Rejuran vs. Exosome Injections: Why the Evidence Isn’t Equal

Rejuran’s active ingredient, purified polynucleotide, is an injectable that went through a Phase III trial before reaching the Korean market, while exosome products are sold only as topical cosmetics and injecting them under the skin falls outside that approval. Deciding which to try first comes down to which one has actually been checked in a clinical trial. If you are choosing a first skin-booster session toward smoother, more hydrated-looking skin, start with the option that has trial data and a market authorization behind it.

The short answer is that Rejuran and exosome injections do not have comparable amounts of evidence backing them. One has a randomized clinical trial published in a peer-reviewed journal. The other has case reports of severe adverse reactions appearing in the literature, with the injectable form still lacking approval anywhere. Knowing that difference before you book lets you weigh the result you can realistically expect against the risk you would be taking on.

Polynucleotide and Exosomes Work on the Skin in Different Ways

Polynucleotide is a purified, high-molecular-weight substance derived from salmon DNA. A clinical trial paper published by Chang Sik Pak and colleagues in the Journal of Korean Medical Science in 2014 describes the substance as acting on fibroblast metabolic activity within the skin, increasing production of extracellular matrix components and fibrous material. The same paper states that the product is designed to be injected into the superficial dermis. The pathway is straightforward: the skin’s own density and elasticity improve, and fine lines and texture become less pronounced as a result. The injection target is quality improvement of the superficial dermal layer, not volume replacement.

Exosomes are nanosized vesicles that cells secrete. A paper by Kui Young Park, of the Department of Dermatology at Chung-Ang University College of Medicine, and colleagues, published in the Journal of Cosmetic Dermatology in 2025, summarizes exosomes as mediators of cell-to-cell signaling that can modulate immune response and support tissue repair, which is why they have drawn interest for skin regeneration and hair applications. The mechanism itself is an active research area. The problem is where the verification stands: how that mechanism performs when injected into human skin is still an early-stage question, not a settled one.

What patients describe as “glass skin” is really two things layered on top of each other: how well the dermis holds onto water, and how even the surface texture looks. Different treatments address these differently. That is why we don’t take “I want glass skin” at face value in a first consultation. We ask which specific thing bothers you in the mirror. Someone concerned about fine lines and thinning around the eyes and someone concerned about makeup sitting unevenly on rough texture are not answered by the same product.

The Evidence Ladder: One Side Has a Trial, the Other Does Not

Look closely at what backs Rejuran. The 2014 trial randomized 72 patients in a double-blind, split-face design. One side of the face received the purified polynucleotide product; the other received a non-cross-linked hyaluronic acid product as the comparator. Patients received three sessions two weeks apart and were followed for 12 weeks, with the same two investigators performing every injection and every evaluation. On the primary and secondary efficacy measures, there was no statistically significant difference between the two sides, and no unexpected adverse events occurred. The investigators concluded the product could be useful for wrinkle improvement.

What that data does and does not establish is worth being precise about. It passed a randomized, controlled design in humans. It showed no safety signal over 12 weeks. It performed comparably to an established comparator. It does not show that polynucleotide outperforms hyaluronic acid; the paper draws no such conclusion.

Exosomes sit on different footing. The 2025 paper from Kui Young Park’s team states that exosome products are approved and sold in most countries strictly as topical cosmetics, and that intradermal injection is unapproved and unregulated, including in Korea. The paper itself exists to report four cases of severe skin adverse reactions, including granulomas, that followed intradermal injection of unregulated exosome formulations. How common these reactions are relative to the total number of procedures performed is not something the current literature has tallied.

None of this means every exosome injection ends badly. It would overreach to say that. But the literature currently sitting on this topic leans toward adverse-event reporting rather than randomized efficacy data, and that imbalance is the reason we do not offer exosome injections as a first-line option for skin texture concerns.

Why Approval Status Changes the Conversation

Approval status decides what you can point to if something goes wrong.

The U.S. Food and Drug Administration maintains that no exosome product has been approved for therapeutic use by injection, intravenous administration, or implantation. In Korea, the Ministry of Food and Drug Safety revised its cosmetic labeling and advertising guidelines in January 2025 to restrict human-derived terms such as “exosome” in cosmetic marketing. The intent behind that change is to stop cosmetic advertising from reading like a medical claim.

An unapproved formulation shifts three burdens onto the patient. First, if a reaction happens, it is harder to pin down which substance caused it, since formulation and manufacturing details are not standardized across products. Second, there is no standardized way to confirm what is actually in a given product or at what concentration. Third, if you are visiting Korea for a short stay and a problem surfaces after you fly home, there is little documentation to hand to a doctor back home explaining what was actually injected.

That is why, during consent, we walk international patients through the approval status of the formulation itself, in plain terms. Our Gangnam location keeps Japanese-, Chinese-, and English-speaking staff on site so that explanation happens in the patient’s own language, in the room, before any decision is made. If a patient still wants an off-label option after hearing this, we make sure they understand exactly which parts fall inside approved use and which do not before proceeding.

The Option That Often Gets Left Out of This Comparison

Framing the question as “Rejuran or exosomes” quietly drops a third option that is actually indicated for the concern most people mean by “glass skin”: surface texture and hydration.

SKINVIVE by JUVÉDERM, a hyaluronic acid microdroplet injectable, is indicated specifically for skin smoothness. Allergan Aesthetics announced in May 2023 that the product received FDA clearance for cheek skin smoothness improvement in adults 21 and older. In the randomized, multicenter, evaluator-blinded trial cited in that announcement, the share of patients achieving at least a 1-point improvement on the Allergan Cheek Smoothness Scale was 58% (73 of 125) at one month and 56% (69 of 124) at six months. In patient-reported outcomes from the same trial, 72% of patients agreed their skin looked and felt moist at six months, compared with 24% at baseline.

That means a subjective goal like “glass skin” has actually been measured on a validated scale and cleared by a regulator, with six-month data published. When a patient asks how long results will last, this is the range I can answer with actual evidence behind it.

At our Gangnam clinic, the skin-booster options we work with are Rejuran, SKINVIVE, Juvelook Volume, and hyaluronic acid boosters. If the goal is dermal density and fine lines, we look first at the polynucleotide family. If the goal is surface texture and hydration, we look first at the hyaluronic acid microdroplet family. When both concerns are present, we split them across separate sessions rather than treating them as one problem.

Translating Maintenance and Session Counts Into a Travel Schedule

The maintenance windows below reflect each product’s published clinical observation period; individual results vary with skin condition and habits.

	Polynucleotide (Rejuran family)	HA microdroplet (SKINVIVE family)	Intradermal exosomes
Primary direction of effect	Dermal density, elasticity, fine lines	Surface texture, hydration	Under active research
Published randomized human trial	Yes (2014, JKMS, 72 patients, 12 weeks)	Yes (Allergan Aesthetics, 2023, 6-month data)	No efficacy trial; adverse-event case series instead
Approval status for injection	Reached market after Phase III trial	FDA-cleared for cheek skin smoothness	Not approved for injection in Korea or the U.S.
Published observation window	12 weeks (after 3 sessions, 2 weeks apart)	6 months (at optimal treatment)	Not applicable
What we check in consultation	History of salmon-derived allergy	Treatment area and target scale	Approval scope and adverse-event literature

Translated into a travel schedule, this looks like the following. The published polynucleotide protocol is three sessions, two weeks apart. A patient who flies in for two or three days and receives one session has completed the first session of that protocol, not the full course. We say this plainly before treatment: a single session is unlikely to reproduce the trial’s full result on its own. The HA microdroplet family is different in this respect, since six-month data exists after a single session, which lines up better with a short stay where one decision has to carry the visit.

Recovery belongs in the same planning window. Both families involve multiple needle passes into the dermis, so swelling and bruising at the injection sites are possible. The 2014 trial reported no unexpected adverse events; localized swelling and bruising within the expected range are handled separately in our aftercare guidance. If you have a flight or a photographed event scheduled the day after treatment, tell us before the session so we can adjust the treated area and volume accordingly.

How We Sequence Treatment for a Short Stay

Most patients at our Gangnam clinic are visiting Seoul specifically for treatment, arriving from abroad. Diagnosis, treatment, and recovery all have to fit inside a window of two to seven days.

When consultation and treatment are split between different people, patients often find themselves re-explaining their history on day two of the trip. On a short visit, that repetition costs real time the itinerary does not have.

The route through the building is also part of the plan. Our Gangnam location sits on the second and third floors of the UH FLAT SIGNATURE Gangnam hotel, so consultation, treatment, and recovery happen inside one building. UHC hotel guests can choose one complimentary benefit: a 30-minute oxygen chamber session or a vitamin IV drip. If both are used, the vitamin IV drip costs KRW 55,000. In the window right after treatment, when outdoor movement and sun exposure should be minimized, that distance shrinks to a few floors by elevator. Procedures are carried out in a private treatment room.

Our Seocho director, Dr. Kim Kyungsoo, holds medical licenses in both Korea and Japan. For patients arriving from Japan who want a credential they can verify through their own country’s licensing system, that is the relevant reference point. On my side, I completed graduate training at Seoul National University and trained at Seoul National University Hospital, and I currently work as Allergan faculty and as a Potenza and Ulthera Key Doctor.

When We Don’t Recommend a Skin Booster

Some patients come in asking for a booster when sagging is actually their main concern. Surface smoothness and the position of facial contours are problems in different layers, and a skin booster only reaches the first one. In these cases, we look at lifting treatments first and put the booster decision on hold.

Overlapping pigmentation is another common reason skin looks dull, and injections alone will not even out tone in that situation. Pigmentation has to be approached by layer and type, which is a separate sequencing question we cover in our companion guide on treating dullness and pigment in Gangnam.

A history of salmon-derived allergy rules out the polynucleotide family entirely. We check for this during consultation, and if it applies, we design around a different formulation from the start.

Readers who want the broader comparison across both product families can also read our guide on [how Rejuran and HA skin boosters actually differ](https://uhcell.com/en/rejuran-vs-ha-skin-boosters-what-actually-differs/).

FAQ

Can I get Rejuran and an exosome injection on the same day?

We don’t layer two formulations with different approval statuses into the same session. If a reaction occurs afterward, there would be no way to tell which one caused it. If you want to try both, we separate them into different visits and check how your skin responds after each one before deciding on the next step.

How many days after treatment can I wear makeup?

Since the treatment leaves fine needle marks at the injection sites, we ask patients to avoid makeup on the treated area on the day of the procedure. Gentle products are often fine starting the next day, but this depends on the area and the volume injected, so ask for guidance specific to your treatment before you leave the clinic.

What if my flight home is the day after treatment?

Tell us the timing in advance and we’ll adjust the treatment area and session accordingly. Cabin dryness and long periods of sitting are not favorable for swelling recovery, so narrowing the treated area to your highest-priority concern rather than the full face is usually the more realistic approach.

Do male patients get skin boosters too?

Yes. Skin thickness and sebum patterns differ in male patients, so we adjust injection depth and volume accordingly. Checking the approval status of the formulation is a step we apply the same way regardless of sex.

If one session isn’t enough, should I switch to a different treatment?

Before switching, we look at what was actually missing. If the protocol you tried is published as three sessions two weeks apart, judging the result after one session is premature. If the underlying concern was sagging or pigment rather than texture, changing the formulation is the right call. We reassess this at the next consultation with photos.

If you are weighing a first skin-booster session toward smoother, more hydrated skin, it helps to start by naming what your own skin is actually missing rather than which product to book. Diagnosis, planning, and treatment, with recovery built around your travel schedule, are part of what we walk through in consultation at UH CELL Clinic’s Gangnam location.