|Name||INCI||Usage Rate||pH Range||Maximum temperature||Solubility||Usage Notes|
|Euxyl® K 703||Phenoxyethanol (and) Benzoic Acid (and) Dehydroacetic Acid||0.4–1.2%||3–6, with better efficacy at lower pH||Best added below 40°C (104°F)||Oil; low water solubility.||Broad spectrum preservation at pH 6 or lower. Not suitable for anhydrous products. Effective in anionic, cationic, and non-ionic environments.|
|Euxyl® K 712||Water (and)|
Sodium Benzoate (and)
|0.5–1.5%||Maximum 5.5||Best added below 40°C (104°F)||Water||Broad spectrum. Effective in anionic, cationic, and non-ionic environments. Good surfactant compatibility.|
|Euxyl™ k 903||Benzyl Alcohol (and) Benzoic Acid (and) Dehydroacetic Acid (and) Tocopherol||0.4–1.2%||3–6, with 5–5.5 being recommended. More effective at lower pH ranges.||Maximum is 80°C for no more than 4 hours, but the manufacturer recommends adding it below 40°C.||From Ashland: “Euxyl™ k 903 preservative is only limitedly soluble in water. 100g of water at 20°C dissolve 1.2g of Euxyl™ k 903 preservative." Read the full Encyclopedia entry for further details.||Broad-spectrum. Slight chemically smell that can come through in unscented products.
“In formulations as a result of the presence of iron ions, e.g. from mineral thickeners, yellow discolorations were observed.” –Ashland
|Euxyl® PE 9010||Phenoxyethanol (and) Ethylhexylglycerin||0.5 - 1.0%||Up to 12||Up to 120°C (248°F)||Oil, propylene glycol, propanediol 1,3. Low water solubility.||Broad spectrum. Blend of 90% Phenoxyethanol, 10% Ethylhexylglycerin. Effective in anionic, cationic, and non-ionic environments. High levels of ethoxylated surfactants can reduce efficacy.|
|Geogard® 221||Dehydroacetic Acid (and) Benzyl Alcohol (and) Water||0.2–1.1%||2–7||None found||Water||Anionics may cause discolouration. Manufacturer lists lip products as a possible application.|
|Geogard® ECT, Preservative Eco, Mikrokill ECT, Plantaserv M||Benzyl Alcohol (and) Salicylic Acid (and) Glycerin (and) Sorbic Acid||0.6–1%||3–8||45°C (113°F)||Said to be water soluble, though some have reported challenges with it in entirely hydrous products.||Broad spectrum. Almond-like aroma. Manufacturer lists lip products as a possible application. Due to salicylic acid content EU use for children under 3 is not allowed.|
|Geogard Ultra, NeoDefend™, Gluconolactone SB||Gluconolactone (and) Sodium Benzoate (and) Calcium Gluconate||0.75–2%||3–6/7||No maximum temperature found; listed as "heat stable"||Water||Can cause pH to drift downwards. Sodium benzoate works against bacteria and fungi. Gluconolactone is a chelator and antioxidant. Effective in anionic, cationic, and non-ionic environments. Avoid use in formulas where L-Ascorbic Acid is present.|
|Germaben® II||Propylene Glycol (and) Diazolidinyl Urea (and) Methylparaben (and) Propylparaben||0.5–1%||3.0–7.5||60°C (140°F)||Water||Broad spectrum. For products with an oil phase of 25% or less. Add to cool down before adding fragrance.|
|Liquid Germall Plus||Propylene Glycol (and) Diazolidinyl Urea (and)||0.1–0.5%||3–8||50°C (122°F)||Water||Broad-spectrum. Cationic, anionic, and non-ionic compatible. Surfactant compatible.
The limiting ingredient for regulations is Iodopropynyl Butylcarbamate. The maximum usage rate of 0.5% Liquid Germall™ Plus results in 0.002% Iodopropynyl Butylcarbamate in finished formulations, which is well below the maximum usage rate for leave-on and rinse off purposes in the USA, EU, and Japan.
In the EU Iodopropynyl Butylcarbamate is not to be used on children under 3 years of age unless in rinse-off products. No such restriction exists in the USA or Japan, so it is up to you if you would use this preservative on people under 3 years.
Not to be used in aerosols, but mists are ok.
|Naticide, Plantaserv Q||Parfum||0.3–1%||4–9||Add during cool down||Glycol, alcohol. Water up to 0.6%.||Broad spectrum. Vanilla-like scent. Expensive!|
|Optiphen™||Phenoxyethanol (and) Caprylyl Glycol||0.5–1.5%||4–8||60°C (140°F)||Water||Phenoxyethanol is mostly effective against gram negative bacteria, while Caprylyl Glycol boosts efficacy and can offer some protection against bacteria. Both components are weak against fungus.|
|Optiphen™ Plus||Phenoxyethanol (and) Caprylyl Glycol (and) Sorbic Acid||0.75–1.5%||Works best below 6||80°C (176°F)||Water||Phenoxyethanol is mostly effective against gram negative bacteria, while Caprylyl Glycol boosts efficacy and can offer some protection against bacteria. Sorbic acid offers protection against yeast, fungus, and mold. Can thin emulsions.|
|Phenonip||Phenoxyethanol (and) Methylparaben (and) Ethylparaben (and) Butylparaben (and) Propylparaben (and) Isobutylparaben||0.5–1%||3–8||80°C (176°F)||Oil, water soluble up to 0.5%.||Broad spectrum. Good choice for harder to preserve formulations, lower concentrations can be effective. Can be used in surfactant systems and with some levels of ethoxylated compounds. See fact sheet for more information.|
|Phenoxyethanol||Phenoxyethanol||0.25–1%||3–10||85°C (185°F)||Oil soluble, with slight water solubility.||Not broad spectrum. Faint rose scent, inactivated by highly ethoxylated compounds. Mostly effective against gram negative bacteria, weak against yeast and mold.|
|Potassium Sorbate||Potassium Sorbate||0.1–0.5%||More effective at lower pH values, most active at pH 3||60°C (140°F)||Up to 58% water soluble||Not broad spectrum. Active against mold, ok against yeast, poor against most bacteria. Can oxidize, so include an antioxidant. Can yellow from UV exposure (Gluconolactone can prevent this).|
|Sodium Benzoate||Sodium Benzoate||Up to 1%||More effective at lower pH values, most active at pH 3||None found; can be added to heated phase||Up to 55% water soluble||Not broad spectrum. Very pH dependent, inactivated by non-ionics. Mostly anti-fungal with some anti-bacterial action. Avoid use in formulas where L-Ascorbic Acid and Citric Acid are present.|
- Product pages from:
- Cosmetics & Toiletries: Caprylyl Glycol: A Versatile Material to Boost Preservatives
- Geogard 221 fact sheet
- Geogard ECT fact sheet
- Phenonip fact sheet
- Euxyl® K 712 fact sheet
- Harry’s Cosmeticology