Polyethylene is a cheap (plastic) chemical ingredient cosmetic manufacturers use to fill there product. The only thing cheaper is water, so some cosmetic manufacturers use it in their anti-aging product as well. Polyethylene is also a main component of Polyethylene Glycols, or PEGs.
The National Library of Medicine’s has done a study and they found evidence that Polyethylene is an immune system toxicant.
Do not use any an anti-aging product with polyethylene if you have a damaged skin. It can cause irritation and systemic toxicity.
Sources: http://www.nlm.nih.gov/medlineplus/druginfo/meds/a603032.html