The true cause of hair loss: The relationship between DHT, stem cells and progenitor cells

A lot of people have emailed us and are asking this simple question: We thought DHT is the primary cause of male and female pattern hair loss. But now all these scientists are saying something about how progenitor cells or malfunctioning stem cells cause baldness. Which is it… DHT or stem cells?

Well, that’s a doozy of a question, so let me try to answer it as best I can.

It’s true, the dominant theory for what causes male and female pattern baldness is a genetic hypersensitivity (like an allergy) to dihydrotestosterone (DHT), a derivative from the male sex hormone testosterone.

Make no mistake: DHT is potent stuff. It causes hair follicles to shrivel up and stop producing new hair. It’s also the hormone that causes benign prostatic hyperplasia, or BPH, also known as an enlarged prostate.

Your body converts testosterone into DHT by means of an enzyme, 5-Alpha-reductase, which comes in two forms.

So, we have three elements in this equation: the male sex hormone testosterone… the enzyme 5-Alpha-reductase… and the product of the two of them, dihydrotestosterone (DHT).

You could try to reduce the amount of DHT by reducing the amount of testosterone in your body, but that has all sorts of negative consequences, such as impotence. You can try to reduce the amount of DHT on your scalp by means of anti-DHT lotions. Or, finally, you can try to block the action of the enzyme 5-Alpha-reductase.

This latter approach is known as 5-Alpha-reductase inhibitors… and these potent drugs, available by prescription only, were first used as a treatment for BHP until patients and doctors noticed the unexpected side effect of reduced hair loss.

So far, so good. But about a year ago, cutting-edge stem cell research threw a monkey wrench into the scientific consensus. Dr. George Cotsarelis at the University of Pennsylvania Medical School discovered that hair follicles in the scalps of bald men are not “dead,” as previously thought, but actually merely dormant. More precisely, Dr. Cotsarelis discovered that the hair follicles of bald men contain as many immature stem cells as healthy hair follicles but these stem cells don’t produce as many mature progenitor cells, also known as “workhorse cells,” that actually produce hair.

The key research question right now is: How do you re-active these dormant stem cells and get them to turn into the progenitor cells that grow hair? That’s the million dollar question (literally). At the moment, it looks like the answer involves chemical signals known as growth factors and cytokines – the key ingredients in products like RegenRXx and Histogen’s upcoming Hair Stimulating Complex – but which growth factors, in which combination, and delivered how?

But before answering that question, there is another one: What is the role DHT plays in this process?

And right now, the best guess seems to be that it is DHT that keeps hair follicle stem cells from growing up and becoming progenitor cells that grow hair. In other words, it’s not so much the hair follicle itself that has a genetic hypersensitivity to DHT but the stem cells in the hair follicles.

So, what are the practical implications of this research?

FIRST, 5-Alpha-reductase inhibitors are still effective although increasingly it looks like the side effects may be worse than we thought.

SECOND, protecting hair follicle stem cells from the baleful effects of DHT may not be as difficult as we thought.

In the fall 2011, scientists at Yale University discovered chemical signals from fat cells can stimulate hair follicle stem cells to “grow up” and become the much-wanted progenitor cells that grow hair.

In an article in the scientific journal Cell, the Yale researchers reported that, at least in mice, a special kind of stem cell found in fat – known as adipose precursor cells – was necessary for hair follicles to produce hair. More specifically, fat stem cells produce chemicals known as platelet-derived growth factors (PDGF), and it is these growth factors that may be the missing “on switch” that tell stem cells in hair follicles to turn into mature progenitor cells that grow hair. That’s one of the reasons why we’re so excited about Cygenx.

In other words: We’re pretty darn close to figure out the chemical mechanism that causes male and female pattern baldness. This is huge!

That’s why, despite all the cynicism you hear on the various hair loss forums – in which many denounce all research and leads as “scams” and con games – the research into stems cell hair treatments is truly moving forward. The problem is that science moves at a snail’s pace… and we’re all understandably impatient.

So, to summarize: It looks increasingly like DHT somehow acts like pixie dust on Peter Pan and keeps hair follicle stem cells from growing up and becoming the progenitor cells that produce hair. The result is that the follicles shrink, the hair gets thinner and thinner and eventually stops growing altogether.

If we can figure out how to counteract that process, and send the hair follicle stem cells the chemical signals they need to restart their engines, so to speak, we may at last have a realistic treatment for hair loss in our lifetimes.

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