Exosome therapy

What exosomes are

An exosome is a tiny vesicle of cell membrane that a cell releases to the outside. It contains proteins, fats and small RNA fragments. The umbrella term is extracellular vesicles.

The appeal of the idea: stem cells probably do not work by turning into new tissue, but by releasing signals. Then you do not need the cell, only its mail — no living material, storable in the refrigerator. That is why clinics call it a stem cell alternative.

Why the field is so confusing

The relevant professional society published guidelines in 2018 and again in 2023 on what must at least be measured before one may speak of exosomes. The reason: all sorts of things float in a sample of cell culture supernatant — vesicles of different sizes, protein clumps, fat particles, cell debris.

The guideline states verbatim that claims about special and specific effects of exosomes are experimentally difficult to support as long as the preparation is not properly characterized. In addition: the culture conditions alone change the composition, and even vesicles from the same cell type differ from batch to batch. No product is like another, and often it is not even known what exactly it contains.

What is actually sold

In Germany and Austria, the application usually takes the form of a serum after microneedling, for 400 to 800 euros per session with 3 to 5 sessions, so roughly 1,200 to 4,000 euros. What goes on the skin often comes from plant cells, such as rose stem cells, or from culture supernatant, and is legally classed as a cosmetic.

Internationally, infusions are also given. In Dubai, a dose for the vein costs the equivalent of a little over 200 euros, advertised for everything from nerve function to diabetes. A clinic in Mexico charges 3,950 dollars for an infusion with supposedly 100 billion exosomes, advertised against osteoarthritis, autoimmune diseases, stroke, kidney failure and aging. This figure says nothing about origin, purity or effect.

What the studies show

Mouse study 2022 — and what was left after 60 days

The effects on strength, coordination and frailty were clear on day 30. On day 60 no difference was measurable any more; the authors themselves write that the effect was transient. Two injections, about one month of effect — that is the state of the best animal work.

Hair loss — 9 studies, 125 patients worldwide

A 2025 review compiled what has been published on exosomes for hair loss: 9 clinical studies with a total of 125 treated patients. A Korean study with 30 participants over 24 weeks found greater hair density, but without a control group. An American study, also with 30 participants, reported an investigator-rated improvement in hair quality in 97 percent after microneedling with exosome serum — again without a control group and with the manufacturer’s product.

Why microneedling makes the studies unusable

Microneedling alone has randomized data for hair loss and works. If a serum is additionally applied without a control group, the study cannot show what the serum contributes. That is how most exosome studies in aesthetics are designed.

The 2020 infusion study — 24 patients, no comparison arm

The best-known infusion study dates from the early COVID phase: 24 patients with a severe course, a single infusion of 15 milliliters, open-label and not randomized. 83 percent survived. Without a comparison arm, this figure cannot be assessed; the first author belongs to a private infusion clinic. In the same year, the professional societies for vesicles and for cell therapy declared that they did not support the use of exosomes in COVID for any purpose as long as manufacturing, quality control and study design were lacking.

Where the data stop

For systemic use against aging there is nothing in humans. The only systemic test so far has been an infusion of vesicles from bone marrow stem cells in severe COVID lung failure: the placebo-controlled phase 2 trial with 102 patients missed its primary endpoint, and only a post hoc subgroup fared better; a phase 3 trial is expected to run until the end of 2027. No controlled study has measured whether exosomes change frailty or aging markers in humans. The mouse data cannot be transferred, especially since the effect there had disappeared after 60 days.

For skin and hair, too, the finding remains weak: small numbers of cases, almost all without a control group, often with the respective manufacturer’s product and with ratings by the investigators instead of hard measures. On top of that comes the fundamental question the guidelines raise: without proper characterization of the preparation, nobody knows what was actually administered — neither the customer nor the doctor who hangs up the bottle. For joints and for the advertised internal applications, controlled human data are completely lacking.

Status, approval and legal

No exosome product is approved, neither in the US nor in the EU. The US agency states this explicitly and had sent 6 warning letters to manufacturers by October 2023. Anyone who injects or infuses exosomes in order to treat with them is handling a biological medicinal product that would require approval. In Germany, the Paul-Ehrlich-Institut warns in general about commercial offers of unapproved novel therapies: they are not subject to any binding control of quality and composition. Application in the beauty salon is the gray area: as a cosmetic, a product may care but not heal — injected or infused, it becomes an unapproved medicinal product.

Safety

The greatest risk lies not in the mechanism but in manufacturing. In December 2019, fewer than 5 patients in Nebraska fell ill after an unapproved exosome product made from placental tissue; Escherichia coli, Enterobacter cloacae and mixed infections were found in their blood. The health department then warned all physicians in the state, and the drug agency followed suit. In 2023, a warning letter went to a manufacturer in Florida: over 37,000 vials, aseptic processes not validated, shelf life not demonstrated. The review on hair loss counts at least 10 serious adverse events in dermatology. A Korean case series described in 2025 persistent inflammatory nodules and permanent scars in 4 women after injections of unapproved exosome preparations outside a medical practice. A cell culture product without binding quality control that runs into the vein is a risk in itself. This is not medical advice: what is injected or infused is an unapproved medicinal product and belongs, if anywhere, in a study.

Sources

• Théry et al., J Extracell Vesicles 2018 (MISEV2018)
• Welsh et al., J Extracell Vesicles 2024 (MISEV2023)
• Sanz-Ros et al., Sci Adv 2022
• Queen and Avram, Dermatol Surg 2025
• Sengupta et al., Stem Cells Dev 2020
• Börger et al., Cytotherapy 2020 (ISEV/ISCT)
• Wang et al., Clin Transl Sci 2024
• FDA, Public Safety Notification on Exosome Products 2019
• Park et al., J Cosmet Dermatol 2023 (randomized split-face study)
• Tang et al., Int J Nanomedicine 2026 (review, including Luna-Garza 2026)
• Stack et al., Aesthet Surg J 2026 (meta-analysis, 39 studies)
• Lightner et al., Chest 2023 (phase 2, infusion in COVID ARDS)
• Park et al., J Cosmet Dermatol 2025 (case series after injections)