Formulators often start a preservative discussion with cost, or with a claim they want to make on the pack. Both matter, but the question that narrows the choice fastest is a simpler one: does the product get rinsed off, or does it stay on the skin?
Why the distinction exists
Leave-on products – creams, lotions, serums, sunscreens, wipes – sit on skin for hours. Rinse-off products – shampoos, body washes, hand soaps, cleansers – are in contact for a minute or two before they go down the drain. Regulators treat the two very differently, because exposure to the preservative is very different. The EU Cosmetics Regulation (EC) No 1223/2009 lists permitted preservatives in Annex V, and for several entries the limit depends on the product type, or the substance is allowed in rinse-off only.
What that means for each EsoDant grade
| Grade | Rinse-off | Leave-on | Note |
|---|---|---|---|
| EsoDant 9010 | Yes | Yes | Phenoxyethanol ≤ 1.0 % in the finished product (EU, Japan, China, ASEAN) |
| EsoDant PE | Yes | Yes | Phenoxyethanol ≤ 1.0 %; pair with a booster for leave-on products |
| EsoDant 55 | Yes | Yes | DMDM Hydantoin ≤ 0.6 % (EU); Japan limits rinse-off to 0.02 % and does not allow leave-on |
| EsoDant 510 | Yes | No (EU, Japan) | CMIT / MIT is rinse-off only in the EU at ≤ 0.0015 % |
So if the brief says face cream for export to Europe, the shortlist is EsoDant 9010, EsoDant PE or EsoDant 55, and 9010 is the usual choice because it also supports a paraben-free, formaldehyde-free claim. If the brief says economy shampoo for the domestic market, EsoDant 510 becomes attractive: two modes of action, a very low use level and a very low cost-in-use.
A second question: what temperature and pH does the process run at?
Once application has narrowed the list, the process finishes the job.
- EsoDant 9010, EsoDant PE and EsoDant 55 tolerate up to 80 °C, so they can go in early and survive a hot-process emulsion.
- EsoDant 510 must be added below 40 °C and kept below pH 8, because the isothiazolinone component does not survive heat or alkali.
Neither constraint is a problem when it is known in advance. Both are a problem when they are discovered by a failed challenge test.
Our recommendation
Tell us the product type, the target markets and the process temperature. With those three facts we can usually recommend a grade and a starting use level in one reply, and send a sample so you can confirm it in your own base.