Written By: Satata Karmakar | Updated : April 17, 2026 4:22 PM IST
Medically Verified By: Dr Debraj Shome
Hair fall not stopping despite treatment? Expert explains the science behind failed hair regrowth
Patients who come to the clinic after months of minoxidil, PRP sessions, or supplements, and who are not satisfied with the response, are asking the right question: why is the treatment not working? The answer, based on accumulating molecular evidence, is that hair loss in many patients is not a simple lack of stimulation, but rather a biology problem of the stem cell. It is the biology of the hair follicle stem cells (HFSCs) and the highly regulated machinery that controls whether the cells are awake, dividing, and creating hair, or are locked in hibernation.
A paper published in January 2026, "Epigenetic and Molecular Regulation of EGR2 Activates Quiescent HFSCs & Harness Hair Regeneration," in Stem Cell Reviews and Reports, focuses on a transcription factor called EGR2 (KROX20) that acts as a master regulator of the activation process. What does it do? And what impairs it? These questions explain why so many regimens only result in partial or transient responses.
In an exclusive interaction with TheHealthSite.com, Dr. Debraj Shome, Clinical Scientist and Research Mentor QR678, said - "Hair follicles are self-renewing mini-organs that undergo a cyclical sequence of growth (anagen), regression (catagen), and rest (telogen) stages. Hair follicle stem cells (HFSCs) are located in a region of the hair follicle known as the bulge and are the source of each new anagen phase."
He further noted that in androgenetic alopecia (AGA), hair follicles are present, but HFSCs are not activated. Anagen is shortened, telogen is prolonged, and the stem cell pool is increasingly refractory to the regenerative signals that must stimulate HFSCs. "You can't beat a stem cell that has been epigenetically set to dormancy with topical or injectable growth factors or improved scalp blood flow. You must break the molecular lock from within."
Immediate-early transcription factor (IEFT) proteins are a class of genes that are downstream responders to external stimuli and are able to rapidly translate signals from the surrounding environment to changes in transcription within the cell itself. The main function of Egr2 within hair follicle stem cells is to control the transition from quiescent to proliferative state, and it does so via regulation of a number of different pathways, including WNT, which promotes the initiation of the growth phase, BMP, which normally serves to inhibit the growth phase, and MAPK/ERK and PI3K/AKT, which regulate proliferation and survival, respectively. We have found that the expression of EGR2 peaks at the telogen to anagen transition, where it promotes the expression of CCND1 and c-MYC, which drive the proliferation of follicular stem cells, and also controls the progression of the cells through other regulators, p21 and p57. Co-expression with stem cell markers, such as CD34, K15 and SOX9, in the bulge region further substantiates the role of EGR2 within follicular biology.
This is where the science becomes particularly relevant for patients who feel they have exhausted their options. EGR2 activity in stem cells is governed not just by incoming signals but by epigenetic state: the way DNA is physically packaged inside the cell. During telogen, a repressive epigenetic mark, H3K27me3, is placed on the EGR2 gene, effectively locking it shut and keeping stem cells dormant. For a new growth cycle to begin, this lock must be released and replaced with activating marks, a process regulated by enzymes and small molecules, including microRNAs like miR-138 and miR-150.
When this epigenetic unlocking process is impaired, which chronic scalp inflammation, oxidative stress, and hormonal changes can all contribute to, the stem cell does not respond, regardless of what is applied externally. This is very likely why many patients see early improvement with treatment but struggle to sustain it. The topical active is reaching the scalp, but the molecular gate inside the stem cell remains closed.
EGR2 also has a meaningful anti-inflammatory role, regulating macrophage activity and limiting immune overactivation in the follicular niche. Since chronic inflammation is increasingly recognised as a driver of stem cell exhaustion and follicular miniaturisation, this adds another dimension to why niche health matters as much as growth stimulation.
The broader insight from this research is that durable hair regeneration requires the stem cell environment to be in a state that allows it to respond to treatment, rather than being overwhelmed by additional stimulatory inputs. Agents that engage this deeper regulatory layer, such as patented inventions like the QR678 derived products, which modulate EGR2-linked pathways and also other biological pathways, have shown clinical promise in hair loss disorders. For patients who have not seen the results they expected, the follicles are very likely still present. What is often missing is the restored molecular environment that allows those stem cells to do their job.
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