Euxyl® K 510

Product Information

CosmySupplies supplies Euxyl K 510 Preservative by Ashland (INCI: DMDM Hydantoin, Methylchloroisothiazolinone, Methylisothiazolinone) in India. A liquid, broad-spectrum cosmetic preservative effective against bacteria, yeasts, and moulds in rinse-off personal care formulations. Use level 0.10 to 0.40%. Effective in anionic, cationic, and non-ionic systems. pH range 5.0 to 8.0. For rinse-off applications only. COA available on request. Shipped from Bengaluru across India. Available at cosmysupplies.com.

INCI: DMDM Hydantoin (and) Methylchloroisothiazolinone (and) Methylisothiazolinone

CAS: DMDM Hydantoin 6440-58-0 | MCI 55965-84-9 | MI 55965-84-9 / 2682-20-4

Manufacturer: Ashland Inc., Consumer Specialties | Trade name: Euxyl K 510 | Bulletin: VC-5705-1

Form: Liquid | Colour: Nearly colourless to light blue | Odour: Characteristic

Use level: 0.10 to 0.40% | Application: Rinse-off cosmetic products ONLY

Mechanism: Dual-action. DMDM Hydantoin releases formaldehyde as bactericide. MCI/MI provides biocidal activity against bacteria, yeast, and mould.

Benefits

Dual-mechanism

Euxyl K 510 combines two chemically distinct preservation mechanisms in one ready-to-use liquid. DMDM Hydantoin acts as a formaldehyde-releasing bactericide, continuously releasing small amounts of formaldehyde to inhibit bacterial growth across a broad spectrum including both gram-positive and gram-negative organisms. MCI/MI provides direct biocidal activity against bacteria, yeast, and mould through a different mechanism. The combination of these two distinct mechanisms in a single product means that at the low recommended use level of 0.10 to 0.40%, the formulator achieves coverage that would require higher individual use levels from either component alone. MIC data from VAH testing confirms efficacy against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Candida albicans, Aspergillus niger, and Penicillium pinophilum at use concentrations within the recommended range.

Effective at low use levels

The recommended use level of 0.10 to 0.40% of the total formula is at the lower end of the cosmetic preservative spectrum. At 0.10 to 0.40% in a shampoo or body wash formula, Euxyl K 510 delivers full broad-spectrum protection without requiring the 0.5 to 1.0% typical of single-ingredient preservative systems. For a startup brand producing at 10 to 50 kg batch sizes, this represents a meaningful cost reduction in the preservation budget. The cost-effective claim on the Ashland TDS reflects this low active level required.

Works in anionic, cationic, and non-ionic surfactant systems

A common formulation problem with preservatives is incompatibility with surfactant types. Quaternary ammonium preservatives, for example, are typically incompatible with anionic surfactants. Euxyl K 510 is confirmed effective in anionic systems (including sulphates, ether sulphates, and sulphosuccinates), cationic systems, and non-ionic systems per the Ashland TDS. For a formulator building across multiple rinse-off product types with different surfactant bases, this means a single preservative stock item can serve all rinse-off formats without compatibility testing for each surfactant class.

Vapor phase activity protects the product headspace

Euxyl K 510 has confirmed vapor phase activity, meaning it is active against microorganisms in the air above the product surface as well as in the liquid formulation itself. This is a distinct advantage for products stored in containers with air gaps, such as pump dispensers, flip-top bottles, and wide-mouth jars. Products that are repeatedly opened and exposed to ambient air are at higher risk from airborne contamination. Vapor phase activity provides an additional layer of protection beyond what liquid-phase-only preservatives can offer.

Acidic pH stability

Acidic pH values have no negative influence on the effectiveness of Euxyl K 510 (confirmed from Ashland TDS). This makes it particularly suitable for shampoos, conditioners, and body washes formulated in the 4.5 to 6.5 pH range typical of hair and skin care rinse-off products. The single constraint is pH above 8.0, which should be avoided. For the typical rinse-off formulation pH range, Euxyl K 510 remains fully effective.

Good surfactant compatibility 

Compatibility testing data from Ashland confirms good compatibility with anionic surfactants including sulphates, ether sulphates, and sulphosuccinates, as well as with non-ionogenic surfactants. No significant discoloration has been observed in general cosmetic ingredient compatibility testing. This reduces formulation development risk and compatibility testing burden for the formulator.

Applications and Usage Rates

Shampoo and hair cleansers

Use at 0.10 to 0.40% in the final formulation. Add at the cool-down phase at below 40 degrees Celsius, typically alongside fragrance. Euxyl K 510 is compatible with anionic surfactant bases including SLES, SLS, and cocamidopropyl betaine systems standard in Indian shampoo formulations. At 0.20 to 0.30%, it provides complete broad-spectrum protection for a standard sulphate-based or sulphate-free shampoo at typical preservative challenge test conditions. Avoid sulphite-containing ingredients above 20 ppm in the same formula.

Conditioners and hair rinses

Use at 0.10 to 0.40% in rinse-off conditioner bases. Compatible with cationic conditioning systems including cetrimonium chloride and behentrimonium chloride. Add at below 40 degrees Celsius in the cool-down phase. Conditioners formulated in the pH 4.0 to 5.5 range are well within the effective pH window for Euxyl K 510. 

Body wash and shower gel

Use at 0.10 to 0.40% in surfactant-based body wash and shower gel formulations. Both anionic and non-ionic surfactant systems are compatible. Typical body wash pH of 5.0 to 6.5 is within the effective range. The vapor phase activity is particularly relevant for products stored in squeeze bottles and pump dispensers that may be repeatedly exposed to humid shower environments.

Liquid hand wash and facial cleansers

Use at 0.10 to 0.40% in liquid hand soaps and surfactant-based facial cleansers. Suitable for rinse-off facial cleansers formulated in the standard pH 5.0 to 6.5 range. Not suitable for facial cleansers intended to be left on the skin before rinsing later, or for cleansing balms or oils that remain in contact with skin before being emulsified off. Rinse-off requirement applies strictly.

Other rinse-off personal care formulations

Euxyl K 510 is suitable for any aqueous rinse-off personal care formulation within the pH 4.0 to 8.0 range. This includes bath gels, shower creams, micellar cleansers used as rinse-off products, and scalp treatment rinses. Use at 0.10 to 0.40% in all cases. A preservation challenge test per ISO 11930 or equivalent is recommended for every finished formulation before commercial launch, regardless of the preservative used.

How to Use

Addition method and temperature

Add Euxyl K 510 at below 40 degrees Celsius in the cool-down phase of formulation. Ashland recommends adding it together with the fragrance. Do not add to a hot phase above 40 degrees Celsius as elevated temperature may affect preservative stability and efficacy. The product is a liquid and fully soluble in water and most polar organic solvents. Mix until fully incorporated before filling.

Use level and titration

Start at 0.20% in a standard shampoo or body wash formulation. The recommended range is 0.10 to 0.40%. Note that the global approvals table in the Ashland TDS states use concentrations are based on average active content. Pay attention to the COA for the specific batch to confirm active content and adjust use level accordingly. Run a preservation challenge test (ISO 11930 or equivalent) to confirm the finished product passes before commercial release. 

pH range

Formulate within pH 4.0 to 8.0. Acidic pH has no negative effect on efficacy. High pH above 8.0 should be avoided as efficacy decreases above this level. 

Sulphite incompatibility

Euxyl K 510 is inactivated by sulphite ions. Excessive sulphite above 20 ppm must be avoided in the same formulation. If your formula includes sodium metabisulphite, sodium sulphite, or other sulphite-based antioxidants or reducing agents, confirm the total sulphite level in the finished formula is below 20 ppm before relying on Euxyl K 510 for preservation. If sulphite exceeds 20 ppm, a different preservative system must be selected.

Protein-containing formulations

The presence of proteins may decrease the efficacy of Euxyl K 510. If the formula contains hydrolysed proteins, silk proteins, collagen peptides, or similar at significant concentrations, run a preservation challenge test to confirm the system is adequate. If the protein concentration is high, consider a higher use level within the approved range or supplementing with an additional preservative.

Claims You Can Make

For your label :

Preserved with Euxyl K 510 | Broad-spectrum antimicrobial preservation | Protected against bacteria, yeast, and mould

For your formulator brief:

INCI: DMDM Hydantoin (and) Methylchloroisothiazolinone (and) Methylisothiazolinone | CAS: DMDM Hydantoin 6440-58-0, MCI 55965-84-9, MI 55965-84-9/2682-20-4 | CIR reviewed: DMDM Hydantoin safe in current usage levels per CIR assessment . MCI/MI CIR safety assessment published 2010, amended 2014, confirmed rinse-off safe at 0.0015%. | EU Regulation 1223/2009 Annex V listed: DMDM Hydantoin max 0.6% (Annex V/33). MCI/MI combination max 0.0015% rinse-off only (Annex V/39, EU Regulation No 1003/2014). | Ashland TDS use level 0.10 to 0.40% confirmed effective at MIC testing . | Effective in anionic, cationic, non-ionic systems. | Addition temperature: below 40 degrees Celsius . | Incompatible with sulphites above 20 ppm. | ISO 16128 natural ingredient score: 73 .

 

For usage rate guidance, formulation support, or sample requests, contact the CosmySupplies team.

WhatsApp | Email: info@cosmysupplies.com

Technical Information

Pairs Well With

Sodium Lauryl Sulphate (SLS) or Sodium Laureth Sulphate (SLES)

Primary anionic surfactant in shampoo and body wash. Euxyl K 510 is confirmed compatible with sulphate and ether sulphate surfactant systems. Build the preservation system around your anionic base and add Euxyl K 510 at 0.20% in the cool-down phase.

Cocamidopropyl Betaine

Amphoteric co-surfactant used to reduce irritation potential in shampoos and body washes. Compatible with the preservation system in Euxyl K 510. Standard rinse-off formulation pairing.

Glycerin

Humectant in aqueous rinse-off formulations including conditioning shampoos and moisturising body washes. Fully compatible with Euxyl K 510 in the water phase.

Cetrimonium Chloride

Cationic conditioning agent in rinse-off conditioners and conditioning shampoos. Euxyl K 510 is effective in cationic systems. Standard conditioning rinse-off product pairing.

Panthenol

Hair and skin conditioning active in shampoos and body washes. Fully water-soluble and compatible with the preservation system. Standard rinse-off formulation active.

Citric Acid

pH adjuster used to bring shampoo and body wash formulations to the 4.5 to 6.5 range. Essential pairing for any rinse-off product using Euxyl K 510, since the preservative is most effective in the acidic to neutral pH range. 

Important Information

DMDM Hydantoin is a formaldehyde-releasing preservative. Formulators using Euxyl K 510 in finished products must test the finished product for free formaldehyde content. Under EU Regulation 2022/1181, any finished product where released formaldehyde exceeds 0.001% (10 ppm) must carry the label warning 'releases formaldehyde'. Formulators selling in EU-aligned markets must ensure compliance. 

Euxyl K 510 is inactivated by sulphite ions above 20 ppm. Do not formulate with sodium metabisulphite, sodium sulphite, or other sulphite-based ingredients at concentrations that result in sulphite levels above 20 ppm in the final product.

MCI/MI (Methylchloroisothiazolinone and Methylisothiazolinone) are known contact allergens and sensitisers. Products preserved with this blend are not appropriate for formulations targeting sensitive skin, allergy-prone skin, eczema-prone consumers, or children. Always disclose the INCI names on the finished product label.

This product is classified as a dangerous good for transport (UN 3082, Packaging Group III). Handle according to SDS guidelines. Store in original sealed container protected from frost, heat, and direct sunlight.

A preservation challenge test (ISO 11930 or equivalent) is recommended for every finished formulation before commercial launch. The TDS recommended use level is a starting point based on average active content.

COA is available on request. Contact us via WhatsApp or email.