Half of people get nausea at about 4 mg of copper:
Nausea threshold in apparently healthy individuals who drink fluids containing graded concentrations of copper
(Olivares, 2001 Jun)
https://pubmed.ncbi.nlm.nih.gov/11407930/
I believe the cause of the nausea is fluoride detox.
Fluoride is quickly attracted to copper in the stomach, and fluoride is what really causes the nausea.
You can adapt, and get used to copper.
Copper binds with fluoride, making both a copper II fluoride molecule and a more stable copper/fluoride/phospherous molecule.
Most people have 2600 mg of fluoride in their bodies, and only 72 mg of copper.
It will take a while to take enough copper to detox all the fluoride.
First, start out taking no more than 1, 2, or 3 mg of copper. Take it with food and plenty of water.
After a few weeks, you can increase the copper, and take up to 3 mg multiple times a day. Even this can cause nausea at first. I know that quite a few people have puked on 3 mg of copper. You can read about this in the reviews of copper supplements at amazon.com.
This is not an indication of “copper toxicity”. This is not an indication that “copper is not right for me”. It is an indication of fluoride toxicity, not copper toxicity. It is an indication that you need copper more than other people! It’s the opposite of what you might think.
You can also take iodine, and boron, to help get past the fluoride detox, as both of those minerals also help to detox fluoride. For more on iodine and boron, why and how to take them, and how much, and sources:
The other best way to get past fluoride detox in the stomach is to apply copper topically, to the skin. I apply up to 70 mg of copper to my skin. Copper sulfate is well absorbed through the skin.
Copper supplements often come in pills, not liquids. You will likely need to make your own. It is very easy, just under half a teaspoon of blue copper sulfate crystals into 2 oz. of water in a 2 oz. dropper bottle, makes a solution containing 1 mg of copper per drop, so you can accurately determine how much you are getting.
I’m currently taking about 70 mg of copper, 50 mg of iodine, and 50 mg of boron daily.
I took 3-9 mg of copper for a year. It continued to make me nauseated on occasion. The second year, I continued to get nausea, on occasion, while trying to take from 20-30 mg of copper per day. In my third year taking copper, I very rarely got nausea. In my fourth year taking copper, I recently got a tiny bit nausea taking 8 mg of copper in my coffee, if I did not add any milk. Now I’m up to 10 mg of copper in my coffee, with milk, with no nausea.