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.
Dipropylene Glycol is a solvent, emulsifier, viscosity decreasing, and masking agent. It helps to extract useful chemicals from plants and leaves, making natural components in a product more effective. It also helps to hydrate the skin. Considered safe for health and doesn't irritate the skin in common concentration.
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.
Betaine is used a lot in “organic” skincare products. It is a good moisturizer that not only hydrates the skin but also strengthens the cell membrane. This helps to lower the water loss over time. It also softens the skin and reduces irritation and redness. It’s often used at a 3-5% concentration depending on the product.
1,2-Hexanediol can do a lot of good things for the formulation of the product. It’s an emollient, preservative, and humectant. It keeps skin hydrated and soft. It’s a good component for dry and dehydrated skin.