| What is it? |
Geogard® ECT is a liquid natural broad-spectrum preservative from Arxada (previously Lonza). It is comprised of (source: Arxada):
It is also sold under many other names like Preservative Eco, Mikrokill ECT, and Plantaserv M, so be sure to check the INCI on what you’re purchasing. Geogard® ECT is part of the Geogard® line; the “ECT” part of the name is very important as the different products within the line all have different INCIs. Other Geogard® products include Geogard Ultra®, Geogard® 221, Geogard® 111S, Geogard® 111A, and Geogard® Boost PHC. |
| INCI |
Benzyl Alcohol (and) Salicylic Acid (and) Glycerin (and) Sorbic Acid |
| Appearance |
Clear, pale yellow liquid |
| Usage rate |
0.6–1% |
| Scent |
Almondy/marzipan-y |
| pH |
Effective from 3–8. Geogard® ECT will cause the pH of your formulations to drop. |
| Solubility |
While the product description on UL Prospector says Geogard® ECT is water soluble (as of May 2024), the data sheet states that it works best in emulsified systems. In my experience, Geogard® ECT does not mix well into totally hydrous formulations like watery serums and room sprays without a suitable solvent or solubilizer. |
| Why do we use it in formulations? |
Geogard® ECT protects our formulations from microbial spoilage (bacteria, yeast, fungus); I’ve found it to be an effective and easy-to-use natural preservative option. |
| Do you need it? |
You should have at least one broad-spectrum preservative; Geogard® ECT is a decent choice if you prefer natural preservatives and don’t mind the almondy scent. |
| Refined or unrefined? |
Geogard® ECT only exists as a refined product. |
| Strengths |
Unlike many natural preservatives, Geogard® ECT has a maximum functional pH range of 8 (most natural preservatives require an acidic pH to function well). The manufacturer lists lip products as a possible application. It’s relatively easy to source. |
| Weaknesses |
Noticeable almondy scent that can get stronger as the formulation ages. Can cause the pH of a formulation to drop so much that it needs to be raised (dropping to below 4 is not uncommon). This can also be problematic if your emulsifier doesn’t work at lower pHs as your emulsion could break when the preservative is added, so you’d need to include a base in the formulation to counter that large pH drop before you added the preservative. Due to the salicylic acid content, Geogard® ECT cannot be used in products for children under 3 except for shampoo. If you are using Geogard® ECT to preserve a formulation that contains salicylic acid as a skincare active, the salicylic acid content in the preservative will count towards the maximum allowable concentration of 2%. If we assume Geogard® ECT contains 15% salicylic acid, when used at 1%, the overall formulation will contain 0.15% salicylic acid. This leaves room for 1.85% additional salicylic acid. The manufacturer advises a shelf life of 12 months from the date of manufacture. |
| Alternatives & Substitutions |
You’ll need another broad-spectrum preservative. Liquid Germall™ Plus and Optiphen™ Plus are effective, versatile choices, but aren’t natural. Natural alternatives include Geogard Ultra™ and Euxyl k 903, though both have a lower effective pH range, and Geogard Ultra™ requires a buffer system to prevent downwards pH drift over time. |
| How to Work with It |
Include Geogard® ECT in the cool down phase of your formulations, and ensure the final pH of the formulation is the in 3–8 range. |
| Storage & Shelf Life |
Store somewhere cool, dark, and dry. The manufacturer advises a shelf life of 12 months from the date of manufacture. |
| Tips, Tricks, and Quirks |
Looking for a natural way to add an almondy scent to your formulation? Preserve it with Geogard® ECT! |
| Recommended starter amount |
30mL (1fl oz) Due to the short shelf life, avoid purchasing more than you can use in ~6 months. |
| Where to Buy it |
Purchase Geogard® ECT from an online DIY ingredient supplier. It can be helpful to do a Google search for the INCI as this product is sold under a variety of names.
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Want to learn more about preservatives and compare them? Check out this chart!