When Kathy wrote in to ask me to look at 18-MEA, I embarked on the quest with enthusiasm. 18-MEA is a relatively new discovery that explains healthy, shiny hair (or lack thereof). Unfortunately, my research quickly became an exercise in frustration.

First of all, what is 18-MEA or Methyl eicosanoic acid? Dry hair consists of around 95% proteins and 2% lipids. A substantial amount of the lipids are present as 18-methyl eicosanoic acid at the surface. The rest of the hair is made of 'nuclear' remnants, carbohydrates and inorganic salts. These lipids are on the outside of each cuticle to protect the surface and give hair its smoothness and ‘slip’.

The exciting part about the discovery of 18-MEA is that researchers say it minimizes future damage and actually halts the aging process. It can target and repair each hair, attaching itself to the damaged areas, restoring the surface.

Meanwhile, many of us are doing our best to undo the good work. The ammonia and hydrogen peroxide present in all permanent hair dyes removes this 18-MEA layer from the hair shaft. So can we restore 18-MEA? Is it possible that a shampoo or conditioner could contain this lipid or some kind of analogue? This is where things started to get really frustrating.

I found a grand total of three brands using - or claiming to use - 18-MEA. One is the British company, Trevor Sorbie, who calls it a "breakthrough" ingredient that is in Shampoo for Long Straight Hair and a range for aging hair called rejuvenate. I couldn't find a detailed ingredients list for either of the Sorbie shampoos. Nor could I for the second brand I found called After Tan.

Interestingly, the third (mentioned by Kathy and the only other brand I could find), DHC, does publish a full ingredients list, but 18-MEA is nowhere to be found. I went through each of DHC's Light & Smooth Conditioner ingredients one by one. There is cocamide MEA. However, this is different thing altogether: a coconut derived fatty acid that is in hundreds of hair care products. I also had to check out etidronic acid, which was new to me. It is a cheleating agent that must be rinsed off immediately because it can cause irritation.

Everything else in DHC was positively identified and many of the ingredients are run of the mill surfecants, preservatives (including BHT, which is banned for use in food in Japan and several other countries and from use in baby food in the US) and irritants. Even if Light & Smooth does contain 18-MEA, given all the other junk in it, I wouldn't use it.

By the way, I even took a look at the DHC Light & Smooth that is sold in the UK, in case anything had got lost (or could be found) in translation. Still no 18-MEA.

There is a company that sells 18-MEA as an ingredient for shampoo makers under the name of Incroquat 18-MEA-40. But I couldn't turn it up in any actual products.

So, Kathy, thank you for quest. At this stage, however, all I can suggest is that you live with declining 18-MEA or give up seeing your colorist.