Optiphen™ Plus

What is it?

Optiphen™ Plus is a broad spectrum preservative that works well to preserve products like lotions, creams, cleansers, and shampoo bars. Due to its phenoxyethanol content it is not natural, but is often considered ‘more’ natural than Liquid Germall™ Plus.

Optiphen™ Plus is approximately 52% phenoxyethanol, 42% caprylyl glycol, and 6% sorbic acid (source).

Optiphen™ Plus is part of Ashland’s larger “Optiphen™” line, so when you’re looking at ingredients with “Optiphen™” in the name, always check the INCI so you know exactly what it is—Plus, 200, HD, GP, OD, BSP, BSB-W, etc… or just plain “Optiphen™”. They’re all different!
INCI

Phenoxyethanol (and) Caprylyl Glycol (and) Sorbic Acid
Appearance

Clear semi-viscous fluid
Usage rate

0.75%–1.5% (I usually use it at 1.5%)
Scent

Nothing really noticeable, especially in a finished formulation.
Approximate Melting Point

Liquid at room temperature.
Effective pH range

Works best at a pH below 6 due to the sorbic acid, which is most effective at pH 4.4
Solubility

Due to its phenoxyethanol and caprylyl glycol content Optiphen™ Plus has limited solubility in water, but good solubility in ethanol, isopropanol (aka isopropyl alcohol/rubbing alcohol), ethylene glycol, propylene glycol, butylene glycol, and glycerin.

Because of its limited water solubility Optiphen™ Plus isn’t a great choice for preserving really watery formulations like hydrous serums unless you include an adequate solvent or solubilizer.
Why do we use it in formulations?

Optiphen™ Plus preserves our formulations so they don’t grow mould and get all gross and icky.
Do you need it?

No, but it is a good preservative choice and I like having it on hand.
Refined or unrefined?

Optiphen™ Plus only exists as a refined product.
Strengths

Effective and versatile preservative with relatively high heat tolerance (up to 80°C [176°F]), making it a good choice for using in products that need a preservative but will be too solid to add one at typical cool down phase temperatures (~40°C and cooler).
Weaknesses

Optiphen™ Plus is not very water soluble and as such doesn’t work very well in watery products like hydrous serums unless the formulation includes a compatible solvent.

As with all preservatives that contain phenoxyethanol, Optiphen™ Plus can thin emulsions—though just how much thinning you’ll experience can vary a lot with the formulation.
Alternatives & Substitutions

You’ll need another broad spectrum preservative.

I use Liquid Germall™ Plus a lot; it is more water soluble than Optiphen™ Plus but has a lower heat tolerance.

Optiphen™ (INCI: Phenoxyethanol, Caprylyl Glycol) and Euxyl® PE 9010 (INCI: Phenoxyethanol, Ethylhexylglycerin) are good options. Plain phenoxyethanol can also work, depending on the formulation.
How to Work with It

Optiphen™ Plus can be hot or cold processed as long as your heated phase doesn’t exceed 80°C (176°F). I usually include it in the cool down phase of emulsions.

For the best performance, ensure formulations preserved with Optiphen™ Plus have a pH below 6.

I’ve had great experience using it in emulsions and low-water content formulations like shampoo bars and conditioner bars.

If you want to use Optiphen™ Plus in a watery formulation like a hyaluronic acid serum, pre-distribute it in a suitable solvent (glycerin, propylene glycol, and propanediol 1,3 are probably the easiest options) before adding the water. I’d try using 3–5x the amount (eg. 1.5% Optiphen™ Plus, 4.5–7.5% solvent) and see how that works. (This strategy was suggested to me by cosmetic chemist Valerie George from Simply Ingredients.)
Storage & Shelf Life

Stored somewhere cool, dark, and dry, Optiphen™ Plus should last two years.
Tips, Tricks, and Quirks

I find Optiphen™ Plus tends to lower the pH of formulations a little bit, and that can be really useful.

There are a few INCI-identical preservatives out there, including:

  • Novaguard PCS (ChemQuest International)
  • GimarPreserv PCS (Gimar Distribution, Inc.)
  • Phenoxyethanol SA (MakingCosmetics Inc.)

You cannot assume any preservative with the same INCI is just Optiphen™ Plus under a different name, which means you also cannot be certain it will perform identically. Make sure you research and test!
Recommended starter amount

30g (1.06oz)
Where to Buy it

Buy it from an online DIY ingredient supplier.

Want to learn more about preservatives and compare them? Check out this chart!

 

Some Formulations that Use Optiphen™ Plus

Originally published on August 30, 2022