Researchers presenting at the World Congress for Hair Research have reported an unusual two-part strategy for keeping human scalp follicles in active growth: combine tropoelastin, the soluble building block of elastic fibres, with a minute concentration of hepatocyte growth factor (HGF). The experimental blend, called NUL-5, was tested on microdissected living human hair follicles maintained outside the body.
After six days, the treated follicles showed several changes associated with a healthier anagen phase. The investigators reported significantly longer anagen maintenance, increased proliferation of hair-matrix keratinocytes, stronger alkaline-phosphatase activity in the dermal papilla, more elastin around key follicular structures, reduced expression of the catagen promoter TGF-beta2 and lower secretion of DKK1, a natural inhibitor of Wnt signalling.
That is a compelling mechanistic package, but it is essential to frame it correctly. This was an ex vivo laboratory experiment using follicles from three healthy donors, not a clinical trial in people with androgenetic alopecia. It does not prove that applying NUL-5 to a scalp will regrow hair, establish an effective dose or demonstrate long-term safety. What it does provide is a new, testable hypothesis: supporting both the follicle’s extracellular matrix and its growth-factor signalling may help the dermal papilla resist the molecular slide into catagen.
What Is It and How Does It Work?
NUL-5 is an investigational blend containing 0.2% tropoelastin and 1 ng/mL HGF. Its proposed action is not hormonal. Instead, it appears to target the structural and signalling environment surrounding the dermal papilla, the small cluster of specialised cells at the base of a growing follicle that instructs matrix cells to build the hair fibre.
- Tropoelastin may reinforce the follicle’s support matrix: Tropoelastin is the soluble precursor used to assemble elastin. The study found elastin around the bulge connective-tissue sheath, dermal cup and dermal-papilla stalk in untreated scalp tissue. NUL-5 significantly increased elastin expression in the dermal papilla and in the connective-tissue sheath surrounding the bulge.
- HGF may stimulate follicular epithelial growth: Human dermal papilla cells can express HGF, while hair-bulb keratinocytes respond to it. Earlier laboratory work found that HGF stimulated DNA synthesis in human hair-bulb keratinocytes and supported hair-follicle growth in organ culture.
- DKK1 reduction may release a Wnt brake: DKK1 suppresses canonical Wnt signalling. NUL-5 reduced DKK1 secretion in the cultured follicles, potentially allowing more Wnt activity to reach dermal-papilla and matrix-cell programs associated with anagen.
- Lower TGF-beta2 may delay catagen: TGF-beta2 is one of the signals capable of pushing a follicle toward regression. The reported reduction in outer-root-sheath TGF-beta2 fits with the observed prolongation of anagen, although it does not prove that this pathway alone caused the effect.
- Dermal-papilla identity appeared stronger: Alkaline phosphatase activity increased significantly and versican expression showed an upward trend. Both are commonly used as indicators that dermal-papilla cells retain more of their hair-inductive character.
The Science: Human Scalp Follicles Showed Multiple Pro-Growth Signals
The investigators first mapped elastin in healthy human scalp samples. They then microdissected full-length follicles and maintained them in organ culture for six days with either NUL-5 or a vehicle control. Quantitative immunomorphometry was used to assess follicle cycling, matrix-cell proliferation, dermal-papilla markers and extracellular-matrix changes.
- Anagen was significantly prolonged: Treated follicles remained in the active growth stage for longer and had a lower hair-cycle score, indicating less progression toward catagen during the six-day culture period.
- Hair-matrix cells proliferated more: The rapidly dividing keratinocytes that generate the hair shaft showed a significant increase in proliferation.
- Hair-shaft production trended upward: The follicles tended to produce more shaft material, but the abstract did not report this as a statistically significant result. That distinction matters.
- Elastin increased in biologically relevant regions: The clearest increases occurred in the dermal papilla and the connective-tissue sheath near the bulge, structures involved in epithelial-mesenchymal communication and follicle anchoring.
- Wnt inhibition decreased: Lower DKK1 secretion is consistent with less suppression of the Wnt/beta-catenin pathway, which is central to maintaining the hair-inducing activity of dermal-papilla cells.
The evidence is interesting because the readouts point in the same general direction: stronger dermal-papilla identity, less catagen signalling, more matrix-cell proliferation and better anagen maintenance. However, the donor count was only three, the experiment lasted six days and healthy follicles outside the body do not reproduce the hormonal, inflammatory, vascular and mechanical environment of a balding scalp.
When Will It Be Available?
- Current stage: Early preclinical human-tissue research presented as a conference abstract. It is not evidence of clinical efficacy.
- What must happen next: The formulation needs independent replication, penetration testing, dose-ranging work, toxicology assessment and controlled human trials that measure terminal-hair count and shaft diameter over at least six to twelve months.
- Availability: NUL-5 should be treated as experimental. A commercial product containing similarly named ingredients cannot be assumed to reproduce the concentration, delivery or biological effect reported in an organ-culture laboratory.
How you can benefit from this treatment now
You cannot yet use this study as a clinically validated treatment protocol. Its practical value today is as a filter for evaluating future claims.
- Look for human clinical endpoints: A convincing next study should report terminal-hair density, shaft diameter, standardized photography, adverse events and a vehicle-controlled comparison. Marketing photographs alone are not enough.
- Do not self-source injectable HGF: Growth factors are biologically active proteins, not ordinary cosmetic ingredients. Unregulated injection or microneedling of research-grade material carries infection, dosing and tissue-response risks.
- Do not replace proven care: People with progressive pattern hair loss should discuss established options such as minoxidil and, where appropriate, anti-androgen therapy with a qualified clinician. Waiting for an experimental blend can allow further miniaturization.
- Track the mechanism, not the hype: Future NUL-5 data become more credible if improvements in hair counts accompany the same mechanistic signals seen here: lower DKK1 and TGF-beta2, maintained dermal-papilla markers and sustained anagen.
Action: Save the product name and the trial requirements above, but do not buy or compound an imitation formula on the strength of this abstract. The responsible milestone to watch for is a registered, randomized human scalp trial.
Sources: ESDR abstract book: NUL-5 ex vivo human follicle study; World Congress for Hair Research conference listing; human dermal papilla HGF research; Wnt signalling and dermal-papilla hair-inducing activity; 2026 review of Wnt signalling in skin and hair follicles.