The reports of a class-action lawsuit claiming that Wen hair cleanser has caused hair loss for 200+ women have been all over the news. The lawsuit and controversy have actually been going on for a few years now, and there have actually been multiple lawsuits pending over the last couple years. Since the story is gaining traction over the mainstream and social media, I thought I would put forth my two cents on the topic.
I first learned of the issue a couple years ago when a woman emailed me asking for my opinion regarding the ingredients of Wen. She told me that she had used Wen on her daughter's hair and within minutes her daughter was losing hair in clumps. It was not a delayed reaction or slowly thinning hair, but actual clumps and bald spots that happened immediately. She told me that there were some lawsuits brewing and asked if I had any thoughts about the issue. I can only speculate, but I have recently developed some thoughts on the matter.
Some reports have said that the hair loss is caused by clogged hair follicles. Because it's a cleansing conditioner, they postulated that it isn't strong enough to cleanse the scalp, leading to buildup that irritated hair follicules and thus hair loss. It's an interesting theory, however many of the reports of hair loss with the product were like those from the woman with whom I spoke--immediate hair loss, in clumps. This wouldn't happen were it caused by gradual buildup.
Some have speculated that an irritant or allergen could be to blame. The formula contains several potential allergens including hydroxycetronellal, Hydroxyisohexyl 3-Cyclohexene Carboxaldehyde, and previous versions of the formula also contains methylisothiazolinone, also a known allergen.
Stearamidopropyl dimethylamine is another consideration that I haven't seen being discussed. In older versions of the formula it was listed lower on the label; current versions it appears to be higher on the list. I don't know if this is a formulation change or a listing change, or just a variation from scent to scent, but it is an ingredient to consider. While stearamidopropyl dimethylamine is a fairly widely used products (in more than 400 known formulas) it can cause contact allergen dermatitis (usually in a delayed fashion) when used at too high of a concentration. The culprit is a manufacturing byproduct called 3,3-dimethylaminopropylamine (DMAPA) that's usually left over in the finished product. (Source) Contact allergen dermatitis can cause telogen hair loss, happening a couple weeks after the initial allergic reaction. (Source) One theory that I pose is that perhaps there was a batch of the stearamidopropyl dimethylamine that contained a higher amount of DMAPA and it created sensitization/allergic reaction in some individuals.
However, these are all purely theories and plaintiffs in the case have yet to provide evidence as to exactly how Wen causes hair loss. There actually have been two different lawsuits with about 200 people involved in each. With 10 million bottles of Wen sold over the years, that's really quite a low number of people. A .004% reaction rate. Although the statistics are not available, to me, it wouldn't be out of the realm of possibility that if you sold 10 million of anything that 400 people could have an allergy or problem with it. I mean this with no disrespect to the women in the case--while statistically they remain a small number, their hair loss is in no doubt emotionally distressing to say the least. Additionally, there are probably more people who had a problem but are not part of the lawsuits, so this statistic may not be accurate.
So, if this case has been going on since 2013, why are we just now seeing it on the news? Well, they've been going back and forth with legal posturing for the last couple of years. This costs a lot of money--something that Guthy Renker (makers of Wen) has a lot of. So, they presumably have not had a problem with a drawn out legal battle. The plaintiffs on the other hand, without strong evidence of causation, and perhaps dwindling funds/patience, needed a strategy to get Wen to settle the case out of court. Sending press releases and news pitches to the national media about the emotional story that Wen was causing hair loss was just the thing to push Wen to start talking about a settlement. And indeed it worked--one day after the story broke, both cases against Wen started mediation. (Source)
The bottom line:
While Wen has a number of suspect ingredients that could cause an allergic reaction strong enough to cause hair loss, there has not been definitive proof that it did indeed cause these women to lose their hair. At the same time, these anecdotal reports appear to be legitimate and something indeed happened to those women. But until direct causation can be shown, the issue remains under investigation.
The big issue to me, however, is that the product is marketed as this natural and oh-so-healthy option, but it's filled with potentially harmful synthetics. The three that I named above, as well as:
Behentrimonium methosulfate--quaternary ammonium compound potentially linked to endocrine disruption
Phenoxyethanol--potential estrogen mimicker
PEG-60 and Polysorbate 60--ethoxylated chemicals created with the carcinogen ethylene oxide, traces of which, along with its carcinogenic byproduct 1,4-dioxane can remain in the product
Fragrance--can contain anything from a list of over 2500 different synthetic chemicals, including endocrine-disrupting phthalates