A high-performance humectant that provides prolonged hydration with a smoother, less tacky finish than standard Glycerin. It functions by binding water to the skin surface, improving the moisture barrier while enhancing the overall sensory profile of cosmetic formulations.
- INCI Name:
- Diglycerin
- Chemical/Scientific Name:
- 3,3′-Oxydipropane-1,2-diol
- Common Aliases:
- Diglycerol, Alpha,alpha’-diglycerol
| Category: | Moisturizers |
| Source Origin: | Plant-derived (typically from rapeseed or palm oil) or Synthetic |
| Comedogenic Rating: | 0 |
| Primary Industries: | Skincare, Color Cosmetics, Hair Care |
| Solubility: | Water-soluble |
At a Glance: Properties & Effects
| Hydration/Moisture | |
| Texture Enhancement | |
| Barrier Repair | |
| Irritation Risk |
- Primary Benefits: Long-lasting moisture retention, reduced TEWL (transepidermal water loss), non-sticky skin feel, and enhanced formula stability.
- Potential Risks: Extremely low; generally considered non-irritating and non-sensitizing even at high concentrations.
Biological Action & Cosmetic Profile
The molecular configuration of this polyol involves two Glycerin molecules joined via an ether bond. This structural modification results in a higher molecular weight and increased viscosity compared to its monomeric counterpart. Because of its larger size, the substance penetrates the stratum corneum more slowly than traditional humectants, allowing it to remain on the skin surface longer to provide a sustained moisturizing effect. Four hydroxyl groups per molecule facilitate robust hydrogen bonding with water, effectively anchoring moisture within the upper epidermal layers.
Structural variations allow it to act as a bridging agent between the skin’s surface and deeper hydration needs. Clinical observations indicate that while Glycerin provides immediate water binding, this dimer offers a “slow-release” hydration profile that maintains skin suppleness over several hours. Furthermore, it possesses a lower vapor pressure, meaning it is less likely to evaporate or draw moisture from the deeper dermis in dry environments—a common critique of smaller humectants.
Broader Applications & Origins
Vegetable oils typically serve as the primary feedstock for production, where glycerol is polymerized under controlled conditions to create the ether-linked dimer. The resulting liquid is clear, odorless, and highly stable against oxidation. Beyond its humectant properties, formulators value this ingredient for its ability to reduce the “soaping” effect (white streaks) in emulsions and for its utility as a solvent for botanical extracts that require more stability than Sorbitol or Propanediol can provide alone.
Routine Integration
- Synergies: Pairs exceptionally well with Sodium Hyaluronate for multi-depth hydration and Panthenol to reinforce the moisture barrier. It is often combined with Butylene Glycol to improve the spreadability of facial serums.
Clinical Consensus & Safety
Toxicological assessments by the Cosmetic Ingredient Review (CIR) Expert Panel and listings in the European Commission’s CosIng database classify this substance as safe for cosmetic use without specific concentration limits. Research published in dermatological journals highlights its superior biocompatibility, noting a complete absence of dermal irritation in patch testing. Because it is chemically similar to the lipids and polyols found naturally in the skin, it is tolerated well by those with compromised barriers or sensitive skin types.
Is Diglycerin better than regular Glycerin?
It is not necessarily “better” in terms of hydration capacity, but it is superior in terms of sensory experience. It provides a smooth, silky finish without the tackiness often associated with high-dose Glycerin, making it ideal for elegant serum and gel formulations.
Is this ingredient safe for acne-prone skin?
Yes. It has a comedogenic rating of 0, meaning it does not clog pores. Its water-soluble nature ensures that it provides hydration without adding the oiliness that can exacerbate certain types of acne.
Can it be used in natural skincare?
Most versions used in the industry are vegetable-derived and Ecocert/COSMOS compliant. It is a preferred choice for clean beauty brands looking for high-performance moisturizers that are biodegradable and sustainably sourced.