Plant-derived, oil-soluble cosmetic active for long-lasting hydration, skin barrier support and beautifully elegant skincare formulations.

Hydra Synol® DOI is a multifunctional lipophilic skin hydrator, barrier-supporting active and high-performance emollient for modern skincare formulation.

Its INCI name is Isosorbide Dicaprylate.

Unlike a conventional emollient that mainly softens the skin or improves slip, Hydra Synol® DOI has been developed as a functional skincare active. Sytheon reports clinically demonstrated long-lasting hydration of more than 48 hours, together with support for skin barrier function.

At the same time, it provides an elegant skin feel and can help solubilise certain lipophilic ingredients, making it particularly interesting for formulators who want one ingredient to contribute to both formula performance and skin benefits.

Perfect for:

• Facial serums
• Moisturisers
• Barrier creams
• Lightweight lotions
• Gel-creams
• Facial oils
• Body care
• Sensitive-skin formulations
• Sun-care products
• Self-tanning formulas
• Colour cosmetics
• Hair-care formulations

What is Hydra Synol® DOI and How is it Used in Cosmetics?

Hydra Synol® DOI is the trade name for Isosorbide Dicaprylate, a lipophilic ingredient derived from naturally occurring plant-based starting materials using green chemistry.

Sytheon describes it as a smart skin hydrator and barrier builder designed to support the skin's own hydration network.

It combines two very useful formulation characteristics:

It behaves like an elegant oil-phase ingredient

and

It provides active hydration and barrier-supporting benefits

That makes Hydra Synol® DOI particularly interesting when you want to move beyond simply adding another botanical oil or emollient to your formula.

Hydra Synol® DOI at a Glance

Trade Name: Hydra Synol® DOI

INCI: Isosorbide Dicaprylate

Appearance: Clear to pale yellow liquid

Solubility: Lipophilic / oil-phase compatible

Recommended Use Level: 2–4%

Recommended Formulation pH: Below 6.5

Origin: Plant derived / green chemistry

Natural Origin: 100%

Certifications: COSMOS / natural positioning according to manufacturer documentation

Primary Functions: Skin hydrator, barrier-supporting active, emollient and lipophilic solubiliser

Suitable For: Serums, creams, lotions, gel-creams, oils, sun care, colour cosmetics and hair care

Formulation Level: Beginner to intermediate

Manufacturer and distributor technical information specifies a recommended concentration of 2–4%, with Hallstar listing a recommended formulation pH below 6.5.

Why Do Formulators Use Hydra Synol® DOI?

Because moisturising the skin is not simply about putting more oil on top of it.

Good hydration depends on the skin's ability to:

move water • retain water • maintain its barrier • reduce unnecessary water loss

Hydra Synol® DOI was developed around this wider understanding of skin hydration.

Sytheon's research links the ingredient with pathways including Aquaporin-3 and proteins involved in tight-junction and barrier function.

This makes it much more interesting than a standard sensory emollient.

Long-Lasting Hydration

One of the headline benefits of Hydra Synol® DOI is its ability to support long-lasting controlled skin hydration.

Sytheon reports hydration benefits lasting for more than 48 hours following use in tested formulations.

This makes it particularly interesting for products such as:

Barrier moisturisers

Dry-skin creams

Overnight treatments

Hydrating facial serums

Body lotions

Long-lasting moisturising products

Rather than simply giving the skin an immediate soft feeling, the formulation can be designed around longer-term hydration support.

Hydra Synol® DOI + Glycerin

This is one of the most interesting formulation combinations.

Sytheon specifically recommends exploring:

2% Hydra Synol® DOI + 2% Glycerin

The two ingredients approach hydration from different sides.

Glycerin is a classic water-soluble humectant.

Hydra Synol® DOI is lipophilic and supports the skin's hydration and barrier network.

Manufacturer data report synergistic hydration benefits when the two are used together.

For formulators, this creates a very elegant concept:

Hydration from both sides of the emulsion.

Water phase:

Glycerin

Oil phase:

Hydra Synol® DOI

More Than Just an Emollient

A normal emollient may help the skin feel:

softer • smoother • silkier

Hydra Synol® DOI can provide those sensory advantages while also being positioned as a functional skin-hydration active.

This makes it valuable when trying to keep an ingredient list purposeful.

Instead of adding:

one ingredient for slip,

another for moisturisation,

and another for barrier positioning,

Hydra Synol® DOI can contribute to several formulation objectives at the same time.

How Does Hydra Synol® DOI Work?

Sytheon describes Isosorbide Dicaprylate as supporting several biological systems involved in skin hydration and barrier homeostasis.

These include pathways associated with:

Aquaporin-3

Aquaporin-3 helps transport water and glycerol through the skin.

Tight Junctions

These structures help maintain an effective skin barrier.

CD44

A receptor associated with hyaluronic-acid-related skin biology.

Ceramide Synthase 3

An enzyme involved in ceramide production and epidermal barrier function.

Sytheon's published product information associates Hydra Synol® DOI with these hydration and barrier pathways.

In simple formulation language:

Hydra Synol® DOI helps the skin manage hydration rather than simply coating it with oil.

How to Use Hydra Synol® DOI in Cosmetic Formulations

One of the advantages of Hydra Synol® DOI is that it is relatively easy to work with.

Because it is lipophilic, it is normally incorporated through the oil phase of an emulsion or directly into an anhydrous formulation.

Step 1 – Decide Your Use Level

A good starting range is:

2–4%

For a 100 g formulation:

2% = 2 g

3% = 3 g

4% = 4 g

You do not need extremely large amounts to formulate effectively with Hydra Synol® DOI.

Step 2 – Add to the Oil Phase

Blend Hydra Synol® DOI with your oils, esters and other compatible oil-phase ingredients.

For example:

Hydra Synol® DOI + Squalane

Hydra Synol® DOI + Isoamyl Laurate

Hydra Synol® DOI + Jojoba Oil

Hydra Synol® DOI + Caprylic/Capric Triglyceride

Hydra Synol® DOI + THDC

Sytheon reports miscibility with a wide range of emollients, including caprylic/capric triglycerides, C12-15 alkyl benzoate, silicones and vegetable oils such as jojoba, sunflower and olive oil.

Step 3 – Create Your Emulsion

If making a cream, lotion or gel-cream, combine the oil phase with your aqueous phase using the emulsification system appropriate for your formulation.

Hydra Synol® DOI is not itself a replacement for your primary emulsifier.

Step 4 – Adjust the Final Formula

For optimum formulation conditions, aim for a final product below approximately pH 6.5, in line with current distributor technical guidance.

Always check the pH requirements of your other active ingredients as well.

Step 5 – Evaluate Your Finished Product

Check:

• Appearance
• pH
• Viscosity
• Skin feel
• Emulsion stability
• Colour
• Odour
• Packaging compatibility
• Elevated-temperature stability
• Freeze-thaw performance where appropriate

As with every cosmetic raw material, successful incorporation on Day 1 does not replace proper stability testing.

Formulator's Tip – Pair Hydra Synol® DOI With a Water-Soluble Humectant

One of the most elegant ways to formulate with Hydra Synol® DOI is to pair it with a classic aqueous humectant.

For example:

Water Phase

2% Glycerin

Oil Phase

2% Hydra Synol® DOI

You now have two complementary hydration strategies within the same formulation.

This is much more interesting than simply loading your moisturiser with increasingly large quantities of glycerin.

Sytheon specifically reports synergistic hydration when 2% Hydra Synol® DOI is combined with 2% glycerin.

An Excellent Partner for Modern Emollients

Hydra Synol® DOI works particularly well conceptually with modern lightweight emollients.

Consider combinations such as:

Hydra Synol® DOI + Squalane

For sophisticated barrier-support moisturisers.

Hydra Synol® DOI + Isoamyl Laurate

For lightweight lotions and gel-creams.

Hydra Synol® DOI + Hemisqualane

For extremely light facial emulsions.

Hydra Synol® DOI + Jojoba Oil

For botanical moisturising formulations.

Hydra Synol® DOI + Caprylic/Capric Triglyceride

For versatile everyday creams and lotions.

Hydra Synol® DOI as a Solubiliser

Hydra Synol® DOI has another interesting formulation property.

Sytheon describes it as an excellent solubiliser for UV filters and various lipophilic active ingredients.

This can make it particularly useful in more advanced formulas where an oil-soluble ingredient is difficult to incorporate.

The manufacturer specifically reports good solvency for ingredients including certain organic UV filters and lipophilic actives.

Always perform your own solubility and stability testing for the particular active and concentration being used.

What Can You Make With Hydra Synol® DOI?

Smart Hydration Facial Serum

Create a lightweight emulsion serum containing:

Hydra Synol® DOI + Glycerin + Ectoine + lightweight emollients

for a multi-dimensional hydration concept.

Barrier Gel-Cream

Combine Hydra Synol® DOI with:

Squalane + Ceramides + Cholesterol + Glycerin

to create a modern barrier-supporting moisturiser with an elegant skin feel.

Lightweight Daily Moisturiser

Use Hydra Synol® DOI alongside lightweight esters such as Isoamyl Laurate to create moisturisation without an overly rich finish.

Overnight Hydration Cream

Build a more nourishing emulsion around Hydra Synol® DOI, glycerin and barrier-supporting lipids.

Vitamin C Facial Emulsion

Hydra Synol® DOI can be explored within the oil phase of formulations containing oil-soluble actives such as Tetrahexyldecyl Ascorbate (THDC).

Sensitive-Skin Moisturiser

Manufacturer information positions Hydra Synol® DOI for sensitive, dry and problem-skin applications, making it interesting for minimalist barrier-focused creams.

Body Lotion

The combination of long-lasting hydration and elegant spreadability also makes it suitable for sophisticated body moisturisers.

Ingredients You Could Pair With Hydra Synol® DOI

Glycerin

Probably the most interesting partner.

Sytheon specifically recommends the 2% DOI + 2% glycerin combination for synergistic hydration.

Ectoine

Useful for modern hydration and barrier-support formulation concepts.

Ceramides

Excellent for sophisticated barrier-focused moisturisers.

Cholesterol

Useful alongside ceramides and other skin lipids in advanced barrier formulas.

Squalane

Creates a smooth, elegant oil phase without excessive heaviness.

Tetrahexyldecyl Ascorbate

An oil-soluble Vitamin C derivative that can be incorporated through the same oil phase.

Bakuchiol

Another oil-soluble active suitable for sophisticated facial emulsions.

Bisabolol

Can complement calming and sensitive-skin formulation concepts.

Hydra Synol® DOI vs Squalane

Both are useful oil-phase skincare ingredients, but they serve different purposes.

Squalane

Primarily:

• Emollient
• Skin softener
• Lightweight lipid
• Sensory ingredient

Hydra Synol® DOI

Provides emollient properties but is also positioned as:

• Lipophilic skin hydrator
• Barrier builder
• Active skincare ingredient
• Lipophilic solubiliser
• Functional formulation ingredient

You therefore do not necessarily need to choose one or the other.

A formula containing:

Hydra Synol® DOI + Squalane

can be more interesting than simply increasing the level of either ingredient alone.

Hydra Synol® DOI vs Glycerin

These two ingredients are especially interesting because they are fundamentally different.

Glycerin

Water soluble

Classic humectant.

Lives primarily in your aqueous phase.

Hydra Synol® DOI

Lipophilic

Lives primarily in your oil phase.

Supports hydration and barrier function through a different mechanism.

Rather than asking:

“Which one should I use?”

the more interesting formulation question may be:

“Why not design the formula around both?”

Sytheon reports a synergistic effect when the two are combined.

Is Hydra Synol® DOI Natural?

Hydra Synol® DOI is derived from naturally occurring plant-based starting materials through a green chemistry process.

Sytheon describes the ingredient as:

• Plant derived
• Bio-based
• Biodegradable
• ECOCERT-COSMOS natural

Hallstar lists the ingredient as 100% natural and COSMOS/NaTrue approved.

This makes it particularly interesting for formulators who want to combine natural-origin positioning with sophisticated technical performance.

Is Hydra Synol® DOI Suitable for Beginners?

Yes.

We would describe Hydra Synol® DOI as a beginner-to-intermediate formulation ingredient.

If you already know how to make a basic emulsion, it is extremely easy to start experimenting with.

The key skills required are:

• Accurate weighing
• Understanding oil and water phases
• Basic emulsification
• pH measurement
• Stability testing

Unlike some advanced powder actives, there is no difficult dissolution step.

Frequently Asked Questions

What is Hydra Synol® DOI?

Hydra Synol® DOI is the trade name for Isosorbide Dicaprylate, a plant-derived lipophilic cosmetic active used for long-lasting hydration, skin barrier support and improved formulation performance.

What is the INCI Name of Hydra Synol® DOI?

The INCI name is:

ISOSORBIDE DICAPRYLATE

What Percentage of Hydra Synol® DOI Should I Use?

The manufacturer's recommended use level is:

2–4%

Sytheon also specifically recommends exploring 2% Hydra Synol® DOI together with 2% glycerin.

Is Hydra Synol® DOI Water Soluble?

No.

Hydra Synol® DOI is lipophilic and is normally incorporated into the oil phase or an anhydrous formulation.

Can Hydra Synol® DOI Be Used in a Serum?

Yes.

It is particularly suitable for emulsion serums and oil-based serums.

For a conventional completely water-based serum, an appropriate solubilisation or emulsification system would be required.

Can Hydra Synol® DOI Be Used in Creams and Lotions?

Yes.

Creams, moisturisers and lotions are among the manufacturer's recommended skincare applications.

What pH Should I Use With Hydra Synol® DOI?

Current Hallstar technical information recommends:

pH below 6.5

The final pH must also be compatible with the other ingredients and preservation system in your formulation.

Can I Combine Hydra Synol® DOI With Glycerin?

Yes — and this is one of the ingredient's most interesting combinations.

Sytheon recommends 2% Hydra Synol® DOI with 2% glycerin and reports synergistic hydration performance from this pairing.

Can I Combine Hydra Synol® DOI With Ceramides?

Yes, they can form part of the same carefully designed barrier-supporting formulation.

Hydra Synol® DOI can contribute hydration and barrier support while ceramides provide important barrier lipids.

Can I Use Hydra Synol® DOI With THDC?

Yes.

Both are lipophilic and can be explored within the oil phase of an appropriately designed emulsion or anhydrous formulation.

Always confirm final-formula stability.

Is Hydra Synol® DOI Just an Emollient?

No.

Although it provides an elegant emollient skin feel, Sytheon positions Hydra Synol® DOI primarily as a smart lipophilic skin hydrator and barrier builder with clinically studied hydration performance.

Does Hydra Synol® DOI Replace an Emulsifier?

No.

Hydra Synol® DOI is an oil-phase active and multifunctional ingredient.

If your formula contains both oil and water phases, you still need an appropriate emulsification system.

Storage & Handling

Store Hydra Synol® DOI:

• Tightly sealed
• In a cool, dry place
• Protected from contamination
• Protected from excessive heat and direct light

Use clean, dry formulation equipment and close the container promptly after dispensing.

Important Formulation Information

Hydra Synol® DOI supplied by JustGlow is a cosmetic raw material for formulation purposes.

It is not a finished cosmetic product and should be incorporated into a properly designed formulation before use.

The recommended 2–4% level refers to the final cosmetic formulation.

Formulators producing finished products commercially are responsible for appropriate:

stability testing • preservation assessment • packaging compatibility • cosmetic safety assessment • regulatory compliance

before placing the finished product on the market.

Why Formulate With Hydra Synol® DOI?

There are hundreds of oils and emollients available to cosmetic formulators.

So why choose another one?

Because Hydra Synol® DOI is not simply another oil.

It allows you to think about your oil phase differently.

Instead of asking:

“What oil should I add to make this cream feel moisturising?”

you can ask:

“What can my oil phase actually contribute to skin hydration and barrier performance?”

A smart hydration serum.

A sophisticated barrier gel-cream.

A lightweight moisturiser.

A ceramide cream.

A Vitamin C emulsion.

A dry-skin treatment.

With Hydra Synol® DOI, the oil phase becomes part of the active skincare strategy, rather than simply the part of the formula that makes the skin feel soft.

For cosmetic formulation use only.