Understanding how to use a peptide serum is worth starting with something more basic than determining whether it should be included in morning or evening skincare: by determining what product we are dealing with and reading the instructions for the specific formulation.
„Peptide serum” does not mean a single, standardized type of cosmetic product. Products designated in this way can significantly differ in peptide composition, base, consistency, additional ingredients, method of application, and formulation development method. Lightweight water-based serum, denser emulsion, acid-containing formulations, and products tested in conjunction with dermatological treatments do not need to be applied according to the same principles.
For the same reason, the term „peptide serum” does not specify a universal number of drops, the frequency of application, the order in which cosmetics are applied, or the need to apply the product to wet skin.
Studies can show how a specific formulation behaved under a specific method of use. However, if researchers do not directly compare different application schemes, the study usually does not allow them to determine whether the applied scheme was actually the best.
For example, if study participants applied peptide serum twice daily and after a certain period of time certain changes were observed, we obtain data regarding this product used twice daily. This does not automatically prove that application twice daily is more effective than once daily, nor that any other peptide serum should be used with the same frequency.
This distinction is of fundamental importance for the correct interpretation of studies on peptide serum.
Below, we explain how to interpret product instructions, application timing, layering, formulation, tolerance, and measured results without converting limited data about specific products into a universal skincare regimen.
How to determine the intended use of a specific product?
First, check what the product actually is.
The front of the cosmetic packaging may describe it as serum, booster, ampoule, concentrate or essence. These terms help describe the form, consistency, or method of positioning the product, but do not represent the full chemical composition or the conditions under which the preparation was tested.
A better starting point is to determine what the finished product is intended for and how the manufacturer plans to use it.
It is worth checking the application site to see if the product remains on the skin, if it is rinsed off, how often the manufacturer recommends its use, and whether the current instructions contain restrictions regarding damaged skin, specific ingredients, or treatments.
It is equally important to distinguish a finished cosmetic product for local use from a peptide material intended for research or a preparation developed for another route of administration.
Evidence showing that serum containing the peptide was applied topically to undamaged facial skin does not mean that the same formulation is suitable for injection, application to an open wound, or use in conjunction with a microblading device.
Such exposure routes create completely different biological and clinical conditions. We describe more about why the route of administration is important for the interpretation of data regarding peptides in an article about injections of peptides and other routes of administration.
For example, in a randomized split-face study, serum containing a tripeptide and a hexapeptide was evaluated as a complement to nonablative laser resurfacing.[1] The results refer to a specific serum, procedure, comparator product, and controlled study conditions.
They should not be converted into instructions for self-reproducing such an exposure at home.
The mere presence of peptides in both situations does not make conventional topical application and professional treatment equivalent.
Analyze the composition, but do not treat the INCI list as a manual of use.
Finding the name of the peptide on the list of ingredients indicates that it is present in the product. However, this does not automatically tell how the entire formulation should be used.
Peptide serums may also contain humectants, emollients, plant extracts, preservatives, exfoliating acids, niacinamide, retinoid ingredients, or other substances that affect the properties of the formulation and its tolerability.
Therefore, the entire formulation is more important than the individual component highlighted on the packaging.
In a small prospective study, for example, a gel containing a peptide together with retinoid components, glycolic acid, salicylic acid, and niacinamide was evaluated. The preparation was applied according to a specific evening regimen.[2]
This does not mean that all peptides should be used only in the evening.
The study shows rather why the instructions for the application cannot be derived from a single designated component, especially when several active substances are present in the same formulation.
In the case of such products, it is also useful to separately analyze the issues related to peptides and niacinamide, peptides and retinol and peptides and exfoliating acids. The mere fact that several ingredients are present in a single formulation does not create a universal rule for all products containing these substances.
The list of ingredients is also not a stability report.
Based on the label, it is not possible to determine how much intact peptide remains in the product after many months of storage, how effectively the substrate releases the peptide, or how deeply the specific peptide penetrates the skin.
Appropriate analytical, formulation or penetration testing are needed to answer such questions.
Separate cosmetic claims from clinical claims
Before evaluating the effectiveness of the serum, it is worth determining what effect is actually being analyzed.
Cosmetic serum can be evaluated for changes in the visibility of fine lines, the smoothness of the skin surface, softness, hydration or texture.
However, these results are not equivalent to the treatment of a recognized dermatological disease.
Similarly, an improvement in the appearance of the skin does not automatically indicate the treatment of the underlying disorder; and an increase in measured hydration in itself does not confirm complete structural skin repair.
Different claims require different measurement methods.
Sentence „my skin seems less dry” describes a subjective or sensory sensation.
Statement „the measured depth of the wrinkle has decreased” describes another type of observation, requiring appropriate measurement techniques.
Even stronger statements, such as „serum increased collagen production”, It requires biological evidence and cannot be confirmed solely by ordinary photos before and after the product is applied.
Defining exactly what effect is being declared helps avoid turning cosmetic observations into a much broader biological conclusion.
Use the current instructions for the specific version of the product
Cosmetics can change over time.
Manufacturers can modify formulas, change concentrations, packaging, or introduce similarly named products intended for other areas of the skin.
Therefore, the instruction should be checked for exactly the version of the product that is currently being used.
A post on social media describing an older version of the cosmetic product may not correspond to its current formulation.
Similarly, instructions for face serum should not be automatically transferred to an eye serum, a scalp serum, or any other cosmetic product just because it contains the same peptide.
If the information on the packaging appears to contradict the online description, the discrepancy is best explained by the manufacturer or an appropriately qualified specialist.
This uncertainty should not be resolved by assuming that every cosmetic product containing the word "fragrance" is a fragrance. „peptide” it is subject to the same rules.
Peptide serum in the morning or evening?
The time of use is part of the protocol, not evidence of superiority
Peptide serum studies often specify a specific application schedule, but it should not be automatically interpreted as scientifically optimal.
In a randomized, placebo-controlled study involving peptide serum aimed at improving line visibility, a product was used. twice a day for 12 weeks. [3]
This provides information about the product's action in exactly the same pattern.
However, the study did not assign the participants separately to the groups that used the serum only in the morning, only in the evening, and twice a day.
Therefore, it cannot be determined on the basis of this data whether the double application was better than the single one, or whether the time of day had an effect on the result.
The same principle applies to studies that use only the evening schedule.
If researchers choose one application schedule, the results describe what happened within that specific schedule. They do not prove that untested alternatives are ineffective.
The time of application may also depend on other ingredients, the consistency of the product, its place in the overall skincare routine, or the intended use specified by the manufacturer, rather than the peptide itself.
The available evidence therefore does not justify the universal statement that Every peptide used topically becomes biologically active only at night.
They also do not show that the twice-daily application of each peptide serum must provide twice the effect than the once-daily application.
Direct comparative studies would be needed to reach such conclusions.
The instructions of one manufacturer remain the instructions for a specific product
Manufacturer's instructions can be a useful example, provided they remain relevant to the specific product.
The current recommendations for The Ordinary Multi-Peptide + HA Serum state that it should be applied in the morning and evening and placed before a moisturizing cream in accordance with the manufacturer's recommended skincare regimen.[4]
This information describes the method of use. of this particular formulation.
It is not a clinical evidence that applying it in the morning and evening is the best solution for the entire category of peptide serums.
It also does not specify the method of application of another peptide emulsion, a booster, a cream or a serum containing acids.
Therefore, it is not necessary to copy the scheme of one company for all peptide products.
A more reliable approach is to verify and properly interpret the instructions of a specific formulation.
Peptide serum is not automatically a sunscreen
The ability to use the product in the morning does not mean that it provides protection against ultraviolet radiation.
If the product has not been specifically developed, tested and labeled as a sunscreen, the presence of peptides or antioxidant ingredients should not be interpreted as an SPF claim.
Similarly, the improvement in smoothness, hydration, or the visibility of fine lines after using a peptide serum is not a measure of UV protection.
This distinction is particularly important when the routine contains exfoliating ingredients.
The FDA’s information regarding AHA products includes precautions related to exposure to the sun, because under certain conditions these ingredients can increase skin sensitivity to radiation.[5]
The addition of a care phase with peptides does not prove that these products are no longer relevant.
The cosmetic effect and UV protection are separate results that require other evidence.
Regularity does not mean ignoring unwanted reactions
Regular application may be part of the study protocol, but this does not mean that the cosmetic product must be used continuously despite a significant adverse reaction.
If the product causes persistent discomfort, worsening redness, swelling, or other significant reaction, it becomes more important to determine whether further exposure is appropriate.
Continuing to use the product despite increasing discomfort does not prove that a better cosmetic effect will appear over time.
The American Academy of Dermatology recommends testing a skincare product before widespread use and discontinuing its use in the event of a reaction.[6]
Such instructions relate to tolerance and have a different function from the dosing schedule specified in the efficacy study.
Applying serum, consistency and other products
The consistency may affect the convenience of use, but it does not indicate penetration.
The consistency of the product can affect the comfort of the entire routine.
Lightweight serums are applied differently than thick creams or emulsions, and applying one product on top of another can change the way they are applied or cause visible deposits.
These are important practical issues.
However, they do not show how much of the peptide reaches the specific layer of the skin.
When it is said that a product „quickly absorbed”, It usually describes the sensory impression—the speed at which the surface of the skin stops being wet, sticky, or oily.
This is not equivalent to the analytical measurement of peptide penetration.
Experimental studies of acetyl hexapeptide-8 showed that the change in the composition and internal structure of the emulsion influenced the delivery of the peptide in a pig skin model.[7]
This shows that the substrate matters.
However, it does not establish a universal rule that every skincare regimen must start with the least-concentrated product and end with the most concentrated one, nor that applying additional cosmetics automatically increases the penetration of peptides.
In another in vitro study using human cadaveric skin, most of the applied acetyl hexapeptide-8 remained recoverable from the skin surface, and no peptide was detected in the normal skin under experimental conditions.[8]
This result applies to a specific preparation and specific conditions.
Other formulations may behave differently.
The study shows, however, why the impression that the serum has been „absorbed” cannot replace a real penetration test.
Peptide serum for dry or oily skin?
This is one of the most frequently asked questions regarding peptide serum.
The analyzed studies do not indicate a universal advantage of the application on wet or completely dry skin.
To answer this question directly, it would be necessary to investigate the same serum under comparable conditions, One group would apply them to wet skin, the other to dry skin, and then the appropriate results would be measured.
Without such a comparison, the use of one method in a study does not prove that it is better.
Some products may contain specific instructions for preparing the skin.
In this case, you should follow the instructions provided with the formulation.
If the serum contains hyaluronic acid, but the manufacturer does not specify the need to apply it to wet skin, the mere presence of a humectant does not prove that wet skin is scientifically necessary.
We describe more about this component and the way to interpret such combinations in the article. peptides and hyaluronic acid.
At the same time, the lack of comparative studies should not lead to the absolute opposite conclusion that skin moisture can never affect the product's performance.
The most scientifically cautious conclusion is:
Available studies do not establish a single optimal „moist or dry skin” rule for all peptide serums.
Layering is not the same as mixing
Applying two skincare products one after the other is not the same as physically mixing them before application.
When applied in a layered manner, each formulation initially retains its designed composition before it begins to interact with the second product on the skin surface.
Mixing cosmetics in the hand or pouring them into a single container, on the other hand, changes their relative proportions and the immediate formulation environment.
Data regarding the stability, maintenance, and tolerance of individual products do not automatically apply to the newly created mixture.
In laboratory studies of formulations containing acetyl hexapeptide-8, analytical and physical methods were used to characterize the intentionally designed systems.[9]
Such an assessment cannot be replaced by the observation that two cosmetics seemingly mix well together.
The homogeneous appearance of the mixture does not preclude changes in pH, the preservative system, the stability of the ingredients, or the method of their delivery.
Visible miscibility is therefore not evidence of chemical compatibility.
The combinations of active ingredients require their own evidence
A multi-product routine study can show what happened when specific cosmetics were used together.
It does not automatically prove that every component in one category improves the performance of every component in another category.
For example, in one study, serum with hyaluronic acid was evaluated in combination with a cream rich in peptides and an improvement was noted across the entire routine [10].
This does not prove that every product with hyaluronic acid increases the effectiveness of every peptide serum.
Similarly, studies of niacinamide compounds, postbiotics, and peptides refer to specific formulations, not all possible combinations of these categories.[11]
The same principle applies peptides and vitamin C, peptides and ceramides and the combination of peptides with retinoids or exfoliating acids.
A properly formulated multi-ingredient formulation does not invalidate the restrictions regarding an entirely different product.
On the other hand, a restriction regarding a specific formulation does not automatically establish a universal chemical incompatibility for the entire category of peptides.
The most important data and instructions remain the products actually analyzed.
Swelling of the product is not a test of peptide stability
Rolling, often referred to as pilling, occurs when visible lumps or ridges of the product form on the skin surface during application.
This may indicate that the cosmetics do not work well in terms of usability under certain conditions.
However, it does not allow determining which component is responsible for this effect or whether the peptide has undergone chemical degradation.
Appropriate analyses are needed to confirm the degradation.
The reverse rule also applies.
A routine that looks perfectly smooth and comfortable does not prove that every active ingredient remained chemically intact, reached a specific layer of the skin, or produced the proposed biological effect.
Appearance, sensory perception, chemical stability, penetration, and clinical action are different issues.
How often should you use a peptide serum?
The study schedule is not a universal dose-response curve
If an improvement was observed in a clinical study after a specific application schedule, it means that it was observed with exactly that exposure.
This does not automatically determine minimum effective frequency, maximum usable frequency, nor maximum tolerable frequency for all people.
The real question regarding the dose-response relationship requires comparing different levels of exposure while maintaining as similar other conditions as possible.
In an open-label study involving peptide serum and the accompanying skincare regimen, 29 women were observed for 14 weeks. [12]
The observed changes provide information about a specific routine.
However, since it included several elements, the study does not allow for a precise determination of the contribution of each of them.
It also does not show that increasing the frequency of applications would provide faster or greater results.
The same caution applies to the amount of product.
Type instructions „apply a few drops” they contain instructions regarding the specific formulation, the dispenser and the intended area of use.
The drop is not a standardized scientific unit of exposure to peptides for all cosmetic serums.
The amount recommended by one manufacturer should therefore not be turned into a universal rule.
Read the instruction as a whole
Product instructions are most useful when they are interpreted as a whole, rather than choosing individual sentences.
The following may be relevant: the application site, the requirement to apply to undamaged skin, the recommended amount, the frequency, the product status as leave-on or rinse-off, restrictions and storage conditions.
Choosing the frequency itself from a single source and omitting the other information can lead to a method of use that was never intended or tested.
For example, an instruction specifying use on undamaged skin determines the conditions under which the recommendations apply.
A clinical study related to the treatment does not automatically remove this restriction from the instructions of a regular cosmetic product.
Storage is also part of the product instructions
Storage conditions are important for maintaining the prepared formulation.
Temperature, light, packaging, and time after opening can all affect the cosmetics.
The very fact that the serum contains a peptide does not automatically mean that the finished product should be stored in a refrigerator or freezer.
Laboratory peptide powder and ready-made cosmetic serum are different systems.
Studies of the formulation of products containing peptides show why stability should be evaluated with respect to the entire preparation. [9]
Storage conditions should therefore correspond to the instructions for the finished product, unless there are reliable information regarding the specific formulation indicating otherwise.
We discuss the issues of temperature, light, packaging and stability in more detail in the article. Storage of peptides.
Visible changes in the smell, color, consistency, or appearance may be a reason to check the information with the manufacturer or to discontinue use in accordance with the appropriate recommendations.
The absence of visible changes does not, however, mean that all the components have remained chemically unchanged.
The concentration or molecular integrity of a peptide cannot be determined solely by the appearance of the bottle.
Peptide serum and professional treatments
Products containing peptides studied in combination with professional treatments require particularly careful interpretation.
For example, in a study on laser resurfacing, certain serums containing a tripeptide and a hexapeptide were compared with a neutral moisturizing preparation.[1]
This was a study of a specific clinical situation.
It does not prove that every peptide serum is suitable for use after each laser treatment, microdermabrasion, chemical peel, or other procedure.
Treatments can change the skin environment and exposure conditions.
Therefore, in the case of professional procedures, the instructions of the person performing the procedure remain important.
The label of a regular cosmetic product or an unrelated peptide study should not be used to make a self-determined conclusion about the product's suitability for therapeutic use.
How to assess tolerance and effects?
Tolerance is more than the absence of serious adverse effects
Scientific publications can describe tolerance in various ways.
The studies may separately report redness, dryness, burning, itching, withdrawal of participants, and serious adverse reactions.
Therefore, the statements „no serious adverse reactions were reported” It should not be automatically interpreted as information that no one has experienced discomfort.
Small studies also have limited ability to detect rare reactions.
Testing on a small area of skin can sometimes help to spot an adverse reaction before it spreads more widely.
However, it does not guarantee future tolerance or diagnose a specific allergy.
Clinical skin tests used in suspected contact allergies are another type of test.[6]
Therefore, serum should not be considered universally non-irritating just because it was well tolerated by a small group of study participants.
First, determine what change you are actually measuring
Different observations answer different questions.
The feeling of softer skin may describe the cosmetic comfort, but it does not itself confirm the biological activity of a particular peptide.
The increase in instrumentally measured hydration describes the water-related properties of the outer layers of the skin, but does not indicate the formation of new collagen or the complete restoration of the barrier.
Less visible fine lines describe the appearance under certain observation conditions, but by themselves they do not indicate a permanent structural change.
Changes in standardized imaging of skin surfaces describe the measured surface characteristics, but without proper control they do not indicate which component was responsible for the result.
The change in tissue marker, however, is a specific biological measure, but in itself does not prove the superiority of the entire product or the universal benefits.
These distinctions are important because a favorable result from one measurement does not automatically mean an improvement in all skin properties.
For example, a randomized study of hyaluronic acid reported an advantage in one hydration-related outcome, but no significant difference between groups was shown in terms of periorbital water loss or the evaluated symptoms.[13]
This was not a study of a peptide serum, but it does demonstrate an important principle of interpretation:
moisturizing, skin barrier parameters, symptoms, and structural changes should be treated as separate endpoints, rather than being combined into a broad claim about „skin repair.”.
Compare similar conditions
When observing cosmetic changes, it can be helpful to take photographs under as similar conditions as possible.
Lighting, camera distance, facial expression, angle of photography, and time of day can significantly affect the appearance of the skin.
Even well-standardized own photos do not, however, form a control group.
Weather, other cosmetics, treatments, changes in hydration and expectations can all influence the observed effect.
Clinical studies can use appropriately selected controls or comparative preparations to answer more detailed questions.
A controlled study of a moisturizing cream containing palmitoyl pentapeptide is an example of such a project.[14]
The photo taken before the entire routine began and after it ended, however, answers a broader, less precise question, because it does not allow determining which element was responsible for the observed change.
Expectations should correspond to the quality of the evidence
The immediate feeling of smoother or softer skin can be a real cosmetic effect.
However, it should not be described automatically as a rapid reconstruction of deeper-lying tissues.
Similarly, a multi-week study may show changes during product use, but it does not necessarily determine how long they persist after discontinuation.
The longest available study in a given category also does not specify the exact duration of action of all other products.
When analyzing the theorem, it is worth checking whether the result comes from consumer assessments, instrumental measurement, researcher assessment, biological marker, or controlled clinical comparison.
It is also necessary to determine whether the formulation examined in the publication is actually the same product to which the claimed claim refers.
Such questions provide much more information than the assumption that all peptide serums should produce identical results in a single universal time.
Frequently asked questions
Should every peptide serum be in the same skincare phase?
No. Peptide serums can use very different bases and contain additional active ingredients, so their place in the routine cannot be determined solely by the word „peptide.” A single manufacturer’s instructions for a multi-peptide serum containing hyaluronic acid describe a specific product, not all peptide formulations. [4] Experimental studies also show that the base composition can affect the delivery of the peptide. [7] It is therefore most reliable to follow the instructions for the exact product being used.
Should peptide serum be applied to wet or dry skin?
The product instructions should be followed because available studies do not show a universal advantage of applying to wet skin over applying to dry skin. A study that uses one method of skin preparation does not compare all possible conditions. [3] If the instructions do not specify the need to apply to wet skin, the mere presence of a humectant such as hyaluronic acid does not prove that it is necessary.
Are peptides only suitable for evening skincare?
No. The mere presence of a peptide does not establish the requirement to use the product exclusively in the evening. Published studies can be found that include both peptide serums applied twice daily and multi-component peptide preparations applied in the evening. [2][3] Different protocols show that study protocols can vary, but they do not indicate a single universally best time.
Does using it twice a day mean that the once-a-day application is ineffective?
No. A study evaluating the app only twice a day provides information about that specific schedule, but it does not show what would happen with once-daily use. To determine the advantage of one frequency, comparable groups using different schedules would be needed. [3]
Does rapid „absorption” mean that the peptides have reached the living layers of the skin?
No. The sensation of absorption and the measured penetration of the peptide are different things. In an in vitro study using human skin, acetyl hexapeptide-8 was directly analyzed and limited penetration was observed under certain conditions [8]. Other formulations may yield different results, but this cannot be determined based on the mere touch of the skin.
Can two serums be mixed in one bottle?
Data regarding the two original products do not automatically confirm the stability, maintenance, or performance of the new mixture. Purpose-prepared peptide formulations are evaluated using analytical and physical methods, and not just based on whether the ingredients visually mix well. [9] Combining two serums can change their ratios and formulation environment, therefore a new mixture should not be automatically considered equivalent to the original products.
Can peptide serum replace a cream with a filter?
No. The presence of peptides does not mean sun protection. UV protection requires appropriate evidence and labeling of the product, whereas peptide serum studies typically address other results such as appearance, hydration, or skin texture. If the routine also includes an AHA product, appropriate sun safety precautions remain essential.[5]
Does rolling the cosmetic product mean that the peptide has been broken down?
No. Rolation is a visible surface phenomenon, not a chemical analysis. Appropriate analytical methods are used to study the stability of peptides. [9] Rolation may indicate that the products do not adhere well to the skin under the given conditions, but does not prove the degradation of the molecule.
Does a higher serum amount mean faster results?
Not necessarily. To determine the relationship between the amount of product and the effect, it would be necessary to examine different levels of exposure in terms of efficacy and tolerance. Testing a single specific routine does not allow one to predict what will happen after doubling the amount or frequency of application. [12] A higher amount of product should not be automatically equated with a faster or stronger effect.
Can facial serum be used automatically around the eyes?
No. The usefulness of a product for one area of the face does not automatically mean it is useful for another, especially the eye area. The application site should be checked in the instructions for the specific product. A general examination of a face serum does not answer all questions about exposure and tolerance in the eye area.[3]
Does pinching mean that the peptide serum is working?
No. The tingling does not indicate activity of the peptide. The reaction may be due to other ingredients or the entire formulation, and dermatological recommendations indicate the need to discontinue use of the cosmetic product in the event of a significant reaction. [6] Tolerability and cosmetic efficacy should be treated as separate issues.
Does a successful test on a small fragment of skin guarantee the absence of a subsequent reaction?
No. A trial in a limited area can provide information about immediate tolerance, but it does not guarantee an identical response during all future applications. The area of application, frequency, skin condition, and other elements of the routine may vary. A home trial of a product also differs from clinical fee-for-service testing used in the diagnosis of suspected contact allergies.[6]
Can the serum used during the procedure be used as a guide for daily skincare?
Only with great caution. The procedure alters biological and clinical conditions. The study of serum containing tripeptide and hexapeptide concerned its use in combination with non-ablative laser resurfacing, and not all types of daily care or all dermatological procedures. [1] The results should therefore remain linked to the intervention that was actually studied.
Do all peptide serums need to be stored in the refrigerator?
No. The need for cooling cannot be inferred solely from the presence of peptides. Stability depends on the entire finished formulation, including the base and packaging. Studies of finished peptide systems show why the storage conditions of laboratory-grade peptide material should not be automatically transferred to cosmetic serum. [9] The instructions for the finished product should take priority.
Does the improvement in hydration indicate a structural change in wrinkles?
No. Hydration and structural remodeling are different outcomes. A study may show an improvement in a water-related parameter without an analogous change in other skin properties. [13] Better hydration can make the skin surface appear smoother, which is an important cosmetic effect, but it alone does not prove the formation of new supportive tissue or permanent structural remodeling.
Can the improvement after the entire routine be attributed to the serum itself?
Not without a study design that allows isolation of the serum effect. A study of serum with hyaluronic acid used together with a peptide-rich cream assesses the entire regimen, similarly to a care program involving several products used simultaneously.[10][12] Such studies show what happened during the entire routine, but do not always allow determining the role of a single product.
How best to evaluate claims regarding the use of peptide serum?
The most reliable interpretation starts with checking whether exact product, formulation, application schedule, participant population, comparator product, and measured result they correspond to the stated claim. A controlled comparison answers a different question than an uncontrolled study of the entire routine before and after its use.[12][14] The manufacturer's instructions describe the intended way of using the product, whereas the clinical study only supports those results and conditions that have actually been evaluated.
Summary
Does not exist one scientifically established method of use that can be applied to any peptide serum.
The term „peptidic serum” encompasses products that differ in peptide sequences, base material, additional ingredients, application site, and formulation properties. Therefore, questions regarding use in the morning or evening, on wet or dry skin, the order of application, frequency, or storage cannot be reliably answered based solely on the presence of a peptide.
The best starting point remains the exact, ready-made formulation and its current instructions.
Studies can provide valuable information, but their conclusions should remain linked to the conditions that were actually evaluated. A study using the app twice a day shows what happened with such a regimen, but it does not prove its effectiveness. Using a multi-ingredient product containing a peptide in the evening does not mean that all peptides should be used at night. A study of a product used during a procedure is not automatically a routine daily care instruction.
Formulation studies also show why consistency should not be confused with the delivery of the substance. Serum that appears to be quickly absorbed does not therefore demonstrate penetration into a specific layer of the skin. Similarly, rolling the product does not confirm peptide degradation, and an aesthetically pleasing and comfortable routine does not automatically demonstrate molecular stability or clinical efficacy.
The same distinction applies to measured results.
Moisture, surface smoothness, visibility of fine lines, biological markers, penetration, tolerance, and structural changes in the skin are different endpoints. Evidence regarding one of them should not be automatically extended to the others.
The most reliable interpretation therefore remains linked to a specific product and specific evidence: It is necessary to specify the exact formulation, check the current instructions, determine what effect is being declared, and verify whether the study actually measured this effect under comparable conditions.
This approach allows for the transformation of the protocols of individual products into universal principles for all peptide serums, while at the same time enabling the practical and scientifically justified interpretation of the available studies.
Disclaimer
This article is for educational and scientific information purposes only. It explains issues related to cosmetic instructions, formulation, and the interpretation of research on peptide serums. It does not present an individual skincare regimen, does not constitute medical or dermatological advice, and does not contain instructions for the use of a specific product containing peptides.
Studies involving a single peptide serum, the application schedule, formulation, participant population, or professional treatment should not be automatically interpreted as establishing the optimal method of use for all other peptide products.
Similarly, information regarding layering, application frequency, wet or dry skin, storage, tolerance, or use in conjunction with treatments should remain linked to the specific formulation and the evidence discussed.
The current instructions for a specific finished product should be followed. Significant or persistent irritation, swelling, worsening rash, or other concerning skin reactions require appropriate professional evaluation rather than further experimentation with the product.
If a product containing peptides is considered before or after a laser procedure, microneedling, chemical peel, or other professional procedure, the instructions of a properly qualified person performing the procedure should take priority.
References
- Wang, J. V., Christman, M. P., Feng, H., Ferzli, G., Jeon, H., & Geronemus, R. G. (2020). Topical tripeptide and hexapeptide treatment as adjunct to nonablative fractional resurfacing for photodamage: A randomized split-face trial. Journal of Cosmetic Dermatology, 19(12), 3245–3250. https://doi.org/10.1111/jocd.13795
- Villani, A., Annunziata, M. C., Cinelli, E., Donnarumma, M., Milani, M., & Fabbrocini, G. (2020). Efficacy and safety of a new topical gel formulation containing retinol encapsulated in glycospheres and hydroxypinacolone retinoate, an antimicrobial peptide, salicylic acid, glycolic acid and niacinamide for the treatment of mild acne: Preliminary results of a 2-month prospective study. Giornale Italiano di Dermatologia e Venereologia, 155(5), 676–679. https://doi.org/10.23736/S0392-0488.20.06581-5
- Nguyen, T. Q., Zahr, A. S., Kononov, T., & Ablon, G. (2021). A randomized, double-blind, placebo-controlled clinical study investigating the efficacy and tolerability of a peptide serum targeting expression lines. Journal of Clinical and Aesthetic Dermatology, 14(5), 14–21. https://pubmed.ncbi.nlm.nih.gov/34188744/
- The Ordinary. (n.d.). Multi-Peptide + HA Serum. Retrieved September 25, 2026, from https://theordinary.com/en-us/multi-peptide-ha-serum-100613.html
- U.S. Food and Drug Administration. (n.d.). Alpha hydroxy acids. Retrieved September 25, 2026, from https://www.fda.gov/cosmetics/cosmetic-ingredients/alpha-hydroxy-acids
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