Stem cell therapy: Injecting cells or just their components? Evidence and considerations based on type

In cosmetic stem cell therapy, there are two approaches: one that injects cells themselves extracted from your own fat, and another that uses only the components secreted by cells[1][2]. The component-only method can more easily avoid challenges associated with cell therapy; however, research in humans is still limited, and standardization of production methods is incomplete[3][4]. Which approach suits you depends on the type of concern and the application method—topical or injection[3].

What characterizes the method of injecting cells themselves?

The cell injection method has reports of skin changes, but whether cells survive is a major challenge. When adipose-derived stem cells are injected into skin, increases in skin thickness, appearance, hydration, and the number of fine blood vessels have been reported[1].

When produced without in-clinic cultivation, the extracted material contains many types of cells mixed together in addition to stem cells[1]. In experiments with animals and other models, there are also reports that adipose-derived stem cells promoted tumor progression, and a cautious perspective exists[5].

How does conditioned medium differ from cells?

Conditioned medium differs in that it does not contain cells and uses only the components secreted by cells. Conditioned medium is the liquid remaining after stem cells have been cultured, and it contains various growth factors (substances that support cell function)[6].

The method using only components secreted by cells has attracted attention as a potentially safer alternative to using cells themselves[2]. However, much of the research involves test-tube and animal experiments, and results must be evaluated separately from human studies[2].

How much is known about exosomes?

Exosomes hold great promise, but research in humans is still in an early stage[4]. They are extremely small particles approximately 40–160 nm in size secreted by cells[7], and they are involved in information exchange between cells[4].

They are noted as having advantages including greater stability than cells, easier storage, and a lower likelihood of triggering immune responses[3]. On the other hand, quality variation depending on the source cells, extraction complexity, and long-term safety data remain unclear[4].

Reviews of research examining wound healing are at the animal experiment stage, and effectiveness is not yet confirmed[5].

Does safety differ depending on whether it is applied topically or by injection?

Yes, it does. Particular caution is needed when used by injection. There are reports indicating no safety concerns in evaluations when adipose-derived stem cell exosomes are applied topically[3].

In contrast, the injection method into the skin has been noted as lacking clinical approval[3]. There are also reports of skin necrosis (skin damage and darkening) occurring after lyophilized exosomes were injected into skin[3].

Efficacy varies greatly among individuals, and there is said to be insufficient long-term safety data[3]. Research is also being conducted on use for assisting recovery following procedures such as laser treatments[8].

Do regulations differ by country or system?

Human cell-derived components are regulated quite differently across countries. In Europe, the use of human cell or tissue-derived components in cosmetics is prohibited[9]. Many countries are reported to have strict restrictions or prohibitions on the use of human-derived exosomes for cosmetic purposes[9].

In Japan, treatment using processed cells (cellular processed products) falls under "regenerative medicine technologies"[10]. It is required to describe the cell collection and processing methods and to explain the intended use as specifically as possible[10].

Which is right for me? Guidelines for choosing

The guideline hinges on two things: what you introduce into your body and how it is used.

Injection targeting skin thickness and hydration: There are reports for the method using cells themselves, but cell survival is a challenge[1]

Do not want cells injected: Conditioned medium and exosomes are candidates, but human research is still limited[2][4]

Want to support recovery after treatment: The method of applying exosomes topically is being researched[3][8]

What should be confirmed during consultation?

Which type suits you cannot be decided without examining your skin condition and concerns first. Start by asking how this treatment is positioned relative to other treatments.

During consultation, confirm whether what is being introduced is cells or components, whether the source cells are your own, how the product was made, and whether it will be applied topically or by injection.