Can dormant hair follicles grow?

For years, the story was simple. Your hair follicles are either “alive” or “dead.” If they are dead, game over. No shampoo, serum or laser can bring them back.

But new research is quietly rewriting that story.

A review in Stem Cell Research & Therapy and other recent studies suggest something surprising: even follicles that look “empty” or dormant can still hide living stem cells and support cells. Under the right conditions, those cells may be able to wake up and restart hair growth. PMC

In 2025, University of Virginia scientists reported a previously overlooked group of stem cells in the upper and middle parts of the hair follicle. These cells were still present even in bald scalp samples. The team believes that if these cells can be reactivated and guided back to the “bulge” area (the classic stem cell niche), they might help regrow hair in areas that look completely bald. UVA Today

At the same time, Cambridge researchers described a mobile “healer army” of regulatory T cells (a type of immune cell) that travels through the body. These cells can shut down inflammation and help repair tissues like muscle, fat, and yes, hair follicles. They have already shown in mice that they can attract these cells to specific organs and boost repair. University of Cambridge

Put simply:

• Many “bald” follicles are not truly dead.
• They may be in a deep, stubborn sleep.
• The challenge is finding safe ways to wake them up.

So, can dormant follicles grow again? Sometimes yes. But the answer depends on why the follicle went quiet, whether its structure is still there, and what kind of tools we have to nudge it back to life.

Let’s unpack how this works.

How hair follicles normally behave

Before we talk about “dormant,” it helps to know what “normal” looks like.

Each hair follicle cycles through three main phases:

1. Anagen (growth phase)
• Hair actively grows from the follicle.
• This phase lasts years on the scalp.
2. Catagen (transition phase)
• Growth stops. The lower part of the follicle shrinks.
3. Telogen (resting/shedding phase)
• The hair eventually falls out.
• New hair should start growing from the same follicle.

In conditions like androgenetic alopecia (pattern hair loss), the follicle does not simply “die.” Instead:

• The growth phase gets shorter.
• Hairs become thinner and shorter (miniaturization).
• Eventually the follicle produces tiny, almost invisible vellus hairs.

Reviews on hair follicle regeneration and hair loss show that, in many cases, the follicle structure and its stem cells are still there. They are just not doing their full job. PMC

Where things do become permanent is in scarring alopecias (like lichen planopilaris). There, inflammation destroys the follicle structure and replaces it with scar tissue. In those zones, there really is nothing left to “wake up.”

So, “dormant” usually means:

• The follicle is still physically present.
• Stem cells are reduced or sluggish, but not fully gone.
• The local environment is hostile (hormones, inflammation, poor blood flow, etc.).

This is where the new science becomes exciting.

New discovery: hidden stem cells in “bald” areas

The UVA team led by Dr. Lu Q. Le looked at human hair follicles more closely and found a previously under-appreciated stem cell population in the upper and middle sections of the follicle. UVA Today

Key points from their findings:

• These stem cells act like early “ancestors” of hair, feeding the classic bulge stem cells.
• When the researchers depleted this population in lab models, hair growth stopped.
• In scalp samples from bald men, these stem cells were still present in the upper follicle even though visible hair was gone.

Their hypothesis:

If we can reactivate these upper follicle stem cells and guide them back down to the bulge, they could repopulate the hair-growing region and restart hair production in bald areas. UVA Today

Separate reviews describe the hair follicle as an “underutilized source” of stem cells for tissue regeneration, not only for hair but also for wound healing and other applications. PMC

In other words, even follicles that look “empty” may still contain:

• Epithelial stem cells
• Dermal papilla and dermal sheath cells
• Other progenitor cells that can, in principle, support regeneration

So structurally, many dormant follicles are more like abandoned houses than piles of rubble. The walls are still standing. They just need repair crews and power.

The immune system twist: regulatory T cells as “healers”

Now to the Cambridge research you mentioned.

Traditionally, regulatory T cells (Tregs) were seen mainly as “peacekeeping” immune cells. They prevent your immune system from overreacting.

The Cambridge group found something bigger:

• Instead of being fixed in specific tissues, these cells form a single mobile population that constantly travels through the body.
• They look for damage, shut down inflammation and help repair tissue.
• In mice, this “unified healer army” could repair muscle, improve fat cell insulin response, and regrow hair follicles. University of Cambridge

They also showed that it is possible, at least in animals, to:

• Attract more of these T-reg cells to a specific organ.
• Activate them there.
• Promote organ-specific healing without suppressing the entire immune system. University of Cambridge

This is important for dormant follicles because:

• Chronic low-grade inflammation around follicles is a big driver of miniaturization and dormancy.
• If you can locally send in T-reg “healers,” you can turn off that inflammation and push the follicle back toward regeneration.

How it works

Let’s translate your bullet points into a simple story.

• Immune cells can regenerate tissue
  Regulatory T cells are not stuck in one place. Cambridge researchers showed they move through many tissues, including skin, where hair follicles live. They act like roving repair crews. University of Cambridge
• They get a “grow hair here” signal
• Hormones called glucocorticoids act as an instruction signal for these T-reg cells.
• When the signal is right, T-reg cells in the skin change their behavior.
• They release a key protein: TGF-beta3
• In response to glucocorticoids, T-regs produce TGF-beta3, a signaling protein.
• This molecule talks directly to hair follicle stem cells. University of Cambridge
• Stem cells wake up
• TGF-beta3 tells dormant hair follicle stem cells: “Time to get to work.”
• Those stem cells start dividing and differentiating.
• A new hair follicle structure can form, or an existing miniaturized follicle can re-enter active growth.
• The result: potential hair regrowth
  In animal models, this sort of immune-driven regeneration can restart hair growth in places where follicles had become inactive.

Parallel research adds other layers:

• Photobiomodulation (low-level laser therapy) has been shown to activate hair follicle stem cells by increasing β-catenin signaling, partly via reactive oxygen species and Wnt proteins. Bohrium
• Adipose-derived stem cells plus ATP improved hair regrowth in a mouse model of androgenetic alopecia, likely by boosting the energy and signaling capacity of follicle cells. BioMed Central

The common theme:

Dormant follicles are not totally empty. If you provide the right immune signals, growth factors and energy, many can restart the hair cycle.

Potential applications

If scientists can safely control these mechanisms, several big possibilities open up.

1. Hair regrowth for pattern hair loss

For androgenetic alopecia (male and female pattern baldness), the dream is to:

• Calm down local inflammation and androgen-driven stress on follicles.
• Reactivate resident stem cells.
• Push miniaturized or dormant follicles back into anagen with thicker hair shafts.

Regenerative approaches under study include:

• Stem cell injections (e.g., adipose-derived stem cells, hair follicle stem cells)
• Conditioned media and exosomes derived from stem cells (protein- and vesicle-rich fluids that carry growth factors)
• Immune-targeted drugs that bring T-regs or similar “healer” cells to the scalp. BioMed Central

2. Treatments for alopecia areata and other immune hair loss

Alopecia areata is driven by the immune system attacking hair follicles. In this context, powerful local immune “off switches” plus repair signals could:

• Stop immune cells from attacking follicles.
• Help follicles rebuild and restart growth.

T-reg based therapies or precise immune modulators could be very useful here, if targeted carefully. University of Cambridge

3. Broader tissue repair

The Cambridge work is not only about hair. The same T-reg “healer army” can:

• Help muscle recover
• Improve fat cell function
• Potentially repair other organs after injury or autoimmune damage

Being able to direct these cells to specific tissues could change the way we treat many inflammatory or degenerative diseases, not just baldness. University of Cambridge

4. Targeted, local drug delivery

Today’s anti-inflammatory drugs are often systemic. They calm the entire immune system and come with side effects.

Newer approaches aim for:

• Local immune tweaking (for example, only in the scalp)
• Nanotechnology-based delivery systems that send growth factors or drugs specifically into hair follicles rather than the whole skin. Estudo Geral

If this works, you could theoretically wake up sleeping follicles without major systemic side effects.

Where does the research stand right now?

Short version:

• The science is promising.
• Most of it is early-stage.
• We are not yet at the “rub this cream and fully regrow a Norwood 6” stage.

Key realities:

• Much of the work is in animals or lab models
• The adipose stem cell + ATP study was in a DHT-induced mouse model of androgenetic alopecia. BioMed Central
• T-reg migration and tissue repair have been shown strongly in mice so far. Human trials are planned but not yet finished. University of Cambridge
• Human data exist, but are still limited
• Stem cell–based therapies (like autologous fat-derived “SVF,” PRP, and exosomes) are already used in many clinics, but the evidence is mixed and often based on small, uncontrolled studies. Europe PMC
• UVA’s new stem cell population has been identified in human follicles, including bald scalp, but translating that into a routine treatment is a big technical leap. UVA Today
• Regenerative medicine for hair is still experimental
  Reviews of hair follicle regeneration repeatedly say the same thing:
• We understand the biology better than ever.
• We can regenerate or even create hair follicles in mice.
• Doing this safely, predictably, and affordably in humans remains an unsolved engineering problem. PMC

So yes, the field is moving fast. But no, we do not yet have a guaranteed “wake all dormant follicles” therapy approved by major regulators.

When will it be commercially available?

Everyone wants a timeline. Unfortunately, biology does not care about our calendars.

A few clues:

• The Cambridge team explicitly mentions that they are fundraising to set up a spinout company and hope to start human clinical trials “within the next few years.” That is only the start of the trial process. University of Cambridge
• The Stem Cell Research & Therapy work on adipose stem cells and ATP was published in 2025. It is preclinical. It will take multiple phases of trials before anything like this becomes a mainstream, off-the-shelf option for pattern hair loss. BioMed Central
• Reviews of regenerative therapies emphasize that we are in the early-to-middle stage: promising mechanisms, growing pilot data, but not yet large, long-term randomized human trials that regulators love. PMC

Realistically:

• Small, boutique or experimental treatments (PRP, microneedling, off-label stem cell injections, exosomes) are already being sold in many clinics. Quality and evidence vary a lot.
• Truly targeted “wake-the-dormant-follicle” drugs (for example, T-reg guided therapies, precise stem cell reactivation) are probably several years to a decade away from broad, evidence-based use, if they succeed at all.

So think in terms of:

• Incremental improvements over the next 5–10 years.
• Occasional breakthroughs that might help subsets of patients sooner.
• No guaranteed “hair cloning for everyone” on a fixed date.

Key risks and limitations

It is easy to get carried away. Let’s be blunt about the risks.

• Not all follicles are salvageable
• If scarring has destroyed the follicle structure, there is nothing left to reboot.
• Advanced, shiny, scarred areas may have very limited regenerative potential. PMC
• Hype around “stem cell” and “exosome” treatments
• Many clinics already market “stem cell” or “regeneration” packages at high prices.
• Some use poorly characterized products, with limited safety data.
• Risks include infection, scarring, immune reactions and simply wasting money on something that does not work. Europe PMC
• Immune manipulation is not trivial
• T-reg–based therapies sound elegant, but if you suppress or redirect the immune system incorrectly, you could:
• Increase infection risk
• Impair tumor surveillance
• Trigger unwanted tissue changes
• This is why regulators will insist on careful, phase-by-phase trials. University of Cambridge
• Translation from mice to humans is hard
• Mice regrow hair more easily than humans.
• Their skin, hair cycles and immune systems differ from ours.
• Many “miracle” mouse studies never become human therapies. PMC
• Cost and access
• Early regenerative treatments will likely be expensive and concentrated in specialized clinics.
• Insurance coverage is uncertain, especially for conditions considered “cosmetic.”

What you can realistically do today

Even without futuristic therapies, there are ways to help your remaining follicles.

1. Get the diagnosis right
   See a dermatologist or hair specialist to figure out:

• Is it androgenetic alopecia, telogen effluvium, alopecia areata, or something else?
• Is there any scarring?
• Are there correctable triggers (iron deficiency, thyroid issues, medications, stress)? PMC

2. Consider evidence-based treatments

Depending on your case, your doctor might suggest:

• Topical minoxidil
• Oral minoxidil (low dose, off-label in some regions)
• Finasteride or dutasteride (for androgen-driven hair loss, primarily in men)
• Anti-androgen therapies in women (like spironolactone, under supervision) PMC

These do not “resurrect” dead follicles, but they can:

• Prolong the growth phase
• Thicken miniaturized hairs
• Reduce future miniaturization

3. Useful adjuncts with growing evidence

• Low-level laser therapy (LLLT) caps or combs
• Microneedling
• Platelet-rich plasma (PRP) injections in some cases

Reviews suggest these can stimulate follicle activity and may synergize with standard treatments, though results vary and protocols are not standardized. PMC

4. Take care of the basics

• Address nutritional deficiencies (iron, vitamin D, B12, protein, zinc) if present.
• Manage stress and sleep as much as you realistically can.
• Avoid harsh chemical or heat damage that stresses already vulnerable hair.

None of this replaces future regenerative therapies, but it helps preserve and optimize the follicles you still have, which is exactly what those future treatments would be trying to work with.

Conclusion:

So, can dormant hair follicles grow?

Here is the honest answer:

• Many follicles that look gone are not truly dead.
• They can contain quiet stem cells and support cells that, in principle, could be reactivated.
• New research on follicle stem cells, immune “healer” cells, and regenerative therapies is proving that dormancy is more reversible than we once thought. PMC

But:

• We do not yet have a perfect, widely available, clinically proven method to wake every sleeping follicle in humans.
• Most of the exciting stuff is still in the lab or early trials.
• Your best move today is a mix of realistic optimism and evidence-based care: protect your existing follicles now, while the science works on more powerful options for the future.

Dormant follicles can grow again under the right conditions. The world’s labs are racing to figure out how to create those conditions safely and reliably on real human scalps.

References

• Cambridge University. Discovery of “new rules of the immune system” could improve treatment of inflammatory diseases. 2024.
  https://www.cam.ac.uk/research/news/discovery-of-new-rules-of-the-immune-system-could-improve-treatment-of-inflammatory-diseases-say University of Cambridge
• Times of India. Hair loss may no longer be permanent: Natural, drug-free regrowth could soon be possible without transplant; scientists reveal. 2025.
  https://timesofindia.indiatimes.com/life-style/beauty/hair-loss-may-no-longer-be-permanent-natural-drug-free-regrowth-could-soon-be-possible-without-transplant-scientists-reveal/articleshow/122850024.cms The Times of India
• López Bran E, et al. Hair growth stimulated by allogenic adipose-derived stem cells supplemented with ATP in a mouse model of dihydrotestosterone-induced androgenetic alopecia. Stem Cell Research & Therapy. 2025.
  https://stemcellres.biomedcentral.com/articles/10.1186/s13287-025-04372-9 BioMed Central
• UVA Today. Hair Today, Gone Tomorrow – But Maybe Not for Long. 2025.
  https://news.virginia.edu/content/hair-today-gone-tomorrow-maybe-not-long UVA Today
• Kiani MT, et al. The Hair Follicle: An Underutilized Source of Cells and Biomaterials for Regenerative Medicine. 2018.
  https://pmc.ncbi.nlm.nih.gov/articles/PMC5905671/ PMC
• Liu D, et al. Status of research on the development and regeneration of hair follicles. Int J Med Sci. 2024.
  https://pmc.ncbi.nlm.nih.gov/articles/PMC10750333/ PMC
• Correia MAL, et al. Nanotechnology-based techniques for hair follicle regeneration. Biomaterials. 2023.
  (Overview summary: https://www.semanticscholar.org/paper/8673f4028b5642364e6c928aa3118f616fb3ca8b) Estudo Geral
• Jin H, et al. Photobiomodulation therapy for hair regeneration: A synergetic activation of β-catenin in hair follicle stem cells by ROS and paracrine WNTs. Stem Cell Reports. 2021. Bohrium

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