Propylene Glycol and Butylene Glycol plays multiple roles in the formula. It's solvent, humectant, and auxiliary preservative cooperating with D-Panthenol and Glycerin. EWG website categorizes Propylene Glycol as moderate hazardous because it has the possibility to cause the allergy. But in one scientific article shows that the among the toxicity test, the testers got the patch with 100% of Propylene Glycol and 14% of the tester had allergy reaction. Also, it stressed that skin reactions due to propylene glycol are rare and should not bring the preparation into unnecessary discredit. (Skin irritation caused by propylene glycols. February 1982 Der Hautarzt 33(1):12-4)
Sodium Hyaluronate, is a long chain hyaluronate salt. Because it is a big molecular, it stays on the top of skin to catch moist on the surface of stratum corneum.
Glycerin/Glyceryl Acrylate/Acrylic Acid Copolymer/Propylene Glycol These ingredients are a complex raw material that is used for thickening and skin conditioning.
Hydroxyethylcellulose is an easy to use thickener that is synthesized with the cellulose from the plant resource. Some articles showed the concern in terms of the residues of ethylene oxide and 1,4 dioxane. However, these residues are at very low amount and regulated strictly by Taiwan FDA and USA FDA. We closely checked the residues amount of our raw material, which is less than 0.0001%. Therefore, the safety concern is not necessary toward to this ingredient.
Xanthan Gum and Sodium Polyglutamate are both thickeners and humectant. Both are from natural resources, corn starch and Natto.
Tocopheryl Acetate is the acetate formation of Vitamin E. However, it doesn’t play the same role as Vitamin E as anti-oxidant. It can only prevent the ingredients from oxidizing. Here we use it to protect the chemical activeness of Acerola extract and Licorice extract. This ingredient needs to be at acidic environment to release Hydroquinone that would cause allergy.
DMDM Hydantoin and Iodopropynyl Butylcarbamate is a very strong preservative that preserves the product with very little amount. And it is in the same family of formaldehyde. We know that formaldehyde may cause skin irritation or allergy when formaldehyde is present in the air at levels higher than 0.1 parts per million (ppm) which is, 1 ppm = 1.25 mg/m3. (American Cancer society/ WHO Regional Office for Europe) This means, if your room is 5 square meters, you need 156.25 mg formaldehyde to get you irritated. Therefore, the preservative we use in this mask would not cause irritation neither allergy in this definition. But if you still have the concern, please tear small piece of the mask and test it on your arm for 15 minutes.
This is the last product we use this preservative system. We tried to change it, but we didn’t because of several reasons. First, this is a very mature formula and we have very few customers and users responded claimed that they had bad reaction with this product, probably 0.00047%, which means only 1 person reported out of 209,000 people. Secondly, the preservative would release formaldehyde into the air after you open the mask bag. It won’t stay on your skin. Neither, it won’t re-dissolve into the product, unlike other cream or lotion product in a seal container.
PEG-40 Hydrogenated Castor Oil is a used to cover Rose oil to dissolve in the formula. Even though EWG website categorized it as moderate hazardous due to its residues, Ethylene Oxide and 1,4-dioxane, PEG-40 Hydrogenated Castor Oil has less than 0.001%. So, safety won't be a concern.
While we are selecting the ingredients, we must consider many things, including safety recheck, pH vale, Hydrophile-Lipophile Balance (HLB) value, quantity, convivence to utilize in the formula and cost. After evaluating all the points, we eventually decided to go for polysorbate 20 at 0.015% in this formula.