Tanning peptides are usually described as substances capable of influencing the biological pathways associated with skin pigmentation, specifically as synthetic analogues of the alpha-melanotropic hormone (α-MSH). However, the term „tanning peptide” is an informal collective term rather than a name for a specific drug, a standardized category of cosmetics, or a guarantee of safety, efficacy, purity, or regulatory approval.
This distinction is important because this term appears in very different contexts. It can refer to early experimental studies, such as melanotan II, historical studies of melanotan I, an approved medicinal product containing afamelanotide, or unapproved products advertised online as injections, nasal sprays, drops, or other preparations.
Studies involving humans have shown measurable changes in pigmentation after the use of certain melanocortin analogs under controlled experimental conditions.[1][2] This confirms that specific compounds can influence the biological processes responsible for pigmentation. However, this does not mean that every product sold under a similar name contains the same substance, has the same concentration and purity, provides the same biological exposure, or has been produced in accordance with the standards used in published clinical studies.
Similarly, demonstrating increased pigmentation does not mean that cosmetic tanning with such substances has been approved, nor that darker skin obtained as a result of pharmacological action provides complete protection against ultraviolet radiation, DNA damage, photoaging, or skin cancer.
From a scientific point of view, it is therefore more useful to ask specific questions instead of a general question such as „do sunscreens work?”.
Which molecule was studied? What formulation was used? By what route was it administered? What population participated in the study? What outcome was evaluated? How long were the participants observed? What adverse reactions were reported? What is the regulatory status of the specific product in question?
Separating these issues allows us to avoid situations where a real biological or clinical outcome is expanded into a claim that the original study never confirmed.
What does the term „sunscreen peptide” mean?
The term „sun tanning peptide” usually refers to peptide analogues related to the melanocortin system and pigmentation. However, the terminology can lead to misunderstandings because several related compounds have similar names and a partially common history of research.
Understanding these differences is essential before interpreting both the test results and the commercial claims.
Melanotan I, afamelanotide and melanotan II are not names that can be used interchangeably.
Afamelanotide, historically associated with the name melanotan I, is a synthetic analogue of the hormone alpha-melanotropin. Melanotan II, on the other hand, is another cyclic peptide analogue.
Their related biological origin does not mean that they are the same molecules.
They differ in structure as well as in the history of clinical development, formulations, the scope of available evidence, regulatory status, and the context in which they were studied.
Early human studies evaluated the pharmacokinetics and the effect of melanotan I and II on pigmentation in very small groups of volunteers.[1][2] Later and much more developed clinical studies of afamelanotide focused on specific diseases, particularly erythropoietic protoporphyria (EPP).[3]
This distinction is particularly important when reading information available on the internet.
The marketing material may use the known name of the molecule, but the name itself does not confirm that the product actually contains the same substance that was used in the published study.
Even if the chemical identity were confirmed, this would not automatically imply the reproduction of the formulation used in the clinical trial, the production control, the route of administration, the method of delivering the substance, the storage conditions, the monitoring of participants, the criteria for their qualification, or the medical supervision.
The scientific publication therefore provides evidence regarding the intervention that was actually studied, and not every subsequent product labeled with a similar name.
A drug used for light sensitivity does not mean general approval for cosmetic tanning
A particularly important example is Scenesse, an implant containing afamelanotide.
Scenesse is approved in the European Union for the prevention of phototoxicity in adults with erythropoietic protoporphyria (EPP).[4][5]
EPP is a rare disease in which there is an abnormal accumulation of light-sensitive substances. Exposure to light can cause severe, and sometimes long-lasting, pain.
Such a clinical situation is fundamentally different from that of a healthy person who wants to achieve a darker skin tone for cosmetic reasons.
The benefit-risk assessment on the basis of which afamelanotide is used in EPP concerns the specific drug, formulation, route of administration, population, disease burden, and therapeutic indication.
This does not mean approval of every product containing afamelanotide.
It does not mean approval of Melanotan II.
It does not change the online aerosols or vials into approved medicinal products.
It also does not constitute general approval of pharmacologically induced cosmetic tanning.
At the same time, to maintain scientific precision, one should avoid the opposite simplification.
It would not be correct to claim that no drug related to this area of research on melanocortins has ever been approved. There is an approved medicinal product containing afamelanotide.
The identity of the product and a specific indication are of crucial importance.
Sunscreen peptides are different from skin-colored cosmetics.
Another important distinction applies to traditional self-tanning products.
Dihydroxyacetone (DHA) causes the surface of the skin to become colored through a chemical reaction with the amine groups in its outer layers. Bronzers, on the other hand, can temporarily color the skin by leaving the dye on its surface.
These mechanisms are fundamentally different from the pharmacological effects on melanocortin receptors through peptide analogues.
The FDA describes self-tanners containing DHA and bronzers as cosmetic products.[6]
A similar cosmetic goal, namely achieving a darker appearance of the skin, does not therefore imply the equivalence of mechanisms.
This distinction is of particular importance in the case of reporting products.
Substances administered topically cannot be evaluated as if they behaved similarly to a balm applied to undamaged skin. Topical administration involves different issues regarding absorption, systemic exposure, formulation, and effects on local tissues and product quality.
Marketing terms such as „sunless”, „natural-looking”, „beauty product” or „tanning aid” do not answer these questions.
More about why the route of administration is important for the exposure and interpretation of evidence is explained in the article „Peptide injections and other routes of administration”.
Mechanisms of pigmentation studied
The biological basis of pigmentation associated with the melanocortin system is real and well-established at a mechanistic level.
Understanding the mechanism is not, however, equivalent to confirming the safety or effectiveness of every product that is attributed with an effect through this mechanism.
Melanocortin signaling combines a molecular signal with pigment production
Melanocytes are specialized cells involved in the production of pigment.
One of the important receptors present in this biological system is the melanocortin type 1 receptor (MC1R). It is involved in signaling pathways related to melanogenesis, the process of melanin formation.
The receptor can be considered as an element of the molecular system for recognition and signal transmission. When the appropriate ligand interacts with the receptor, there may be a change in intracellular signaling and the appearance of further biological effects.
Activation of the receptor does not, however, automatically mean that all the resulting effects will be beneficial.
A 2021 structural study analyzed MC1R complexes involving alpha-MSH, afamelanotide, and another experimental ligand. The researchers characterized the molecular components involved in ligand recognition and receptor binding.[7]
Such studies are valuable because they help to explain how molecular interactions occur.
However, they are not equivalent to a clinical trial.
The structural study cannot confirm that the unverified product advertised online as a tanning product is effective, properly manufactured, or safe when used repeatedly by humans.
Mechanistic evidence explains the biological plausibility of a given phenomenon.
Only clinical studies answer the question of what actually happens in humans.
The production of pigment is not the only possible biological effect
Analog melanocortin can potentially cause effects that go beyond the visible changes in skin pigmentation.
This was already evident in the early studies of melanotan II in humans.
In a small pilot phase I study, researchers observed changes in pigmentation, but also reported symptoms including nausea, fatigue or drowsiness, and spontaneous erections.[1]
The combination of these observations illustrates an important principle.
A substance can be promoted because of one easily visible effect, while simultaneously causing biological effects in other parts of the body.
Pigmentation is particularly easy to use in marketing because it can be shown in photos.
Other effects may be less noticeable, occur intermittently, require clinical measurements, or only become apparent after prolonged exposure.
„Before and after” photos can therefore showcase the desired cosmetic effect, while providing very little information about systemic exposure, adverse effects, the composition of the product, or long-term effects.
Higher pigmentation is not synonymous with sun protection
Melanin, especially eumelanin, has properties relevant to skin interactions with light. The therapeutic mechanism of afamelanotide in EPP is partly related to an increase in eumelanin production.
However, this mechanism should not be taken as a general statement that pharmacologically increased pigmentation is equivalent to sunscreen protection.
The biological mechanism associated with pigmentation does not automatically establish a specific SPF, broad-spectrum protection, DNA damage prevention, photoaging protection, or a reduction in the risk of skin cancer in people who use such substances for cosmetic purposes.
These are separate endpoints.
Phototoxic pain associated with EPP is one of them.
Sunburn is different.
DNA damage caused by UV radiation is another example.
The long-term incidence of skin cancer is another matter.
The intervention may affect one outcome without demonstrating a clinically significant effect on all the others.
The official information on the product Scenesse still recommends the use of appropriate sunscreen during treatment and addresses issues related to skin monitoring. [5]
The existence of an approved drug that affects pigmentation should not therefore be interpreted as evidence that increased pigmentation allows one to forgo conventional protection from sunlight or ultraviolet radiation.
Studies involving humans and their limitations
There are human studies involving melanocortin analogs, but the range of evidence varies significantly depending on the specific substance and the clinical question being investigated.
Early studies regarding pigmentation involved very small groups.
Later studies of afamelanotide in EPP were much more developed, but they concerned a specific disease and a specific product, not cosmetic tanning in the general population.
Early studies of pigmentation involved very small groups
The 1996 Phase I melanotan II trial involved only three men and was single-blind, placebo-controlled. [1]
Increased pigmentation was observed in two participants. Adverse effects were also reported.
This study is important because it provides real-world, early data involving humans indicating that melanotan II may affect pigmentation under the tested conditions.
However, its limitations are equally important.
With only three participants, the study cannot provide reliable estimates regarding rare adverse reactions, differences between broader populations, long-term safety, or the risk associated with repeated exposure.
The goal of an early-phase study differs from that of a large clinical safety study as well.
The 1997 study of melanotan I also included only three men and compared different routes of administration.[2]
Pigmentation was evaluated using reflectance photometry, and not solely based on subjective visual assessment.
In the case of the studied oral administration, no measurable concentrations of the substance were detected, while the studied parenteral routes led to measurable exposure and pigmentation.
This does not prove that no future oral formulation of the related molecule could ever provide systemic exposure.
However, it shows something more fundamental: the way of giving is important.
The results obtained for one road should not be automatically transferred to another.
None of these early studies can determine the long-term safety profile of modern products advertised online as nasal sprays, drops, vials, or other formulations.
The tested substance, formulation, route of administration, experimental conditions, and the method of monitoring the participants constitute an integral part of the evidence.
They cannot be removed from the interpretation while maintaining only the desired result regarding pigmentation.
Studies of afamelanotide concerned a specific disease
The significantly stronger evidence base regarding afamelanotide comes from studies on EPP.
A 2015 publication described two randomized, double-blind, placebo studies of the afamelanotide implant, involving 74 participants in Europe and 94 participants in the United States.[3]
The studies concerned people from the EPP.
The researchers evaluated, among other things, the time of painless exposure to direct sunlight, phototoxic reactions, quality of life, and adverse effects.
Afamelanotide prolonged the time without pain from sunlight exposure, and most of the adverse reactions reported during the study periods were mild in nature.[3]
These are clinically significant results for people living with EPP.
However, the population and the estimated endpoints determine the scope of the conclusions.
Extending the time that people with light sensitivity disorder can spend outdoors without pain is not the same scientific question as assessing cosmetic satisfaction in healthy people.
It is also not equivalent to assessing the risk of melanoma over the entire lifespan, long-term cosmetic safety, or the safety of non-research-related products available online.
The clinical study also cannot confirm the pharmaceutical equivalence between the implant under investigation and the online product that claims to contain afamelanotide or another melanocortin analogue.
The common name of the molecule is not evidence of identical formulation, production, method of delivery of the substance, purity, stability, or clinical efficacy.
Different types of research answer different questions
Receptor, molecular, or cellular studies can help determine the biological plausibility of the mechanism. They can show that the molecule interacts with MC1R or alters a specific signaling pathway. However, they cannot independently confirm the safety of the therapy in humans or verify the efficacy of the commercial product.
A small Phase I study may provide early information regarding exposure, tolerance, pharmacological activity, and possible adverse effects. However, due to the small number of participants, it usually does not allow for a reliable assessment of rare or delayed adverse effects.
A controlled study on EPP can confirm the results for a specific intervention in people with EPP. It cannot automatically confirm the cosmetic safety of other formulations in healthy users.
The case report can indicate an important clinical event occurring after exposure. Such publications can be a valuable source of safety signals, especially in the case of rare or serious events. However, they usually do not allow determining the causal relationship or the frequency of occurrence of a given event.
An analytical study of the product can determine the identity, the measured quantity, impurities or other properties of the samples actually tested. It does not automatically determine the quality of all batches offered by all sellers.
A „before and after” photo can document the appearance under certain conditions. However, without standardization and an appropriate control group, it is not possible to reliably determine the causality, the identity of the product, UV damage protection, or long-term safety.
This does not mean that the evidence found below in the traditional hierarchy is useless.
A single, well-documented case can reveal an unexpected serious event requiring further investigation.
Similarly, a small controlled study can provide strong evidence regarding a narrowly defined biological effect.
The most important principle is that the conclusions correspond to what the given research project can actually show.
The photos do not rule out other possible explanations.
„Before and after” photos are popular in cosmetic marketing because they create an immediate visual impression.
From a scientific point of view, however, many variables can affect the appearance of skin in photographs.
Lighting, camera exposure, white balance, angle of the photo, image processing, background, exposure to sunlight, simultaneous use of cosmetics and other factors can all affect the apparent degree of pigmentation.
Without standardized measurements and an appropriate control group, photography does not allow the effect of the peptide to be reliably distinguished.
Even if the actual increase in pigmentation has been objectively measured, this only answers one question.
Assessment of adverse reactions, systemic effects, abnormal staining changes, and other safety aspects still requires other methods and longer observation periods.
Therefore, a visible effect is not equivalent to a full assessment of safety.
Product declarations and regulatory approvals
Regulatory information can be misleading when the approval of one specific product is used to suggest approval of another.
Therefore, for each claim regarding the approval, the exact product, molecule, formulation, route of administration, indication, and jurisdiction must be specified.
The exact product to which the approval information applies should be determined.
The European approval of Scenesse applies to the implant containing afamelanotide and its use in EPP. [4] [5]
The original approval documentation in the United States from 2019 also referred to an EPP-related indication.[8] The historical label is useful for documenting the original approval, but it should not be treated as a complete representation of the current product information in the USA.
Advertising may truthfully state that a given molecule is associated with an ingredient used in an approved drug, while nevertheless creating a misleading impression if it does not explain that the product being advertised is not that approved drug.
Regulatory approval does not automatically transfer between products simply because they have a similar ingredient name, a related chemical structure, or act within a similar biological pathway.
It also does not automatically transfer between the delivery routes.
The approved implant does not mean that the nasal spray is approved.
The authorised medicinal product containing afamelanotide does not mean that melanotan II is authorised.
Readers in Poland and the other countries of the European Union should therefore check the regulatory status of a specific medicinal product in official sources regarding medicines and in accordance with the applicable national requirements.
Information about availability or approval in the United States, Australia or another country does not in itself determine the rules for prescribing, selling, supplying or importing the product in Poland.
Availability on the internet does not mean approval
The product may be visible and available online, even though it has not been approved for the purpose for which it is advertised.
The Australian Therapeutic Goods Administration indicates that melanotan is not approved in Australia for sale or use as a tanning agent. The warning applies to products promoted in various forms, including aerosols, and draws attention to the uncertainties regarding their content and possible adverse effects.[9]
This is the position of the Australian regulatory authority.
It should not be presented as a universal legal ruling that applies identically in all countries.
However, it illustrates a broader principle: the availability of a product on the internet and its regulatory approval are two separate issues.
The website may remain accessible even when the method of delivering the product or the declarations presented raise concerns with regulatory authorities.
Similarly, customer reviews and popularity on social media do not confirm product approval.
Quality declarations require verification of specific material
Even if studies show that a specific molecule actually causes a given biological effect, this does not confirm the authenticity of the commercial product sold under the same name.
A 2015 study analyzed products containing melanotan II purchased from three online stores. The researchers found that the measured amounts were lower than the values declared on the labels, and samples from two suppliers contained unidentified impurities. [10]
The study used validated analytical methods, which makes it provide useful information regarding the analyzed samples.
However, the number of products was limited.
The study therefore does not allow for determining the frequency of incorrect labeling or the presence of contaminants throughout the market.
It does not prove that every salesperson has the same problem.
It also does not allow you to judge the quality of a product solely based on the price, packaging, or appearance of the website.
The most important conclusion is of a methodological nature: the evidence regarding authentic melanotan II does not automatically confirm the identity or quality of another sample sold under that name.
Chemical identity, quantity, purity, formulation, regulatory status, and clinical evidence are separate issues.
Terms such as „research grade”, „laboratory tested” or „high purity” describe the declared purpose or specific analytical property.
They do not independently confirm the product's admissibility or its suitability for cosmetic use in humans.
Safety and regulatory issues
The safety assessment includes both what has already been observed and what is still unknown.
Small studies may reveal frequent or easily noticeable reactions, but the absence of a specific event in several participants does not mean that rare or delayed adverse effects never occur.
Similarly, an adverse event occurring after exposure requires analysis, but it does not automatically mean that it was caused by the substance in question.
Both observed adverse effects and unknown effects are important.
Concerns about products containing melanotan are not limited to pigmentation or local reactions associated with administration.
The 2019 case report described acute low-flow priapism following exposure to melanotan. During the four-week observation period described, the erectile dysfunction did not completely resolve. [11]
A single case report does not allow us to determine how often such an event occurs.
It also does not provide the same level of certainty as a controlled study regarding the causal relationship.
However, it constitutes a signal of a potentially serious clinical event and is important for safety assessment, especially since compounds acting in the melanocortin system can cause biological effects beyond pigmentation.
This leads to the more important principle: a severe or persistent reaction should not be interpreted as evidence that the product is „working”.
Clinically significant or persistent symptoms require appropriate medical evaluation.
Changes in the characteristics and reports of blackleg require careful interpretation
Reports concerning melanoma require particularly precise language, because both excessive conclusions and unfounded reassurances can distort the state of the evidence.
In one published case, skin melanoma was described following exposure to melanotan II combined with the use of a solarium.[12]
Another case report concerned oral mucosal melanoma in a person who had previously used a topical spray containing melanotan II.[13]
These reports constitute safety signals.
They do not prove that melanotan II caused these tumors.
Case reports generally do not allow determining the frequency of the event or determining to what extent a given exposure increased the risk, if any.
In the case of skin melanoma, the use of a solarium is a particularly important factor that interferes with the disease, as exposure to ultraviolet radiation independently contributes to skin damage and the risk of melanoma.
The unknown composition of the product, other exposures, individual susceptibility, and the lack of controlled comparison further limit the ability to attribute a causal relationship.
However, these limitations should not be ignored and used as evidence of proven safety.
The correct conclusion is that these reports raise legitimate questions that require careful interpretation, but the causal relationship remains undetermined.
The available evidence therefore does not justify either a categorical statement that „melanotan II causes melanoma” or a categorical assurance that „melanotan II cannot affect the risk of melanoma”.
New or changing pigmented lesions require appropriate clinical evaluation.
Their significance cannot be reliably determined based on a photo on the Internet, the seller's assurances, or the assumption that pigmentary changes are the expected effect of the peptide's action.
Pigmentation does not eliminate the risk associated with UV radiation
The FDA describes ultraviolet radiation tanning as a biological response associated with skin damage and points out significant risks, including premature skin aging and skin cancer.[14]
This statement specifically applies to exposure to UV radiation.
It should not be taken to mean that pharmacological pigmentation occurs in exactly the same way as sunburn caused by UV radiation.
The scientific conclusion should be more precise.
A darker skin complexion does not mean that subsequent exposure to UV radiation has become harmless.
Pigmentation itself does not confirm the prevention of sunburn, DNA damage, photoaging, or skin cancer.
Each of these claims would require appropriate evidence.
Therefore, it should not be assumed that a product that causes tanning works as a sunscreen just because the skin becomes darker.
Pregnancy, children, interactions and repeated exposure are separate issues.
The study conducted on a small group of adults cannot confirm safety during pregnancy, breastfeeding, childhood, or adolescence.
It also does not allow to determine all possible interactions with other medications or coexisting diseases.
The official information on Scenesse describes the restrictions and conditions regarding specific populations and interactions in the context of the approved medicinal product. [5]
These limitations cannot be removed by labeling another product as „natural,” „bioidentical,” „research grade,” or „needle-free.”.
Changing the administration form also does not automatically resolve questions regarding general systemic safety.
An assessment of long-term safety requires a sufficiently long period of research and observation.
The apparent change in pigmentation that occurs in a relatively short time provides little information about the consequences of repeated or prolonged exposure.
The reviewed evidence does not establish a general protocol for cosmetic tanning, an optimal application regimen, a universally safe route of administration, or a safe source of online products.
The most common questions about tanning peptides
Does tanning mean protection against sun damage?
No. A darker skin appearance does not confirm protection against sun damage, because pigmentation, sunburn, DNA damage caused by UV radiation, photoaging, and skin cancer are separate biological and clinical processes. The FDA points out the significant risks associated with sun exposure under UV radiation.[14] Therefore, apparent tanning should not be interpreted as confirmation of sun protection or as evidence that continued exposure to ultraviolet radiation has become harmless.
Does the change in pigmentation confirm the safety of the product?
No. A measurable change in pigmentation confirms the biological effect on appearance under specific study conditions, but does not constitute a complete assessment of safety. In early studies of melanotan, pigmentation was observed along with adverse effects. [1] [2] Small studies do not allow reliably detecting rare or delayed adverse effects, and photographs provide even less information about safety.
What is melanotan II?
Melanotan II is a synthetic, cyclic analog of the hormone alpha-melanotropin. Early Phase I studies in humans showed an effect on pigmentation, while overall systemic effects were also noted. [1] The study constituted an early biological observation and not a confirmation of the overall safety of cosmetic use. The molecule’s very name does not also confirm the authenticity of the product offered by the online retailer.
Are melanotan I and melanotan II the same substance?
No. These are different peptide analogs with different structures and research histories. Melanotan I is a historical term associated with afamelanotide, while melanotan II is a different, cyclic analog. Early studies evaluated these compounds separately.[1][2] Similarity in names does not justify transferring efficacy, adverse reaction, formulation, or clinical conclusions from one molecule to the other.
Are there approved peptide drugs related to this mechanism?
Yes. Scenesse, an implant containing afamelanotide, has an approval for a specific medical use in the EPP. [4] [5] [8] This does not mean approval for non-related tanning sprays, online vials, preparations containing melanotan II, or general cosmetic use. Any claim regarding approval should indicate the exact product, formulation, indication, and jurisdiction.
Does the study of afamelanthate confirm the effect of the online aerosol on tanning?
No. Controlled studies of the afamelanotide implant in people with EPP provide evidence regarding a specific intervention and the population studied. [3] The separately sold nasal spray differs in formulation, route of administration, intended use, production context, and potentially even verified chemical identity. The evidence cannot be transferred simply because similar molecular terminology appears in both products.
Are the sunscreen peptides that are reported to be safer than the injections automatically safer?
No. The absence of a needle eliminates some of the risks associated with a particular route of administration, but does not confirm the safety of the active substance, the formulation, the amount absorbed into the body, possible impurities, or repeated systemic exposure. The reported administration is associated with its own pharmacological and formulation questions. The published case of melanoma following the use of a reported melanotan II is an inconclusive safety signal rather than evidence of a causal relationship. [13]
Do tanning peptides work the same way as sunscreens with DHA?
No. Self-tanners containing DHA cause superficial discoloration as a result of chemical reactions occurring in the outer layers of the skin, whereas peptide analogues of melanocortin affect biological signaling pathways. The FDA is discussing self-tanners containing DHA and bronzers as a separate category.[6] The common cosmetic goal does not mean equivalence in chemistry, systemic exposure, regulatory status, or safety evidence.
Do the „before and after” photos confirm the effect of the peptide on tanning?
The photographs themselves do not allow a reliable determination of the causal relationship. Lighting, camera exposure, photo processing, background, UV radiation, and the simultaneous use of other products can affect the appearance of the skin. In early human studies, controlled conditions and objective methods of measuring pigmentation, such as reflectance photometry, were used.[2] Even objectively confirmed pigmentation only answers the question of this particular effect, not the long-term safety.
Has melanotan II been proven to be the cause of melanoma?
No. The case reports included in the evidence reviewed do not show that melanotan II causes melanoma. They describe tumors occurring after exposure, in some cases along with other relevant factors such as sunbed use. [12] [13] The case reports do not allow the calculation of incidence rates or prove a causal relationship. However, they constitute safety signals that should not be ignored. The available evidence therefore indicates an unresolved safety issue, not a proven causal relationship or proven absence of risk.
Can the effects of peptides on tanning go beyond skin pigmentation?
Yes. In early studies of melanotan II, systemic symptoms were reported in addition to pigment changes, and in a later case report, severe priapism was described following exposure to melanotan.[1][11] These are different types of evidence and do not allow for determining the frequency of such events in the population. However, they do show why a visible skin color cannot be considered a complete picture of the biological action or safety of the melanocortin analog.
Does the absence of sunburn mean that there is no damage caused by UV radiation?
No. The absence of visible burns does not confirm the absence of biological damage related to ultraviolet radiation. Redness is only one of the possible reactions. Photoaging, DNA damage, and the risk of cancer involve additional biological processes and a much longer period. Therefore, the absence of immediate redness is not sufficient evidence that the exposure was harmless. [14]
Does the similarity to a natural hormone mean that the tanning peptide is safe?
No. Structural or functional similarity to a naturally occurring hormone does not confirm safety. Synthetic analogs may differ in receptor activity, sometimes action, exposure, formulation, and pharmacological behavior. Molecular studies of MC1R show specific ligand-receptor interactions, not a universal safety property. [7]
Does the report on laboratory purity confirm the product's usefulness for humans?
No. The laboratory report describes specific analytical tests performed on the identified material. Pharmaceutical quality systems encompass a much broader range of controls, and the result regarding chemical purity does not independently confirm sterility, appropriate formulation, regulatory status, clinical safety, or suitability for human use. [15]
Has the safety during pregnancy or breastfeeding been established?
Based on the evidence reviewed, no general conclusion can be drawn regarding safety during pregnancy or breastfeeding. Even information regarding approved afamelanotide contains limitations and issues related to specific populations. [5] Small studies conducted in adult volunteers do not allow a determination of the risk regarding pregnancy, the fetus, the newborn, or breastfeeding.
Does the availability of tanning peptide online mean that it is approved in that country?
No. The presence of an online offer confirms the availability of the site, not the regulatory approval of the product. The warning from the Australian TGA shows that products containing melanotan can be promoted despite the lack of approval as sun tanning agents in this jurisdiction.[9] Regulations vary from country to country, so the status of a specific product and its intended use should be checked in official sources specific to the jurisdiction in question.
Limitations of evidence regarding peptides for tanning
The first significant limitation is terminology. „Sun tanning peptide” does not mean a specific scientific substance. Afamelanotide, the historical terminology for melanotan I, melanotan II, experimental melanocortin ligands, and unverified commercial preparations should not be considered equivalent products.
The second limitation is the very small number of early studies of human pigmentation. The early studies of melanotan I and melanotan II included only three men.[1][2] Such studies can reveal an early pharmacological signal, but do not allow the characterization of rare adverse effects, long-term exposure, diverse populations, or contemporary commercial products.
The third limitation concerns the transfer of evidence between indications. Afamelanotide has significantly stronger clinical evidence regarding EPP, including data from randomized controlled trials. [3] This evidence supports conclusions regarding a specific medical intervention for individuals with a specific hypersensitivity disorder to light. It does not automatically confirm the overall safety of cosmetic sun tanning.
The fourth limitation concerns product verification. Published studies of authentic compounds cannot confirm the identity of material sold online independently. Analysis of selected products containing melanotan II showed differences between the declared and measured quantities and unidentified impurities in some samples.[10] The identity and composition of a specific product are therefore a separate evidentiary issue.
The fifth limitation is the route of administration. Oral, injectable, implantable, transdermal and local routes cannot be considered equivalent. The early melanotan I study alone showed differences in measurable exposure between the administered routes. [2]
The sixth limitation is long-term safety. Short-term observations of pigmentation or tolerance do not allow determining the consequences of repeated exposure lasting months or years.
The seventh limitation concerns evidence related to cancers. Published cases of melanoma following exposure to melanotan II constitute clinically relevant safety signals, but do not demonstrate a causal relationship or specify the frequency of occurrence. [12] [13] Factors such as sunbed use and uncertainties regarding the composition of commercial products further complicate interpretation.
The eighth restriction is the transfer of regulatory status. The approval of Scenesse for use in the EPP does not mean the approval of melanotan II or related cosmetic products. [4] [5] Regulatory applications cannot also be automatically transferred between countries.
Finally, visible pigmentation is only one endpoint. The product may cause a noticeable change in skin appearance without confirmation of ultraviolet radiation protection, long-term dermatological safety, absence of systemic effects, or a reduction in the risk of skin cancer.
Summary
Studies on sun-related peptides show that some synthetic analogs of melanocortins can affect human skin pigmentation. Early studies involving melanotan I and melanotan II showed measurable pigmentary effects under controlled experimental conditions.[1][2]
This biological effect is real.
However, his interpretation should remain precise and limited to what the studies actually showed.
Melanotan I, afamelanotide and melanotan II are not products whose names can be used interchangeably.
Afamelanotide was developed as the approved medicinal product Scenesse for a specific medical use related to erythropoietic protoporphyria.[3][4][5] This approval does not mean approval of melanotan II, online tanning sprays, unverified vials, or the general cosmetic use of these substances.
Studies also show why pigmentation should not be considered the only significant biological effect. In early studies of melanotan II, systemic effects were noted alongside pigment changes [1], and later literature describes potentially serious clinical events following exposure to melanotan. [11]
Reports of melanoma following exposure to melanotan II require particularly cautious interpretation. [12] [13] They constitute safety signals, but cannot independently confirm a causal relationship or determine the additional risk of developing cancer. Therefore, a scientifically justified position does not consist either in a categorical attribution of causality or in a categorical assurance of safety.
The quality of the products introduces another independent source of uncertainty. Analysis of selected products containing melanotan II purchased online revealed differences between the declared and measured quantities and unidentified impurities in some samples. [10] Therefore, evidence regarding a scientifically characterized molecule cannot confirm the authenticity of a separately purchased commercial product.
Pigmentation should not be confused with confirmed protection against ultraviolet radiation.
The darker appearance of the skin does not independently confirm sun protection, DNA damage prevention, or protection against skin cancer. Even the official information regarding the approved product containing afamelanotide maintains the recommendations for sun protection and skin monitoring.[5]
The available evidence therefore requires a clear separation between proven pigment biology, medical evidence regarding specific diseases, unapproved cosmetic claims, product quality issues, and still unresolved questions regarding long-term safety.
These categories should always remain separate when discussing tanning peptides.
Disclaimer
This article is for educational and scientific information purposes only. It does not constitute medical or dermatological advice, purchase instructions, dosage or administration information, nor recommendations for obtaining or using melanotan I, melanotan II, afamelanotide, tanning injections, tanning aerosol sprays, or any other peptide product.
The discussion of published studies regarding pigmentation does not confirm the safety or usefulness of the self-administration of these substances for cosmetic purposes. The references to Scenesse relate to a specific, approved medicinal product containing afamelanotide and its specific medical indication, and should not be interpreted as an approval of other products.
In the event of a severe or persistent reaction after exposure to an unapproved product, appropriate medical evaluation is necessary. New or changing pigmentary signs also require professional evaluation, rather than diagnosis based on photographs or information found online.
References
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