Making Citrulline Malate

[SupplementGuy]

Hello. Thank you in advance for reviewing my question. I work in the nutraceutical industry, and citrulline malate has become an increasingly popular supplement in sports nutrition. Some supplement brands claim to sell Citrulline Malate, which is L-citrulline chemically bonded to DL-malic acid. It appears, however, that many are actually selling citrulline and malic acid that have been simply blended together and not chemically bonded.  

Now to my questions:
1) How can one determine if a brand's citrulline malate is a bonded form (a chelated amino acid) or simply citrulline mixed with malic acid?

2) I've read that citrulline powder and malic acid acid powder react to form citrulline malate when added to water. Is this true? Although very different compounds, when you combine calcium carbonate with citric acid they combine to create calcium citrate. Does something similar happen between citrulline and malic acid?

[Gail207Martinez]

Hi,

To determine if a brand’s citrulline malate is chemically bonded or simply a blend, you can look for the following:

Third-Party Testing: Check if the product has been tested by an independent lab. These tests can confirm if the citrulline and malic acid are chemically bonded.
Product Label and Claims: Reputable brands often provide detailed information about their manufacturing process and the nature of their ingredients.
Regarding your second question, citrulline powder and malic acid do not chemically bond simply by being mixed in water. They need specific conditions and processes to form a true citrulline malate compound.

Best Regards,

Mary Kay Inc

[SupplementGuy]

Hi @Gail207Martinez ,

Thank you for your contribution to this question. Although you are correct that a third-party CofA would shed some light on the exact formula, many brands, unfortunately, don’t share their CofAs. A lab would have to perform a more detailed analysis to determine if a product is truly bonded citrulline malate or a blend of citrulline + malic acid. I would imagine an HPLC test would do this. There may be other ways of determining this which is why someone with a solid chemistry background might be able to help.

I came across this comment on another forum, which suggests that you can create bonded citrulline malate when you mix citrulline with malic acid. It was this post that prompted me to post something on the AskACS forum.  

“Citrulline malate has no covalent bond between citrulline and malic acid, but an ionic bond. by mixing citrulline with malic acid, an acid base reaction occurs, generating a positively charged citrulline and negatively charged malic acid. Citrulline has 1 basic residue, while malic acid has 2 acidic residues. therefore, every molecule of malic acid can react with 2 molecules of citrulline, hence why it’s citrulline malate (2:1). Simply mixing the two in water will cause this acid base reaction to occur due to their differences in pKa.”

You mentioned “citrulline powder and malic acid do not chemically bond simply by being mixed in water. They need specific conditions and processes to form a true citrulline malate compound.” Can you please elaborate? What conditions and processes are required?