L-Lysine Monohydrochloride

Feed additive makers ferment sugar to produce lysine. They remove the bacterial cells, purify the lysine, then form a dry hydrochloride crystal that food makers can weigh into a recipe.^4,7

1. 01 // Source Sugar and nutrients Sugar from crops such as corn, beets or sugarcane feeds the fermentation culture.
2. 02 // Process Fermented Bacteria produce lysine in a liquid broth supplied with sugar and nutrients.
3. 03 // Process Cells removed Filtration removes bacterial cells and other solids before the dissolved lysine is purified.
4. 04 // Process Crystallized Hydrochloric acid converts the purified lysine to its hydrochloride form, which is crystallized and dried.
5. 05 // Output Dry lysine crystals A concentrated powder is packed for use as a measured feed ingredient.

1. 01

   Fills a lysine gap

   Lysine is essential to dogs. A small addition lets a formulator raise that amino acid when the other ingredients do not supply enough.^1,4

2. 02

   Limits protein overshoot

   Adding one measured amino acid can avoid increasing an entire protein ingredient solely to meet a lysine target. That gives formulators a way to control ingredient use.^1,4

3. 03

   Raises crude protein slightly

   Lysine contains nitrogen, which counts in the crude protein test. The additive still supplies only one amino acid, so the number cannot describe protein quality.^4,6

How much A dog trial added 0.43 to 0.77% L-lysine on a dry basis, but did not identify its salt form.²

1. Critics say

   It raises protein without adding meat

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. None

   AAFCO explains that crude protein is calculated from nitrogen multiplied by 6.25. Added lysine contributes nitrogen, so it can lift that figure. The small addition supplies only lysine, not the full set of amino acids in a protein ingredient.^4,6

2. Brands say

   It fills a shortfall in dietary lysine

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. None

   A study of 13 adult dogs measured a dietary lysine requirement, and a feed safety panel judged this salt an effective lysine source for animals like dogs. The dog study tested lysine intake, not this particular salt in commercial kibble.^1,4

3. Brands say

   It protects muscle during weight loss

   Outruns the evidence

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. None

   Two short experiments involving 6 and 8 hounds found changes in measures of protein turnover as dietary lysine changed. They did not demonstrate lasting muscle preservation or isolate the effect of L-lysine monohydrochloride.²

4. Owners say

   A synthetic lysine salt is toxic to dogs

   Outruns the evidence

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. None

   A feed safety panel found no target animal risk from the assessed additive under its proposed use. That does not make unlimited lysine safe: an AAFCO review describes impaired puppy growth when diets contained a large lysine excess alongside low arginine.^4,5