Thank you for your questions. It is not possible to recommend a single brand as there are so many great brands serving different countries and regions. I purchase mine in Australia where I reside. I used to use Solgar products in Europe. They were expensive but reliable. Family members, friends and colleagues order from iHerb which offers many reputable brands in the US and ship to many countries. You may check their websites on reputable brands including various forms of Magnesium which has now specials https://iherb.co/YqLjVaHF

I explained six types of magnesium with different benefits. You may not need all six but having a few different types can make synergistic effect. The key is choosing the most bioavailable form. Reviewing this short article before choosing a brand or a product can be useful for making a decision. https://medium.com/sensible-biohacking-transhumanism/magnesium-is-not-just-another-mineral-f1ae8b89401e