Category Archives: George Cotsarelis

Two Decades of Quotes from Dr. George Cotsarelis

University of Pennsylvania’s Dr. George Cotsarelis is a legend in the hair loss world. He has been among the three most quoted hair loss researchers in the world over the past two decades (with the other two being Dr. Angela Christiano and Dr. Ken Washenik). I have covered all three of these US-based researchers numerous times on this blog in the past.

Dr. Cotsarelis’ first hair related study that I could find is dated all the way back from 1990. Since then, the doctor and his lab (sometimes in collaborative efforts) have been responsible for a number of groundbreaking discoveries in relation to androgenetic alopecia. These include crucial findings related to progenitor cells, prostaglandin D2, skin regeneration, Wnt signaling, wounding and more.

Dr. Cotsarelis is a co-founder of Follica, a company of paramount importance to us. I therefore thought it would be of interest to find some important quotes and thoughts that Dr. Cotsarelis has given in interviews over the past two decades to major newspapers and scientific publications.

George Cotsarelis Quotes

The quotes below give a good indication about the overall progression of hair loss research in the US during the past several decades. They also suggest major revisions in Dr. Cortsarelis’ prognostications about when a hair loss cure will finally arrive.


Science News (need subscription)

“Ideally, you would like to turn on beta-catenin just in an adult and see if you have the same effect: production of hair follicles.”



“If someone thinks this is going to lead to a baldness cure in a year or two, that’s completely unrealistic. I think seven to 10 years is more realistic.” 


BioScience (need subscription)

“The discovery of the human homologue of the mouse hairless gene defect beautifully shows that the hair follicle in the mouse is very similar to the human, and that’s heartening because a lot of people are working on mouse and assuming that it’s going to be relevant to humans.”

“It’s not crazy by any means. At some point in the future, I wouldn’t be surprised if there were some type of gene therapy for hair loss.”


The Guardian

“I think this or something like it will be available in the next five to 10 years” said George Cotsarelis, a dermatologist at the University of Pennsylvania school of medicine who led the research.”



“Dr. George Cotsarelis, a dermatology professor at the University of Pennsylvania School of Medicine in Philadelphia who led the study, said the findings dispel the dogma that hair loss is permanent in people and other mammals, and that once they are lost new hair follicles cannot grow. Cotsarelis said the findings could pave the way for remedies for male-pattern baldness and other types of hair-loss. He said the idea would be to apply compounds to get epidermal cells to turn into hair follicles. Cotsarelis is involved with Follica Inc., a privately held start-up company that has licensed the patent on the process from the University of Pennsylvania. He said it probably would be more than five years before a treatment was possible.”


Scientific American

“For this to become therapeutic, you’d probably have to find ways to activate the Wnt pathways with a topical agent,” Cotsarelis says. He notes that he and his colleagues have founded a small start-up company called Follica to create a product that could be applied to injured skin as it heals to “activate the right pathways … [that trigger] follicle formation.” Cotsarelis says the for-profit venture is now only doing preclinical experiments, but if all goes perfectly, there could be a product on the market in two to three years.” 


Penn Medicine

A great overview of Dr. Cotsarelis’ work through 2008 can be found in the above publication and is worth a complete read. Key quote:

“When cells move in to close a wound, they are trying to make a decision: Should I make epidermis or should I make a hair? If there is a lot of Wnt around, they choose to become hair follicles.”

My Note: Besides an instructive summary of how the lab’s hair research has developed and progressed every few years, I was very surprised to read about how important Dr. Mayumi Ito’s work has been in some of the key findings, especially wounding. Dr. Ito now works at her own lab in New York and has been covered on this blog a number of times in the past.



“This implies that there is a problem in the activation of stem cells converting progenitor cells in bald scalp. The fact that there are normal numbers of stem cells in bald scalp gives us hope for reactivating those stem cells.”


Daily Mail

“Dr Cotsarelis, a dermatologist, whose work was part-funded by the US government and by L’Oreal, believes a treatment could be on the market within a decade.”


NY Times

“Dr. Cotsarelis, who describes himself as enamored with the hair follicle, has been hard at work on balding scalps since he identified hair follicle stem cells in mice in 1990, when he was a postdoctoral fellow. We were able to show that when we isolated the cells and injected them into another mouse, he said, the mouse made new hair follicles.”



“George Cotsarelis, professor and chair of dermatology at the Perelman School of Medicine at the University of Pennsylvania, in Philadelphia, is skeptical of product claims. Topical products can change the hair’s appearance but not the follicle itself, he cautions. It’s like throwing gasoline on your car and expecting it to go.”

My Note: Maybe he forgot about topical Minoxidil and topical Finasteride?



“Cotsarelis was adamant about it because male pattern baldness isn’t related to the immune system.”

My Note: It is therefore a bit strange that Follica (Puretech) classifies androgenetic alopecia to be an immune system related problem per recent presentations.



“In the end, I think there are going to be multiple ways to treat male pattern baldness, and some will work fabulously well in some people and not so well in others.”


The Telegraph

“Essentially, we can manipulate wound healing so that it leads to skin regeneration rather than scarring.”


In June 2019, Dr. George Cotsarelis made an interesting presentation titled “Two Decades of Riding the Hair Wave”:


In 2023, Dr. Cotsarelis was interviewed by the ISHRS and said that despite advances in hair regeneration, he does not thing that hair transplant surgeons “need to be worried about going out of business”.

Follica Updates its Website and it Looks Encouraging

As always, thanks to commentator “Mike” who regularly seems to find the latest developments with Follica immediately.  He notified us of the updated Follica website earlier today in a comment to the last post.

I have covered Follica (a subsidiary of US-based PureTech Health) many time on this blog before in spite of the fact that until recently I was very skeptical about the company (since it was founded ten years ago, but has yet to commercialize its skin perturbation + topical compound technology despite years or supportive evidence). Moreover, some people on hair loss forums have over the years postulated that the company’s technology is basically just glorified Minoxidil, since skin damage allows for greater penetration of Minoxidil.  However, the company has never specified what compound it is using, and I highly doubt it is just Minoxidil.  In some of their patents they have mentioned various potential ingredients including Minoxidil, but I am too lazy to go through all the links in my past Follica posts at the moment to get the details.

I bolded the words “until recently” above because a few months ago, Follica pleasantly surprised us and announced that it was aiming for a 2018 product release as a best-case scenario.

Now it seems like Follica just made a major upgrade to its previously barren website.  Nothing really of major surprise in there, but much better elaboration of the technology with useful photos/product renditions.  We already knew that the skin disruption process (which requires great precision and knowhow) would be undertaken at a doctor’s office and the compound application would be the responsibility of the patient at his or her home.  Now Follica has provided images of both the in-office and at-home devices.  The company will have a smartphone app to monitor progress (Edit: It seems like the app will also be able to measure the accuracy of your dosage via wirelessly communicating with the at-home device).

No information is provided about the costs, but they do discuss re-ordering of the compound, which makes me wonder if this will be a lifelong commitment just like with Minoxidil?  Assuming that you do get new hair follicles, how susceptible will they be to the ravages of dihydrotestosterone (DHT), and will taking Finasteride or Dutasteride to reduce DHT levels prevent the need for re-ordering Follica’s compound?

Some key quotes from Follica’s new website:

“We’ve teamed up with leading dermatologists with expertise in hair loss and epithelial stem cell biology to develop a new system aimed at not just improving existing hair growth, but also growing new hair”.

“Our technology is based on a proprietary approach intended to create an “embryonic window” in adult skin, allowing new follicles and new hair to form from epithelial stem cells”.

“Following skin disruption, cells that migrate to help healing are forced to make a decision: Should I make epidermis, or should I make a hair? There is a window of opportunity in which we can potentially push them to choose the latter, and we believe there are multiple biological pathways to target to enhance this outcome. This regenerative effect is called hair follicle neogenesis”.

Dr. George Cotsarelis and his own Hair Loss

Finally, if anyone lives near where Dr. George Cotsarelis (Follica’s co-founder and technology inventor) works in Pennsylvania, it would be good to know if the small bald patch on the back of his head is gone or still there. To see what I mean, check out the below video links that start in the most relevant places. I am very serious and do not mean to belittle Dr. Cotsarelis (and hope he does not mind), but I feel like most people who can fill back a small bald patch on their crown region would always do so if they had the technology at their disposal. Usually, only those who totally shave their heads are comfortable with their hair loss, while those with small bald spots are not.  Maybe I am being too judgmental here and Dr. Cotsarelis does not care about his minor hair loss at all?  But if he were to suddenly have thick hair at the top/rear of his scalp, I would get even more excited about Follica.

Dr. Cotsarelis has been involved in hair loss research for at least 20 years as far as I can tell, and there is no-one in the world who has been cited in hair loss related magazine articles as much as him.  For those who are interested, in some of my past blog posts about Follica, I have discussed and linked to various wounding related patents and studies attributed at least in part to Dr. Cotsarelis.

Link to Dr. Cotsarelis Video 1

Link to Dr. Cotsarelis Video 2