I'm an high-level athlete and I take 3000 UI of Vitamin D3 and 1800 mg of EPA/DHA (fish oil) on a daily basis and I didn't have a depression in years.

Dosage could vary from person to the other but the one I use is the result of years of education on the subject and personal experimentation.
Coupled with gym 3 times a week, depression will be a thing of the past, trust me.
Those 2 supplements will chase depression, help with your cardiovascular health, your psychological health, your muscles, your bones, your brain, your mood, your sleep, so many other things, I have only good to tell you about them.
Highly recommend! Taken daily (without exception), it could change your life!