Can I just add: In addition to this, if you struggle with anxiety or have some sort of ADHD, then try cutting out caffeine entirely . Not just switching to "decaf" (which isn't), but cutting out tea and coffee, and switching to an alternative like Barleycup. Doing this has had a massive positive effect for me, and combined with decent nutrition and daily exercise, has been wonderful.
Can you describe what else you tried? Other supplements? Any other non-food/supplement techniques like journaling, breathing, etc.? Any therapy and other similar human interventions?
After all those - is it / was it still the case that cutting caffeine drove the best outcome?