These are the ingredients that are most often used in lip gloss or chap sticks:

Ingredients: Lanolin Oil, Hydroylated Lanolin, Polybutene, Microcrystalline Wax, Ethylhexyl Palmitate, Isopropyl Myristate, Ceresin, Isopropyl Lanolate, Aloe Barbadensis Leaf Extract, Sesamum Indicum (Sesame) Seed Oil, Allantoin, Tocopherol, Ascorbyl Palmitate, Propylparaben, Fragrance.

May contain: Titanium Dioxide, Iron Oxides, Mica, Carmine, Red 6 Lake, Red 7 Lake, Red 21, Red 27 Lake, Red 30 Lake, Red 33 Lake, Red 36, Orange 5, Yellow 5 Lake, Yellow 6 Lake, Blue 1 Lake.

What it means is that lipsticks are made of a

solid waxy material (it has to spread easily but stay solid in the tube) like Lanolin Oil, Hydroylated Lanolin, Polybutene, Microcrystalline Wax

different pigments ( for color) like Titanium Dioxide, Iron Oxides, Mica, Carmine, Red 6 Lake, Red 7 Lake, Red 21, Red 27 Lake, Red 30 Lake, Red 33 Lake, Red 36, Orange 5, Yellow 5 Lake, Yellow 6 Lake, Blue 1 Lake and

esters or fatty acids (myristates) to give it a stickiness, for example Ethylhexyl Palmitate, Isopropyl Myristate, Ceresin, Isopropyl Lanolate Wheat Germ Triglycerides, Aloe Extract, Soyabean OilMost often the companies add a fragrance for better smell.

How does lip gloss work?

Lips chap when they get too dry. Dry air for example can pull moisture out of the top layer of the epidermis faster than it can diffuse in from the underlying layers, causing it to dry out. This is true all over the body in arid weather, however thinner layers, especially on the lips, dry to the point of becoming brittle and cracking open with the slightest movement. So, the most important consideration in treating chapped lips is keeping the skin sufficiently hydrated. The best way to do this is to apply a sealant to the skin which prevents water from escaping. This works by simply covering the lips with a material that is impermeable to water. In all cases, this impermeable material is some form of long-chain hydrocarbons (or fatty acids); the differences in length and saturation of the carbon chains determining whether the balm is waxy or greasy.

In terms of actual molecular interactions, about the only forces at play in lip balms are Van Der Waal forces and hydrophobicity. Van der Waal's force involves the attraction between non-polar molecules due to transient polarization of their electron clouds. This is the weakest of molecular forces but is still sufficient to hold the long-chain hydrocarbon molecules snugly together so that water molecules have a hard time getting through. The interactions between the wax/grease molecules help to form a solid barrier to water, but more importantly, water doesn't try to cross the barrier because wax and oils are hydrophobic, meaning they repel water.

A note about sunscreen: Because the lips are highly sensitive to UV light it is a good idea to protect them. Many lipsticks have Titanium Dioxide or Zinc oxide as ingredient which are also good sunscreens. But there are also chemical ingredients as sunscreen that can be added to the lipstick. Maybe you want to look at a sun safety website for more info:
sunscreen

Here is a site on Cosmetic Chemistry if you are interested to read more:
cosmetic chemistry