Human life starts from one single stem cell in a fertilized egg. Stem cell is unique in that it has the capability of both proliferating itself and differentiating to a new and different cell type. There is much research ongoing to take advantage of the unique characteristics of stem cell in the field of medicine. Regenerative medicine is a new approach to the treatment of degenerative diseases, hardly curable by currently available medications, by the power of stem cell.

There are sub-categories of stem cells, including embryonic-, adult-, and induced pluripotent stem cell.  Adult- or mesenchymal stem cell (MSC) is of special interest in regenerative medicine as 1) it can be obtained without ethical issue (as opposed to embryonic stem cell) and 2) the safety is confirmed in many non-clinical and clinical studies (as opposed to induced pluripotent stem cell). All seven stem cell drugs approved so far in the world are based on MSC. MSC secrets a variety of cell to cell signaling molecules, in the process of proliferation and differentiation, which include growth factors, cytokines and chemokines. Physiological functions of such molecules play a key role in the therapeutic efficacy of stem cell drugs. A collection of such molecules secreted by stem cell is called ‘Stem Cell Conditioned Media’, and the physiological functions of the stem cell conditioned media are collectively called ‘Paracrine Effect’. The paracrine effect includes activation of indigenous stem cells which is noteworthy especially in the application of the stem cell conditioned media to skincare.


Skin is one of the typical organs in human body where its functions and structures change significantly in the process of aging. Skin aging comes with change in look and feel of skin including wrinkle, loss in elasticity and dark spot. It has been known that stem cells are present in the skin, both in the epidermal and dermal layers of the skin. The skin stem cell governs metabolism of skin and thus is responsible for homeostasis of skin. Studies have shown that the number and activities of the skin stem cell diminishes rapidly after age of 30, and such decrease of skin stem cell is proposed to be one of the root causes of the skin aging.

Professor Keiko Uyama at Tokyo Dental University suggested that stem cell conditioned media containing a variety of growth factors and cytokines is one of the best candidates as a cosmetic ingredient for reversing or at least delaying the skin aging at the cellular level. She proposed “Regenerative Skincare” as a next generation of cosmetics in her book titled “Beauty in the Cell (細胞美人)”.

Caution should be taken though in the choice of a stem cell conditioned media as an active ingredient in cosmetic products. It should be noted, for example, whether the stem cell used for the preparation of conditioned media is of human origin, whether the eligibility of stem cell donor in term of age or health status is carefully checked up, and whether the content of stem cell conditioned media in the product is enough, as they are all important in terms of safety and efficacy on the skin .


 Stem cell is a ‘super cell’ which has a capacity to proliferate and differentiate in to different cell type in our body.
 Skin stem cell exists in our skin and plays an important role against skin aging.
 Symptoms that come with skin aging including wrinkle, lack of elasticity, pigmentation and dark spot may be the result of a rapid loss of skin stem cells after age about 30.
 Skincare at the cellular level is needed as an ultimate solution for skin aging.
 Stem cell conditioned media containing various growth factors and cytokines is gaining attention as a next generation cosmetic ingredient against skin aging.
 All stem cell conditioned media are not same, and care should be taken in terms of its origin, donor eligibility and content in selection of the conditioned media for maximum efficacy and safety.