# Correctly converting the weight of compounds (e.g. Alpha GPC) to the weight of their FDA-recognized essential nutrients

Chemicals such as Magnesium L-threonate have to have a conversion ratio applied based on their molecular formula and molar mass to determine their nutritional value. In the case of Magnesium L-threonate, the common dose of 2000mg is equivalent to 169mg of dietary Magnesium.

Is there such a conversion for these common forms of choline to dietary choline and, if so, is my attempt to calculate it correct?

Molar mass, Alpha GPC = $$\pu{257.22 g mol^-1}$$.

Molar mass, CDP-Choline = $$\pu{488.32 g mol^-1}$$.

Molar mass, Choline Tartrate 1:1 = $$\pu{253.25 g mol^-1}$$.

If I do a PubChem search on "choline" the returned result has a molar mass of $$\pu{104.17 g mol^-1}$$. Is that the correct result?

Can I just use the ratios? So...

(104.17/257.22)*100 = 40.49% for Alpha GPC

(104.17/488.32)*100 = 21.33% for CDP-Choline

(104.17/253.25)*100 = 41.14% for Choline Tartrate 1:1

Is this correct? As a non-chemist, part of my concern is that I'm unclear if just because it has the term "choline" embedded at the end of its name it means that it can really be counted as choline in this way (Alpha GPC, for example)? From a nutritional perspective Alpha GPC is highly related to choline and acetylcholine, but I thought it best to confirm that my understanding and calculations are correct.

• One thing is equivalence in context of the same molar amount, other thing is equivalence in context of metabolism and biochemical paths. Your numbers are correct in the former context, but I cannot comment for the latter. Commented Dec 17, 2022 at 23:43
• They may mean that, based on the prior question, you should be already able to answer the question on your own, at least in the previous former context. There is time to learn concepts of molar mass, molar amount and molar equivalence and reuse it for similar cases. Commented Dec 18, 2022 at 4:31