What are exosomes and polynucleotides?
Although these two names are often mentioned together, they are different groups of products. Both are the newest members, with the most limited evidence, of the broad family described in our guide “Skin Booster Injections”.
- Polynucleotides: these are produced by purifying and fragmenting DNA obtained from the reproductive cells of fish such as salmon or trout. This is why they are popularly called 'salmon DNA' or, in Turkey, the 'salmon vaccine' (somon aşısı). Closely related products called polydeoxyribonucleotides come from the same source. They are given by injection into the skin.
- Exosomes: these are very small vesicles that cells release when communicating with one another, carrying proteins and genetic signalling molecules. The source of the products offered in aesthetics is highly variable: human stem cell cultures, umbilical cord tissue, blood products and even plants may be cited as the source. Some are offered for application to the skin, others for injection.
In both groups the word 'vaccine' is misleading: these products are not vaccines that provide immunity. It is worth knowing that, because the names are similar, products containing plant extracts, vitamin mixtures or other ingredients may also be offered under the same names.
How are they promoted, and what does the evidence show?
These products are often presented with expressions such as 'cell renewal', 'rejuvenation' and 'regenerative medicine'. The findings from laboratory and animal studies are indeed interesting, and research is continuing. However, an effect in the laboratory does not show that a meaningful and safe result is achieved in human skin. To see the gap, it is useful to take the claims one by one.
| Commonly heard claim | Current state of the evidence |
|---|---|
| It renews the skin and reduces wrinkles | Short-term improvement has been reported in some small studies; large, long-term and independent studies are lacking |
| It is scientifically proven | The quality of the existing studies has been rated in reviews as low to moderate |
| It is approved and safe | There is no FDA-approved exosome product in the USA; licensing status varies with the country and the product and should be asked about case by case |
| Because it is natural it has no side effects | Every injection carries a risk of infection, allergy and tissue reaction; long-term safety data are limited |
| It is superior to other methods | There are next to no strong studies comparing it directly with established methods |
The state of the evidence for exosome products
An overview published in 2025, which examined 17 systematic reviews on the subject together, draws attention to a widespread methodological problem in exosome studies: the description of the product's source and of the active components in it falls short of international scientific criteria. The authors conclude that, despite the optimism about treatment, the field first needs to achieve consistency of method and comply with regulatory rules.
A systematic review published in 2026, which searched only for human studies, found 19 studies; most of them were not randomised. The studies reported short-term improvement in measures such as hydration, elasticity, wrinkles, pores and uneven tone, but the authors stressed that the studies differed greatly from one another and that the follow-up periods were inadequate. According to the same review, the safety data mostly relate to products applied to the skin; there are individual reports of risks associated with off-label use by injection.
The basic problem here is this: two products offered under the name 'exosome' may be completely different from each other. The source, the production method, the quantity of vesicles they contain and the purity are not standardised. For this reason the result of a study carried out on one product cannot be transferred to another product.
The state of the evidence for polynucleotides (salmon DNA)
The number of clinical studies on polynucleotides is somewhat greater than for exosomes, but the picture is still limited. A 2025 systematic review examining aesthetic use found only nine studies and a total of 219 patients, and rated the quality of the studies as low to moderate. The studies reported improvement in wrinkles, skin texture and elasticity, and mild, temporary side effects. The authors' conclusion, however, is cautious: there is limited consensus on optimal use, and rigorous, high-quality studies are needed to confirm efficacy and safety.
Another review from 2026, which searched only for randomised trials, was able to find seven trials and a total of 183 participants across all of the areas of skin rejuvenation, scars and wound healing; four of these concern skin rejuvenation. The most consistent findings are not in aesthetics but in wound healing. The authors state that the evidence is limited by small samples, differing protocols and variable outcome measures.
When reading the studies, conflicts of interest also need to be looked at. For example, two of the authors of the 2025 review openly declared a relationship with a manufacturer or distributor of polynucleotides. This does not invalidate the findings; however, it is a reminder that with new products a significant proportion of the studies may be linked to the manufacturer, and of the value of independent confirmation.
Licensing status: what does the FDA say?
On 6 December 2019 the US Food and Drug Administration (FDA) issued a public safety notification about exosome products. The notification states that multiple serious adverse events had been reported in patients in the state of Nebraska who were treated with unapproved products said to contain exosomes, and that at that date there were no exosome products approved by the FDA. The FDA also stresses that exosomes used to treat diseases and health conditions are regulated as drugs and biological products, which means that they require review and approval before being marketed.
The consumer alert that the FDA published in 2020 and kept current in 2024 repeats the same information: there is no approved exosome product, and a great deal of misleading information is circulating on the internet about the conditions for which these products may be used. The FDA advises people considering an exosome product to ask whether the treatment has been reviewed by the agency and, if they are going to have a procedure in another country, to learn about that country's rules.
This information relates to the USA. In other countries, the category in which products are placed on the market (medicine, medical device, cosmetic) and the conditions attached differ; some polynucleotide products are sold as medical devices in certain countries. You need to find out the position in the country where you live not from general information but in relation to the specific product that will be used on you. The way to do this is to ask your physician for the product's licence or registration document.
Is applying it to the skin the same as injecting it?
No; this distinction matters in terms of both risk and oversight. Some of the products said to contain exosomes are sold as cosmetic products, that is, for application to the skin. According to the FDA's statement, cosmetic products and their ingredients (other than colour additives) do not need the agency's approval before they are marketed in the USA. So the fact that a cosmetic product is on sale does not show that its effect or its contents have been approved by an authority.
Delivering into the skin with a needle a product that was made to be applied to the skin is a completely different matter: the product may not have been tested for sterility and safety for this purpose. Products applied immediately after procedures that open the skin barrier, such as laser or “Microneedling”, also pass through the skin more than usual; for this reason this use is not regarded as the same as applying an ordinary cream either. It is reasonable to ask for which route of use the product that will be used on you has been licensed.
What is known about long-term safety?
Very little. The existing studies have mostly followed people for between weeks and a few months. There are no reliable data on the effect of repeated treatments over years, on delayed immune reactions or on the frequency of late problems such as nodules. With biological products of human or animal origin there is, in addition, a theoretical possibility of carrying an infectious agent and of provoking an immune response; how small this possibility is depends on the quality of production and oversight. The fact that much is unknown does not mean that there is harm; but nor does it mean that safety has been demonstrated.
With exosome and polynucleotide products, the studies are still few, small and short-term; what we know about long-term safety is limited. For anyone considering such a treatment, asking in writing about the product's licence, contents and source, and waiting if no answer is given, is a reasonable stance.
Dr. Hamza GemiciMedical Director, DoktorClub · Aesthetic Medicine Physician
What is the position for people with a fish allergy?
Because polynucleotides are obtained from fish, this question is asked often. In the reviews we examined, there are no systematic data showing that the risk is, or is not, increased in people with a fish allergy; the subject has not been studied enough. In fish allergy the reaction usually develops against proteins in the flesh of the fish, whereas the products contain purified DNA; however, whether purification provides sufficient assurance with regard to allergy may vary with the product. For this reason, if you have a fish or seafood allergy, be sure to tell your physician and go through the warnings in the product's instructions for use together. For the symptoms of allergic reactions, see our article “Allergic Reactions in Aesthetic Treatments”.
Who is it not suitable for, and what should you watch out for?
With a product for which the evidence is limited, the threshold for caution is kept low. In the following situations these treatments are generally postponed or not recommended:
- Pregnancy and breastfeeding (there are no safety data)
- Active infection, a cold sore, an acne flare or an open wound in the treatment area
- A history of allergy to the components of the product, to a local anaesthetic or to substances of fish origin
- Uncontrolled autoimmune disease or treatments that suppress the immune system
- People with a diagnosis of cancer or whose cancer treatment is continuing (there are no data for products that may affect cell proliferation; the decision should be made with the relevant physician)
- A bleeding disorder or use of blood-thinning medication (do not stop your medicine on your own)
- People under eighteen
- Any product whose licence, contents or source cannot be documented
Who should perform it, and where?
An injection is a medical procedure and should be carried out by a trained physician in a licensed healthcare facility. Products whose box has already been opened, whose label is in a foreign language with no translation, whose cold chain is uncertain or which were bought online should not be accepted. The risks of treatments offered at home, in beauty salons or through social media are explained in our articles “Counterfeit Products and Unlicensed Treatments” and “Needle-Free Filler Pens and At-Home Treatments”.
Before the procedure: what should you ask your physician?
- Licence: in which category (medicine, medical device, cosmetic) and for which route of use is this product registered in the country we are in? May I see the document?
- Contents: what exactly is in the product? Which substances does it contain other than exosomes or polynucleotides?
- Source: from which organism or cell was the product obtained? If it is of human origin, how have donor screening and infection testing been documented?
- Evidence: is there a clinical study carried out with this specific product in people similar to me? Who funded it?
- Route: was the product made for injection or for application to the skin? By which route will you use it?
- Record: will you give me the product's name, batch number and expiry date in writing?
If you cannot get clear, documented answers to these questions, postponing the procedure is a reasonable decision. A setting in which you are hurried is a warning sign in itself.
The day of the procedure, step by step
- The physician assesses your skin and discusses with you your expectations and the answers to the questions above; the consent form is read without hurry.
- The product box is opened in front of you; the name, batch number and expiry date are recorded in your file.
- The skin is cleaned and wiped with an antiseptic solution; a numbing cream is applied if needed.
- The product is given by the route for which it is licensed: with injectable products, into the skin with a fine needle as a large number of small points.
- At the end of the procedure you are given aftercare advice and details of how to reach the physician if there is a problem.
After the procedure: the first 24 hours, the first week, the first month
Follow-up is the same as for other injections into the skin. In the first hours, small bumps, redness and tenderness at the injection points are expected; these mostly subside within a few hours to a few days. Not pressing on the area, postponing make-up, intense exercise, saunas and Turkish baths for as long as the physician recommends, and protecting yourself from the sun are generally advised. For the general principles, see our article “Aftercare Following Medical Aesthetic Procedures”.
Because long-term data on these products are limited, it is important not to end follow-up with the first week. Report any firmness, swelling, redness or discolouration that appears weeks later to the physician who treated you, and keep the product information.
Expected side effects and warning signs
- Small bumps, redness and tenderness at the injection points
- Bruising and mild swelling
- Itching or a feeling of tightness
These symptoms usually decrease within a few days. Steadily increasing pain, redness, discharge or fever are outside the expected course; our article “Infection after Aesthetic Treatments” offers guidance on the signs of infection.
If you have shortness of breath, rapidly increasing swelling of the face and tongue or feel faint, call 112 (or your local emergency number) without waiting; for the other symptoms, contact the physician who treated you immediately
- Shortness of breath, widespread itching and hives, rapidly increasing swelling of the face, lips or tongue (allergic reaction)
- Redness, warmth or pain that increases over days, pus-like discharge, or fever and chills
- Sudden, severe pain during or immediately after the procedure; whitening of the skin or a purplish discolouration spreading like a net
- Problems with vision, facial drooping, impaired speech, or weakness in an arm or leg
- Firm areas that appear weeks later and are growing or painful
When is the result seen, and how long does it last?
There are not enough data to give a reliable answer to this question. The studies are short-term, and the products used and the session schedules differ from one another. The numbers of sessions and durations of effect mentioned in promotional material are mostly based on manufacturers' recommendations, not on independent long-term follow-up studies. If your physician states a duration, it is reasonable to ask which data it is based on.
Realistic expectations: what can and cannot be said today?
- Can be said: short-term improvement in the appearance of the skin has been reported in some small studies.
- Can be said: the side effects reported with polynucleotides have mostly been mild and temporary in the studies.
- Cannot be said: that these products are more effective than established methods.
- Cannot be said: how long the effect lasts and in whom it works.
- Cannot be said: that repeated treatments are safe over years.
- Cannot be said: that two products bearing the same name will give the same result.
Being new does not mean being more effective. If you are thinking of trying a product that is at the research stage, you need to make your decision knowing that it is not a treatment with strong evidence but one whose outcome is uncertain.
Alternatives with stronger evidence
| Option | What it does | Point to note |
|---|---|---|
| Sun protection and regular skin care | The basis for maintaining skin quality | The effect is slow; needs to be kept up |
| Prescription topical treatments | Evidence going back many years for fine lines and textural problems | On a physician's advice; may cause irritation |
| Hydrating injections containing hyaluronic acid | Moderate evidence for skin hydration and elasticity | Injection-related risks apply |
| Chemical peels, laser and device treatments | Established options for texture, pigmentation and fine lines | The risk varies with skin type |
| Mesotherapy and PRP | Used in some situations; the level of evidence varies with the method | Risks specific to injection and to the method apply |
| Having no procedure, or waiting | Not taking a risk until stronger evidence has accumulated | Always a valid option |
For details of the methods in the table, see our articles “Mesotherapy” and “PRP (Platelet-Rich Plasma)”.
This page is for general information and does not recommend any product. The approach that is right for you can only be determined by an examination and a physician's assessment.
Aftercare timeline
Treatment day
Do not press on or rub the area. Small bumps and redness are expected. If you have shortness of breath, rapidly increasing swelling of the face, sudden severe pain, whitening of the skin or problems with vision, get emergency help immediately. Keep a record of the product name and batch number.
Day 1
Wait for the period your physician recommends before make-up, intense exercise, saunas and Turkish baths. Protect yourself from the sun. The bumps have mostly reduced.
Day 3
Redness and bumps have usually subsided. If pain or redness is increasing, if the area is becoming warm, or if you have discharge or a fever, contact your physician.
Day 7
Bruises have mostly faded. If there is firmness that can be felt, new swelling or an itchy rash, tell your physician.
Day 14
Keep watching your skin. If late redness, firmness or discolouration appears, show it to your physician without waiting.
Day 30
Before a new session is planned, assess the result of the first treatment and any side effects with your physician. Report any firmness or swelling that appears weeks later.
Questions to ask your physician
- In which category and for which route of use is this product licensed or registered in the country we are in? May I see the document?
- What exactly is in the product, and from which source was it obtained?
- Is there a clinical study carried out with this specific product; in how many people, for how long and with whose funding?
- Was the product made for injection or for application to the skin?
- Is there an option with stronger evidence for what I am hoping for?
- Would my fish allergy or other allergies be a problem with this product?
- What are the unknowns about long-term safety?
- Will you give me the product's name, batch number and expiry date in writing?
- What approach would you take if late firmness or a late reaction appeared?
Frequently asked questions
Is 'salmon DNA' really obtained from salmon?
Polynucleotide products are produced by purifying DNA obtained from the reproductive cells of fish such as salmon or trout. The word 'vaccine' sometimes used for them, however, is misleading; these products are not vaccines that provide immunity.
Is exosome treatment approved?
In the USA, the FDA clearly states that there is no exosome product it has approved. In other countries the position varies with the category of the product and the route of use. For this reason, rather than a general answer, you need to ask your physician for the licence or registration document of the product that will be used on you.
Do exosomes or salmon DNA work?
Improvement in the appearance of the skin has been reported in some small, short-term studies. However, the studies are few, their quality has been rated in reviews as low to moderate, and the products differ from one another. The present position can be summarised as 'at the research stage, evidence limited'.
Is an exosome serum applied to the skin the same as an injection?
No. Cosmetic products applied to the skin and products that are injected are regulated under different rules, and their levels of risk are not the same. Injecting a product that was made to be applied to the skin is a form of use for which that product has not been tested.
Can I have polynucleotides if I have a fish allergy?
There are not enough studies on this; it is not known whether the risk is increased. If you have a fish or seafood allergy, be sure to tell your physician and assess the warnings in the product's instructions for use together.
Could it be harmful in the long term?
This is not known. The existing studies have mostly followed people for between weeks and a few months; there are no reliable data on the effect of repeated treatments over years.
How many sessions are needed, and how long does the effect last?
There is no reliable answer based on independent studies. The numbers of sessions and durations mentioned are mostly based on manufacturers' recommendations. If your physician suggests a plan, you can ask which data it is based on.
Does it make sense to wait?
Yes, it is a valid option. There are methods with stronger evidence, and research on these products is continuing. There is no medical reason that calls for haste.
Sources
- Public Safety Notification on Exosome Products — U.S. Food and Drug Administration (FDA), 2019
- Consumer Alert on Regenerative Medicine Products Including Stem Cells and Exosomes — U.S. Food and Drug Administration (FDA), 2020
- FDA Authority Over Cosmetics: How Cosmetics Are Not FDA-Approved, but Are FDA-Regulated — U.S. Food and Drug Administration (FDA), 2025
- Exosomes Exposed: Overview Systematic Review on Evidence Versus Expectation in Aesthetic and Regenerative Medicine (Rahman E et al.). Aesthetic Plast Surg 49(2):557–568 — Aesthetic Plastic Surgery, 2025
- Efficacy of Exosome-Based Therapies for Skin Rejuvenation: A Systematic Review of Human Studies (Flores Rodríguez JC et al.). Cureus 18(2):e104182 — Cureus, 2026
- The Effectiveness of Polynucleotides in Esthetic Medicine: A Systematic Review (Lampridou S et al.). J Cosmet Dermatol 24(2):e16721 — Journal of Cosmetic Dermatology, 2025
- Polynucleotides and Polydeoxyribonucleotides for Skin Rejuvenation, Postoperative Scar Prevention, and Wound Healing: A Systematic Review of Randomized Clinical Trials (Alhussain AM et al.). Cureus 18(7):e112403 — Cureus, 2026
Medical Aesthetics Expert Board
This article has been reviewed by the DoktorClub Medical Aesthetics Expert Board.
