The topic is short and compact
Same active ingredient, same concentration, different carrier system: stability, release, and penetration depth can differ significantly.
Encapsulation protects sensitive active ingredients, but turns the carrier into a testing challenge: track leakage, oxidation, and particle size throughout storage.
Intentionally manufactured, insoluble, or biopersistent materials measuring between 1 and 100 nanometres are considered nanomaterials: notification is required six months prior to market launch, and "nano" must be indicated in the INCI list.
In anhydrous formats such as body butter, aqueous vesicles can hardly be stably incorporated; there, dissolved fat-soluble active ingredients and the lipid system carry the function.
Under Regulation (EU) No 655/2013, claims regarding penetration and efficacy require evidence relevant to the finished product; raw material studies using a different vehicle are generally not sufficient.
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Why do two products with the same active ingredient have different effects?
Because the skin is built as a barrier, and the formulation determines how an active ingredient reaches this barrier. The stratum corneum limits how well active ingredients penetrate the skin. According to the review by Zhou et al. (2021) on nanocarriers in cosmetics, intact carrier systems cross the stratum corneum predominantly via the intercellular spaces between cells; hair follicles and sebaceous glands also play a role. Molecules with high molecular weight or pronounced polarity penetrate poorly; the authors cite hyaluronic acid and madecassoside as examples.
For product development, this means: two serums with the same active ingredient at the same concentration can differ significantly in release, stability, and penetration depth. Decisive factors include:
Solubility and partition: whether the active ingredient is in the aqueous or lipid phase and whether it is dissolved, dispersed, or crystallized there.
Carrier system: free solution, emulsion, vesicles, or lipid particles.
Excipients: emulsifiers, alcohols, and lipids that affect the stratum corneum itself.
Stability: whether the active ingredient remains in an effective form until the end of its shelf life.
Why the mechanism of action matters more than the name of the active ingredient is described in more detail in our article Mechanism of action instead of active ingredient name.
Which carrier systems are used in cosmetics?
Common delivery systems differ in structure, active ingredient loading, and processability. Zhou et al. summarize micro- and nanoemulsions, liposomes and their deformable variants, solid lipid nanoparticles (SLNs), nanostructured lipid carriers (NLCs), lipid liquid crystals, as well as polymeric and inorganic carriers. They cite 10 to 1,000 nanometers as the size range for nanocarriers.
Carrier system | Structure | Typical benefit | Formulation limitation |
|---|---|---|---|
Liposomes | Phospholipid bilayers with an aqueous core | Encapsulation of water- and fat-soluble active ingredients | Leakage, susceptibility to oxidation and hydrolysis, osmotically sensitive |
Transfersomes, ethosomes | Vesicles with edge activators or with 20 to 45% ethanol | higher deformability, penetration into the stratum corneum | Surfactant or alcohol content must match skin compatibility and base |
SLNs and NLCs | solid or partially liquid lipid matrix | Protection of sensitive active ingredients, occlusion | predominantly retained in the stratum corneum due to their lipophilicity |
Micro- and nanoemulsions | finely dispersed oil-water systems | higher solubility, better diffusion into the skin | high surfactant levels can alter and irritate the stratum corneum |
Polymeric and inorganic carriers | e.g., polymer capsules, mesoporous silica | controlled release, protection from light and air | Particle size and persistence can trigger classification as a nanomaterial |
For formulation development, it is less decisive which system penetrates the furthest, but rather which one is stably compatible with the active ingredient, base, sensory profile, and packaging. The review by Lens (2025) on phospholipid-based vesicles also points out that the phospholipid content of the stratum corneum is below 0.1%, which complicates the use of phospholipid carriers. Thus, similarity to cell membranes does not guarantee penetration.
What does encapsulation contribute to stability, and where does it fall short?
Encapsulation protects light-, air-, and heat-sensitive active ingredients, but shifts the problem to the stability of the carrier. For example, Zhou et al. report that NLC significantly increase the stability of tocopherol and microemulsions protect ascorbic acid. In an in vitro study cited by Lens, ethosomes loaded with rosehip extract retained 80.7% of their antioxidant activity after six hours, compared to 15.5% for the free extract. These values apply to this experimental design and cannot be transferred to other active ingredients.
Typical formulation problems
Leakage: The active ingredient leaks out of the vesicle during storage; the encapsulation then exists only on the label.
Oxidation and hydrolysis: Phospholipids are themselves sensitive. Antioxidants, pH control, and packaging with low oxygen ingress become part of the system.
Incompatible accompanying substances: surfactants, electrolytes, and higher alcohol contents in the base can destabilize vesicles. The choice of emulsifier is therefore also a question of carrier stability, not just texture.
Process conditions: Shear forces during homogenization and temperatures in the hot phase can destroy carriers. Encapsulated active ingredients are therefore usually only incorporated during the cooling phase.
Costs: Lens cites high manufacturing costs as a disadvantage of liposomes. They arise as raw material costs and as additional testing expenses.
What should be tested
Beyond standard stability testing, it is advisable to track particle size distribution, active ingredient content, and, where measurable, the encapsulated fraction at the beginning and over the course of storage, specifically in the original packaging. Only when these values remain stable over the intended shelf life does the encapsulation have meaningful validity. How stability and safety testing interact before launch is described in our article on stability and safety testing for cosmetics.
When does a carrier system become a nanomaterial?
Whenever it meets the definition of the Cosmetics Regulation. According to Art. 2(1)(k) Regulation (EC) No 1223/2009, a nanomaterial is an insoluble or biopersistent and intentionally manufactured material with one or more external dimensions, or an internal structure, on the scale from 1 to 100 nanometres. Additional obligations apply to products containing such ingredients:
Notification: According to Art. 16(3) Regulation (EC) No 1223/2009, a product containing nanomaterials must be notified six months prior to placing it on the market in addition to the CPNP notification, including particle size, physicochemical properties, estimated annual quantity, toxicological profile, and reasonably foreseeable exposure conditions. Exempted under Art. 16(2) are nanomaterials regulated as colorants, UV-filters, or preservatives in the Annexes.
Labelling: According to Art. 19(1)(g) Regulation (EC) No 1223/2009, the name of each ingredient in the form of a nanomaterial must be followed by the word "nano" in brackets in the list of ingredients.
The distinction is not trivial. The SCCS Guidance on the Safety Assessment of Nanomaterials (SCCS/1655/23) points out that a material that dissolves only partially and over a long period cannot automatically be considered "soluble" and thus outside the definition. For nanoencapsulated ingredients, it requires evaluating both the individual components and the encapsulated entity as a whole, including composition, stability, and skin penetration.
In practice, this means: Particle size distribution, solubility, and a statement on the nano-status must be requested from the raw material supplier before the formulation is finalized. The classification belongs in the safety report and in the product information file. If a nanomaterial is identified late, the six-month notification lead time will delay market entry.
How deep can a cosmetic delivery system penetrate?
Only to the extent that it is compatible with the cosmetic purpose. According to Art. 2 para. 1 lit. a Regulation (EC) No 1223/2009, a cosmetic product is intended to come into contact with the external parts of the human body (epidermis, hair system, nails, lips and external genital organs) with a view exclusively or mainly to cleaning them, perfuming them, changing their appearance, protecting them, keeping them in good condition or correcting body odours. A claim of a systemic or therapeutic effect falls outside this scope.
Moreover, more penetration is not automatically better. The SCCS guidance states that increased absorption and bioavailability resulting from nanoencapsulation must be taken into account in the toxicity assessment. A delivery system that carries an active ingredient deeper thereby alters the exposure assumptions of the safety assessment, particularly for active ingredients with concentration limits in the annexes to the Regulation.
For product management and regulatory affairs, the viable question is therefore not how deeply an active ingredient penetrates, but whether it reaches the site where the advertised cosmetic effect occurs, in sufficient quantity and without shifting the basis of the safety assessment.
How is a penetration or encapsulation claim substantiated?
With evidence on the finished product. Regulation (EU) No 655/2013 requires in the Annex under the criterion of evidential support that claims are supported by adequate and verifiable evidence. Studies used as evidence must be relevant to the product and the claimed benefit. A claim that extrapolates properties of an ingredient to the finished product must also be substantiated, for example by demonstrating an effective concentration in the product.
Which evidence matches which claim
Claim | Suitable evidence | Limitation |
|---|---|---|
“with encapsulated active ingredient” | Raw material specification, use concentration, proof of intact encapsulation in the product throughout storage | describes the technology, not the effect |
“reaches the upper layers of the skin” | In vitro penetration study with the finished product, methodologically based on OECD Test Guideline 428 on intact skin, which also references the SCCS guidance for skin absorption | Result only applies to the tested formulation and dose |
Efficacy claim such as “visibly smooths” | User trial or instrumental study with the finished product | Raw material studies with a different vehicle are generally not sufficient |
A common mistake is adopting the penetration data from the raw material supplier. These studies often run in a proprietary vehicle; emulsifiers, oils, and alcohols in one's own formulation can alter release and penetration. The claim is then either limited to the technology or newly substantiated on the finished product. Which wordings hold up in the EU is summarized in our article on cosmetic advertising claims in the EU.
In anhydrous formats such as body butter, balm, or stick, the water phase that liposomes and many other vesicles rely on is missing. As a rule, aqueous vesicle dispersions cannot be stably incorporated there. Viable options are dissolved fat-soluble active ingredients, oil-based encapsulations, or, if a vesicle system is required, an emulsion base. The lipid film itself acts occlusively; Zhou et al. describe for lipid nanoparticles that they hydrate the skin via occlusion. For moisturizing claims, the lipid system is therefore often the stronger lever than an additional carrier.
Manufacturing and Filling Limitations
Temperature window: Body butter is frequently processed and filled hot. Heat-sensitive or encapsulated active ingredients need a window in which they are incorporated before the mass sets.
Crystallization: Shea butter and other fats tend to form grains under unfavorable cooling profiles. A carrier system must not further disrupt crystallization.
Packaging: Jars expose a large surface area to the air each time product is removed. Oxidation-sensitive active ingredients argue in favor of tubes or airless dispensers.
The lipid system, texture, and packaging of body butter are covered in our article Having body butter manufactured.
Labtree is a B2B cosmetics developer and cosmetics manufacturer with its own laboratory and production capacities in Germany. Formulations and laboratory samples are created in our in-house laboratory, manufacturability is already tested during development rather than only upon scale-up to production, and approved formulations move into cosmetics production. A carrier system is thus part of the formulation development process and not just a raw material on a procurement list. Samples of pre-qualified formulations are usually dispatched from the sample warehouse within 24 hours, allowing texture and sensory profile to be evaluated early on the physical product.
For planning purposes: A new private label development typically takes 3 to 6 months to reach market readiness. A white label product based on a tested Labtree formulation in standard packaging is generally ready for delivery in 2 to 3 months. A complex carrier system, extended stability testing, or a nano-notification can extend the timeline. The minimum order quantity is generally 1,500 units per product, depending on the product type, fill size, and packaging. The process from conceptualization to production is outlined on the page Have cosmetics developed.
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FAQ
Are liposomes nanomaterials within the meaning of the Cosmetics Regulation?
Not automatically. The definition in Art. 2(1)(k) of Regulation (EC) No 1223/2009 covers insoluble or biopersistent, intentionally manufactured materials ranging from 1 to 100 nanometres. Whether a liposome or lipid carrier falls under this definition depends on its size, solubility, and persistence; the SCCS cautions against prematurely classifying partially soluble materials as soluble. The classification should be backed by supplier data and documented in the safety report.
Is the raw material supplier's penetration study sufficient as evidence for an advertising claim?
Generally not for a claim about the final product. According to Regulation (EU) No. 655/2013, a claim that attributes the properties of an ingredient to the product must be substantiated, for example through an effective concentration. If the vehicle used in the supplier study differs from your own formulation, the claim must be limited to the technology or supported by a study on the finished product.
Can a cosmetic product be advertised as having a deep-acting effect?
Only within a cosmetic scope and only with supporting evidence. Claims regarding reaching deeper skin layers should refer to the upper layers of the skin and be backed by a penetration study conducted on the final product. Claims about systemic or therapeutic effects are incompatible with cosmetic purpose under Article 2 of the EU Cosmetics Regulation. Learn more in our magazine article "Cosmetic Advertising Claims in the EU: Rules, Evidence, and Prohibited Claims".
How long does it take to develop a product with a carrier system?
At Labtree, developing a new private label product usually takes 3 to 6 months to reach market readiness. A complex carrier system, extended stability testing, or a nano-notification—which must be submitted six months prior to market launch—can extend the timeline. These influencing factors are detailed in the magazine article “Cosmetics Development: Realistic Timelines and What Drives Them.”
Can liposomes be incorporated into a body butter?
Typically not stable in anhydrous butter or balm formats because aqueous vesicle dispersions do not find a water phase there. Practical solutions include dissolved fat-soluble active ingredients or oil-based encapsulations. If a vesicle system is chosen, the base is generally formulated as an emulsion, such as a body cream with a butter-like texture.
What additional costs does a carrier system incur?
A fixed surcharge cannot be reliably stated without a specific formulation. Cost drivers include the raw material price of encapsulated active ingredients, additional analysis for particle size and active ingredient content, extended stability testing, penetration studies where applicable, and low-oxygen packaging. If the carrier falls under the nano-definition, the documentation effort required for notification is added.
What role do delivery systems play in trending active ingredients like PDRN or peptides?
Large or polar molecules generally penetrate the stratum corneum poorly; Zhou et al. cite hyaluronic acid as an example. For polynucleotides such as PDRN or longer-chain peptides, the carrier system therefore plays a key role in determining which efficacy claims can be substantiated for the final product. Background information on the active ingredient is provided in the magazine article "Sourcing Trending Active Ingredients: Formulating and Scaling Peptides, PDRN, and Niacinamide".
