Water is a great solvent. It’s neutral and doesn’t provide any strong positive or negative effects. It just helps components to mix better and to transport active components.
Vitamin C is known for its strong antioxidant activity. It helps to slow down aging processes. The other positive effect of this ingredient is that it helps to make skin tone even. It's a great ingredient to counter dark areas and uneven skin tone. It's well-researched and considered safe. But it's acid and can irritate the skin if used too often.
Butylene Glycol is a very popular synthetic alcohol. It helps the product to absorb deeper and faster. It is also a solvent for other ingredients. As for the skin benefits, it helps to attract water and helps to make the skin softer.
Unlike many other “Glycols”, it is not harmful and that's why it is used in many products. It was approved by US FDA and US EPA for usage.
