Updated: Mar 31
Scientists are still not completely sure why androgenic alopecia (AGA; pattern hair loss) occurs. This is one of the reasons that we do not yet have a cure that can reverse hair loss completely.
Most scientists agree that AGA is the result of a genetic sensitivity to DHT and can be worsened by a lack of adequate blood flow, which is why the most widely used treatments, finasteride, minoxidil, and low-level laser therapy target both of those areas respectively. But what if hair loss is caused by more than just those two factors? This is a question that many people are not only willing to explore, but also develop various treatments around.
One such treatment that we will be exploring throughout this article is called stemoxydine. It is often compared to minoxidil, one of the most effective treatments we currently have available, and has gained traction as a possible viable alternative to it.
We will take a look at what stemoxydine is, how it (supposedly) works, and ultimately determine whether or not it is worth trying for yourself.
What is stemoxydine?
Stemoxydine is a topical hair loss solution that was patented in 2012 by the popular cosmetic brand L’Oreal. It is classified as a prolyl-4-hydroxylase (P4H) inhibitor (more on this in a bit).
Previously, L’Oreal had an active ingredient called aminexil in their hair growth products, but eventually aminexil was replaced by stemoxydine in all of their products, eventually becoming the standard.
Now that you have a little background on stemoxydine, let’s talk about how it works.
How stemoxydine works
Like I said, stemoxydine is a P4H inhibitor, but what does this mean? To understand how a P4H inhibitor works you need to have a surface level understanding of the hair cycle.
The hair cycle is essentially a pattern that the hair follicle follows. It is commonly recognized as having four phases: anagen (growth), telogen (resting), catagen (regression), and exogen (shedding), but there is a fifth “phase” (in parentheses because it has not been fully established as its own official phase) called kenogen.
Kenogen is essentially a short time when the hair follicle is physiologically inactive and occurs after the shed and before new growth starts (i.e. between exogen and anagen phases). It was discovered (1) that the kenogen phase is longer in people with hair loss, which could be a possible cause of miniaturization and ultimately baldness. Even though correlation does not equal causation, this research article makes a good case for extended kenogen phases possibly contributing to hair loss (2).
So, what does all of this have to do with stemoxydine? It may be able to shorten the kenogen phase in people with hair loss.
During the kenogen phase, all of the hair follicle compartments are regenerated by reservoirs of stem cells (which eventually kickstarts the anagen phase). In a study done by L’Oreal (3) it was found that under hypoxic conditions (a fancy word for low-oxygen) the stem cells were essentially more effective at creating and maintaining new hair follicles. In people with hair loss, the CD34+ layer (the layer near the skins surface) had higher oxygen levels, meaning that the higher oxygen levels could be correlated with a longer kenogen phase and would prove L’Oreal’s hypothesis to be true.
The researchers claim that by inhibiting P4H (told you we would get back to it), stemoxydine is able to create a hypoxia environment and shorten the kenogen phase, therefore creating longer and denser hair.
What the research says
The research around stemoxydine is pretty limited, although (besides the L’Oreal study) there have been three studies that were conducted.
There were two intra-individual studies done on 16 and 23 men with a 5 day-per-week application schedule of stemoxydine. The other inter-individual study was done on 100 men with a daily application of stemoxydine (4).
In all three studies, there was a significant increase in hair density when taking stemoxydine vs. a placebo. Also, it was noted that there was a decrease in the percentage of hair in the kenogen phase, again suggesting that it might be correlated with hair loss.
Unfortunately, even though these results are somewhat promising, there is still not enough evidence that suggests that 1. stemoxydine is for sure effective, or 2. that it is safe. Also, the correlation between kenogen phase length and hair loss has not yet been fully uncovered, meaning no conclusions can yet be made and FDA approval status is still far off.
Any treatment that explores a different avenue to try to cure hair loss is interesting, especially when it has even a small amount of evidence supporting it.
In stemoxydine’s case, what minimal research has been done not only suggests that the length of the kenogen phase may be correlated with hair loss, but also showed that stemoxydine may be able to help. But should you take it?
The side effect profile is still unknown, as well as how effective it is in a large-scale clinical trial. If you were to take it, it would be at your own risk and I would only recommend considering so if you have exhausted most, if not all, of your other options. And remember to always talk to your doctor before starting any treatment.