For millions, a receding hairline or a widening part feels like an inevitable one-way street. Science is now proving that the journey back might just be possible.
The question, "But will it grow back?" is a quiet hope for the nearly 60% of men and 50% of women who experience hair loss in their lifetime. For decades, the answer was often a resigned sigh, with treatments offering modest slowdowns rather than true restoration. Today, that narrative is changing. Groundbreaking discoveries are unraveling the very biology of the hair follicle, fueling a revolution not just in treating hair loss, but in potentially reversing it. This article explores the cutting-edge science, from a surprising experiment in Taiwan to the AI-designed drugs that are turning the dream of hair regrowth into a tangible reality.
of men experience hair loss
of women experience hair loss
days for hair regrowth in mice study
To understand how to regrow hair, we must first know why it falls out. The most common culprit is androgenetic alopecia, or male and female pattern baldness. Driven by genetics and hormones, it causes hair follicles to undergo a process of "miniaturization."
Androgenetic alopecia is primarily driven by genetics, making some individuals more susceptible to hair loss.
DHT (dihydrotestosterone) sensitizes follicles, causing them to shrink over time through miniaturization.
Essentially, a hormone called dihydrotestosterone (DHT) sensitizes follicles, causing them to shrink over time. The growth, or anagen, phase of the hair cycle shortens, and the resting, or telogen, phase lengthens. The result is that thick, terminal hairs gradually become fine, barely visible vellus hairs before eventually ceasing to produce hair altogether 8 9 .
For years, the beauty and medical industries have relied on two FDA-approved pillars: minoxidil, a topical treatment that may improve blood flow to follicles, and finasteride, an oral drug that reduces DHT levels. While effective for many, their results can be variable, require lifelong use, and don't work for everyone 4 8 . The hunt has always been for a treatment that doesn't just slow the process but actively wakes up dormant follicles.
Growth Phase
(2-7 years)
Transition Phase
(2-3 weeks)
Resting Phase
(3 months)
Shedding Phase
For a long time, scientists believed hair growth originated from stem cells in a part of the follicle called the "bulge." However, a groundbreaking 2025 discovery from the University of Virginia School of Medicine has turned this belief on its head.
Hair growth originates from stem cells in the "bulge" region of the follicle.
A previously under-appreciated population of stem cells in the upper and middle sections of the hair follicle act as the earliest ancestors of our hair.
Researchers led by Dr. Lu Q. Le identified a previously under-appreciated population of stem cells in the upper and middle sections of the hair follicle. These cells act as the earliest ancestors of our hair, essential for supplying and nourishing the bulge. Even more promising, the team found that in human bald scalp, these specific stem cells are still present—they're just inactive. This means the hardware for hair growth may still be there; it simply needs to be rebooted 2 .
"This means that if we could reactivate these cells to migrate down and repopulate the bulge, they could potentially regrow hair in bald scalp," said Dr. Le 2 .
In late 2024, a study from National Taiwan University sent ripples through the scientific community and sparked headlines worldwide. Researchers, led by Professor Sung-Jan Lin, had developed a serum that prompted dramatic hair regrowth in mice in just 20 days 3 6 .
The researchers began with a simple, known phenomenon: skin injury can sometimes stimulate hair growth. They aimed to uncover the precise biological chain of events behind this.
The team applied sodium lauryl sulfate (a common irritant in shampoos) to the shaved skin of mice, causing mild irritant contact dermatitis 3 .
They observed that this irritation triggered macrophages, a type of immune cell, to infiltrate the skin's underlying fat tissue, known as the dermal adipose tissue 3 6 .
The macrophages signaled the nearby fat cells (adipocytes) to break down their stored fats and release them as free fatty acids—specifically, monounsaturated fatty acids (MUFAs) like oleic acid and palmitoleic acid 6 .
These MUFAs were absorbed by nearby, dormant hair follicle stem cells via a transporter called CD36. Inside the stem cells, the fatty acids acted as fuel, powering their activation and pushing them from a resting state into a growth state, ultimately regenerating new hair fibers 3 6 .
The most compelling part of the experiment came next. The team bypassed the injury step entirely, topically applying these specific monounsaturated fatty acids directly to the mice's skin. The result: hair regrew just as effectively, in approximately 20 days 6 .
The study's dramatic results are summarized in the table below, which compares the fatty acid serum to a control and to minoxidil, a standard treatment.
| Treatment Group | Regrowth Observation Time | Key Finding |
|---|---|---|
| Control (No treatment) | 20 days | Minimal to no hair regrowth |
| Topical Monounsaturated Fatty Acids (Oleic & Palmitoleic) | ~20 days | Robust, full hair regrowth |
| Topical Minoxidil (Standard treatment) | 22 days | Hair growth in only one-third of mice 7 |
The scientific importance of this experiment is profound. It identifies a completely novel pathway for hair regeneration that is non-hormonal and based on cellular metabolism. Unlike finasteride, it doesn't block hormones, and unlike minoxidil, its mechanism is precisely understood: it directly "charges" the stem cells with the energy they need to awaken 3 .
However, experts universally caution that mouse skin and human scalp are very different. As Dr. George Cotsarelis of the University of Pennsylvania noted, mice have all their follicles in a resting stage, so stimulation looks dramatically effective. On the human scalp, most follicles are already growing, and the challenge is specifically targeting the dormant ones affected by pattern baldness 3 .
The journey from a discovery in a lab to a treatment in a clinic relies on a suite of specialized tools and reagents. The following table details key materials used in modern hair regrowth research, many of which were pivotal in the Taiwanese experiment.
| Reagent / Material | Function in Research |
|---|---|
| Monounsaturated Fatty Acids (e.g., Oleic Acid) | Used to topically activate hair follicle stem cells by providing a metabolic fuel source, bypassing the need for skin injury 3 6 . |
| Sodium Lauryl Sulfate (SLS) | A chemical irritant used in controlled settings to induce a mild inflammatory response and study its subsequent effects on hair follicle activation 3 . |
| CD36 Transporter Inhibitors | Used to block the fatty acid transporter on stem cells. This helps researchers confirm the specific mechanism of action by showing that blocking CD36 prevents regrowth 6 . |
| CASLite Nova Phototrichogram Software | A sophisticated imaging system that provides precise, standardized analysis of hair parameters like density, thickness, and the count of new vellus hairs, which is critical for objective efficacy data 8 . |
| Testronix Tensile Hair Tester | An instrument that measures the mechanical strength of regrown hair strands, providing data on hair quality and health beyond mere visibility 8 . |
| Bradford Assay Kits | Used to quantitatively measure keratin protein levels in hair and scalp samples, giving researchers an objective biomarker for hair health and strength 8 . |
The field is exploding with innovation beyond fundamental discoveries. Here's a look at the other promising technologies on the horizon:
A company called Absci has used artificial intelligence to design an injectable drug called ABS-201. It targets a different pathway—the prolactin receptor—to push dormant follicles back into the growth phase. In preclinical trials on macaques, the treatment led to full hair regrowth and even repigmentation of gray hair within six months. It is now entering human clinical trials 7 .
Robotic hair transplantation systems are bringing new levels of precision to follicle extraction and placement, improving outcomes and reducing recovery time 1 . Furthermore, techniques like the Vitruvian FUE™ are being enhanced with adjunct therapies like PRP (Platelet-Rich Plasma) and exosomes (cell-derived vesicles) injected into the scalp to boost graft survival and stimulate the patient's native follicles 1 .
The Distant Horizon: While still in early research, hair follicle cloning (generating an unlimited supply of follicles from a small donor sample) and gene therapy (directly correcting the genetic predispositions to hair loss) represent the ultimate goals for a permanent cure 1 .
| Treatment | Mechanism | Stage of Development |
|---|---|---|
| Stem Cell Reactivation (UVA Discovery) | Reactivating a newly discovered population of resident stem cells in the follicle. | Foundational research; potential therapies are years away 2 . |
| Fatty Acid Serums (Taiwan Experiment) | Using specific fatty acids (e.g., Oleic Acid) to metabolically fuel dormant stem cells. | Preclinical (mouse studies); human trials are the next step 3 6 . |
| ABS-201 Injectable | An AI-designed biologic that targets the prolactin receptor to restart the hair growth cycle. | Entering Phase 1 human clinical trials in late 2025 7 . |
| Exosome Therapy | Using vesicles from stem cells to deliver pro-growth signals to aging follicles. | Available in some clinics but considered an adjunct; larger studies needed for standardization 1 . |
The age of resigned acceptance of hair loss is ending. The question, "But will it grow back?" is now being met with a resounding, and scientifically backed, "It might." From the rediscovery of our own biology's hidden potential to the power of AI and cellular metabolism, the pathways to regeneration are multiplying.
Future treatments will be tailored to individual genetic and biological profiles.
New approaches target the root causes of hair loss rather than just symptoms.
The focus is shifting from slowing loss to actively regenerating new hair.
While it's crucial to maintain a healthy skepticism toward overnight "miracle cures"—especially those not yet tested in humans—the collective force of these discoveries is undeniable. The future of hair restoration is shaping up to be personalized, potent, and regenerative. For anyone on this journey, the most important step remains consulting a dermatologist or healthcare professional to navigate these exciting options as they transition from the lab to the clinic. The road back is being built, strand by strand.