One test was baking at 350 degree for 10-15 min and black tar comes out throw away - and one is look at the label:

If it says
vitamin b2 riboflavin
vitamin c ascorbic acid
vitamin d calciferol
vitamin e dl-alpha tocopherol
vitamin k menadione or phytonadione
pantothenic acid calcium D-pantothenate
folic acid pteroylglutamic acid

Synthetic mineral names will usually end in one the following:
ascorbate, aspartate, carbonate, chloride, citrate, disulfide,
gluconate, glycerophosphate, iodide, lactate, malate, methionine,
orotate, oxide, picolinate or sulfate

Synthetic minerals are not the bad guys. In most cases the formula aids the minerals in adsorption. I agree with the tar discovery. You don't want that.

Ascorbic acid is synthetic. It is used in clinical studies, because vitamin C is very unstable. Ascorbic acid is too, but less so.

Citrate is a good binder for most minerals, especially magnesium and calcium, because it will help those minerals to be more bioavailable. Riboflavin is the best way to get B2 for use in the body. Malate is not synthetic. It is manufacture for sure, but it is malic acid. We have several posts describing how very helpful malic acid is. It mostly comes from the skin of apples. It is the very best binder for magnesium that you can get.

Iodide is essential. In the Lugol's formula, it is bound with potassium for easier assimilation. Iodine and potassium iodide. Each are stored in nearly all body tissue. Iodide is stored in the prostate to keep it healthy as much as Iodine is stored in the breasts. They kind of go together.

So manufactured might be a better word, and that is not necessarily bad.

__________________
-
- Jim

"If stupidity got us into this mess, then why can't it get us out?" �Will Rogers