The Material Safety Data Sheet (MSDS) for Propylene Glycol states:  

"Implicated in contact dermatitis, kidney damage and liver abnormalities; Can inhibit skin cell growth in human tests and can damage cell membranes causing rashes, dry skin and surface damage. Acute Effects: May be harmful by inhalation, ingestion or skin absorption. May cause eye irritation, skin irritation, exposure can cause Gastro-Intestinal disturbances, Nausea, Headache and Vomiting, Central Nervous System depression."

Many cosmetics and over-the-counter products contain propylene glycol. All regulatory groups consider it safe. Yet, the warnings above appear in the official documents that accompany this chemical. Many of our formulas contained propylene glycol. It is useful in solubilizing active ingredients and it adds a pleasant feeling to the finished cream or lotion.

We have heard from a handful of customers that they had developed rashes or redness when they used our compounded products. With just a little investigation we found that the culprit may be propylene glycol. We modified a formula for one patient – replacing the propylene glycol with glycerin – and the skin irritation cleared immediately. This seemed to be evidence against the propylene glycol. When a second person had a similar complaint we modified her prescription – and again the irritation cleared.

Two complaints out of thousands of compounds does not prove conclusively that propylene glycol is generally harmful. But, the fact that the problems resolved when we switched to glycerin, combined with the information described in the above MSDS, make it difficult for us to continue using propylene glycol.

Therefore, we have removed propylene glycol from our topical and transdermal compounds. There are other agents that are as good (or better) – that do not pose a health risk.