even more nicotine than they would from a combustible tobacco product: Users can buy extra-strength cartridges, which have a higher concentration of nicotine, or increase the e-cigarette’s voltage to get a greater hit of the substance."