Nexxus Pro Mend

In the cosmetics and hair care industry, a continual stream of new products are introduced into the market. Most seem to be variations of whatever happens to be the current popular theme. On occasion though, new products emerge onto the scene bearing remarkable claims that demand closer examination.

One such recent case is the Nexxus Pro-Mend system, which the manufacturers assert can nourish hair and actually heal split ends. Who wouldn't be intrigued by promises that the product could repair up to 92% of split ends in the first use? It seemed a sufficiently brazen claim to warrant some scientific detective work to determine if the claims are credible, and if so, what the chemical basis is for the reported miracle cure for split ends.

Too Good to Be True?

The initial response many may have when hearing such a claim is that it is preposterous. We have all been taught that hair is a "dead" protein, and that topical treatments such as hair products are incapable of providing anything other than cosmetic, superficial, and temporary benefit. However, our understanding of and facility with protein and polymer chemistry has been continually advancing in unexpected and oftentimes brilliant ways. For this reason, I am willing to temporarily set aside my skepticism and entertain the notion that maybe someone has finally found a way to repair split ends without a pair of scissors.

There is a general procedure one can follow to gain fundamental insight into the technology behind a new product. The first step to understanding is to examine the ingredient list and look for anything new or unusual combinations of materials. Next, it is helpful to review the company's marketing material and instructions for use of the product. Finally, one can gain a tremendous amount of valuable information by scouring the relevant technical literature and patents (even those of competitors or for products used for completely different applications).

Analysis of the Ingredients

Nexxus Pro-Mend Leave-In Treatment Cr̀eme Ingredients

Water, Phenyltrimethicone, Dimethicone, Stearamidopropyl Dimethylamine, Polyquaternium 37, Polyquaternium 28, Cetyl Alcohol, Glycerin, Cyclopentasiloxane, Aspartic Acid, Propylene Glycol, Dicaprylate/Dicaprate, Fragrance (Parfum), PPG 1 Trideceth 6, Glyceryl Stearate, PVM/MA Copolymer, Dimethiconol, DMDM Hydantoin, Disodium EDTA, Sodium Hydroxide, Hexylcinnamal, Butylphenyl Methylpropional, Limonene, Coumarin, Linalool, Alpha Isomethyl Ionone, Cocos Nucifera Oil (Coconut), Keratin Amino Acid,Jasminum Officinale Flower Extract (Jasmine)

I was slightly taken aback by the ingredients for the products in the Pro-Mend line, which were not exactly what I expected to see in a novel intense conditioning formula. The major components listed are silicones and polyquaternium conditioning agents. The use of cationic polymers (polyquaterniums) is not surprising, as they are selectively attracted to damaged areas of hair (which bear a negative charge). For this reason, they can be particularly useful in smoothing damaged cuticles and managing split ends. However, this is not a novel application of these materials. At first glance, nothing else jumped out as a likely character that would be able to repair split ends.

The first eight ingredients after water are found in many conditioning products, so no surprises there. After that are oils, emulsifiers, humectants, solvents, one fixative, and other common conditioning agents. But again, none of these ingredients are really known for doing anything terribly novel in terms of hair repair. Most are topical film-formers possessing varying ability to smooth, condition and protect the surface of the hair.

So, was that it? Was Pro-Mend merely another iteration in the long line of conditioning products available? Perhaps not. After further contemplation of the formula, I began to think there was more to these products than first meets the eye.

Several ingredients stood out in the list and nagged at my subconscious. Among these were Aspartic Acid, DMDM Hydantoin, Sodium Hydroxide, Hexylcinnamal, Butylphenyl Methylpropional, and Keratin Amino Acids. These ingredients are not uncommon and each has its own typical and often mundane purpose in a product. However, some of these are capable of performing double duty, and the presence of all of these ingredients together led me to have some suspicions as to how this product could possibly do the things they promised it could do. But, I needed more information.

The Marketing Story

The marketing materials for these products were the next step in the investigation. Nexxus says that after one use of the system (shampoo, conditioner, leave-in creme, and heat protection spray), 92% of your split ends would be repaired. This is such an exact number, which can be quite convincing when used in advertising, but I could find no data published anywhere to support this. There was no description of how they defined, ascertained, or quantified repair, but they did show a nifty video of a damaged hair strand coming back together. Their marketing materials use words such as "binding" and "healing" and "nourishing" to describe the effects of their products on damaged hair.

The thing that most interested me was a brief video in which they provide instructions for the proper use of the product. After shampooing, conditioning, applying leave-in cream, and using the thermal protector spray, the consumer is directed to blow dry her hair using a round brush and to follow up with a flat iron. The celebrity stylist assures us that the repair and strengthening results will be instantaneous and will last two to three months or longer with continued use of the product.

Ding, ding, ding! With this last piece of information, my glimmer of suspicion transformed into a raging hypothesis. (Is there such a thing as a raging hypothesis? How about a really excited, bouncing up and down hypothesis? I know, I am a science nerd.)

The Proposed Mechanism

The combination of several aldehydes (hexylcinnamal, butylphenyl methylpropional), a formaldehyde-donor preservative (DMDM hydantoin), a drop of base (NaOH), a few keratin amino acids, and a recommendation to use high heat (flat iron) all indicate to me that this hair system could be exploiting the same chemical mechanism used in the Brazilian keratin straightening treatments. (reference this previous piece for more detailed chemical information about Brazilian Keratin Treatments) The general idea is that aldehydes react with amino acid side chains of hair keratin and also with the hydrolyzed keratin amino acids in the product. This enables them to effectively form bridges between the split pieces of hair and to bond new keratin onto the surface of the hair. These bridges could "glue" the hair strand back together and also give it a smoother, glossier appearance.

If this is indeed the mechanism being utilized, it is important to note that while the effect may be cosmetically pleasing and somewhat sturdy, the split ends of the hair are bound in a manner similar to a torn piece of paper that has been glued back together. It will hold and may look nice, but the weakness or flaw is still there. The crosslinked bridges that are formed by the aldehydes are not permanent and usually last two or three months.


The scientists at Alberto Culver (parent company to Nexxus) have developed and cleverly marketed a very interesting new product that promises to repair and prevent split ends. Traditional moisturizing conditioners and protein treatments provide topical smoothing for hair and can fill in some gaps in the cuticle and hair shaft. However, none have been able to bind together pieces of a hair that has split into pieces. Analysis of the product ingredients leads me to believe that this product may in fact be binding the pieces of hair together via aldehyde reactions with keratin amino acids. If so, this is a very creative application of this technology.

Without direct confirmation from someone at Alberto Culver (soon to be Unilever), I am purely speculating about the chemical mechanism of the Pro-Mend products. I did consult the literature and patent space though, and happened across at least two patents that indicate that my hypothesis is plausible. It would be wonderful to learn the exact truth, but in this competitive market, it is best to keep one's cards close to one's chest.

The important things to note about this product are that it does seem to be an effective conditioning system, and many have reported an improvement in the appearance and strength of their hair. However, it does contain aldehydes and the makers do recommend using high heat on your hair for best results—something which many of us tend to avoid due to concerns of thermal damage. Finally, while the Pro-Mend system may chemically glue split ends back together temporarily, there is just no replacement for regular haircuts.