Peptides and ceramides often occur together in moisturizing creams, serums, and cosmetics aimed at the skin barrier. However, they belong to completely different chemical groups and should not be treated as ingredients with the same effect. Ceramides are lipids closely related to the organization and function of the skin barrier, while peptides are chains of amino acids whose properties depend on the precise sequence, chemical modifications, concentration, and formulation.
A product containing both types of ingredients can provide hydration or other cosmetic effects. However, the mere presence of peptides and ceramides on a single list of ingredients does not demonstrate repair of the skin barrier, stimulation of collagen, increased peptide transport, synergy, or greater effectiveness than when using the individual ingredients separately.
The interpretation of the studies requires additional caution, because publications containing both the words „peptide” and „ceramide” do not always refer to a cosmetic containing both ingredients. Some studies analyze ceramides along with peptides naturally produced by skin cells, For example, endogenous antimicrobial peptides. Others involve creams containing ceramides, but without added cosmetic peptides.
These studies remain scientifically valuable because they help to understand skin biology, the mechanisms of barrier function, and the properties of specific ingredients. However, they should not be presented as direct clinical studies of serum or cream containing both peptides and ceramides simultaneously.
The most reliable approach therefore consists of distinguishing between mechanistic studies, studies of individual components, and studies of finished products, and then determining which type of evidence actually supports a specific claim.
What are ceramides?
Lipids are the barrier of the skin, not proteins
Ceramides belong to a family of lipids called Sphingolipids. Structurally, they consist of a sphingoid base combined with a fatty acid. In this respect, they are clearly different from peptides, which form amino acids linked by peptide bonds.
In the outermost part of the skin, especially in the stratum corneum of the epidermis, Ceramides participate in the formation of a structured lipid environment surrounding skin cells. This system helps regulate water loss and influences the way various substances move through the skin barrier.
Their biological role therefore differs fundamentally from the potential function of a signaling peptide or another peptide added to a cosmetic formulation in order to influence specific parameters of the skin appearance.
It is also worth remembering that the term „ceramide” does not mean a specific molecule.
Ceramides form a structurally diverse family of lipids, and differences in their structure can influence biological properties. Studies on the synthesis of acylceramides, including work indicating the importance of the enzyme CYP4F22, show how specific lipid structures and metabolic pathways are involved in the proper functioning of the skin barrier. [1]
Such mechanistic studies help to understand why ceramides are important components of the skin.
However, they do not prove that every moisturizing cream containing the word „ceramide” on the label reproduces the complex lipid organization of healthy human skin.
Specific substances, such as How Ceramide NP, Also known as ceramides. This terminology provides more information than the general term „ceramide,” but it still does not describe the entire lipid environment of the finished formulation.
The name of the component itself does not inform about its concentration, organization, interactions with other lipids, stability in the product, or the actual effect after application.
The list of ingredients therefore helps to determine the composition of the product.
However, it does not replace the tests of a ready-made formulation.
Why is the whole mixture of lipids important?
The skin barrier is not made up solely of ceramides.
Its extracellular lipid environment contains a complex mixture of different lipid classes, and their proportions and organization influence the barrier's behavior.
Experimental studies of physiological lipid mixtures have shown that their composition can affect barrier regeneration.[2] A significant portion of these studies included experimentally damaged barriers, animal models, and preliminary observations in humans.
However, the most important conclusion is not that every cream should contain a specific ratio of lipids.
The studies show, first and foremost, that The entire lipid environment is important.
Modern moisturizing cream can combine ceramides with other lipids, humectants, emollients, occlusive substances, and additional ingredients to improve the consistency, stability, or retention of water.
Each of these elements can influence the final moisturizing effect.
Therefore, if a cream containing ceramides improves hydration or reduces the visibility of skin dryness, the entire effect should not be attributed automatically to the ceramides themselves, neglecting the product base and the other ingredients.
This is particularly important when comparing two commercial products. A formulation containing several different ceramides does not necessarily have to be more effective than a product containing fewer of them if the remaining components of the formulation differ significantly.
It's ready formulation remains a real intervention under study.
Skin biology and an externally applied ingredient are two different topics
Understanding the natural function of ceramides in the skin is important scientifically, but The biological significance of a naturally occurring substance does not automatically prove the effectiveness of this component used in a cosmetic product..
For example, a disruption of a specific lipid synthesis pathway can help scientists understand the biological basis of abnormal barrier function.
However, it does not prove that the use of a specific cream available without a prescription completely corrects such a disorder.
The transition from a biological mechanism to clinical or cosmetic benefits requires additional evidence.
It is necessary to determine whether the material used externally, in the actual formulation and the tested concentration, causes a measurable effect in humans.
In this way, an important hierarchy of evidence emerges.
Molecular research can explain, why a given mechanism is biologically plausible.
Studies of the component can determine, how a specific material behaves under certain conditions.
The testing of the finished product, however, can show, what happens when people actually apply the given formulation.
These levels of evidence are related to each other, but they answer different questions.
What are the differences between the functions of peptides and ceramides?
Evidence regarding peptides must include the specific sequence
Term „peptide” describes a broad class of molecules, a standardized cosmetic ingredient, not a single standardized cosmetic ingredient.
Peptides can significantly differ in their amino acid sequence, chain length, chemical modifications, concentration, stability, and proposed biological function.
Some cosmetic peptides are lipid-modified. Others are found in complex mixtures or delivery systems. These differences can affect both the peptide's behavior in the formulation and the type of evidence that can be derived from it.
The mere presence of a peptide in a moisturizing cream does not automatically mean that the product increases ceramide synthesis, repairs the skin barrier, or stimulates collagen production.
Each of these claims is a separate scientific hypothesis that requires appropriate evidence.
In a controlled study involving humans, for example, the cream containing palmitoyl pentapeptide Compared to the corresponding formulation without this peptide. During a 12-week study, improvements in selected facial skin characteristics related to photoaging were described.[3]
The study provides information regarding the specific peptide, formulation, comparison used, and the evaluated appearance parameters.
It does not prove that every peptide cream improves TEWL, rebuilds lipid barrier or accelerates skin barrier regeneration.
It also does not show that adding ceramides to the peptide formulation under study would increase its effectiveness.
Studies of creams with ceramides often focus on other endpoints, such as hydration, visible dryness, water loss from the skin, and lipid content.
A product combining peptides and ceramides can theoretically address more than one cosmetic problem, but complementary potential functions are not evidence of synergy.
Synergy requires direct comparative data.
Endogenous skin peptides are not the same as added cosmetic peptides
The word „peptide” This can cause particular confusion when searching for scientific studies on ceramides.
Human skin naturally produces many peptides that are involved in normal biological processes. These include, among others: antimicrobial peptides, which participate in innate immunity and other processes occurring in the skin.
Such naturally produced peptides should not be confused with cosmetic peptides that are intentionally added to a cream.
For example, in a laboratory study of exogenous ceramides in human keratinocytes, the differentiation of cells and signaling associated with endogenous antimicrobial peptides were analyzed.[4] The researchers noted that some effects differed depending on the type of ceramide being studied.
This provides valuable mechanistic information regarding ceramides and the biology of skin cells.
However, it does not prove that a cream available on the market containing an added cosmetic peptide and ceramide will produce the same effect.
In a small study involving three patients with atopic dermatitis, antimicrobial peptides and TEWL were also measured during therapy involving tacrolimus and an emollient containing a predominance of ceramides.[5]
Also here the peptides were biological markers measured in the skin.
They did not constitute the peptide components found in the emulsion.
A very small number of participants also significantly limits the possibility of drawing broader conclusions regarding comparative effectiveness.
This distinction is extremely important when creating an article based on research in scientific databases.
The publication may simultaneously contain dates. „peptide” and „ceramide”, And yet it answers a completely different question than:
„Does a cream containing both cosmetic peptides and ceramides provide additional benefits?”
Therefore, search results require scientific selection before they are used as evidence.
Composed mixtures require equally careful interpretation
Complex formulations introduce an additional level of difficulty.
In a randomized split-face study, the evaluation was postbiotic cream containing a mixture of substances derived from fermentation. The formulation contained peptides and an enzyme associated with the production of ceramides. Compared with placebo, researchers noted an improvement in several cosmetic parameters. [6]
This is important evidence regarding this particular postbiotic formulation.
However, it is not equivalent to a study of a traditional cream containing one precisely defined cosmetic peptide and one added ceramid.
Because the formulation contained many components, the study does not allow the contribution of the peptide component itself to be isolated.
It also does not prove that every product advertised as a combination of peptides and ceramides will achieve such results.
Precise terminology is particularly important here.
The product that contains ceramides, The formulation that supports or influences the production of ceramides, and a mixture containing enzyme involved in the synthesis of ceramides they describe three different scientific situations.
Similarly, the presence of peptides derived from fermentation does not automatically mean that the intervention is equivalent to a conventional synthetic cosmetic peptide.
The claims should remain linked to the formulation that was actually tested.
Cosmetics targeted at the skin barrier
Moisture, water loss and skin comfort
Moisturizing creams targeted at the skin barrier can be evaluated using several different parameters.
Scientists can measure skin hydration, transdermal water loss, apparent dryness, flaking, itching, comfort, tolerance, or a combination of these endpoints.
Although these results are related, they are not equivalent.
Devices used to measure moisture usually estimate properties related to the water content in the outer layers of the skin.
Transcutaneous water loss, or TEWL, describes the amount of water that moves from the skin to the surrounding environment under controlled conditions.
Clinical assessments or those reported by participants may, however, describe dryness, roughness, itching, or general comfort.
The product can improve one of these parameters without showing an improvement in all the others.
In a randomized split-site study involving 24 people with dry skin, a cream containing Ceramides 1, 3 and 6-II with a hydrophilic cream. Scientists analyzed the short-term effects of regular use for 28 days and the period after the application was completed. [7]
The formulation containing ceramides yielded favorable results regarding hydration and barrier-related parameters under the conditions of this study.
This is a useful example of evidence regarding a finished product.
However, it does not allow for the complete isolation of the effect of the ceramides themselves, as the creams being compared may have also differed in other elements of the formulation.
It also does not prove that identical results would occur with a face serum containing peptides.
Place of application, formulation, comparator product, study population and observation time they remain integral elements of the evidence.
Measurement of skin lipids provides additional information
The clinical assessment and moisture measurements can be supplemented by biochemical analysis.
In another study, the effect of a cream containing ceramides on dry skin of the lower limbs was analyzed in a randomized, investigator-blinded split-leg model. Clinical results and hydration were evaluated, and after four weeks, changes were also analyzed. lipid composition of the stratum corneum of the epidermis. [8]
Researchers noted an increase in the measured levels of ceramides, cholesterol and free fatty acids.
Such biochemical measurements provide more information than the participant's mere statement that their skin has become softer.
However, they require careful interpretation.
The increase in the measured lipid levels does not in itself prove that the natural skin barrier architecture has been completely restored.
It also does not show that lipid changes are responsible for any observed clinical improvement.
Most importantly, in the context of peptides and ceramides, this study did not analyze whether the addition of a peptide provided an additional benefit.
Such a question was not included in the experimental comparison.
A scientifically justified claim should therefore indicate both the product, as well as the specific measured effect.
For example, it can be stated that the formulation under study improved hydration or reduced dryness in a specific population.
A much broader claim that cream „It repairs everything the skin barrier needs”, It goes beyond the scope of such measurements.
Sensitive skin is not a single unified condition
Term „sensitive skin” it encompasses very different experiences and should not be treated as a single unified biological state.
In a study involving 39 women with sensitive skin, the ceramide complex was compared with a placebo. The reaction to the milk acid test, barrier-related parameters, and ceramide profiles were evaluated.[9]
Improvements were observed in some of the parameters related to sensations in both groups, while the ceramide preparation showed an advantage in selected assessments.
This provides data regarding the specific formulation, the participants, and the provocative model used.
It does not prove that every product containing ceramides prevents irritation caused by all other cosmetic ingredients.
It also does not mean that adding a peptide automatically makes the product suitable for people with rosacea, eczema, or active skin inflammation.
These are different populations and different clinical questions.
A more recent controlled-release study evaluated emolient containing ceramide NP C15 in 50 participants. Both the active formulation and its base improved subjective symptoms, while a beneficial effect on TEWL was described in participants with impaired barrier function. [10]
The study shows two important principles.
First of all, the cosmetic base alone can provide a significant moisturizing effect.
Secondly, the initial state of the skin can affect the size or detectability of the effect.
The beneficial outcome observed in the subgroup with impaired barrier function should therefore not be automatically presented as a universal effect occurring to the same extent in all individuals.
Cosmetics and the treatment of dermatological problems
A moisturizing cream can help reduce dryness, improve comfort, or serve as an element of daily care, but it does not necessarily treat the underlying cause of the persistent inflammation.
The presence of ceramides, peptides, or both of these components does not mean that the cosmetic product is a treatment for a recognized dermatological disease.
This distinction is particularly important when products are selected primarily based on the reputation of a particular ingredient.
Persistent inflammation, skin cracking, pain, increased itching, or a gradual worsening of the changes may be due to a problem that cannot be evaluated solely based on the list of ingredients in the cream.
The continuous addition of new products based on keywords such as „repairing the barrier” he does not have to solve the cause of the problem.
Cosmetic moisturizing and clinical treatment should therefore remain separate concepts.
How to evaluate a product combining peptides and ceramides?
Start by defining the intervention being studied in detail
The first question during the evaluation of any study concerning peptides and ceramides should be:
What exactly did the scientists study?
The publication may concern the final commercial product, an earlier prototype, a single component solution, skin cell culture, reconstructed skin, an animal model, or a complex mixture containing several biologically active components.
These are not equivalent interventions.
A cellular experiment funded by the component supplier may provide interesting mechanistic data requiring further research, but it cannot determine the clinical effect of any finished product containing this substance.
Similarly, a study of ceramide cream without peptides does not demonstrate any additional benefit resulting from the addition of the peptide.
The most informative studies of products specify the exact formulation, the site of application, the population being studied, the duration of use, and the comparator product.
If this information is not available, the uncertainty should remain clearly indicated.
Missing data should not be used to assume that all products belonging to the same category behave in the same way.
The type of control determines which question the survey can answer.
The product evaluated before and after the end of use can show whether certain parameters have changed during the study. However, it does not completely rule out the influence of time, changes in care, or other factors.
Comparing a product without intervention can show whether the tested regimen worked better than not using the product in that particular location, but it does not isolate the effects of a specific component.
Comparing the product with a properly matched base allows a better assessment of whether the added ingredient provides an advantage beyond the effects of the base formulation.
Comparing the combination of the components with each of them separately and with the substrate, however, can help determine whether the combination adds additional value and what the share of each component is. However, this requires a properly planned and sufficiently large study.
Comparison of two ready-made creams, however, shows how the entire formulations behave. The differences between them cannot be automatically attributed to a single ingredient.
This is of particular importance in the case of a deadline. „synergy”.
Demonstrating that a multi-component product works is not proof of synergy.
A scientifically significant claim of synergy requires a design and analysis that demonstrate that the combined intervention produces an effect greater than the respective expected contribution of the individual components.
The fact that the two components have biologically plausible and potentially complementary functions is a good reason to investigate such a combination.
However, it does not constitute evidence of synergy.
Check whether the measured result actually justifies the given claim
Scientific claims should be derived directly from what has been measured.
If the test shows an increase in moisture, the data support the claim regarding moisture.
If TEWL decreases compared to the corresponding control product, the result may support the claim regarding the reduction of water loss through the barrier under the conditions of the study.
If participants report that their skin appears more firm, such subjective observation does not directly prove an increase in collagen structure.
Similarly, the detection of changes in the stratum corneum lipid layer does not prove that the cosmetic peptide has penetrated through the skin.
Studies of ceramide creams are particularly valuable because they often combine different types of measurements—clinical, instrumental, and biochemical.[7][8][9]
The compliance of several relevant parameters can strengthen the interpretation.
However, the results should still be presented separately, rather than combined into an imprecise phrase such as „total skin repair”.
Precision improves both the scientific accuracy and the reader’s understanding of the content.
Consider the time of the study, uncertainty, and tolerance
A few weeks of use of the product can provide useful information about cosmetic effects, but short-term studies do not prove its unlimited duration of action.
It also does not rule out rare adverse reactions.
During the interpretation of the study, it is worth checking how many participants were included, how many completed the study, how many were included in the analysis, whether adverse events were reported, and how large the observed difference was.
If the claim concerns the maintenance of the effect, the observation after the end of product use is particularly valuable.
A small study can still provide valuable data.
However, it should not be treated as conclusive evidence regarding all populations and all formulations.
The characteristics of the participants also matter.
If the study included people with essentially healthy skin, it cannot automatically answer questions about people with eczema, allergies, rosacea, or skin that is currently being treated with prescription medications.
The full formulation and the individual response remain important regardless of the proposed functions of the main components.
Claims regarding ingredients and data regarding the finished formulation
The three levels of evidence should remain separate
Evidence regarding peptides and ceramides can generally be divided into three levels.
Mechanistic evidence They relate to molecules, pathways, and biological processes. They help explain why a given effect may be biologically plausible.
Evidence regarding the component they evaluate specific material under specific experimental conditions.
Evidence regarding the finished product they analyze the actual formulation or care regimen used by humans.
Each of these levels can provide valuable information.
The problem arises when data from one level are presented as if they directly prove something from another level.
For example, studies of ceramide synthesis support knowledge about the biological significance of specific skin lipids.[1]
A clinical study of a cream containing ceramides provides data regarding this formulation and the parameters measured therein. [8]
A separate, controlled study of a cream containing a peptide, however, provides information regarding the formulation itself and a specific peptide comparison.[3]
Placing these publications side by side does not create a clinical study of the combination of peptides with ceramides.
This is one of the most important principles when evaluating claims about multi-ingredient cosmetics.
Similar caution is needed with other popular combinations of cosmetic ingredients. This applies, among other things, to formulations that combine peptides and niacinamide, peptides and hyaluronic acid, peptides and vitamin C or peptides and retinol. In any case, biological knowledge about the individual components should be separated from data regarding the specific finished formulation.
What do the analyzed evidence actually support?
The analyzed studies allow for a cautious discussion biochemistry of ceramides, creams containing ceramides, and research on specific peptides.
They also show why publications concerning endogenous antimicrobial peptides require careful selection before using them as evidence regarding cosmetic peptide ingredients.
The studies available here do not establish a universal, encompassing the entire category of the synergistic benefits resulting from the addition of cosmetic peptides to ceramide creams.
This statement also requires proper interpretation.
It describes the limitations of the evidence set under analysis.
It does not prove that no appropriate study of the specific combination of peptides and ceramides can exist.
A new study of a specific product could answer a narrower question, and manufacturers may have additional, unpublished data.
Such information should still be evaluated according to the same criteria: the research design, the comparator product, the population, the measured results, the statistical reporting method, and the consistency of the evidence with the stated claim.
How to read the ingredient list sensibly?
The INCI list is useful for determining what is in a product.
However, it should not replace evidence regarding the action of a ready-made formulation.
A longer list of peptides does not automatically mean a stronger product.
Similarly, the presence of several different ceramides does not indicate greater clinical effectiveness.
The number of ingredients is not a validated measure of effectiveness.
It is more useful to determine the composition and then check whether The finished product has been tested for the effect it is attributed to it..
A moderate, precisely defined claim supported by appropriate controlled research is usually more informative than a broad promise constructed from several independent studies of individual components.
Frequently asked questions
Are ceramides peptides?
No. Ceramides are lipids, whereas peptides are chains of amino acids. Research on ceramides concerns specific lipid structures, the pathways of their synthesis, and functions related to the skin barrier, rather than peptide bonds or amino acid sequences. [1] Both types of ingredients can be found in the same cream, but their common presence does not make their chemistry or biological functions identical. Therefore, when interpreting cosmetic claims, they should be evaluated as separate components.
Does every peptide cream support the skin barrier?
No. The mere presence of a peptide does not prove barrier-supporting action. For example, in a controlled study of palmitoyl pentapeptide, skin appearance parameters related to photoaging were assessed.[3] These results cannot simply be translated into evidence of reduced TEWL or accelerated barrier regeneration. The base of the cream itself may have an effect on hydration, whereas the claim of the peptide’s specific action on the barrier requires appropriate measurements and a proper comparison.
Can the cream contain both peptides and ceramides at the same time?
Yes. A ready-made cream can be formulated using both categories of ingredients. However, the mere presence of peptides and ceramides in one formulation does not prove their compatibility, stability, delivery to the skin, or clinical efficacy. Separate studies of ceramide creams and products containing peptides provide information about the formulated products tested, not each new product combining these ingredients.[3][8] With a specific claim, the data regarding the specific ready-made product is much more valuable.
Does the addition of peptides increase the effectiveness of a ceramide cream?
Not necessarily. To demonstrate that the addition of a peptide improves the efficacy of a ceramide cream, a proper comparison is required. The beneficial study of the ceramide cream and the independent beneficial study of the peptide remain two separate experiments. [3][8] They do not prove that the combination of ingredients will provide a greater effect. A study comparing a possibly identical formulation with and without the peptide would provide stronger data. Complementary biological functions justify conducting the study, not proving additional efficacy.
Are all ceramides the same?
No. Ceramides form a structurally diverse family, not a chemically uniform substance. Laboratory studies have shown that specific types of ceramides can differ in metabolism and their effects on cell differentiation and signaling.[4] However, this does not constitute a simple cosmetic ranking because the concentration, delivery, accompanying lipids, and the entire formulation also play a role. Therefore, before transferring data from one type of ceramide to another, it is necessary to determine which material was actually studied.
Does a higher number of ceramides mean a better cream?
No. Counting the names of ceramides in the list of ingredients does not allow determining the clinical advantage of the product. Experimental studies of lipid mixtures show that the composition of the lipid environment can affect barrier performance, but do not establish a simple rule that a higher number of listed ceramides always means a better effect. [2] The importance is the concentration, organization of lipids, quality of the formulation, other ingredients, and the results of controlled human studies.
Does hydration mean repairing the skin barrier?
No. Hydration and barrier function are related to each other, but they are not the same thing. Studies of ceramide creams often analyze both water-related parameters and TEWL because they address different questions. [7] The product may improve hydration without demonstrating the complete restoration of all barrier components. The hydration result should therefore remain evidence of hydration and not automatically be extended to claim comprehensive barrier repair.
What does a lower TEWL result mean?
A lower TEWL score indicates less water loss through the skin under the conditions used during the measurement. It can provide data relevant to the function of the barrier, but does not automatically indicate which component was responsible for the change or demonstrate the restoration of all structural elements of the barrier. Studies of controlled substrates for ceramide also show that the initial barrier state and the characteristics of the subpopulation can influence the observed effect.[10] TEWL results should therefore remain linked to the specific study project and the population being studied.
Can skin lipid testing prove the complete restoration of the barrier?
No. Skin lipid measurement provides valuable biochemical information, but by itself does not demonstrate full restoration of the natural barrier. In one study of ceramide cream, an increase in measured ceramides, cholesterol, and free fatty acids of the stratum corneum was noted along with other results.[8] This strengthens the characterization of the product's response, but the amount of lipids alone does not describe all aspects of their barrier organization or function. A stronger basis for interpretation is provided by the combination of several complementary measurements.
Are products containing ceramides automatically gentle on the skin?
No. The presence of ceramide does not guarantee that the entire formulation will be well tolerated by everyone. A study on sensitive skin provided information about specific effects of a particular ceramide complex, but the applied provocative model did not represent all possible irritants, allergies, or inflammatory skin diseases. [9] The tolerance may also be influenced by preservatives, fragrance substances, solvents, and other components. Therefore, the finished formulation and the individual skin reaction are important factors.
Can a cream with peptides and ceramides replace eczema treatment?
The mere presence of peptides and ceramides on the list of ingredients does not mean that a cosmetic moisturizing cream can replace eczema treatment. A study involving an emollient with a predominance of ceramides and endogenous antimicrobial peptides concerned a very specific clinical context and included only a few participants. [5] This does not allow us to conclude that every peptide-ceramide cosmetic cream treats eczema or can replace the recommended therapy.
Why do some studies of ceramides mention antimicrobial peptides?
Some studies measure peptides produced naturally by skin cells, They are not cosmetic peptides applied to the skin. In laboratory studies, ceramides were analyzed for signaling associated with endogenous antimicrobial peptides, while in clinical studies their expression was measured after the application of a specific intervention.[4][5] These publications are important for understanding the biology of the skin, but they should not be automatically classified as studies of peptide-ceramide creams.
Does the study of postbiotic cream demonstrate the interaction of specific peptides and ceramides?
No. A complex postbiotic mixture is not equivalent to an exactly defined cosmetic peptide combined with added ceramide. In a controlled study, a formulation derived from fermentation was evaluated that contained peptides and an enzyme associated with ceramide production. [6] Since the intervention involved many ingredients and did not isolate a specific peptide-ceramide pair, the results should remain attributable to the tested mixture.
Can the results of the ankle skin tests be directly transferred to a face serum?
Not directly. Studies performed on dry skin of the heel can provide valuable information regarding hydration and barrier properties, but the body site, skin properties, formulation, and intended use are different from a peptide serum applied to the face.[8] Such data can provide context, but their transferability should be evaluated rather than assumed. Direct testing of a product intended for the face in a suitable population provides stronger evidence for claims about that product.
How long do the effects of creams containing ceramides persist after use has ended?
There is no universal period of persistence of the effects of all ceramide creams, as it depends on the formulation, the parameter being studied, and the population. One controlled study included a seven-day observation after 28 days of use of the product and showed that some of the beneficial effects persisted under the conditions of this study.[7] This does not mean that every ceramide cream will have the same duration of effect after discontinuation of use. Claims of the durability of the effect are most reliable when the study actually includes measurements after discontinuation of the product.
Does a change in the microbiome clinically demonstrate a significant improvement in the barrier function?
No. The detection of changes in the microbiome parameters in itself does not demonstrate a clinically significant improvement in barrier function. A more recent study of ceramide emollients included observations of the microbiome along with assessment of symptoms and barrier parameters.[10] These are different types of endpoints and should be interpreted separately before proposing a relationship between them. A change in the microbiome may be of scientific interest, but its clinical significance must be demonstrated rather than assumed.
What is the most important question when evaluating a product containing peptides and ceramides?
The most useful question is: did exactly this formulated formulation show the declared effect compared to the corresponding control? Available studies provide valuable data regarding individual ceramide creams and specific peptide formulations, but separate studies do not demonstrate a universal synergy between these two categories of ingredients.[3][8] A transparent study of a specific product that clearly specifies the formulation, population, comparator product, duration, and measured effects provides stronger evidence than a compilation of several independent studies of the ingredients.
Summary
Peptides and ceramides can occur together in a well-designed cosmetic formulation, but their common presence in the list of ingredients does not constitute evidence of synergy or automatically mean a more effective barrier repair, collagen stimulation, or greater hydration.
Both categories of ingredients differ fundamentally in terms of chemistry. Ceramides are lipids associated with the organization and function of the skin barrier, while peptides are chains of amino acids whose properties strongly depend on the sequence, modification, concentration, and formulation.
Studies of ceramides are most useful when the results are described in accordance with the actual measurements performed. Hydration, TEWL, visible dryness, assessment of symptoms, and analysis of skin lipids can provide valuable information, but they should not be lumped together into a single imprecise concept of „skin repair.”.
Evidence regarding peptides requires similar precision. Results regarding a single peptide or a specific peptide formulation cannot be automatically transferred to other sequences. Similarly, a positive peptide study and a positive study of ceramides cannot simply be combined and treated as if scientists were testing their combination.
Special caution is also needed when scientific publications mention both ceramides and peptides at the same time. In some studies, peptides are mentioned first. endogenous antimicrobial peptides measured in the skin, These are the ingredients added to the product, not the cosmetic ingredients. Other publications deal with complex postbiotic blends, creams containing only ceramides, or experimental models instead of traditional peptide-ceramide formulations.
The strongest claim regarding such a connection would therefore require research. the actual finished product containing peptides and ceramides compared to the corresponding control, Best done using measurements directly related to the declared effect.
Until such data are obtained for a specific formulation, the most justified interpretation is that peptides and ceramides can play potentially complementary roles in cosmetics, but biological complementarity alone does not prove synergy.
A credible cosmetic claim should always be linked to an accurate the ingredient, formulation, study population, comparator product, and the effect that was actually evaluated.
Disclaimer
This article is purely educational and scientifically informative. It discusses cosmetic ingredients, skin barrier research, and the interpretation of publications regarding peptides, ceramides, and related formulations. It is not intended to diagnose skin diseases, provide individual medical or dermatological advice, or recommend a specific cosmetic product or treatment method.
The mere presence of peptides, ceramides, or both in a cosmetic formulation does not prove that the product repairs the skin barrier, stimulates collagen production, cures inflammatory skin diseases, or provides effects identical to another formulation evaluated in a published study.
Studies involving endogenous antimicrobial peptides, experimental cellular systems, complex postbiotic mixtures, or creams containing only ceramides should not be automatically interpreted as clinical evidence regarding traditional cosmetic products that combine peptides with ceramides.
Similarly, beneficial results regarding hydration, TEWL, skin lipids, or tolerance apply to the formulations, populations, and conditions actually evaluated in a given study and should not be automatically generalized to all products containing similarly named ingredients.
Persistent inflammation, significant pain, skin cracking, swelling, worsening itching, or other persistent skin symptoms may require evaluation by an appropriately qualified specialist instead of further attempts with cosmetics selected solely based on claims regarding ingredients.
References
- Ohno, Y., Nakamichi, S., Ohkuni, A., Kamiyama, N., Naoe, A., Tsujimura, H., Yokose, U., Sugiura, K., Ishikawa, J., Akiyama, M., & Kihara, A. (2015). Essential role of the cytochrome P450 CYP4F22 in the production of acylceramide, the key lipid for skin permeability barrier formation. Proceedings of the National Academy of Sciences of the United States of America, 112(25), 7707–7712. https://doi.org/10.1073/pnas.1503491112
- Man MQ, M., Feingold, K. R., Thornfeldt, C. R., & Elias, P. M. (1996). Optimization of physiological lipid mixtures for barrier repair. Journal of Investigative Dermatology, 106(5), 1096–1101. https://doi.org/10.1111/1523-1747.ep12340135
- Robinson, L. R., Fitzgerald, N. C., Doughty, D. G., Dawes, N. C., Berge, C. A., & Bissett, D. L. (2005). Topical palmitoyl pentapeptide provides improvement in photoaged human facial skin. International Journal of Cosmetic Science, 27(3), 155–160. https://doi.org/10.1111/j.1467-2494.2005.00261.x
- Shin, K. O., Mihara, H., Ishida, K., Uchida, Y., & Park, K. (2022). Exogenous ceramide serves as a precursor to endogenous ceramide synthesis and as a modulator of keratinocyte differentiation. Cells, 11(11), Article 1742. https://doi.org/10.3390/cells11111742
- Park, K. Y., Kim, D. H., Jeong, M. S., Li, K., & Seo, S. J. (2010). Changes of antimicrobial peptides and transepidermal water loss after topical application of tacrolimus and ceramide-dominant emollient in patients with atopic dermatitis. Journal of Korean Medical Science, 25(5), 766–771. https://doi.org/10.3346/jkms.2010.25.5.766
- Catic, T., Pehlivanovic, B., Pljakic, N., & Balicevac, A. (2022). The moisturizing efficacy of a proprietary dermo-cosmetic product (CLS02021) versus placebo in a 4-week application period. Medical Archives, 76(2), 108–114. https://doi.org/10.5455/medarh.2022.76.108-114
- Lueangarun, S., Tragulplaingam, P., Sugkraroek, S., & Tempark, T. (2019). The 24-hr, 28-day, and 7-day post-moisturizing efficacy of ceramides 1, 3, 6-II containing moisturizing cream compared with hydrophilic cream on skin dryness and barrier disruption in senile xerosis treatment. Dermatological Therapy, 32(6), Article e13090. https://doi.org/10.1111/dth.13090
- Draelos, Z. D., Baalbaki, N. H., Raab, S., & Colón, G. (2020). The effect of a ceramide-containing product on stratum corneum lipid levels in dry legs. Journal of Drugs in Dermatology, 19(4), 372–376. https://doi.org/10.36849/JDD.2020.4796
- Nojiri, H., Ishida, K., Yao, X., Liu, W., & Imokawa, G. (2018). Improvement of lactic acid sensations in sensitive skin by stimulating the barrier function and improving the ceramide profile. Archives of Dermatological Research, 310(6), 495–504. https://doi.org/10.1007/s00403-018-1833-9
- Dimmers, F., Reichert, D., Nguyen, T., Lück, N., Ramachandran, H., Bremges, A., Schild, J., Humbek, M., Grether-Beck, S., Rossi, A., Staerk, C., Esser, C., & Krutmann, J. (2026). Monocentric, vehicle-controlled, double-blind study to assess the short- and long-term effects of a ceramide NP C15-containing emollient on the skin microbiome and the skin barrier function in sensitive skin. Skin Pharmacology and Physiology. Advance online publication. https://doi.org/10.1159/000551043