Hydra Synol® DOI – Isosorbide Dicaprylate Cosmetic Ingredient Formulation Guide
Hydra Synol® DOI is a professional cosmetic ingredient with the INCI name Isosorbide Dicaprylate. It is a plant-derived, oil-soluble emollient ester used in cosmetic formulas for elegant slip, spreading, skin conditioning and hydration-oriented product design. It is suitable for anhydrous oils and balms as well as creams, lotions, gel-creams and other oil-in-water emulsions.
This page is a practical Hydra Synol DOI formulation guide for professional cosmetic formulators. It explains what Isosorbide Dicaprylate is, how to incorporate it, how to use it in oil serums and emulsions, how to combine it with glycerin or squalane, how to formulate with oil-soluble actives, and how to assess stability, texture and compatibility.
Raw-material notice: Hydra Synol DOI is a cosmetic ingredient, not a finished skincare product. Do not apply it neat, use it directly on skin or mix it into a finished product in the hand. To purchase the ingredient, see the Hydra Synol DOI product page.
Quick answer: what is Hydra Synol DOI?
Hydra Synol® DOI is the trade name used for Isosorbide Dicaprylate, a lipophilic cosmetic ester. It is oil soluble and is normally added to the oil phase of an emulsion or blended directly into an anhydrous formula. Its main formulation roles are emolliency, spreading, sensory modification, skin conditioning and helping a formula feel less heavy or greasy.
Unlike glycerin, which belongs in the water phase, Hydra Synol DOI belongs in the oil phase. Unlike squalane, it is an ester with a different polarity, spreading profile and solvency behaviour. The choice between Hydra Synol DOI, glycerin, squalane or a combination of them should be based on the complete formula and the desired finished-product feel.
At-a-glance technical profile
| Parameter | Formulation information |
|---|---|
| Trade name | Hydra Synol® DOI |
| INCI name | Isosorbide Dicaprylate |
| Chemical name | Isosorbide 2,5-di-n-octanoate |
| CAS number | 64896-70-4 |
| REACH registration | 01-2120075324-59-0000 |
| Physical form | Clear to pale yellow liquid |
| Functional class | Oil-soluble emollient, skin-conditioning ester, spreading and sensory modifier |
| Solubility / phase | Oil soluble; add to the oil phase or an anhydrous system |
| Typical use level | 2–4% for many cosmetic formulas |
| Broader development range | Approximately 1–20%, depending on product format, oil blend and intended sensory effect |
| Aqueous-formula guidance | Use a suitable emulsifier or solubilisation system; screen the final formula below pH 6.5 where required by the technical guidance |
| Relative density | Approximately 1.026–1.035 g/mL; a typical batch value is about 1.032 g/mL |
| Storage guidance | Store tightly closed at approximately +10 to +30°C and follow the current batch documentation |
Always formulate against the current supplier specification, SDS and batch-specific COA. Technical values can be specification ranges rather than guaranteed results for every batch.
What Hydra Synol DOI does in a cosmetic formula
- Emolliency: adds a smooth, conditioned after-feel to oil and emulsion formulas.
- Spreading: can improve glide and help a product distribute easily across the skin during application.
- Sensory modification: can reduce a heavy, greasy or overly oily impression when balanced with other emollients.
- Lipophilic hydration support: helps formulators design oil-phase hydration concepts that complement water-phase humectants such as glycerin.
- Oil-phase solvency: may help dissolve or carry selected oil-soluble materials, although every active and concentration must be tested.
- Texture design: useful in oil serums, gel-creams, lotions, creams, balms and other products where a refined emollient profile is required.
These are formulation functions, not guarantees about the finished product. The final skin feel, hydration performance, stability and claims depend on the complete formula, application amount, packaging and testing.
How to formulate with Hydra Synol DOI
The basic rule is simple: add Hydra Synol DOI to the oil phase or directly to an anhydrous formula. It is not a water-soluble humectant and should not be added to plain water expecting it to dissolve.
General incorporation sequence
- Weigh Hydra Synol DOI accurately according to the formula percentage.
- Combine it with the other oil-phase emollients, esters, oils and oil-soluble actives.
- Mix until the oil phase is uniform and visually clear or homogeneous as appropriate.
- For a cream or lotion, emulsify the oil phase into the aqueous phase using the selected emulsifier system.
- For an anhydrous product, continue mixing until the finished oil blend, balm or gel is uniform.
- Add heat-sensitive materials at the temperature specified by their own supplier documentation.
- Check the finished formula for appearance, odour, viscosity, pH where applicable and stability.
Hydra Synol DOI can be used in cold or hot processes. Heat is not required simply to incorporate the ester, but it may be included when another ingredient requires melting or when the chosen emulsification process is hot. Avoid unnecessary prolonged heating of the complete formula.
Recommended use levels
| Product format | Useful starting screen | Formulation objective |
|---|---|---|
| Light oil serum | 2–4% | Add refined slip without making the whole formula feel excessively oily |
| Emulsion serum or gel-cream | 2–4% | Improve spread and emollient balance in a low-viscosity or light emulsion |
| Face or body lotion | 2–5% | Support a smooth, conditioned after-feel |
| Rich cream | 3–8% | Modify cushion, glide and the balance between liquid oils and structural materials |
| Anhydrous balm or treatment oil | 5–10% starting screen | Use as a significant emollient and possible carrier for compatible lipophilic materials |
| High-level texture experiment | 10–20% only after screening | Explore stronger sensory and solvency effects in the complete oil system |
The supplier’s preferred working range is commonly 2–4%. The broader range is a development guide, not a recommendation to use 20% automatically. Higher levels may change viscosity, odour, spread, absorption time and the solvency of the oil phase.
Hydra Synol DOI and glycerin
Hydra Synol DOI and glycerin work in different phases and provide different formulation experiences. Glycerin is a water-phase humectant; Hydra Synol DOI is a lipophilic oil-phase emollient. This makes them useful to compare together rather than treating them as direct substitutes.
| Ingredient | Primary phase | Typical formulation contribution |
|---|---|---|
| Glycerin | Water phase | Humectancy and a water-associated moisturising feel; excessive levels can feel tacky |
| Hydra Synol DOI | Oil phase | Slip, spreading, emolliency and a smoother lipid-phase after-feel |
| Hydra Synol DOI + glycerin | Oil phase + water phase | A useful two-phase hydration-oriented development concept with complementary sensory effects |
A practical comparison batch is 2% Hydra Synol DOI plus 2% glycerin in a preserved emulsion, with the remaining formula adjusted to 100%. Compare it against a control without DOI and against a formula containing glycerin alone. Assess immediate feel, after-feel, tack, spread, hydration measurements if available, and stability over time.
Hydra Synol DOI versus squalane
Squalane and Hydra Synol DOI are both oil-phase materials, but they are not interchangeable. Squalane is a hydrocarbon emollient with a very different polarity and sensory profile. Hydra Synol DOI is an ester and can provide a different balance of slip, spreading and solvency.
| Formulation question | Hydra Synol DOI | Squalane |
|---|---|---|
| Phase | Oil phase or anhydrous system | Oil phase or anhydrous system |
| Material type | Diester of isosorbide and caprylic acid | Hydrocarbon emollient |
| Texture contribution | Spreading, conditioning and solvency-oriented ester feel | Silky, cushioning, low-odour emolliency |
| Use in formula | Use alone or balance with oils, esters and other emollients | Use alone or balance with esters and plant oils |
| Best practice | Screen in the exact oil blend; do not assume the same percentage gives the same feel | Screen in the exact oil blend; do not assume the same percentage gives the same feel |
Combining the two can create a more layered sensory profile. For example, a light oil serum might screen 2–4% Hydra Synol DOI with 10–30% squalane and the remainder as a selected blend of lighter and richer emollients.
Using Hydra Synol DOI in emulsions
Hydra Synol DOI can be incorporated into creams, lotions and gel-creams as part of the oil phase. It does not emulsify itself. The complete product requires an emulsifier system suitable for the oil load, processing method and desired texture.
Emulsion process
- Combine Hydra Synol DOI with the other oil-phase ingredients.
- Heat the oil phase only if required for waxes, fatty alcohols, solid actives or the selected emulsifier.
- Prepare the aqueous phase separately according to the emulsifier process.
- Combine the phases at the selected temperature and apply controlled mixing or homogenisation.
- Cool while mixing, adding heat-sensitive ingredients at the correct stage.
- Measure and adjust final pH according to the complete formula.
- Where the technical guidance calls for it, keep the finished aqueous emulsion below pH 6.5 and confirm compatibility with the preservative and active system.
For a gel-cream made with a polymeric emulsifier such as Pemulen EZ-4U, disperse the polymer in the water phase, add Hydra Synol DOI to the oil phase, emulsify, then neutralise and adjust the final pH according to the polymer and complete-formula requirements. The two ingredients have different phase roles and should not be premixed as if they were both water-phase materials.
For the detailed polymer process, see the Pemulen EZ-4U Polymer formulation guide.
Using Hydra Synol DOI in anhydrous formulas
Anhydrous products are often the simplest way to evaluate Hydra Synol DOI because no emulsifier or water-phase preservative system is required. The ester can be blended with other oils, esters and compatible oil-soluble ingredients.
Anhydrous oil-serum method
- Combine the selected liquid emollients in a clean, dry vessel.
- Add Hydra Synol DOI at the selected percentage.
- Add compatible oil-soluble actives, antioxidants, fragrance or essential oils only at their documented use levels.
- Mix until uniform and visually consistent.
- Allow the batch to stand, then recheck clarity, odour and any sediment or crystallisation.
- Fill into a suitable container that protects the formula from contamination and excessive light.
Anhydrous balm method
- Combine the structural oils, waxes or oil-gelling materials and heat only as required.
- Add Hydra Synol DOI to the oil phase and mix until homogeneous.
- Add heat-sensitive oil-soluble ingredients during cool-down at the temperature specified by their supplier.
- Pour or fill at the validated temperature for the chosen packaging.
- Evaluate the finished balm after full set, not only while warm.
In an anhydrous balm, Hydra Synol DOI can be used to change glide, reduce wax drag or help distribute selected oil-soluble ingredients. It does not replace the structural material needed to create a stable balm.
Oil-soluble actives and solvency
Hydra Synol DOI may be useful as part of the oil-phase carrier system for compatible lipophilic ingredients. This can be helpful in oil serums, balms, emulsions and some sun-care or colour-cosmetic formats. However, solubility is ingredient-specific and must be checked at the proposed concentration and storage temperature.
For every oil-soluble active:
- check the active’s supplier-recommended phase and temperature;
- make a small solubility pre-test before scaling up;
- observe the mixture after 24 hours and after cold storage;
- check for crystallisation, haze, sediment, colour change or odour change;
- confirm that the complete emulsion remains stable after the active is added;
- avoid describing an active as solubilised until the finished formula remains uniform through the planned stability screen.
Hydra Synol DOI can be evaluated alongside polar esters, DMI, squalane, hemisqualane and plant oils, but the exact combination determines the result. A clear oil blend at 25°C may become hazy or crystallise at lower temperatures.
Starter formulation frameworks
The following are development frameworks for laboratory screening, not finished-product specifications. All percentages are by weight and water is q.s. to 100% where appropriate.
Framework 1: Hydra Synol DOI oil serum
| Ingredient group | Starting range | Role |
|---|---|---|
| Hydra Synol DOI | 2–4% | Oil-soluble emollient and sensory modifier |
| Light ester or hemisqualane | 20–40% | Spread and lightweight slip |
| Squalane | 10–30% | Cushion and emolliency |
| Selected plant oil | 10–30% | Formula identity and richer emollient character |
| Oil-soluble active | Supplier-guided | Product concept |
| Tocopherol or suitable antioxidant | Supplier-guided | Oxidative-support strategy for susceptible oils |
| Balance | q.s. to 100% | Complete anhydrous oil formula |
Begin with a simple blend. Once the sensory profile is acceptable, add one active or one new oil at a time so that changes in clarity and stability can be traced.
Framework 2: hydration-oriented O/W emulsion
| Ingredient group | Starting range | Phase |
|---|---|---|
| Hydra Synol DOI | 2–4% | Oil phase |
| Total oil phase | 10–20% | Oil phase |
| Glycerin | 2% | Water phase |
| Emulsifier system | Supplier-guided | According to the selected process |
| Water-soluble active | Supplier-guided | Water phase or cool-down |
| Preservative | Supplier-guided | According to pH and temperature guidance |
| Purified water | q.s. to 100% | Water phase |
A useful comparison is a control emulsion, a formula with 2% glycerin, a formula with 2% Hydra Synol DOI and a formula with both 2% glycerin and 2% Hydra Synol DOI. Keep the emulsifier, oil load, preservative, pH and process constant so the sensory and performance comparison is meaningful.
Framework 3: richer cream or gel-cream
| Ingredient group | Starting range | Development note |
|---|---|---|
| Hydra Synol DOI | 3–6% | Balance against the remaining oil blend |
| Other liquid emollients | 10–25% | Use to tune slip and cushion |
| Structural materials | Supplier-guided | Fatty alcohols, waxes or polymeric structure as required |
| Humectants | 2–5% | Water-phase hydration design |
| Emulsifier | Supplier-guided | Match to oil load and process |
| Purified water | q.s. to 100% | Continuous phase |
At higher DOI levels, pay close attention to the finished after-feel and the possibility of a softer or more mobile cream structure. The ester can change the sensory balance even when the measured viscosity changes very little.
Framework 4: anhydrous balm or treatment glaze
| Ingredient group | Starting range | Role |
|---|---|---|
| Hydra Synol DOI | 5–10% | Emollient, spreading and texture modifier |
| Liquid oils and esters | 40–70% | Primary liquid phase |
| Oil-gelling or structural material | Supplier-guided | Set, body and stability |
| Oil-soluble active | Supplier-guided | Product concept |
| Antioxidant | Supplier-guided | Formula protection strategy |
| Total | 100% | Anhydrous product |
Run a 5%, 8% and 10% DOI screen rather than assuming the highest level will feel best. Measure glide, drag, absorption time, gloss, firmness and any sweating or oil bleed from the set balm.
Cold-process versus hot-process use
Cold process
Cold processing is normally suitable for an oil serum, simple anhydrous blend or an emulsion whose other materials do not require heating. Add Hydra Synol DOI directly to the oil blend and mix until uniform.
Hot process
Use a hot process when the selected emulsifier, wax, fatty alcohol, solid active or structural material requires heat. Hydra Synol DOI can be included in the heated oil phase if its current technical guidance permits the selected temperature, but avoid unnecessary prolonged exposure to high heat. Add sensitive materials during cool-down according to their own documentation.
When comparing hot and cold processing, keep the oil blend and mixing energy as constant as practical. Otherwise, a difference in viscosity or stability may be caused by droplet size or shear rather than the presence of heat.
pH guidance
Hydra Synol DOI is an oil-phase ingredient, so it does not have a meaningful water-phase pH in an anhydrous oil. In an aqueous emulsion, the finished product pH belongs to the complete formula. Current technical guidance supports screening aqueous formulas below pH 6.5.
That guidance must be considered together with:
- the pH range of the preservative;
- the stability range of every active;
- the emulsifier and polymer system;
- the packaging and intended market;
- the actual measured pH after equilibration.
Measure pH at a defined temperature after the batch has equilibrated. Do not infer the final pH from the pH of the water phase before emulsification.
Compatibility and stability considerations
Hydra Synol DOI is generally straightforward to incorporate into oil systems, but the complete formula still needs testing. Potential variables include:
- oil polarity and the ratio of esters to triglyceride oils;
- oil-soluble actives and their solubility at low temperature;
- emulsifier choice and total oil load;
- fragrance, essential oils and other volatile materials;
- heat exposure and processing time;
- packaging, light exposure and headspace;
- pH and the aqueous-phase preservative system in emulsions.
A clear oil serum can develop haze or crystals after cold storage. An emulsion can remain smooth at room temperature but show creaming after heat exposure. Evaluate the material in the actual finished product rather than relying only on a raw-material compatibility assumption.
Troubleshooting Hydra Synol DOI formulas
| Observation | Possible causes | What to investigate |
|---|---|---|
| DOI does not dissolve in water | Expected oil-soluble behaviour | Move it to the oil phase and use a suitable emulsifier or solubilisation system |
| Oil serum feels too heavy | High total oil load, too much rich oil, DOI level too high for the blend | Reduce heavy oils, compare a lower DOI level, add lighter emollients |
| Oil serum feels too dry or fast-absorbing | High level of volatile or very light emollients | Increase cushioning oils or compare DOI with squalane and richer esters |
| Haze or crystals appear | Active or oil blend has limited low-temperature solubility | Run a cold-solubility pre-test and check each oil-soluble active separately |
| Emulsion separates | Unsuitable emulsifier, inadequate process, high oil load or poor droplet formation | Review the emulsifier, process, oil ratio, homogenisation and stability data |
| Emulsion is too soft | DOI changed the emollient balance or reduced structural body | Review structural materials and compare a control without DOI |
| Emulsion is too draggy | Too much wax or high-structure material, insufficient light emollient balance | Use DOI as part of a broader sensory screen and reduce drag-producing materials |
| Odour changes during storage | Oxidation of susceptible oils or incompatible fragrance system | Review oil quality, antioxidant strategy, packaging and storage temperature |
| pH is outside target | Final pH measured too early or altered by other ingredients | Allow equilibration, recalibrate the meter and adjust the complete formula carefully |
Stability testing checklist
For a development batch containing Hydra Synol DOI, record the following at day 0, 24–48 hours, one week and during longer-term testing:
- appearance, clarity, colour and odour;
- spread, slip, drag and after-feel;
- pH for aqueous emulsions;
- viscosity or firmness using a repeatable method;
- separation, creaming, oil bleed, sweating or sediment;
- low-temperature clarity and crystallisation;
- elevated-temperature changes;
- freeze-thaw response where relevant;
- packaging compatibility and dispensing behaviour;
- microbiological quality and preservative efficacy for water-containing products.
For meaningful comparisons, keep sample size, container, temperature, measurement time and test method consistent. A small control batch without Hydra Synol DOI can help show whether an observed change comes from the ingredient or from the base formula.
Common questions about Hydra Synol DOI
What is Hydra Synol DOI?
Hydra Synol® DOI is a trade name for Isosorbide Dicaprylate, an oil-soluble cosmetic ester used for emolliency, spreading, skin conditioning and hydration-oriented formula design.
What is the INCI name?
The INCI name is Isosorbide Dicaprylate.
Is Hydra Synol DOI water soluble?
No. It is oil soluble. Add it to the oil phase or an anhydrous formula. Aqueous products need a suitable emulsifier or solubilisation system.
How much Hydra Synol DOI should I use?
A practical starting point for many formulas is 2–4%. A broader development range of approximately 1–20% may be explored depending on the product format and sensory objective, but higher use levels should be screened rather than assumed.
Can I use Hydra Synol DOI in a serum?
Yes. It can be used in anhydrous oil serums or in emulsified serum products. In a water-based serum, it requires an appropriate solubiliser or emulsion system and must not simply be added to water.
Can I combine Hydra Synol DOI with glycerin?
Yes. They occupy different phases and provide complementary formulation functions. A useful development comparison is 2% Hydra Synol DOI plus 2% glycerin in a preserved emulsion, tested against suitable controls.
Can Hydra Synol DOI replace squalane?
It can be evaluated as an alternative or complementary oil-phase emollient, but it is not chemically identical to squalane. The two materials can produce different slip, cushion, absorption and solvency effects.
Can Hydra Synol DOI be used with oil-soluble actives?
It may help carry selected lipophilic materials, but solubility and stability must be checked for each active at the intended level and storage temperature.
Can I heat Hydra Synol DOI?
It can be used in a hot process when the formula requires heating, but unnecessary prolonged high-temperature exposure should be avoided. Follow the current technical guidance and add heat-sensitive actives at their specified cool-down temperature.
What pH should a Hydra Synol DOI emulsion have?
For aqueous emulsions, current technical guidance supports screening below pH 6.5. The final target must also suit the emulsifier, preservative and active ingredients in the complete formula.
Is Hydra Synol DOI a preservative?
No. It is not a broad-spectrum preservative. Water-containing products require a suitable preservation strategy and microbiological assessment.
Is Hydra Synol DOI a medical or therapeutic ingredient?
No. It is a cosmetic raw material. Describe its role with professional cosmetic language such as emollient, skin conditioning, spreading and hydration-supporting formulation ingredient. Do not make disease, treatment or therapeutic claims without the appropriate evidence and regulatory basis.
Storage and handling
Keep the container tightly closed, clean and protected from contamination, excessive light and temperature extremes. Current supplier guidance indicates storage around +10 to +30°C; follow the batch label and latest technical documents. Avoid introducing water into the container and use clean, dry equipment when dispensing.
Read the Safety Data Sheet before handling and use the specified protective measures. The current batch documentation should be used to confirm shelf life, appearance, density, transport and any handling requirements. The available technical record identifies a minimum stability period of five years; confirm the applicable date and conditions for the batch you receive.
Professional compliance reminder
The finished-product manufacturer remains responsible for the complete formula, raw-material verification, safety assessment, claims, microbiological quality, packaging compatibility, manufacturing records and market-specific compliance. In the UK and EU, this may include appropriate GMP, a Product Information File, a Cosmetic Product Safety Report, responsible-person arrangements and product notification. This guide is formulation education and does not replace professional regulatory or safety assessment.
Buy Hydra Synol DOI
Ready to formulate with this oil-soluble cosmetic ester? Visit the Hydra Synol DOI – Isosorbide Dicaprylate product page for pack sizes, availability and current technical documents.
The product listing links back to this Hydra Synol DOI formulation guide in Ingredients A–Z so formulators can move directly between the technical guide and the raw-material page.
Technical documents
Before manufacture, check the current JustGlow Safety Data Sheet and batch-specific Certificate of Analysis on the product page. Technical documents should be reviewed together with the complete formula and the intended market requirements.