| What is it? |
GeogardĀ® 221 is a liquid natural broad-spectrum preservative from Arxada (previously Lonza). It is comprised of (source: Arxada):
Dehydroacetic Acid is the active, acidic form ofĀ Sodium Dehydroacetate (click that link to learn more). GeogardĀ® 221 is part of the GeogardĀ® line; the “221” part of the name is very important as the different products within the line all have different INCIs. Other GeogardĀ® products include Geogard UltraĀ®, GeogardĀ® ECT, GeogardĀ® 111S, GeogardĀ® 111A, and GeogardĀ® Boost PHC. |
| INCI |
Dehydroacetic Acid (and) Benzyl Alcohol |
| Appearance |
Clear, light yellow to orange liquid |
| Usage rate |
0.2ā1.1% |
| Scent |
Arxada describes it as “essential odorless”, but benzyl alcohol has a characteristic almondy/marzipan-y scent that I find noticeable (to varying degrees) in other preservatives that use it, like GeogardĀ® ECT,Ā TRIstat ECO, andĀ Euxylā¢ k 903. |
| Effective pH range | 2ā7 |
| Solubility |
Highly soluble in polar organic solvents (e.g. propylene glycol, ethanol, glycerin). Benzyl alcohol is not very water soluble. In my experience, benzyl alcohol based preservatives do 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? |
GeogardĀ® 221 protects our formulations from microbial spoilage (bacteria, yeast, fungus). |
| Do you need it? |
You should have at least one broad-spectrum preservative; GeogardĀ® 221 is a decent choice if you prefer natural preservatives and don’t mind the almondy scent. |
| Refined or unrefined? |
GeogardĀ® 221 only exists as a refined product. |
| Strengths | GeogardĀ® 221 has a relatively broad effective pH range for a natural preservative, though not as broad asĀ GeogardĀ® ECT. |
| Weaknesses | Arxada notes: “Anionics (carbomers and certain surfactants) can cause discoloration. This can be limited by the addition of reducing agents /antioxidants, in particular BHT or sodium metabisulfite or tocopherol (not tocopheryl acetate).”
GeogardĀ® 221 is not as widely available asĀ GeogardĀ® ECT. |
| Alternatives & Substitutions |
You’ll need another broad-spectrum preservative. Natural alternatives include GeogardĀ® ECT andĀ Euxyl k 903āboth are also primarily based around benzyl alcohol. Liquid Germallā¢ Plus and Optiphenā¢ Plus are effective, versatile choices, but aren’t natural. |
| How to Work with It |
Include GeogardĀ® 221 in the cool down phase of your formulations, and ensure the final pH of the formulation is the in 2ā7 range. |
| Storage & Shelf Life |
Store somewhere cool, dark, and dry. |
| Tips, Tricks, and Quirks | |
| Recommended starter amount |
30mL (1fl oz) |
| Where to Buy it |
Purchase GeogardĀ® 221 from an online DIY ingredient supplier. |
Want to learn more about preservatives and compare them? Check out this chart!