Questions about using 10% Glycolic Acid Solution
Question
I have questions regarding using glycolic acid:
1. I mixed it using grams: `glycolic acid 10 กรัม` with `นัำ 90 กรัม`. Will this result in a 10% concentration, equivalent to using `glycolic acid 10 กรัม` with `น้ำ 90 ml.`?
2. After mixing, how long can it be stored?
3. Can it be used daily? How many months until results are visible? When should I stop using it?
4. Should I apply and leave it on without rinsing, or should I rinse it off? If rinsing, how many minutes should I leave it on?
Answer
Answers to your questions about Glycolic Acid
Here are the answers to your questions regarding your homemade glycolic acid solution:
Concentration Calculation: Mixing 10 grams of glycolic acid with 90 grams of water results in a 10% concentration by weight (mass/mass). Since water has a density of approximately 1 g/mL, 90 grams of water is roughly 90 mL. Therefore, 10 grams of glycolic acid in 90 mL of water is approximately a 10% concentration by weight/volume (mass/volume). While technically different, for practical purposes with dilute aqueous solutions, these are often considered roughly equivalent. So, yes, your mixture is approximately 10%.
Shelf Life: The shelf life of a homemade glycolic acid solution mixed with water can be short, especially without preservatives and sterile preparation. Water-based solutions are prone to microbial growth. Without preservatives, it might be safe for only a few weeks to a couple of months if stored properly (cool, dark, sealed). Signs of spoilage include changes in appearance or odor. For longer storage and safety, using cosmetic preservatives is recommended.
Usage Frequency, Time to See Results, and When to Stop:
- Usage Frequency: Daily use of a 10% solution might be too strong. Start with less frequent application (e.g., 2-3 times per week) and observe your skin's reaction. Increase frequency gradually if tolerated.
- Time to See Results: You might see improvements in texture within weeks. More significant results (pigmentation, lines) can take several months (2-6 months) of consistent use.
- When to Stop: You don't have to stop if your skin tolerates it and you see benefits. Adjust frequency based on needs or take breaks if sensitivity occurs. Stop if you experience persistent irritation or adverse reactions and consult a dermatologist.
Rinse Off vs. Leave On: For a simple 10% solution in water, which likely has a low pH, it is generally safer to use it as a short-contact treatment and rinse it off to avoid irritation. If rinsing, start with a short contact time (e.g., 5-10 minutes) and gradually increase if tolerated. Avoid leaving it on for too long.
Always use daily sunscreen when using glycolic acid. Consider a patch test before full application. Consulting a dermatologist is recommended, especially with homemade solutions or existing skin conditions.