Phenoxyethanol has become the default preservative of the paraben-free era: it is permitted in leave-on and rinse-off products around the world, it is stable across the whole practical pH range, and it is colourless and almost odourless. Its weakness is that, on its own, it is only moderately active, especially against moulds, and it needs to be used close to its regulatory ceiling of 1.0 % to be reliable.
Ethylhexylglycerin is not a preservative – and that is the point
Ethylhexylglycerin is a glyceryl ether, used in cosmetics as a skin-conditioning agent and deodorant active. It is not listed as a preservative in EU Annex V, and it does not need to be. What it does is lower the interfacial tension at the microbial cell membrane. In plain terms, it makes the membrane of a bacterium or fungus more permeable, so that whatever preservative is present gets in more easily and acts faster.
Paired with phenoxyethanol, the effect is large. The combination shows faster kill and a broader spectrum than phenoxyethanol alone at the same phenoxyethanol level, and in practice lets formulators work at 0.5 – 1.1 % of the blend rather than pushing phenoxyethanol to the limit.
Why 90 : 10
The ratio in EsoDant 9010 – 90 % phenoxyethanol, 10 % ethylhexylglycerin – is the industry-standard EHGP blend, and it balances three things:
- Enough booster to matter. Below about 5 % the potentiation is weak.
- Cost. Ethylhexylglycerin is the more expensive component.
- Regulatory headroom. At a 1.1 % dose of the blend, the phenoxyethanol contribution is 0.99 %, just under the 1.0 % EU maximum, so the whole permitted range is usable.
Formulating notes
- The blend is only about 2 % soluble in water, so in clear aqueous systems add it slowly with vigorous stirring, or pre-dilute it in a glycol or a surfactant concentrate.
- In emulsions it can go into either phase. It tolerates 80 °C, so it can be added before homogenisation.
- Because ethylhexylglycerin is a mild deodorant active, the blend contributes a small odour-control benefit in underarm and foot products.
- High levels of ethoxylated emulsifiers reduce the free fraction of phenoxyethanol. If your emulsifier system is polysorbate- or PEG-heavy, start at the top of the use-level range and confirm by challenge testing.
Where it fits in the range
If you need a preservative for a leave-on product with a clean label, EsoDant 9010 is the grade to start with. If cost is the overriding factor and the claim does not matter, EsoDant 55 or EsoDant 510 may be more economical – the product comparison shows where each grade sits.