I am kind of anxious that I will just be taking in twice as much nicotine...
It is very unlikely you will be taking in twice as much nicotine.
In fact, it is far more likely you will be taking in less.
The average amount of juice used is somewhere between 1ml to 5ml per day, with most people at around 2ml to 3ml per day.
Since the juice strength is mg/ml a juice that is 24mg strength will provide 72mg for a person using 3ml per day.
Now here is the part that most people who are worried don't know... we do not absorb all of that nicotine from vaping.
Some studies have shown that we get around 10% of the nicotine from vaping.
Others see flaws in those studies, have done their own testing, and feel we get more like 40% of the nicotine from vaping.
So if using 3ml per day of 24mg strength liquid, you would get anywhere from 7.2mg to 28.8mg of nicotine.
And that would equal about 7 to 28 cigarettes, depending on what cigarettes we are talking about, and how much we really absorb.