Allantoin Dissolution, Hot Sensation, and Formulation Tips for Essence

Subject: Inquiry after mixing

Hello,

I understand you're having issues with Allantoin dissolution and a hot sensation on your face while making your essence.

Based on the information you provided and the expert advice:

1. Allantoin Dissolution Issue:

   • Allantoin has low solubility in water at room temperature (maximum solubility is about 0.5% at 25°C) and dissolves better in warm water (maximum solubility is about 2.5% at 50°C).
   • The issue with your scale not accurately measuring small amounts like 0.3 grams likely caused you to accidentally add more Allantoin than can dissolve in your water-based formula. When you exceed its solubility limit, it will remain as undissolved powder.
   • Recommended Solution: It is recommended to create a Stock Solution by dissolving Allantoin in a larger amount of distilled water, allowing for more accurate weighing of the Allantoin. For example, make 500 grams of a 0.3% Allantoin in water solution (using 1.5 grams of Allantoin), and then use this Stock Solution in your formula according to the required water amount.

2. Hot Sensation on Face:

   • From your formula ingredients and the sensation experienced, the expert suggests it is more likely from Phenoxyethanol than Ethoxydiglycol. Although you previously tested testers without issues, the hot sensation might be due to accidentally adding more Phenoxyethanol than intended (0.65%) because of the difficulty in weighing small amounts accurately.
   • Recommended Solution: If you need to use small amounts of Phenoxyethanol and your scale is not precise enough, it is also recommended to make a Stock Solution of Phenoxyethanol in distilled water. For example, make 500 grams of a 0.5% Phenoxyethanol in water solution (using 2.5 grams of Phenoxyethanol), and then use this Stock Solution in your formula. You can also combine the Stock Solutions of Allantoin and Phenoxyethanol in the same batch of water.

3. Further Questions and Formula Calculation:

   • Stock Solution (Pre-mixed Allantoin/Phenoxyethanol water): It is not necessary to refrigerate it. It can be stored at room temperature as usual.
   • Calculation when using Stock Solution: When using the Stock Solution containing Allantoin and/or Phenoxyethanol in your main formula, calculate the weight of the Stock Solution as the "water" portion of your formula. You do not need to recalculate the individual percentages of Allantoin or Phenoxyethanol within the Stock Solution for the main formula; this simplifies calculation.
   • Calculation when using a Ready-made Base: Similar to using a Stock Solution, when using a ready-made base like Aloe Vera Gel Base in your formula, for ease of calculation, treat the entire weight of the base as the "water" portion of your main formula. You do not need to calculate the individual sub-ingredients within that base separately.
   • Disodium EDTA: It can be pre-mixed in water (including in the Stock Solution you prepare) and stored without any issues regarding shelf life or storage.

In summary, the main issues likely stem from weighing small amounts of ingredients with an imprecise scale, leading to an overdose of Allantoin and potentially Phenoxyethanol. Making Stock Solutions in larger quantities will help you weigh more accurately and resolve the dissolution and potential irritation issues.

I hope this advice is helpful. Please feel free to ask if you have any further questions.