Joy Kong, MDRegenerative Medicine Physician, Educator, and Entrepreneur

Why Your Stem Cells Decline With Age

11 Mar 2026 · 1 min

Watch on YouTube

0:55

In this brief explanatory video, Dr. Joy Kong outlines how stem cell numbers dramatically decrease throughout life—by the teenage years they are only one‑tenth of newborn levels, by the 40s they are a quarter of teenage levels, and by the 80s they are one‑fifth of the 40‑year‑old levels. She links this decline to visible aging signs such as skin wrinkling and reduced tissue repair capacity. Dr. Kong then describes how stem cells can be harvested from bone marrow or adipose tissue and re‑infused systemically, potentially improving conditions like brain disorders or muscle tears. She discusses two possible fates for transplanted cells: immune rejection leading to cell death, or successful adaptation/integration into the host, even noting the theoretical possibility of cross‑species integration. The overall tone is conversational and cautiously optimistic about stem‑cell‑based rejuvenation therapies.

Chapters

When you are a teenager, the number of stem cells in your body is only 1/10 of what you had when you were born. And when you are in your 40s, it's 1/4 of what you had when you were a teenager. And when you are in your 80s, it's 1/5 of what you had when you were in your 40s. This is why our skin is wrinkling when you're older. It's because your body doesn't have enough of what it takes. The stem cells are not quite there. A lot of people can get stem cells from the bone marrow or fat and put them back into the body in the systemic circulation and And all of a sudden, certain conditions will get better. Let's say they have a brain condition, they can get better. They have a muscle tear that can get better. Either they can be attacked by the recipient's immune system and they could be killed. You don't have to worry about anymore. Or another fate is that it adapts to the body. Even between human and animals, there's a chance of integration. So you can imagine between human and human, there's definitely a chance of integration.