If you need a boost beyond caffeine, consider a square of 95% or 100% dark chocolate. It works. It too stresses the heart mildly, and can aggravate reflux a lot, but overall it's significantly safer than any tobacco product. You can also eat more of it if as needed.
The only sane time to take pure nicotine might be if someone is dying from Covid, their lungs are collapsing, and one desperately needs a daytime breathing boost.