Yes, you can buy curcumin online.
As for your kratom questions:
Is it something that will make me more tired or give me energy?
Bali makes me feel relaxed and can make me tired. Maenga da or Green Malay are stimulating.
If it gives energy, is it a jittery type of energy like caffeine, or more mild?
The Maenga da to me is like a strong cup of coffee.
Does it help concentration?
Yes, the stimulating strains do and some people use them to help treat ADHD.
Does it have any health risks associated with use?
Well, it addicting just like opiates so withdraw is an issue. It causes constipation and can worsen anxiety for some. Taken long term and at high doses some believe it can cause darkening of the skin and aggression. If you take too much, you will vomit and get wicked dizzy. Used wisely...I think it is quite safe. Safer than high dose oxy and Fentanyl in my humble opinion.
Glad to hear withdraw is mild.
I sure hope I am feeling better 16 days after I jump. I will have 7 days off from work and then will have to drag my sorry ass back.