E-number database
Amino-acid flavour enhancers versus MSG
Glycine and leucine can be synthetic or gelatin-derived. MSG is a fermentation glutamate with its own page.
- E640 INS 640 Glycine and L-leucine (E640, E641) Source-dependent Halal if verified E640 glycine and E641 L-leucine are amino-acid flavour enhancers. Typical modern supply is synthetic or fermented. syntheticHalal animalHalal if verified undisclosedHalal if verified
- E620 INS 620 E620–E625 (Glutamic acid and glutamates / MSG) Source-dependent Halal MSG (E621, flavour enhancer 621) and the other glutamates, E620 and E622–E625, are made by fermentation. microbialHalal plantHalal
How they differ
Glycine (E640) and L-leucine (E641) are amino acids used as flavour enhancers and, in the case of leucine, as a tablet lubricant. Modern supply is mostly synthetic (glycine) or fermented (leucine). Glycine can also be made by breaking down gelatin, and leucine by hydrolysing hair or feathers, so an unnamed lot is Halal if verified.
They are grouped here with MSG (E621) because all three are listed as flavour enhancers, but MSG is a fermentation glutamate that is simply Halal. The ribonucleotides E627, E631 and E635 are a separate family with their own source question.
On the label
- “Flavour enhancer (glycine)” is E640.
- Leucine in sports supplements may be labelled “fermented” or “vegan”; that settles it.
- Flavour enhancers on the same label may include E621 (fine) and E627 or E631 (check).
Frequently asked questions
Is glycine Halal?
Synthetic or fermented glycine is Halal. Glycine from gelatin follows the gelatin's source, so an unnamed lot is Halal if verified.
Is E641 L-leucine Halal?
Fermented leucine is Halal. Some leucine is made from hair or feathers, so without a vegan or Halal mark it is Halal if verified.