Borax is also called Sodium Borate or Sodium Tetraborate-- sold as a white powder or hydrate. You can buy it as "20 Mule Team Borax"(from the washing isle of supermarkets) and use this to create a liter of water with a little borax in it to drink. To do this, take a liter of water and just add 1/8 tspn to it. Then drink a liter of this for four days only, then stop and take 3 days off(no borax water). Then start again. So, four days drinking borax water, then 3 days off -- no borax water.
See this link: https://www.earthclinic.com/remedies/borax.html
Or you can just buy Boron tablets (whose ingredients will also be listed as sodium borate or tetraborate) and take at least 6 mgs per day.
Borax helps to cure arthritis, helps to modulate the body's hormones, removes body fluoride and is perhaps the ultimate fungal killer.