Blocking Enzymes in Hair Follicles Promotes Hair Growth


Androgenetic alopecia (AA) or ‘male pattern baldness’ is one of the most common causes of hair loss . It can occur due to 3 main factors – genetic predisposition, presence of dihydrotestosterone (DHT) or the age factor.

It is characterized by hair follicle miniaturization, i.e. the hair follicles produce thinner, shorter, more brittle hair with weaker shafts. The hair growth cycle normally consists of 3 phases, i.e. growth (anagen), cessation (catagen), and rest (telogen) phases.

In AA, the hair follicles are unable to reenter the anagen or growth phase again and remain in a dormant state. Researchers at Columbia University Medical Centre have recently discovered a potential cure for AA by establishing that hair growth can be restored by an enzyme that blocks the JAK-STAT pathway in them!

Within 3 weeks, mice that received topical ruxolitinib or tofacitinib had regrown nearly all their hair (center and right photos; drug was applied only to the right side of the mouse). Little to no hair growth occurred in control mice during the same timeframe (left photo). Image credit: From S. Harel et al., Sci. Adv. 1, e1500973 (2015). Distributed under a Creative Commons Attribution Non Commercial License 4.0 (CC BY-NC). 10.1126/sciadv.1500973

The discovery was made accidently as Angela M. Christiano, PhD, and colleagues were testing drugs (JAK-STAT inhibitors) on mouse and human hair follicles to study ‘alopecia areata’, wherein an autoimmune attack on hair follicles leads to hair loss. Their earlier study had revealed that the oral forms of the drug could restore hair growth in a few individuals by shutting off the stimulus for the autoimmune attack.

In the current study, the researchers mainly used USFDA approved JAK inhibitors such as ‘ruxolitinib’ (normally used for treatment of blood disorders) and ‘tofacitinib’ (for treating rheumatoid arthritis). They observed that these inhibitors led to activation and/or proliferation of hair follicle stem cells.

Read more: Scientists explain hair loss at the molecular level

It further led to the initiation of the hair cycle by reawakening of the dormant follicles thus triggering the anagen phase. During their experiments, they also made a key discovery that topical application of the drugs worked better than systemic intake by increasing the local concentration of the enzyme. These inhibitors led to robust hair growth in mice.

Till date, most of the therapies for AA were focused on stopping hair loss and there aren’t any pharmacologic agents in the market which were very successful in restoring the hair growth cycle. In this scenario, the discovery by Christiano and colleagues which leads to restoration of hair growth gives hope to millions who suffer from AA. Yet, the scientists think that further work needs to be done. Christiano said “What we’ve found is promising, though we haven’t yet shown it’s a cure for pattern baldness. More work needs to be done to test if JAK inhibitors can induce hair growth in humans using formulations specially made for the scalp.”

Source: Columbia University Medical Centre – Newsroom

Original Publication: Science Advances


  1. DONT EVER mess with your DHT, either naturally (Saw Palmetto, pumpkin seed) or taking propecia or finasteride if you have any plans to get married. DHT is not causing your hairloss. if that was the case, all 16 year olds will go bald. If you reduce your DHT you will go impotent. Don’t believe in the internet hype that reducing DHT will help baldness. Worst mistake of my life. Just let it go and you will feel so much better bald or short hair