You may be confusing your units. Most of our powder products are sold in increments of 1000 milligrams (mg), that is 1 gram (g). There are 70,000 grams in the average size person. So a single gram, even with the vast range of powder densities, will be a small amount. Less than a tablespoon.
If you do not have experience working with milligram quantities of research material we would advise against purchasing powder products.