What trehalose is

The INCI name is TREHALOSE, anhydrous CAS 99-20-7, formula C12H22O11, molecular weight about 342 Da (the dihydrate is CAS 6138-23-4, about 378 Da). Structurally it is two glucose units joined by an α,α-1,1 glycosidic bond — and that 1,1 linkage is the point: the two anomeric hydroxyls bond to each other, leaving no free aldehyde group in the molecule, which is what makes it a non-reducing sugar. That single fact separates it from glucose, fructose and maltose: reducing sugars undergo Maillard reactions with amino-bearing ingredients in a formula — amino acids, peptides, hydrolysed collagen, certain botanical extracts — causing browning, odour change and loss of active content. Trehalose does not.

The origin has to be stated plainly, because it is the real trap in purchasing: trehalose is named for its discovery in seaweed and certain desiccation-tolerant organisms, but commercial supply today comes almost entirely from elsewhere. Two mainstream routes exist: extraction and purification from yeast (particularly trehalose-rich yeast strains), and enzymatic conversion from starch (maltooligosyl trehalose synthase and hydrolase systems). The two differ in purity, impurity profile, cost and the "natural / fermentation-derived" story you can tell, so purchasing documents must state route, purity and grade, with a COA and source declaration from the supplier. Separate cosmetic grade from food grade as well: trehalose is also a widely used food ingredient, and a food-grade specification does not necessarily meet cosmetic requirements on microbial limits, heavy metals or impurity control — "food grade must be safer" is not a valid reason to use it.

Its physico-chemical profile is exceptionally friendly for volume formats: a white crystalline powder, freely water-soluble, about 45% of sucrose's sweetness (mild, not cloying), heat- and acid-tolerant, stable under conventional emulsification and hot filling; being non-reducing, it holds colour well in formulas containing amino acids, peptides and hydrolysed proteins — exactly why it is often chosen for patch and mask essences that carry a high active load and need a long shelf life. As a humectant its core value is capturing water and holding it in place; the literature discusses at length the hypothesis that it forms a glassy state under drying and substitutes for water to maintain structural stability (often called the water-replacement hypothesis), a mechanism well studied in lyophilised biologics — but in cosmetic language that is background only, and cannot support claims of "repairing cells" or "protecting DNA".

Ingredient fact box

How it works, plainly

The hydration story can be split into three layers, from molecule to appearance: holding water at molecular level, stabilising structure and colour at system level, and reading as less dry and less rough. State this first: this section covers mechanistic hypotheses and literature at the cosmetic application level — it is not a medical explanation and carries no efficacy promise.

• Layer one: hydration and water retention. This is its main job. Multiple hydroxyl groups form hydrogen bonds with water, holding it in place and slowing evaporation, which raises the water content of the stratum corneum. As a small sugar at about 342 Da it behaves in formulation rather like polyol humectants such as glycerin and butylene glycol, but with lower sweetness and a different viscosity contribution, and its feel is usually described as lighter and less tacky than glycerin — which matters especially when the two are combined.
• Layer two: system stability from being non-reducing. This is the core difference from other sugars. No free aldehyde group means no Maillard reaction with amino acids, peptides, hydrolysed collagen and other amino-bearing ingredients, so in patch and mask essences carrying peptides, hydrolysed proteins or amino-acid actives, the long-shelf-life risk of browning and odour is markedly lower than in a reducing-sugar system. It is also heat- and acid-tolerant, performing steadily in hot filling and in mildly acidic formulas.
• Layer three: glassy state and the water-replacement hypothesis. The literature discusses at length how under drying, trehalose forms a glassy state and can substitute for water molecules in hydrogen bonding with biological macromolecules, helping maintain structural stability — a mechanism heavily studied in lyophilised biologics. Be honest: these are observations from in-vitro and industrial contexts and do not translate directly into skin-care efficacy. You may write "helps the look of dryness and roughness around the eyes" or "supports the skin's hydrated state"; you must not write "repairs cells", "protects DNA" or "stress-resilience activation" — those cross the cosmetic claim boundary.
• An honest note on evidence strength. Trehalose is richly studied in food science, biologics lyophilisation and plant stress tolerance, while human studies on topical cosmetic use are comparatively limited. Verify for yourself on PubMed with "trehalose skin hydration" and "trehalose topical". Lifting lyophilisation or oral conclusions into cosmetic copy is not rigorous, and no single study may be written up as proof of efficacy.
• How it divides work with other humectants. Trehalose suits a hydration base rather than being the sole hydration story. Complementary partners include sodium hyaluronate, holding water through a large-molecule surface network (see our hyaluronic acid eye care guide at ingredient.html?s=hyaluronic-acid), glycerin as the lowest-cost base humectant, panthenol for both feel and a soothing story (see our panthenol eye care guide at ingredient.html?s=panthenol), and ceramides for the barrier. Placing trehalose inside a multi-humectant system usually gives a more complete result than using it alone, and makes cost and feel easier to control.

A blunt note for sourcing: for volume formats such as patches, sheet masks and steam eye masks, trehalose is a cost-controllable, process-friendly humectant with an adequate story. But if your selling point is meant to rest on a high-performance active, trehalose's role is the base that carries it in reliably, not the headline. More importantly: supplier literature often carries lyophilisation, plant stress-tolerance and oral research conclusions, and none of that should be copied onto your product page.

Which formats fit trehalose best?

Use level and formulation notes (verify by bench trial)

Common reference level: used as a humectant, trehalose commonly sits at about 1%–5% in eye care formulas; in mask essences and steam eye masks, where skin-feel demands are looser, the level may go higher, but viscosity, tackiness and cost must be assessed first. Three points matter. First, trehalose is a single compound, so the use level is the actual content of that compound — there is no dual "extract versus assay" basis as with botanicals, which makes purchasing documents simpler. Second, the anhydrous form and the dihydrate differ in molecular weight (about 342 Da versus 378 Da), so dosing with the dihydrate must be converted against the declared assay. Third, use levels from food and lyophilisation contexts are not the same system as topical cosmetic levels and must never be cross-quoted. The actual level is set on the bench by format, compatibility, target-market rules and stability data.

• Tackiness is constraint #1. Trehalose is still a sugar, and mid to high dosing brings a sticky feel, with possible slight tightness once dry. The usual approach is to combine it with glycerin, butylene glycol or sodium hyaluronate so that a polyol blend dilutes the stickiness of any single sugar, finishing with lightweight lipids.
• Preservation is constraint #2. Sugars are a microbial nutrient, so aqueous systems and essences containing trehalose must undergo a preservation challenge test rather than inheriting the preservative scheme of a low-sugar formula. This matters most in high-water formats such as mask essences and patches.
• pH and temperature window is wide. Being non-reducing, trehalose is heat- and acid-tolerant and can be added and fully dissolved in the heated water phase, performing steadily under hot filling; long-term stability under strongly alkaline conditions should still be verified with dedicated retained samples.
• Non-browning is the headline — use it deliberately. In formulas containing amino acids, peptides, hydrolysed collagen or hydrolysed proteins, replacing part of the reducing sugars (glucose, fructose) or polyol system with trehalose markedly lowers long-shelf-life browning and odour risk. This is the single point most worth putting into a private label proposal.
• Cost structure belongs in the OEM conversation. Trehalose costs more per kilo than glycerin, and the gap scales linearly with dose. On volume formats the usual approach is glycerin as the base with trehalose carrying the story and the stability benefit, rather than a wholesale swap.
• Stability protocol. 40 °C for 3 months, freeze–thaw and light exposure, with pH drift, viscosity change, colour (browning observation), odour, microbial limits and preservation challenge as release criteria.
• Label and claim review. Before launch a regulatory adviser must confirm the usable boundary of "hydrating / moisturising / eases the feeling of dryness" copy per market; the ingredient list must use the standard name Trehalose, never "海藻提取物" or "marine sugar".

The figures above are common reference levels for eye care formulas; the actual use level is set by the formulation engineer based on dosage form, compatibility and target-market rules. Permitted use conditions, limits and labelling requirements differ by market — complete a compliance review for each destination before shipment. All descriptions here are general cosmetic applications and appearance or skin-feel statements, not medical advice or efficacy guarantees.

Compliance and market notes (verify per target market)

• China: first verify the listing status and historical maximum use level of Trehalose (trehalose) in the Inventory of Existing Cosmetic Ingredients in China (2021 edition) (per the latest NMPA announcement). The ingredient name on the label and in the filing must be the standard name Trehalose — never "海藻提取物" (seaweed extract) or "marine sugar", which point at entirely different ingredient entries. On claims, hydration is among the directions an ordinary cosmetic may claim, but "repair" and "soothing" carry different thresholds by market, so prefer wording such as "帮助改善眼周干燥与粗糙外观" and "Support皮肤水润状态".
• EU (EC) No 1223/2009: declare the ingredient accurately in the CPNP notification, PIF and CPSR and complete the safety assessment; claims must meet the (EU) No 655/2013 common criteria. In EU COSING, trehalose's function categories sit mainly under humectant and skin-protecting. Note: if a supplier quotes a food-grade specification, its microbial and impurity controls do not necessarily meet cosmetic raw-material requirements — accept only against cosmetic grade.
• US MoCRA (2022): facility registration, product listing, safety substantiation, adverse-event reporting and record-keeping apply, with labelling under the FD&C Act and relevant 21 CFR provisions. Cosmetic ingredients and finished products generally do not undergo pre-market approval — never write "FDA approved". Also note that trehalose has a long history of food use in the US, and related health claims must not be carried into cosmetic copy.
• Claim red lines (all markets): never use medical, physiological or absolute wording such as "repairs cells", "protects DNA", "stress-resilience activation", "rebuilds the barrier", "medical-grade hydration" or "treats xerosis". On the Chinese site use appearance and skin-feel wording such as "帮助改善眼周干燥与粗糙外观", "提升水润感" and "帮助维持皮肤水润状态".
• Recommended action: at kick-off, give your regulatory adviser five items — ingredient (with source route and cosmetic-grade declaration), use level and basis, dosage form, target country and proposed claim copy — for one upfront review. Also require the supplier to provide the COA, a source-route declaration and the cosmetic-grade specification together with the quotation, since that is the only guarantee of batch consistency on a trehalose private label project.

Ingredient pairings

• Trehalose + sodium hyaluronate + glycerin: the classic multi-humectant system. Glycerin carries the lowest-cost base water capture, sodium hyaluronate forms the surface film, and trehalose supplies lighter sustained hydration plus non-browning stability — the combination is close to standard in patch and mask essences.
• Trehalose + panthenol + ceramides: a three-part hydration, soothing and barrier structure suited to low-tolerance or itch-prone eye lines; for the panthenol pathway see our panthenol eye care guide (ingredient.html?s=panthenol).
• Trehalose + hydrolyzed collagen + acetyl hexapeptide-8: the combination where trehalose is most underestimated — hydrolysed collagen and peptides both carry amino groups, and a reducing-sugar system brings browning risk that trehalose's non-reducing character removes, while adding immediate hydration and a conforming feel.
• Trehalose + ectoin + beta-glucan: a repair-leaning hydration combination for seasonal change and dry environments; for the ectoin pathway see our ectoin eye care guide (ingredient.html?s=ectoin).
• Trehalose + caffeine: a common skeleton for morning eye creams — caffeine carries the puffiness conversation while trehalose holds hydration and skin feel underneath, both water-soluble with good processing compatibility.
• Use with care: avoid stacking several high-dose sugars and polyols, since cumulative tackiness, post-dry tightness and microbial nutrient load all become unmanageable; sugar-containing systems must undergo a preservation challenge; long-term stability under strongly alkaline conditions should be verified with dedicated retained samples; and assess solubility and crystallisation alongside a high electrolyte load.

Formulation pairing cards

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