Follow my steps at your own risk.
I think I have had a succeeded in making nicotine gum, but man what a big sticky mess. Not sure it is worth it. Also, there is some danger of not mixing the batch up properly and getting a piece of gum with way too much nicotine. Or goofing like I did and making the batch of gum way too strong.
I got my gum base from gleegum DOT com. Don't bother with the starter kit. Get the gum refill. I got the pound bag.
The gum is softer than, say, Nicorette. The release of the nicotine in my gum seems faster, and my gum does not seem to last as long. But I made my gum way too strong, and have to chew tiny pieces. I don't know how to describe how it is different. I am sitting with a piece in my mouth right now. I think it is dead, but when I chew it my mouth feels like it is getting covered with nicotine. It is like you chew it to get to the nicotine, park it in your lip, and then the nicotine is gone. Not like Nicorette where you chew it and then suck on the goodness for a while.
So this is what I did. I put a cup of gum base in one of those rectangular 24 oz. Ziploc semi disposable containers you can get at the grocery store, henceforth known as "the bowl". I stuck the bowl in the microwave without a lid for 30 second intervals until the gum base was molten. With a wooden Starbucks coffee stirrer, I stirred in 30 ml of 40 mg/ml unflavored VG juice. OK, that was way too much. That is 240, 5ml doses. Probably should have used like half of that, or less. I used a small wooden stirrer because the gum is super sticky, and a spoon gets a bunch of gum stuck on it. The coffee stirrer worked but it was kind of flimsy. If I do this again I am going to find a metal rod, or something like that, to do the stirring. I also put in 20 drops of Stevia (sweetener, I could have used more) a couple of eye droppers full of perpermint extract (I could have used more), and some green food coloring (could have used more, the gray goo gum base mixed with the light green food coloring does not look too appetizing - puke green I would call it.) I figured once the food coloring was evenly distributed in the gum the other ingredients would be too.
The VG juice was kind of hard to integrate into the gum. The juice cooled the gum where it touched it, hardening the gum, so the two did not want to mix. I stuck bowl back into the microwave for twenty seconds to warm everything up, and it seemed to go together much better. I had to stick the bowl back in several times because the gum started getting hard while mixing. But it did not take very long in the microwave to get the gum molten again.
The molten gum was not hot enough to vaporise the VG.
After the food color was homogeneously distributed in the gum, I scooped out the gum from of the bowl with the coffee stirrer into a Ziploc quart size bag. I should have used a gallon bag to make things easier on myself. A lot of gum stuck to the bowl. I was later able to get a lot of the stuck gum out of the bowl by freezing the bowl then twisting and flexing the bowl to pop off the frozen gum. Once the gum was in the Ziploc bag I zipped the bag with as little air as possible, and flattened out the the gum inside using a wisky bottle. I stuck the flat Ziploc bag in the freezer to cool.
Once cooled, I could have cut the gum into little pieces, but I just cut off a piece to chew when I want one, cutting right through the plastic bag, peeling the plastic off the piece. I keep the blob inside another Ziploc bag to keep it fresh.
At this strength, a very small piece does the trick. Taste OK but could use more sweetness and more flavor, but that is not really the point of the gum.
Again, it was a sticky messy hassle to do this. I might be able to manage it better now that I know what I am doing a little better. Chewing the gum is not as enjoyable as vaping. I think I need to try it for a while to see how I like it before I decide to try to make another batch.