I am someone who has been dealing with chronic 'low mood' as well as anxiety my entire life, especially once I was a teen. I have tried therapy/ies and medications but I do confess to not having tried many long enough or trying enough variety to truly talk of the good of this vs that.
What I can tell you is that St. John's Wort (a powerful flower-based herbal remedy) is extremely good at stabilising my mood in ways nothing has been before. I am aware that you wouldn't notice that by me on this website as I appear hostile at times but combined with habitual deep breathing and regular meditation, this has made me never once 'lose it'. I'm not saying I need it for that, you can attribute that success to me but without it, the baseline mood is lower and more anxious.
Do not take this if you're pregnant, on menopause medication or other antidepressant medication. Other mood stabilising medication can potentially work in harmony with it, so research carefully.