Do I charge taxes if the business is CAD & the product is manufactured/sold/fulfilled in the USA?

[AshleyVW]

My business is a registered business in Canada and we sell products that are manufactured, sold and fulfilled all within the US through a contract manufacturer (manufacturer) and fulfillment house (shipped from Atlanta). 

Do I charge taxes if I sell in all states? How do I go about tax withholding based on the CAD and USA treaty? Any experts that would be able to shed some light on this very confusing and borderline grey topic because it is not so black and white? 

The product is a supplement if that is an important consideration. 

Any help will go a long way!

Thanks,

S