Glycine

Glycine grades and forms

Glycine is the simplest amino acid and the only standard one without a chiral centre. It therefore has no L- or D- form and appears on specifications and labels simply as glycine. Supplement manufacturers buy it as a white crystalline powder, used as an ingredient in its own right within the amino acids range.

Food grade and pharmacopoeial grades of glycine are both traded. The grade you need follows from your product dossier, your customer’s specification and whether glycine will also serve as food additive E 640. Ask for the grade you need in the quote form.

After the grade, physical form drives the choice. Coarser crystalline grades generally flow better in high-speed filling. Finer powders dissolve faster and distribute more evenly in mixes. Assay, particle size and loss on drying are stated on the specification sheet and certificate of analysis. SoleChem supplies bulk glycine powder from its warehouses in Italy and Spain and sends both documents with the quote.

EU regulatory status

Glycine is not a vitamin or mineral, so the lists in Annexes I and II of Directive 2002/46/EC do not cover it. Amino acids fall among the “other substances” used in food supplements. Their use is governed mainly by national rules, which differ between member states. Some member states also require a food supplement to be notified to the competent authority when it is placed on the market.

Regulation (EC) No 1925/2006 allows the EU to prohibit, restrict or place under scrutiny other substances. Its Annex III holds the current list, so check it before launch. Confirm novel-food status for your intended use against the Union list in Implementing Regulation (EU) 2017/2470; the novel food guide explains how.

Glycine and its sodium salt also form food additive E 640, listed in Annex II to Regulation (EC) No 1333/2008. The additive must meet the purity criteria in Regulation (EU) No 231/2012. Where glycine performs an additive function, the conditions of use set in Annex II of Regulation 1333/2008 apply. Where it is added as a nutritional substance, it is declared as glycine.

Formulation notes

Glycine is declared as the substance itself, so no elemental conversion applies. A label claim of 1,000 mg glycine per serving needs 1,000 mg of material at 100 % assay. Divide by the actual assay on the certificate of analysis, then add any overage with the overage calculator.

Format follows the amount per serving:

• Powders and sachets. Gram-level claims fit best here. Glycine is readily soluble in water and gives clear solutions, which suits unflavoured powders and drink mixes. See ingredients for powders.
• Capsules. Fill volume limits the amount per capsule, so higher claims need several capsules per serving. See ingredients for capsules.
• Tablets. Compression behaviour depends on the grade and particle size. Run trials with your binder and lubricant system. See ingredients for tablets.

Glycine has a distinctly sweet taste. It sits easily in unflavoured blends and is often used to round off bitter notes from other amino acids. Account for the sweetness when balancing flavour systems.

As an amino acid, glycine takes part in Maillard browning with reducing sugars under heat and moisture. Watch for colour change in gummies, sugar-containing powders and heat-processed products. Confirm with stability testing in the final pack.

Glycine is the ligand in mineral bisglycinates such as magnesium glycinate. A bisglycinate is a defined compound with its own identity and elemental content. A physical blend of glycine with a mineral salt is not a bisglycinate and cannot be labelled as one.