Hi xrayspex.
When I first accidentally discovered the anti-anxiety effects of NAG, and starting taking around 3 x 700 mg daily, I noticed it would cause some mild depression in me too. So I reduced the dose to 1 x 700 mg, and the depression side effect more or less disappeared, but the anti-anxiety effect still worked.
So you can consider reducing the dose, and seeing if that works for you.
When I first accidentally discovered the anti-anxiety effects of NAG, and starting taking around 3 x 700 mg daily, I noticed it would cause some mild depression in me too. So I reduced the dose to 1 x 700 mg, and the depression side effect more or less disappeared, but the anti-anxiety effect still worked.
So you can consider reducing the dose, and seeing if that works for you.
I do have a cream I got from UK that has glucosamine and heart chestnut in it that I use on certain joints and have not noticed any depression from that, hopefully its doing something.