Question: what is the best supplement to take during workout?
Answer: Protein. Whey protein has been proven to help with athletic performance, muscle building and fat loss. ... 
Creatine. Pure creatine monohydrate is the most studied and the most beneficial supplement for building strength. ... 
Vitamin D. ... 
Vitamin K2. ... 
Beta-alanine. ... 
Berberine. ... 
Magnesium.