You answered your question for yourself already. Others might have a different opinion, which is apparently not important for you.
If not Thailand...where are you intend to go then? Canada? More value for your (limited) money?
That's what I'm saying: Thailand got it all. Btw: OP was talking about Niacin, which is overdosed if he's over 65. But with a lot side effects which you can avoid by eating proper food instead.
Well, the commercials by pharmaceutical companies are obviously working.π.
Taking a multivitamin tablet a day should give you the feeling to have done everything for a healthy life?π€
A healthy life style doesn't start with a tablet but a change of habits of food intake. No "diet" necessary but common sense.
Thailand offers all on fruits and veggies you need to supply all vitamins and minerals for your body. Your daily multivitamin tablet could be even overdosed with possible side effects.
Actually there is no reason to take supplements in Thailand. You get all what you need in various fruits and vegetables.
And in old age you need only 15 mg Niacin equivalents, which you'll get definitely with your daily food. You might add a handful nuts.
Same story every year. Always same complaints.
It's like riding a dead horse.
Nobody asks them to leave UK, which might the better option anyway to return into safety with a NHS, which will provide health care your unable to pay for in Thailand. These 3 people will end up in a GoFundMe call once.
And...every country gets the government they deserve.