This is a summary of research papers and studies
from the National Center for Biotechnology Information (NCBI)

ABOUT VEGETABLE GLYCERIN

Glycerin, also known as glycerol, is a highly effective, naturally occurring humectant that plays a vital role in maintaining skin health and treating dry skin conditions. Plant-derived glycerin (glycerol) is a natural, viscous, and colorless humectant derived from vegetable fats, acting as a crucial skin-conditioning agent. It treats conditions like xerosis and psoriasis by retaining moisture and soothing irritation. National Institutes of Health As a hygroscopic substance, it attracts and holds water from both the environment and deeper skin layers into the the outermost layer of the skin. 

Effectiveness for Dry Skin Conditions 

Glycerin is considered one of the most effective humectants in cosmetics, capable of holding its own weight in water within just three days. Its effectiveness for dry skin is supported by several findings:

• Significant Hydration Boost: Topical application of glycerin-based creams significantly increases the water content of the stratum corneum.
• Long-term Benefits: Studies show that glycerin-containing emulsions maintain increased hydration and protective functions even during long-term use (up to six weeks).
• Fewer skin reactions.
• Symptom Relief: By restoring hydration, glycerin helps alleviate the scaling, flakiness, pain, and itchiness associated with dry skin.

Role in Skin Barrier Repair 

Glycerin does more than just hydrate; it actively repairs and protects the skin's physical barrier:

• Lipid Phase Stabilization: Environmental factors that cause dryness can force skin lipids into a solid crystalline phase, which impairs the barrier. Glycerin prevents this transition, helping to maintain a functional, liquid-crystalline lipid matrix.
• Reduction of Transepidermal Water Loss (TEWL): By improving the organization of skin lipids and corneocytes, glycerin effectively reduces the amount of water that evaporates through the skin.
• Protection Against Irritants: Glycerin has an anti-irritant effect. It can reduce the pore radius in the stratum corneum, making it harder for external irritants to penetrate and damage the skin.
• Medical Applications: It is used as a therapeutic agent for conditions with altered barrier functions, such as atopic dermatitis and irritant dermatitis, where it helps restore normal skin physiology.
• Mechanical Properties: Proper hydration from glycerin improves skin elasticity, deformability, and plasticity, which are often impaired in damaged or dry skin.

Important Usage Considerations

• Dilution is Mandatory: Glycerin should never be used undiluted. Because it is so hygroscopic (attracts moisture), anhydrous (water-free) glycerin can actually extract water from the deeper layers of the epidermis, leading to further dehydration and skin damage.
• Safety: It has an excellent safety profile and is classified as non-toxic, non-irritating, and non-allergenic