Checking Aloe Vera Gel Formula and Adding Glycerin

Regarding your Aloe Vera Gel formula for oily, sensitive skin:

The ingredients you've chosen are generally well-suited for your skin type:

• Aloe Vera Extract (3%): Known for its soothing and moisturizing properties, excellent for sensitive skin.
• Vitamin B3 (Niacinamide, 4%): Great for oily skin as it helps regulate sebum production. It also strengthens the skin barrier and has anti-inflammatory benefits, good for sensitive skin. 4% is an effective concentration.
• N-Acetyl-D glucosamine (GlucoBright™, 4%): Often used with Niacinamide for synergistic effects on skin tone and also provides hydration. 4% is a typical effective concentration.
• Allantoin (0.5%): A known skin soother and anti-irritant, very beneficial for sensitive skin. 0.5% is a standard effective percentage.
• Phenoxyethanol (0.8%): This is a necessary preservative to keep the product safe from microbial growth. 0.8% is within the standard usage range.
• Pro Polymer™ (Gel Maker, 1%): This is a gelling agent. Adding it to an Aloe Vera Gel Base (which already provides the gel structure) is likely intended to adjust the final texture or thickness after adding the other ingredients.

Regarding your question about Glycerin:
Yes, Glycerin (Vegetable) 99.5% is the same substance as กลีเซอรีน. Glycerin is a very common and effective humectant, meaning it draws water into the skin, providing hydration. It also helps improve the feel of cosmetic products, making them feel smoother and less "tight".

Glycerin is suitable for both oily and sensitive skin types when used at appropriate concentrations. For a gel formula intended for oily skin, adding too much Glycerin can make the product feel sticky. Since your base likely already contains some humectants, adding a small amount of Glycerin (e.g., 1% to 3%) should be sufficient to enhance hydration and improve the texture without causing stickiness.

You may want to start with a lower percentage and test the texture before deciding on the final amount.