Skin Irritation from High pH Due to Incorrect Triethanolamine (TEA) Usage
Question
I made a cosmetic formulation using 5% Triethanolamine (TEA) and experienced skin irritation (stinging/burning) after applying it. I calculated the ingredients by volume (ml) instead of weight (grams).
- Why did this happen?
- What should I do?
Answer
Understanding Triethanolamine (TEA) in Formulations
It sounds like you experienced skin irritation after applying the gel, which is concerning. Let's clarify a few points about using Triethanolamine (TEA) in cosmetic formulations.
Weight vs. Volume
Cosmetic formulations are almost always calculated by weight (grams), not volume (ml). This is because different ingredients have different densities. 5ml of TEA will not weigh the same as 5g, and adding 5ml when you intended to add 5% by weight means you likely added a significantly higher concentration than 5% of the total formula's weight. This is a common mistake and can lead to problems.
Function of Triethanolamine (TEA)
Triethanolamine is a base (alkaline substance) primarily used in cosmetic formulations as a pH adjuster. Its main function is to raise the pH of a product, making it less acidic. It is also used to neutralize thickeners like Carbomers, helping to create a gel structure.
Why 5% Might Be Too Much and Cause Irritation
The recommended maximum usage rate (like "not exceeding 5%") refers to the percentage by weight of the total formulation. Adding 5% TEA by weight is already a relatively high concentration, typically used when significant pH adjustment is needed or when neutralizing a high percentage of a thickener. If you added 5ml thinking it was 5% by weight, the actual concentration could be much higher, leading to a very high pH in your final gel.
Skin has a naturally slightly acidic pH (around 4.5-5.5). Applying a product with a high, alkaline pH can disrupt the skin's barrier, causing irritation, redness, burning, or stinging, especially in sensitive areas like the nasal folds.
What to Do
- Stop using the product immediately. Since it caused irritation, it is not safe to continue using.
- Always calculate formulations by weight. Use a scale to measure all ingredients in grams.
- Measure the pH of your final product. This is crucial when using pH adjusters. Use a pH meter or reliable pH strips to ensure the final pH is in a skin-friendly range, typically between 4.5 and 5.5 for facial products.
- When using TEA for simple pH adjustment, start with a very low concentration (e.g., 0.1-0.5%) and add small amounts gradually while measuring the pH until you reach your target range. 5% is rarely needed just for pH adjustment.
It's important to understand the function and proper usage of ingredients like Triethanolamine to ensure the safety and effectiveness of your homemade cosmetic products.