Replied by Ted (Bangkok, Thailand) on 04/05/2009
I currently don't sell baking soda, but it is a ubiquitous item in Bangkok and you maybe able to get them in shopping centers soon. It's usually found in Central Department Stores in Chiangmai in the supermarket area on aisles where they sell baking products. Lysine in tablet form sold in Bangkok can be powdered or chew. A vitamin C sold by a Thai brand maybe contacted on the back of the labels -they usually have the name of the company and their telephone numbers, where you can purchased in bulk quantities cheaply.
Ted