I take Swiss mens multi every few days, but for brain, i take B12 & Tumeric caps. B12 is good for seretonin production, the tumeric helps with blood pressure, which can be a side effect of these meds.
Look into gut health, 85%+ of seretonin is produced in the gut, so probiotics are great to start with, they help you go to toilet well too, when tappering your body is detoxing so you need to get the number two’s out regulary, eat more veg and probiotics ( yakult is good, one daily) keep regular haha. Lots of water 2-3 litres a day.
And take it slow mate, thats important to take it slow, i’d start by getting a good multi vitamin ( avoid vitamin C it flushes you out so when tappering can cause withdrawal symtoms to worse i found. Then grab some yakult, about 8 bucks for 10.
Alternating the days is a good plan if you cant cut pills.