What Is Lithium Oxidized Polyethylene?
Lithium Oxidized Polyethylene is a special form of polyethylene, the same family of plastic used in many household items, that has been lightly oxidized then combined with lithium salts. The base polymer comes from ethylene gas, which is turned into solid polyethylene through a high pressure process. After the polymer is made, controlled exposure to oxygen adds tiny amounts of oxygen to the chains, creating functional groups that let the material mix better with water based formulas. Finally the oxidized polymer is treated with a lithium compound, usually lithium hydroxide, so the oxygen rich parts become lithium salts. This small tweak improves stability and texture while keeping the ingredient safe for skin.
Polyethylene itself was discovered in the 1930s but the oxidized version did not gain traction in cosmetics until the 1970s when chemists looked for gentler alternatives to waxes. Adding lithium came later as formulators noticed it gave smoother gels. Today Lithium Oxidized Polyethylene shows up in a wide range of products such as face and body lotions, sunscreens, masks, anti aging creams, liquid foundations, lip balms, hair styling gels and even some deodorant sticks. Its job is mostly behind the scenes, helping a formula feel pleasant and stay put on the skin.
Lithium Oxidized Polyethylene’s Cosmetic Benefits/Uses
In a formula this ingredient works in two main ways
- Film forming – it creates a thin flexible layer on the skin or hair that locks in moisture, improves wear time of makeup and gives a smooth finish
- Viscosity controlling – it thickens watery mixtures just enough so lotions do not drip and creams keep their shape which makes the product easier to spread and helps suspend active ingredients evenly
Who Can Use Lithium Oxidized Polyethylene
This ingredient is considered gentle and works well for most skin types, including dry, normal, combination and oily skin. Its lightweight film helps hold moisture without feeling heavy so it rarely upsets balanced or sensitive complexions. People with very acne prone skin should still check the full formula since extremely thick products that rely on lots of waxes or oils in addition to this polymer could feel too occlusive.
Lithium Oxidized Polyethylene is made entirely from petroleum sourced ethylene and mineral lithium. No animal derived material is involved at any stage of production so it is suitable for vegans and vegetarians.
Because the polymer stays on the surface and is not readily absorbed, it is generally viewed as low risk for women who are pregnant or breastfeeding. That said this is not medical advice and anyone who is expecting or nursing should run all skincare choices past a health professional just to be safe.
The ingredient does not react with sunlight and does not make skin more sensitive to UV rays. It is also fragrance free and has no known issues for use on color treated hair or over common actives like retinol or vitamin C.
Potential Side Effects/Adverse Reactions
Reactions to topical Lithium Oxidized Polyethylene are possible but uncommon. The points below describe potential side effects only and most users will not notice any problems when the ingredient is used correctly in a finished product.
- Mild skin irritation such as redness, itching or stinging especially on very sensitive skin
- Contact dermatitis in people who are allergic to polyethylene derivatives
- Temporary clogged pores or small breakouts if the overall formula is heavy and not cleansed off properly
- Eye irritation or watering if the product accidentally gets into the eyes
- In rare cases trapping of other strong actives against the skin longer than intended which can intensify those actives and lead to irritation
If you notice any of the above effects stop using the product and seek advice from a qualified healthcare professional.
Comedogenic Rating
Rating: 1/5
Lithium Oxidized Polyethylene is a large, inert polymer that sits on top of the skin rather than soaking into pores, so it has very little tendency to cause blockages. It also contains no oils or fatty acids that typically trigger breakouts. The rating is not zero because any film former can trap sweat or sebum if used in very heavy formulas or if the product is not cleansed off thoroughly. Overall it is considered safe for people who are prone to acne and breakouts.
Formulation level, presence of other comedogenic ingredients and how thoroughly the product is removed at the end of the day will have a bigger impact on pore clogging than the polymer itself.
Summary
Lithium Oxidized Polyethylene is a modified polyethylene that thickens water based mixtures and leaves a thin flexible film on skin or hair. It boosts spreading, stabilizes actives and helps makeup or sunscreen stay put by creating that barely-there layer. Its thickening power comes from long polymer chains tangling with water while the lithium salts improve compatibility with the rest of the formula.
You will not see this ingredient marketed with flashy claims but it quietly shows up in many lotions, sunscreens, foundations, lip balms and hair gels because it is reliable, cost effective and easy to work with. Newer natural texturizers have dented its spotlight a bit yet formulators still reach for it when they need consistent performance.
Safety wise the polymer is considered low risk, non sensitizing and unlikely to clog pores for most users. As with any cosmetic ingredient it is wise to patch test a new product and monitor your skin just to be sure it agrees with you.