A lot of friends have ended up on prozac or other drugs, with profoundly hit or miss results.
I've struggled at times, but found that vitamin D, magnesium, zinc, decent amount of protein, and good sleep did a lot for me. Regular outside activities, even if just walks, or exercise also a lot for me.
Keep in mind I live in Western Canada, so my walks often happen in -30C weather.
Also just finding something that produces joy was big. Not fun, not cool -- joy. Making less money and doing more things that bring me joy made a big difference. Most of the people I know making "the big money" are miserable people.