GLDA-Na4 for Cosmetics and Personal Care: A Sourcing Guide

A cleaner ingredient list and a retailer questionnaire are pulling personal-care brands away from persistent chelants. GLDA-Na4, the tetrasodium salt of glutamic acid diacetate, is one of the molecules that fits a short, defensible declaration: it is readily biodegradable, carries a natural-origin index, and holds calcium and magnesium across the pH band a cosmetic formula lives in. This guide covers what a formulator or a buyer should check before specifying it.

Why formulators reach for a biodegradable chelant

Trace iron, copper and manganese enter a formula from water, pigments, preservatives and the process itself. Left free, they catalyse oxidation that turns a cream grey, breaks a fragrance, or drops a preservative's activity. A chelating agent ties those ions up so they cannot start. EDTA does this well but persists in the environment, and that persistence is now a line on the audit and a question on the brand scorecard. GLDA-Na4 does the same job and breaks down after use, which is why it appears in reformulation briefs.

The INCI name and what it confirms

GLDA-Na4 carries the INCI name Tetrasodium Glutamate Diacetate and the CAS reference 51981-21-6. The INCI entry is the line that confirms the material to a regulatory reviewer; it is the identity that goes on the label and into the cosmetic product notification. Put it in the specification so that a different salt, a partial EDTA blend or a diluted product cannot arrive under the same name. The number a formulator checks after identity is the chelation behaviour across pH, and GLDA-Na4 holds calcium effectively from roughly pH 2 to 13, which covers acidic toners through to alkaline soaps.

What it does in a formula

In a leave-on cream, GLDA-Na4 protects oils, fragrances and preservatives from metal-catalysed oxidation, which supports shelf life without a second antioxidant. In a rinse-off wash, it softens the water so surfactants lift soil instead of fighting hardness, and it helps prevent the dull film that calcium leaves on skin and hair. In a colourant or a dye, it keeps stray iron from shifting the shade. The dose is small, typically well under one per cent of the finished product, and it is set from the water hardness and the metal load of the other raw materials rather than from a fixed rule.

The natural-origin index buyers ask about

Retailer and brand questionnaires increasingly ask for a natural-origin figure. GLDA-Na4 is built from L-glutamic acid, a plant-derived amino acid, and under ISO 16128 it carries a natural-origin index of 0.56. That figure is not a marketing claim; it is a calculated value from a published standard, and a buyer can request the calculation behind it. It supports a clean-label position that survives scrutiny, provided the rest of the formula carries the same discipline.

Choosing the grade for a leave-on or rinse-off product

GLDA-Na4 is supplied most often as a 38 or 47 per cent aqueous solution, with the higher active grade the common choice for detergents and the lower grade suited to buyers who prefer easier handling or a lower concentration for dosing. Both are clear, light-coloured liquids that blend with typical surfactant and emulsion systems. For a personal-care line the grade choice follows the dosing equipment and the preservative system more than the performance, because the chelation duty is the same at either strength.

Confirm the preservative status of the supplied solution with the manufacturer. A chelant solution is aqueous and can support microbial growth in the drum if left open; the grade you receive should state its in-can protection or its recommendation for handling.

Compatibility with the rest of the formula

GLDA-Na4 works with the anionic, non-ionic and amphoteric surfactants common in personal care, and with many enzymes and proteins. It is a chelant, not a preservative, so it does not carry microbial stability on its own. Where a formula already carries a strong oxidiser, such as a peroxy preservative or a peroxide stage, confirm compatibility, because organic chelants can be affected by prolonged oxidiser contact.

The pH band is wide enough that most cosmetic formats sit inside it without adjustment. Where a formula is strongly acidic or strongly alkaline at the edge of the range, verify the complexation at the actual pH rather than assuming the mid-range figure holds.

The document set for European supply

European buyers ask for specific paperwork before the first order, and a GLDA-Na4 supplier that cannot produce it on request will stall procurement. Request the safety data sheet with the EU-language sections, the certificate of analysis naming the test method for each limit, the technical data sheet, and the OECD 301 biodegradability report. Ask also for the ISO 16128 natural-origin calculation if the clean-label claim is part of the brief.

Keep the retained-sample record and the batch certificate so a later formulation change starts from a known batch. The document set is what lets a regulatory reviewer sign off without a phone call.

What the EU Cosmetics Regulation expects

GLDA-Na4 falls under the EU Cosmetics Regulation (EC) No 1223/2009 as an allowed ingredient where the function is chelation, and its INCI name supports that notification. The regulation sets the safety of the finished product, not of any single raw material, so final-product safety depends on the full formula, the concentration and the consumer exposure. This article describes the ingredient; it is not a substitute for the cosmetic safety assessment that the responsible person must hold for the product.

Confirm the permitted concentration and the function against your product category and your notified formulation before commitment, because the obligation sits with the placed product, not with the raw-material supplier. The technical library carries the mechanism detail behind the amino-acid chelants.

How to qualify a GLDA-Na4 supplier

A supplier earns a place on the approved list by meeting the spec and backing it with paper. Ask for the identity line, the active-content tolerance, the pH and density, the heavy-metal profile, and the residual-intermediate limit by a named method. Request a sample for a bench trial at your actual pH and water hardness, and read the result against the certificate rather than against the leaflet. A second source on the file protects against a raw-material shortage, and a supplier that also holds MGDA-Na3 or IDS-Na4 can simplify the documentation where those molecules appear in the same range.

Frequently asked questions

Is GLDA-Na4 safe in leave-on products? The ingredient is used in both rinse-off and leave-on formats, but the safety of the finished product follows from the full formula and the cosmetic safety assessment, not from the raw material alone. Confirm the concentration against your product category.

Does it replace EDTA gram for gram? Not usually one-for-one, because the active masses differ. Dose on active chelator, screen at pilot, and adjust the co-builder. The wide pH band often means less reformulation than expected.

What is the natural-origin index? Under ISO 16128, GLDA-Na4 from plant-derived glutamic acid carries an index of 0.56. Request the calculation so the figure can be filed with the claim.

Is it biodegradable? Yes. It meets the ready-biodegradability threshold under OECD 301 testing, breaking down to carbon dioxide, water and inorganic nitrogen rather than persisting like EDTA.

Can it be used with preservatives? It is compatible with most preservative systems but is not a preservative itself. Where a peroxy or strong oxidiser is present, confirm compatibility with the supplier before scaling.

A personal-care raw material is judged on performance and on the file behind it. For the GLDA-Na4 specification sheet, the ISO 16128 calculation and a sample for bench trials, contact [email protected] or call +86-537-3739818. Full product details are available at the company website: https://www.yuanlianchem.com