Formulation Advice for Skin Whitening Serum

Okay, I understand you're looking for guidance on formulating a skin-whitening serum with specific ingredients and want to know about the base amount, safe pH, and necessary equipment, especially as you're new to this and planning to purchase ingredients from the store.

Here is some general advice regarding your questions:

1. Amount of Gel Base

The amount of gel base you need depends on the total amount of serum you want to make. The percentages you listed for the active ingredients (Alpha Arbutin 2%, Glutathione 1.5%, B3 2%, N-acetyl-D Glucosamine 4%, Vitamin C 15%) add up to a total of 24.5%.

To make a complete formula, all ingredients (actives, base, water, preservatives, etc.) must add up to 100%.

So, if you only use these actives and a gel base, the gel base amount would be 100% - 24.5% = 75.5%.

• Example: If you want to make 100 grams of serum, you would use 24.5 grams of the combined active ingredients and 75.5 grams of the gel base.
• Important: This calculation assumes you are measuring by weight (grams). Accurate measurement, especially for small percentages, is crucial.

2. Safe pH Level

For skin application, a pH level between 4.0 and 6.0 is generally considered safe and comfortable for the skin's natural barrier.

However, Vitamin C (specifically Ascorbic Acid, which is a common form used at 15%) is most stable and effective at a lower pH, often between 3.0 and 3.5. Formulating at such a low pH can cause irritation for some people.

Balancing the efficacy of Vitamin C with skin comfort when combining multiple actives can be challenging. You might aim for a pH between 4.0 and 5.5, but be aware that the stability of Vitamin C might be reduced at this higher pH, potentially requiring specific stabilized forms or antioxidants in the formula.

You must test the pH of your final mixture using pH strips or a pH meter and adjust it if necessary using a dilute acid (like citric acid solution) or base (like sodium bicarbonate solution), adding drop by drop and re-testing.

3. Necessary Equipment

To accurately measure and mix ingredients for cosmetic formulation, you will need some basic equipment:

• Digital Scale: Essential for measuring ingredients accurately, especially powders and small percentages. A scale with at least 0.01g precision is recommended.
• Beakers or Containers: Glass or plastic containers for weighing and mixing your ingredients.
• Stirring Rod or Spatula: To mix the ingredients thoroughly.
• pH Testing Strips or pH Meter: Crucial for checking and adjusting the final pH of your serum.
• Gloves: To maintain hygiene and protect your skin.
• Pipettes or Droppers (Optional): Useful for measuring small amounts of liquids or adding pH adjusters drop by drop.

Important Advice for Beginners

• Formulating with multiple high-percentage active ingredients can be complex. Ensure all your chosen ingredients are compatible and soluble in your chosen base.
• Always maintain good hygiene when making cosmetic products to prevent bacterial contamination.
• If you are adding water to your formula, you will need to include a preservative to prevent microbial growth.
• Start with smaller batch sizes until you are comfortable with the process.
• Always perform a patch test on a small area of your skin (like your forearm) before applying the product to your face, especially with new formulations or high concentrations of actives, to check for irritation or allergic reactions.

Making your own skincare can be rewarding, but it requires careful measurement, understanding of ingredients, and attention to safety.