Hair Stimulating Complex

Hair Stimulating Complex (HSC660)

Histogen’s lead product application is the Hair Stimulating Complex (HSC660), which is a soluble formulation in development as an injectable for hair regrowth. The cell conditioned media (CCM) that is the base material for HSC660 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. HSC660 is manufactured from purification of CCM to enrich for these growth factors. Key growth factors include 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

Two proof-of-concept clinical trials of an earlier prototype of CCM were completed outside the US, revealing promising efficacy results. In one trial, 84.6% of patients receiving just one 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 46.5% above that seen after a single treatment. Significant improvements were observed in total hair count, terminal hairs and hair thickness at 12 weeks. At one year, hair growth parameters remain substantially above baseline.

The two 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):

These clinical investigations have consistently demonstrated the efficacy of using growth factors targeted to the treatment of hair loss.

Following these initial studies, Histogen plans to conduct a Phase 1 Clinical Study in the US using HSC660, which is purified to enrich for KGF, VEGF, and follistatin and additional growth factors known to be necessary for hair growth: placental growth factor, angiogenin and hepatocyte growth factor.


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 HSC660 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 HSC660 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 HSC660

HSC660 is currently being developed as an injectable for hair growth. The key growth factors within HSC660 have been shown to be important in stimulating resting hair follicles and inducing new follicle formation.