Sodium Dehydroacetate

Sodium Dehydroacetate is the sodium salt of dehydroacetic acid with preservative properties. It can be purchased alone or as part of a blended, multi-ingredient preservative system, and is allowed in ECOCERT/COSMOS formulations.

Sodium Dehydroacetate is not a stand-alone preservative; commercial formulations using it always pair it with some sort of co-preservative and/or preservative boosting ingredient (usually a blend of several).

Trade names include:

• TRIstat SDHA FCC/NF (TRI-K Industries, Inc.)
• Geogard® 111S (Arxada)

Arxada also sells Geogard® 111A (INCI: Dehydroacetic Acid).

Sodium Dehydroacetate

Fine white powder

• 0.1%–0.6%/0.68% (Arxada/Lonza—two different documents give two different upper ranges)
• Europe rinse-off & leave-on max: 0.6%
• Japan rinse-off & leave-on max: 0.5%

Nothing noticeable

pKa of 5.27

2–6.5 (Arxada/Lonza)

Non-ionic

33% water soluble (TRI-K)

Sodium Dehydroacetate is included in our formulations to help protect them from microbial spoilage; it has good anti-fungal properties.

No; I would consider pure Sodium Dehydroacetate to be a more advanced formulating ingredient. If you are newer to working with preservatives I recommend purchasing a professionally developed & blended multi-ingredient broad-spectrum preservative instead.

Sodium Dehydroacetate only exists as a refined product.

• Compatible with anionic, non-ionic, and cationic formulations
• Because dehydroacetic acid’s pKa (5.27) is higher than other acid-based preservatives like benzoic acid (from Sodium benzoate) (pKa of 4.2) and sorbic acid (from Potassium sorbate) (pKa of 4.76), dehydroacetic acid is active across a wider pH range. For example, dehydroacetic acid is 65% active at pH 5 while sorbic acid is only 37% active.

• “May require a bactericide booster” (Arxada)
• Can cause a slight yellowing effect in formulations over time; this can be limited with the inclusion of antioxidants like tocopherol
  • Discolouration tends to amplify with high heat and/or anionic ingredients (like surfactants and anionic carbomers)

If you are newer to working with preservatives I recommend using a professionally developed & blended multi-ingredient broad-spectrum preservative instead of stand-alone Sodium Dehydroacetate.

Otherwise, you’d generally be looking for an ingredient with comparable fungicidal properties that is compatible with your formulation.

Arxada recommends include Sodium Dehydroacetate in the cool down phase, below 45°C, but also notes it can be added at any point in the manufacturing process. My Skin Recipes states it is heat stable up to 80°C.

The performance of Sodium Dehydroacetate is highly dependent on the pH of the formulation; it is more effective at lower pHs. Because it is basic, it will increase the pH of your formulations. After adding, test & lower the pH to improve efficacy; I’d recommend 4.5–5 if possible.

Ensure you support its performance with co-preservatives and preservative boosters; it is often paired with Euxyl® PE 9010 (Phenoxyethanol & Ethylhexylglycerin) and/or a blend of Sodium benzoate and Potassium sorbate.

Stored somewhere cool, dark, and dry, Sodium Dehydroacetate should last at least two years.

Sodium Dehydroacetate is a component of:

• Galguard NT; INCI: Benzoic Acid (and) Sodium Dehydroacetate (and) Capryloyl Glycine (and) Undecylenoyl Glycine

Its acid form, Dehydroacetic Acid, is a component of:

• Geogard 221; INCI: Dehydroacetic Acid (and) Benzyl Alcohol (and) Water

In commercial cosmetic formulations, Sodium Dehydroacetate is often paired with co-preservative/preservatives like:

• GLAMGLOW Youth Cream: caprylyl glycol, phenoxyethanol, sodium benzoate, potassium sorbate
• Elemis SOS Emergency Cream: high level of glycerin, phenoxyethanol, disodium EDTA
• Suqqu Designing Massage Cream: phenoxyethanol, disodium EDTA, sodium metabisulfite
• Garnier Pureactive Bb Cream: salicylic acid, phenoxyethanol, benzyl alcohol
• e.l.f. Nourishing Night Cream: phenoxyethanol, caprylyl glycol, disodium EDTA
• L’Oreal Paris Revitalift Day Cream: disodium EDTA, phenoxyethanol, methylparaben, ethylparaben
• Aesop Exalted Eye Serum: 1-2 Hexanediol, sodium gluconate, benzyl alcohol, phenoxyethanol, sodium citrate
• Anastasia Beverly Hills Blurring Serum Blush: sodium benzoate, potassium sorbate, phytic acid
• Dermalogica Powerbright – Dark Spot Serum: 1,2-Hexanediol, Sodium Levulinate, ethyhexylglycerin, sodium benzoate, Tetrasodium Glutamate Diacetate, Sodium Formate
• Caudalie Resveratrol Lift Firming Serum: caprylyl glycol, ethylhexylglycerin, sodium phytate, high levels of glycerin & butylene glycol

60g (2 oz)

 Buy it from an online DIY ingredient supplier:

• Voyageur Soap and Candle Co. (Canada)
• Formulator Sample Shop (USA)
• Lotion Crafter (USA)
• My Skin Recipes (Thailand)