GLDA (Tetrasodium Glutamate Diacetate)

Overview

GLDA — tetrasodium glutamate diacetate — is a chelating agent built from L-glutamic acid, an amino acid abundant in nature (it is the amino acid behind monosodium glutamate / MSG). Two acetate groups are attached to the glutamic acid backbone, giving it four metal-binding arms similar to EDTA. The cosmetic-grade material is produced from corn or sugar-beet fermentation.

The brand name you will see most often is Dissolvine GL by Nouryon (formerly AkzoNobel). It came onto the cosmetic market in the 2010s as the first natural-origin chelator with performance genuinely close to EDTA, and it has become the favorite of natural-certified brands that need real chelation power.

It comes as a clear, slightly yellow liquid (typically 38-47% active in water) or rarely as a solid powder. Read the supplier label for active percentage.

What it does in a formula

Primary role: strong chelation, biodegradable. GLDA binds metal ions (iron, calcium, copper, magnesium, manganese) with binding constants close to EDTA’s — meaning it neutralizes the metal-catalyzed oxidation that destroys oils, vitamins, and botanical actives.

Compared to sodium phytate, GLDA binds calcium and magnesium more effectively, making it useful in hard-water formulations. Compared to EDTA, it is fully biodegradable within weeks in the environment (EDTA is persistent and that is its main environmental criticism).

Secondary roles: stabilizes the color of plant-derived ingredients, supports preservative performance, and helps in surfactant systems by softening hard water.

How to use

Add to the water phase before heating. Same logic as all chelators — get it in there before the metals can do damage.

Usage range:

• General cosmetic formulas: 0.1-0.3%
• Surfactant systems and shampoos: 0.2-0.5% (especially useful in hard-water regions)
• Sensitive oil-rich emulsions: 0.2-0.3%
• Natural-certified formulations: this is the go-to chelator; 0.2% is standard

If you have a liquid GLDA at 47% active, use 0.2-0.6% of the liquid to land at 0.1-0.3% active. The supplier label always prints the active percentage.

pH range: effective at pH 3-13. This is an advantage over both EDTA and sodium phytate — GLDA works at very low pH where EDTA loses effectiveness. That makes it the preferred chelator for L-ascorbic acid serums at pH 3-3.5.

Fully water-miscible. No special handling required.

Best for / Worst for

Best for: natural-certified formulas, ECOCERT and COSMOS products, low-pH vitamin C serums (works where EDTA wobbles), shampoos and body washes in hard-water regions, products marketed on biodegradability and environmental safety, formulations targeting the “clean beauty” aesthetic.

Worst for: cost-sensitive bulk formulations (GLDA is more expensive than EDTA), formulas where the supplier label is unclear about active content (calculation errors compound), and pure anhydrous balms (it is water-soluble).

Common pitfalls

Treating it as EDTA at 1:1 by weight. GLDA liquids are typically 38-47% active. EDTA is usually 100% active powder. Match by active percentage, not by liquid-to-powder weight.

Adding cool-down. Like all chelators, add early. The metals are present from the start.

Skipping it on natural-certified formulations. Some brands try to formulate “no chelator” natural products and end up with much shorter shelf life. GLDA solves this — it is certified-friendly and effective.

Using it in pure-water rinse-off products. If the formula has minimal raw-material metal load and is rinsed off in under 30 seconds, the chelator’s value is marginal. Reserve it for leave-on products and oil-rich systems where stability matters.

Substitutes

• Disodium EDTA — stronger at standard cosmetic pH, synthetic, less biodegradable but cheaper.
• Sodium Phytate — natural, weaker, fine for simple formulas.
• Tetrasodium Iminodisuccinate — newer biodegradable chelator, similar performance, niche supply.
• Trisodium Ethylenediamine Disuccinate (EDDS) — biodegradable EDTA cousin, photolabile, used in some natural systems.
• Sodium Gluconate — mild chelator for simple formulas; weaker than all the others.