Hair Stimulating Complex

HST 001 – Hair Stimulating Complex (HSC)

Histogen’s lead product application is the Hair Stimulating Complex (HSC), which is a soluble formulation in development as an injectable for hair regrowth. HSC is a safe, minimally-invasive treatment that promotes new hair growth where existing treatments only reduce hair loss.

HSC is produced by neonatal cells grown under simulated embryonic conditions of hypoxia (3-5% oxygen) and suspension. Under these conditions, the cells become multipotent and there is upregulation of growth factors which have been shown to be important in hair viability. HSC is manufactured to enrich for these growth factors, including KGF, VEGF, and follistatin, which are involved in signaling stem cells in the body, and have been shown to be important in hair formation and the stimulation of resting hair follicles. Follistatin in particular has been linked to hair follicle stem cell proliferation.

Clinical Development

Histogen is advancing its HSC program into a Phase 1b Clinical Trial (US IND 108935) to determine optimal dosing in male pattern hair loss.Three previous Company-sponsored proof-of-concept clinical trials have been completed in male pattern and female diffuse hair loss, revealing a strong safety profile and promising efficacy indicators. In one trial, 84.6% of men receiving just one HSC treatment showed a significant increase in terminal hair count and hair thickness at 12 weeks. Improvement of hair growth parameters was still evident after one year.

In the second clinical trial, in which patients received two treatments 6 weeks apart, the increase in total hair count was even more significant. Statistically and cosmetically relevant Improvements were observed in total hair count, terminal hairs and hair thickness at 12 weeks, with hair growth parameters remaining substantially above baseline one year post-treatment.

Completed clinical trials have also revealed efficacy in traditionally difficult-to-treat hair loss populations. Subjects receiving treatment in the temporal recession, which is known to be more difficult to treat than other areas of hair loss, saw marked improvement in terminal hair count, with a mean increase of 22.6% at 12 weeks and 25.2% at the 24 week time point. In both trials, men over 40, normally less responsive to non-surgical treatments, responded well to treatment, including a mean increase of 39% in terminal hairs and 19.4% in total hair count in this age group in the current trial. In addition, excellent hair growth response in women as well as men was observed in a small Investigator-Initiated Trial (US IND 114184).


The hair loss market is both large and underserved – hair loss affects over 40 million men and 21 million women in the United States alone, however less than 7% of sufferers currently seek treatment. This is largely due to the ineffectiveness of currently available options, and the hesitation of many affected to seek invasive surgical treatments.

Future HSC therapy is analogous to the periodic, fast, easily administered injections of Botox, a therapeutic approach that has proven immensely popular with patients and dermatologists. Without the limitations of currently marketed hair loss products, the development of HSC has the potential to expand the hair restoration market by offering a successful option to those that currently have none, and a more effective option to anyone presently using or considering Rogaine or Propecia.


Benefits of HSC

HSC is currently being developed as an injectable for hair growth. The key growth factors within HSC have been shown to be important in stimulating resting hair follicles and inducing new follicle formation.