To be efficient, therefore, a propellant should have a large heat of combustion to yield high temperatures, and should produce combustion products containing simple, light molecules embodying such elements as hydrogen (the lightest), carbon, oxygen, fluorine, and the lighter metals (aluminum, beryllium, lithium).
Vitamin A - Retinyl Palmitate/ Retinol. Vitamin A is a fat soluble vitamin that is stored in our liver. It contributes to normal growth and development while keeping our eyes, skin and immune system healthy. Vitamin A plays a key role in maintaining health.
However, retinol is not as effective as prescription retinoids because itâs a less powerful form of vitamin A. 1  Getty Images Avoid Irritation Retinoids can be irritating, especially when you first add them to your skin care routine.2  So, you may want to start with an over-the-counter retinol to build up your tolerance.etinoids vs. Retinols. Retinoid is the prescription-strength form of vitamin A. Topical prescription retinoids such as tretinoin (Retin-A and Renova) work as an irritant, resulting in a more rapid turnover of skin cells.