When it comes to personal care products, especially intimate lubricants, we trust that manufacturers have our health and comfort in mind. Unfortunately, scientific evidence suggests otherwise. One of the most commonly used ingredients in personal lubricants—glycerin—is far from harmless when used in high concentrations.
In fact, studies show that glycerin concentrations above 30% can cause burning, stinging, and even tissue damage—particularly on sensitive mucosal surfaces like the vaginal lining.
Glycerin: A Chemical, Not a Cure
First, it’s important to understand: Glycerin is classified as a chemical. The U.S. Food and Drug Administration (FDA) lists glycerin as a Generally Recognized as Safe (GRAS) substance for food use, but this classification does not specifically cover internal mucosal use, such as vaginal or rectal tissue exposure via lubricants. Even in cosmetics, industry standards recommend only 3–5% glycerin concentrations for topical skincare products to avoid irritation. Yet many personal lubricants contain 30–40% glycerin—levels far above the amounts deemed safe for ordinary skin, let alone mucosal tissue.Scientific Studies Confirm the Risk
1. Glycerin and Skin Reactions
A 1996 study published in the Journal of Allergy and Clinical Immunology (PubMed – PMID: 8626978) evaluated the effects of glycerin injected subcutaneously in varying concentrations (0% to 30%). The findings were clear:- Pain scores, redness (erythema), and swelling (induration) increased significantly with higher glycerin concentrations.
- The irritation was dose-dependent—meaning the more glycerin present, the worse the pain and tissue reaction.
2. Glycerin and Mucosal Tissue Damage
Further research, such as a study published via JSTOR titled “Irritation Potential of Glycerin-Based Lubricants”, specifically examined the mucosal irritation potential of personal lubricants containing glycerin. The results showed:- Lubricants with higher glycerin content led to greater mucosal irritation in a clear, dose-dependent pattern.
- Higher concentrations correlated with increased tissue inflammation and damage—undermining the supposed safety of these formulations.