Trehalose: a protein-protective sugar that hydrates and shields skin from stress¹

How it works

Trehalose is a non-reducing disaccharide composed of two glucose molecules joined by an alpha-1,1-glycosidic bond. This structure makes it unusually stable compared to other sugars — it resists breakdown by heat, acid, and enzymatic activity. That stability is directly tied to trehalose's most distinctive property: protein protection. Under dehydration stress, trehalose replaces the water molecules that normally surround proteins, forming hydrogen bonds with their polar groups and maintaining their three-dimensional shape. This mechanism, known as the "water replacement hypothesis," explains why organisms that survive extreme desiccation — tardigrades, resurrection plants, brine shrimp — produce trehalose in high concentrations as a biological survival strategy.¹

In skin, this protein-stabilizing behavior translates to meaningful protective benefits. Trehalose shields structural proteins like collagen and elastin, as well as enzymes involved in antioxidant defense, from conformational damage caused by environmental stressors such as heat, UV exposure, and low humidity. At the same time, trehalose functions as a free-radical scavenger, neutralizing reactive oxygen species that contribute to oxidative stress.² This dual mechanism — direct protein stabilization plus antioxidant activity — sets trehalose apart from conventional humectants that hydrate without offering stress protection.

Because of this dual role, trehalose bridges the humectant and protective ingredient categories. It draws moisture into the skin like a classic humectant, but simultaneously shields the proteins that keep skin resilient and functional. This makes trehalose especially valuable in formulations designed for environmentally stressed or aging skin, where hydration alone is not enough and protein integrity matters.²

How trehalose compares to glycerin and other humectants

Not all humectants work the same way. Here is how trehalose stacks up against the most common alternatives:

• Glycerin: The most widely used humectant in skin care. Glycerin draws water from the environment and deeper skin layers into the stratum corneum. It is effective and well-tolerated, but at high concentrations it can feel tacky on skin. Glycerin is a pure hydrator — it does not stabilize proteins or offer antioxidant benefits.
• Trehalose: A protein-stabilizing sugar with dual hydration and stress-protection properties. It hydrates through humectant activity while simultaneously shielding proteins from conformational damage. Trehalose has a lightweight, non-tacky texture, making it comfortable in layered routines. No other common humectant offers this protein-protective mechanism.
• Sodium PCA: A component of the skin's natural moisturizing factor (NMF), making it highly biomimetic. Sodium PCA is a pure humectant — it attracts and holds water effectively but does not provide protein stabilization or antioxidant activity.
• Hyaluronic acid: A large glycosaminoglycan capable of holding up to 1,000 times its weight in water. It provides intense surface hydration and a visually plumping effect. Like glycerin and sodium PCA, hyaluronic acid is a pure humectant without protein-protective properties.

Trehalose's unique value is its protein-protective mechanism. While all four ingredients hydrate effectively, only trehalose actively stabilizes the structural proteins and enzymes that keep skin functioning under stress.

Safety & considerations

Trehalose has a well-established safety profile in both food and cosmetic applications. It is non-irritating, non-sensitizing, and compatible with all skin types, including sensitive and reactive skin.¹ Trehalose works well alongside other humectants, peptides, antioxidants, and barrier-repair ingredients without compatibility concerns.

For a deeper look at how humectants like trehalose fit into a complete hydration strategy, see Ingredients 101: Hydration — The Three-Layer Strategy on the Dermalogica Institute blog.

Tips for use

• Use trehalose-containing products consistently for cumulative hydration and protein-protective benefits.
• Layer with other humectants (glycerin, hyaluronic acid) and emollients for a complete hydration strategy.
• Especially beneficial for dry, dehydrated, environmentally stressed, or aging skin.
• Apply to clean, slightly damp skin to maximize humectant water-binding activity.

Trehalose is one of those quietly remarkable ingredients in modern skin care: a naturally occurring sugar that goes beyond simple hydration. While most humectants stop at attracting water, trehalose adds a layer of protein stabilization that protects skin's structural integrity under environmental stress.¹² Trehalose's hydrating and protein-protective roles complement peptide-driven actives that focus on visible firmness, supporting a multi-layered approach to the look of healthy, comfortable skin.² With consistent use, trehalose helps skin look hydrated, comfortable, and visibly more cared for.²

FAQs

What is trehalose? Trehalose is a non-reducing disaccharide — a sugar made of two glucose molecules — used in skin care as both a humectant and a protein-stabilizing agent. It moisturizes skin while protecting structural proteins from environmental stress damage.¹

How does trehalose hydrate skin? Trehalose functions as a humectant, attracting and binding water molecules in the skin's outer layers.¹ But unlike most humectants, it also stabilizes proteins by replacing water molecules around them during dehydration — a mechanism called the "water replacement hypothesis." This dual action helps skin stay hydrated and structurally resilient.²

What makes trehalose different from other humectants like glycerin or hyaluronic acid? Most humectants (glycerin, hyaluronic acid, sodium PCA) hydrate by attracting and holding water. Trehalose does this too, but it also stabilizes structural proteins and enzymes, protecting them from conformational damage caused by heat, UV, and dryness. No other common humectant provides this protein-protective benefit.

Does trehalose have antioxidant benefits? Yes. Trehalose scavenges free radicals, neutralizing reactive oxygen species that contribute to oxidative stress.² Combined with its protein-stabilizing properties, this gives trehalose a dual protective mechanism: it shields both proteins and lipids from environmental damage.

What skin types benefit from trehalose? Trehalose is suitable for all skin types, including sensitive and reactive skin.¹ It is especially beneficial for dry, dehydrated, or environmentally stressed skin, where both hydration and protein protection are needed.

Can trehalose be combined with peptides? Yes. Trehalose pairs particularly well with peptides because its protein-stabilizing properties help maintain peptide integrity in formulations, providing hydrating and protective support that complements peptide-driven visible firming benefits.²

Why do tardigrades and resurrection plants produce trehalose? These organisms produce trehalose as a survival mechanism against extreme desiccation. When water is lost, trehalose replaces the water molecules around cellular proteins, maintaining their three-dimensional structure and preventing irreversible damage. This same protective mechanism benefits skin when trehalose is applied topically.¹

Further reading from The International Dermal Institute

• Ingredients 101: Skin Longevity Actives: What Reverses Visible Aging (and What's Just Hype)
• Banking Collagen + Elastin: Supporting Skin’s Structural Integrity
• Skin Longevity Strategies for Winter: Why Cold Weather is Your Anti-Aging Advantage
• Skin Longevity: The New Frontier In Dermal Research
• 🧬 Skin Longevity: What Actually Works?
• Ingredients 101: Hydration: The Three-Layer Strategy for Moisture That Actually Lasts
• Ingredients 101: Barrier Repair: The Science of Rebuilding Compromised Skin
• GLP-1 & Skin Laxity: What You Need to Know and How to Support the Skin with Pro NAD

References

1. Emanuele E, et al. Protective Effect of Trehalose-Loaded Liposomes Against UVB-Induced Photodamage in Human Keratinocytes. Biomedical Reports. 2014;2(5):755–759.

2. Maeda K, et al. Functional Properties and Skin Care Effects of Sodium Trehalose Sulfate. Skin Research and Technology. 2024;30(4):e13666.

3. Chmielewski R, Lesiak A. Mitigating Glycation and Oxidative Stress in Aesthetic Medicine: Hyaluronic Acid and Trehalose Synergy for Anti-AGEs Action in Skin Aging Treatment. Clinical, Cosmetic and Investigational Dermatology. 2024;17:2701–2712.