Shampoos, Harsh, Mild and Otherwise

I've examined a number of shampoos (those that I had, I did not buy any for this project) to test the notion that certain detergents (surfactants) are harsh and others are not. I did this through examination of hairs in the shampoo under a transmitted light microscope, in comparison to those hairs dry or in distilled water. When hair is well-saturated with water, it swells. But different hair swells different amounts. Hair treated with coconut oil doesn't swell as much. Fine hair doesn't swell as much. Undamaged hair without many porosities swells less than damaged hair. I measured some hairs, dry vs. wet and found quite a difference in the amount of swelling in water.

Pufferfish, all puffed up.

Pufferfish, not yet puffed up.

Never the less, water alone makes hair swell and in so doing, causes the normally-flat cuticle to lift and this creates porosities for things to leak out or diffuse in. Wetting hair alone has a "damaging" quality. Think of a pufferfish to get the right image of what happens to the cuticle when the hair swells.

Some shampoos dramatically increase this swelling. Detergents are "wetting agents" they make water - which dissolves so many things, even more "wet" and allow more things to be washed away by water. That's an oversimplification, but it's good enough for now because the pictures are the feature of this post. Detergents also can remove oils and soils. Some detergents are very good degreasing agents and some are not. The latter are the ones you want for your skin and hair. Clean is good, but too clean is irritating!

Now the fun part:
These hairs are mostly normal porosity or not porous - not chemically treated but have some damage from sun/heat from the sun, combing and brushing and daily life. I have placed them in what some people call a "sulfate shampoo" (see below).

sulfate shampoo

sulfate shampoo, arrows show raised cuticle

Yikes!

Green/yellow stripes from shampoo uptake

Shampoo with ammonium lauryl and laureth sulfate. Do you see the frilly and ragged edges? You might not want to do this too often. The picture directly to the right is a white hair which has actually held on to the color of the shampoo after rinsing (it was green). These are very effective degreasing detergents.






This is a shampoo with decyl glucoside, lauryl glucoside and cocamidopropyl betaine - Burt's Bees Super Shiny shampoo. Very little visible change taking place. The "glucosides" are regarded as mild - not strong degreasers but good "wetting agents." You can see the cuticles appear to lie smoothly and the edges do not look ragged or frilly.

Burt's Bees

Burt's Bees

Soap bar

This is hair in the "suds" or lather of a soap bar. The non-porous, very fine hair (at left) fared worse than the coarser (thicker) hair shown below. The pH of soap and shampoo bars is high because of the reaction of oils and fats with lye or another hydroxide (strong base) which is how you get oils/fats to turn into soap. This is harsh to hair. Rinsing will immediately begin to restore the hair to its own pH and the hair begins to look normal again. An acidic rinse will speed that process (though both acids and bases can damage hair), and also help remove soap scum which accumulates when oils in soap bond to minerals in hard water.

soap bar

soap bar

Dilute C12-14 olefin sulfonate 

Dilute C12-14 olefin sulfonate

To the right are hairs in a shampoo containing olefin sulfonate, which can be a strong detergent under some circumstances.  It removes oils and soil quite well. This particular shampoo, however, has conditioning agents added and a low concentration of detergent, so you don't see much happening. Concentration matters as much as the actual "harshness" or effectiveness of a detergent.

Concentrated C12-14 olefin sulfonate - see edges
of hair for raised cuticles due to swelling. This is
an ordinary concentration for shampoo.

At left is a hair in a shampoo with a higher concentration of olefin sulfonate which contained a small amount of oil, but not enough to mitigate the shampoo's harshness. Again you can see the ragged edges at left and "lifted" cuticle at right.

Concentrated "mild" shampoo

Above, right is a hair in a "gentle" baby shampoo with decyl glucoside. The detergent may be gentle, but it is concentrated shampoo with a high percent of detergent and you can see the ragged edges showing in the hair's cuticle. Below is a shampoo with the same detergent, but it has been diluted (and thickened, which causes a slightly cloudy appearance). There is little apparent change in the hair in the diluted shampoo. The dilution or reduced concentration makes a harsh detergent less harsh. Even so-called mild detergents can be harsh if they are not diluted properly in a shampoo formula.

Dilute mild shampoo

I don't mean to give the impression that shampoo is all bad! It cleans the scalp and hair more effectively than just water. Dilute shampoos with mild detergents are not very damaging to hair (visibly, anyhow) and do a good job of cleaning soils and excess oils. Even one of the harsh shampoos can be diluted at a rate of 1-2 teaspoons of shampoo in a cup of water (or halve that if it's too much volume) for a shampoo that won't cause as much stress. If you shampoo your hair daily or every other day, you might consider diluting your shampoo or choosing a mild one. The same applies to colored (dyed) hair, chemically treated hair, curly or wavy hair, or hair which gets a lot of sun or heat styling. If you want healthy, strong hair, wash it less often. Washing with a gentle or a diluted shampoo should put less stress on the hair, leading to less damage. Even an occasional wash with a full-strength detergent with good degreasing properties isn't going to "ruin" already healthy hair.

Wavy Pride

What defines wavy hair?©Science-y Hair Blog 2013

Let’s start with this warning. Lots of us who must go online to learn how to care for our hair encounter a hair typing system. On the surface, it can help us understand what we have. But let me say now that I hate labels and categorizing. Remember the “blue eyes / brown eyes experiment?” Yeah, you get the picture. More on this later. First, some quick and dirty “bioengineering.”©Science-y Hair Blog 2013

Hair curls or waves because of the composition of proteins in the cortex of hair fibers and how the strands of proteins are arranged in the hair’s cortex (the mid-portion of the hair strand). There are cells in the cortex of some people’s hair called orthocortical cells, accompanied by paracortical cells, and mesocortical cells. How curly hair will be is determined by the proportion of these cells relative to each other, where they are located in the cortex, and what is the protein composition of the orthocortical cells.©Science-y Hair Blog 2013

This image is sourced from this website: http://www.slideshare.net/dralisyed/1-structureof-hair-euro-july-08 "The Structure of Hair,"  Sayed and Askar.

If you have curly (or wavy) hair but you are not of African descent, then you have a thin layer of orthoroctical cells, especially if your hair is also fine (small in diameter). A person with coarse (thick stranded) and very curly hair who is of African descent has far more orthocortical cells in their hair’s cortex, and a person with straight hair has no orthocortical cells.

This seems to be the best-supported hypothesis so far. And certainly a sample which covers a greater breadth of human geography would tell us more.©Science-y Hair Blog 2013

So here we have a structural and chemical difference to begin with between straight and curly and wavy hair.©Science-y Hair Blog 2013

Now throw away any notions about “hair typing” for a moment (if you have even heard of it). It’s best to avoid classification systems which can lead to value judgments and self-comparison to others. That’s just bad for self-confidence. Seriously. Hearing people wonder if their hair is curly enough to be called “curly” or just wavy or is it 2c or 3a, or looking askance at somebody’s self-declaration of their hair type – give me a break. 

Curly hair is an especially robust wave pattern and wavy hair is relaxed wave pattern. It’s all a wave pattern, looser or tighter. You don’t look at the ocean at sunset and think, “Gee, it’s too bad these waves aren’t curly.” The visual difference is the bounce. Even if your wavy hair can make curls and waves that bounce back 2, 3, 4 inches, it still tends to stay near the scalp, waving and/or curling downward in soft waves and spirals. It’s not engineered to bounce more than that. More bounce would mean that those curls would spring outward, not down. So are loose curls really waves? Are tight or spirally waves really curls? It doesn’t matter. What matters is that you understand the medium.

Get to know your wavy hair!©Science-y Hair Blog 2013

Does your wavy hair have straight ends or ends that flip or curl?

What is your wavelength? The distance from the crest of one wave to the next? Is it different when your hair is styled?

Do your waves have amplitude? Is there much depth in between waves?

Are there areas which wave together next to other areas which also wave together (share a wave pattern)? How many areas like this are there?

How is your hair different in spring, summer, fall, winter?

Visual Aid:

I love visual aids but I don’t draw well with a mouse. So you get some green decorative ribbon. 

On the left, you see what you’d call a curl. It has robust 3-dimensionality which it holds. Next you see a looser wave pattern, nearly smooth on top, curling near the bottom. You’ve seen hair like this! Next to that is a stretched-out curl or a “spiral.” It has a flatter profile in 3-D. If you have wavy hair, you may know this shape well, whether you can coax it out on demand or not. On the right is a lovely (backwards) S-shaped wave. Big and loose and bouncy.

And another: 

Left: curly, next to that, a very loose wave, then the "smooth on top" wave, the loose spiral, and lastly the big, loose S-shaped wave. I like the profile shot because it shows better how these wave patterns "wear" in real life. This set of photos was taken with ribbon of the exact same length. Two were placed higher than the others due to canine interference during photography.

These three are just some forms that wavy hair can take on. There are variations, like wavier on the outer layers  (canopy) of hair and straighter on the underlayers (understorey – borrowing a term from biology/ecology). Or the other way around. Or curly in front and wavy in back (or vice versa). If you have wavy hair, you may have a mix of all these hairs on your head (I do). Then the median takes over.

Curly hair can often be "molded" - you can wrap it around your finger either wet or dry to shape or "set" a curl. Wavy hair rarely does this - the spirals are much softer. If you press a wavy spiral upwards, you might get a coil of an inch in diameter (or more or less) but when you let go, the diameter decreases. Wavy curls don't have the determined springy bounce and preservation of diameter of curly curls. And that's perfectly okay, they have graceful, flowing movement unique to waves. I'm just trying to describe the behavior and motion of the fiber, not put a value on it.©Science-y Hair Blog 2013

"Wavy" seem to be a very misunderstood hair texture – often mistaken for un-brushed, unruly “straight” hair or hair which needs to be “fixed” (curled or straightened), leading many wavy-haired people to never learn to make the most of their locks and never allowing them to feel that this important aspect of visual appearance which belongs to them is good enough for public viewing. Your waves and curls are not broken and they don’t need fixing. They just need to be understood, empathized with, given care and encouragement. Hey, don’t we all!

Sources: ‪Chemical and Physical Behavior of Human Hair 4^th Ed.

Clarence R. Robbins, Springer Verlag 2002

Mysteries of Hydrolyzed Proteins

Updated: October 2017

I have been researching various proteins used in hair products. Claims that this or that protein are high or low molecular weight and therefore good for this or that fell short of an adequate explanation. And some people can use one type of protein, but not another. Some proteins are lauded as being good for certain hair concerns. Okay, why?

The weight of the protein does play a role, and it makes sense if you compare proteins. I converted all weights to the unit “Daltons.” Smaller numbers are easier to deal with, reducing them to Kilodaltons gave some numbers which seemed a bit misleading.

Hydrolyzed Protein Source	Weight in Daltons
©Science-y Hair Blog 2017
Amino Acids	Less than 200 (usually)
Human hair keratin	400
Silk	300-1000
Avocado	300-1200
Keratin	300-3000
Hazelnut	500-1000
Wheat (low molecular weight)	1000-1500
Collagen	1000-10,000 (depends on the supplier)
Amaranth	1500 (approximately)
Corn	1000 (approximately)
Soy	1000 (approximately)
Milk	1000 (approximately)
Oat	1000 (approximately)
Rice	1000-3000
Sweet almond	3000 (approximately)
Gelatin (partially hydrolyzed collagen)	60,000 – 200,000 (from a variety of sources)
Jojoba	180,000-240,000
Quinoa	300-200,000

Each hydrolyzed protein may have amino acids and peptides in the solution as well (smaller molecules).

My sources are varied and so some are showing a range, including peptides (very small “protein” fragments) some show only an average. You can see that some proteins have a broader range of “protein sizes” which refers more to the methods used to identify the protein’s constituents and what I could find reported for that protein.

What is means for your hair: Low-weight hydrolyzed “proteins” are less than 1000 daltons. They’re not whole proteins anymore! Very small molecules (200 to 500 daltons) can penetrate the hair beyond the cuticle. Any and all of these proteins may contain smaller constituents that may penetrate. Penetrating into the hair can help improve elasticity of hair and moisturize deeply.

“Heavy” weights greater than 10,000 (or 80,000 depending on which source you consult) daltons are thought to be good film-formers for shine, body, helping fill in porosities in the cuticle. They are acting at the cuticle, forming a moisture-holding, protective coating and also having the potential to improve hair’s elasticity and strength. 

Medium weight protein hydrolysates (1000 to 5000 daltons) are substantive to hair (bond to hair, don’t rinse off readily). This helps reduce friction (tangling, difficulty combing) which ultimately reduces hair breakage. 

If you want a maximum protein boost, choose a mixture of proteins.

If your hair reacts badly to, say, hydrolyzed rice or quinoa protein but not to keratin, you may have your answer – the hydrolyzed rice or quinoa is forming a film on your hair, first and foremost whereas some of the keratin is also penetrating the deeper cuticle layers and possibly into the hair fiber.

Some hair will respond well to only certain proteins, or only in certain amounts. Light and medium weight proteins help keep hair hydrated by preserving water in and around the hair. Heavy-weight proteins help keep hair hydrated also by forming an invisible film (like a "glaze") over your hair.
There is a post here about the amino acid content of some proteins that further explains why some proteins may work better than others, but for a different reason.

Damaged (porous) hair may appreciate a broad range of proteins, amino acids and peptides to fill in the gaps of damaged cuticles, moisturize, and bond to the hair for ease of combing.

Proteins (top molecules) heated in an acid,
in the presence of water breaking into smaller "pieces"
thus a hydrolyzed protein.
Image from: http://www.chemguide.co.uk/organicprops/aminoacids/proteinhydrolysis.html

Proteins are used as humectants in cosmetics. But they're not humectants like glycerin or sorbitol or propylene glycol which are more "sugary" in nature. In fact - I think a food analogy is good here. If you put some wet brown sugar and some raw egg white on a plate and wait to see which evaporates first - the sugar dries faster. The proteins in the egg white do not release their water as easily. And as you may know - raw egg white dries to a very stiff film. I'm not advocating putting raw eggs in your hair. The proteins are too large to be useful. But you get the idea.

Hydrolyzed proteins in your hair products do the same thing - as humectants they attract and hold water and as protein-based humectants they lose that water slowly. Unlike glycerin or sorbitol or propylene glycol. Because water is what keeps hair hydrated and well-hydrated hair is strong and flexible, this is a wonderful benefit! Proteins or amino acids are ideal for silky or soft hair which is weighed down easily by oils and conditioners. Or for hair that snaps when you run your fingers through it.

There is a list of protein-containing shampoos and conditioners in the "Products By Category" page on this blog.

Deep Conditioning

Sounds so nice – deep conditioning for your hair. And yet it seems impossible because hair is not living tissue. You wouldn’t try to deep condition a damaged, old wool sweater, would you? But then we don’t subject our woolens to the same handling we subject our hair.©Science-y Hair Blog 2013

Deep conditioning hair really means several things: softening the hair, bonding compounds to the damaged areas to make hair “hydrophobic” or water-repelling like healthy hair. Deep conditioning is meant to maximize those things which conditioner does for your hair: reducing friction to prevent tangles and resulting breakage from combing and other mechanical damage, sealing in moisture, adding flexibility and softness.

©Science-y Hair Blog 2013

There are several aspects of deep conditioning: product distribution, substantivity (ingredients bond to your hair rather than rinsing off), product penetration into the hair, duration (time of treatment) and use of heat.©Science-y Hair Blog 2013

Distribution: To thoroughly condition your hair, you need good product distribution which means combing or scrunching in a conditioner. When people use shower caps or plastic wraps, they are also improving distribution. Like painting a wall, the coating needs to be both even and thick.

©Science-y Hair Blog 2013

Bonding: Cationic ingredients and proteins bond to your hair, filling in the gaps (porosities) caused by damage and daily handling, also creating a thin layer of lubrication so that your hair is less prone to tangling, easier to comb, and aligns with the neighboring fibers better - which is key to having lustrous (shiny) hair that feels soft.©Science-y Hair Blog 2013

Penetration into hair: Some ingredients have the potential to penetrate into the hair (beyond the outer, cuticle layers) such as coconut oil and Cetrimonium bromide. Another which I do not have research data for, but which has low enough molecular weights (short enough carbon chain) is Cetrimonium chloride. So if your conditioner has any of these ingredients, it already has greater potential to be a “deep” conditioner.©Science-y Hair Blog 2013

Duration of conditioning treatment: I’ve read that cosmetics chemists (those who design hair products) maintain that a product will not do more good if you leave it on longer than stated on the bottle. And yet I find information to contradict this. It’s probably not a good idea to leave conditioner on your hair for hours or overnight because these are products meant to be rinsed off and you may not want some of these ingredients to have contact with your skin for an extended period. That being said, the longer a hydrolyzed protein, a conditioning polymer such as polyquaternium-4 or quaternium-26 or cationic surfactant such as Cetrimonium bromide stays in contact with your hair, the more is adsorbed to the hair and, where possible, penetrated into the hair. So if you prefer to condition for longer than a few minutes, you may benefit. Or you may end up with limp hair. But it will be soft, limp hair! There is a point at which the hair has bound all the proteins and/or conditioners it can and cannot "use" any more. ©Science-y Hair Blog 2013

Heat: Do products which are not designed to be used with heat, work better with application of heat? Possibly. 
1) Heat liquefies ingredients somewhat and this improves distribution, allowing oils (especially "solid" oils like coconut oil or shea butter) to spread and penetrate if they can. If you’re adding heat, you’ve probably wrapped your hair all up, also improving distribution. 
2) Heat speeds up reactions; when ingredients are bonding to your hair, it is a chemical reaction. Heat also creates a very moist environment, all that moisture is there while the hair is swollen from having been wetted, from being in the presence of a wetting agent (conditioner) – so the humidity created by adding (moist) heat is probably beneficial, protecting the hair from water loss during the process.
You can add heat by putting on a heat wrap or wearing a shower cap or plastic covering over your hair, or you can warm your conditioner first. But don't zap it in the microwave - heat some water in a dish and then set your conditioner in a smaller dish, in that bowl of water to heat gently and evenly.

  

References:

Journal of Cosmetic Science, 56, 323-330 (September/October 2005)

Penetrationon of Cationic Conditioning Compounds into Hair Fibers: A TOF-SIMS Approach

S. B. RUETSCH and Y. K. KAMATH, TRI/Princeton 

Journal of the Society of Cosmetics Chemistry, 43, 259-273 (September/October 1992)

Assessment of the Substantivity of Cationic Quaternary Compounds to Hair by Potentiometric Titration Using the Surfactant Electrode

NGHI VAN NGUYEN, DAVID W. CANNELL, ROGER A. MATHEWS, and HANS H. Y. OEI, Redken

What's Cooking This Week (8-13-11)

Flaxseed curl cream! If you like "all in one" products or are just looking for something new to try without actually shelling out cash, mix up some of this curl cream. The recipe is also at the bottom of the "Recipes and Projects" page.
©Science-y Hair Blog 2013
Flaxseed Curl Cream:

Combine: 
1 tablespoon thick, rich conditioner (use less for fine hair) - add a few drops of canola oil or whatever oil you like if the conditioner has no oil in it
2 tablespoons flaxseed gel (with protein added if your hair likes it)
1 tablespoon strong hold hair gel
optional: 4 drops honey or agave nectar ( or 1/8 teaspoon or more - this is meant to add more "hold")
©Science-y Hair Blog 2013
Apply fairly liberally, style as you usually do.
This gives great curl definition and "clumps," controls frizz, enhances curls and feels soft in the hair. For the hair gel, use whatever feels like "strong hold" to you - whatever you have on hand. You can always use more honey or agave if you need more hold.
©Science-y Hair Blog 2013
Cut the batch! (Trial size) Use:
1 teaspoon of conditioner
2 teaspoons of flaxseed gel
1 teaspoon of strong hold hair gel
(optional) 1-2 drops honey or agave - not as good in high humidity.

The ratio of ingredients if you want an even smaller batch is:
 2 parts flaxseed gel
1 part strong-hold gel
Anywhere from a drop to 1 part conditioner
1-3 drops oil (optional)
1-4 drops agave or honey (optional - not good in high humidity)

Preserving Your Homemade Hair Gels

If you make homemade hair gels (I won’t discuss other products right now because ionic-charged ingredients in conditioners or shampoos makes preserving more complicated), and you do not store them in the refrigerator – or if you usually do, but are going away from home, then you need to think about preservatives. This refers to flaxseed based gels, vegetable gum based gels (guar gum, xanthan gum), aloe based gels, or any other vegetable-based gel (psyllium, okra…).

©Science-y Hair Blog 2013

How Can A Product Go Bad?

Rancidity can happen to oils (aka oxidation) if you use them.©Science-y Hair Blog 2013

Bacteria or fungi can grow, using the sugar and nutrient-rich gel for food, also excreting their metabolic wastes into the gel causing cloudiness, fermentation, changes in thickness and texture and odor.

These are the biggies, not only because they ruin your gel, but because the bacteria (or fungi) growing in your un-preserved, un-refrigerated gel could be pathogenic. Let me get up on my soapbox for a moment. We need not fear bacteria everywhere. Every bit of our bodies is permeated with bacteria and other critters and without them, we would be weak, sick, malnourished and completely different than we know ourselves to be. Having said that, bacteria on your skin, in your guts are not usually making you sick. But if you get a cut, then there’s an opportunity for an infection. If bacteria end up where they should not be, or if they have a chance to colonize a medium and grow like mad (or even form self-protecting biofilms like plaque on your teeth) – then you’ve also got a problem. So if your hair gel turns into growth media for bacteria and fungi and it gets on your hands and then in your eyes, on a tiny cut, in your mouth etc., it’s a problem. Especially for gels based on food-quality items. I found bacteria from the Staph/Strep families, and others which would be food-born pathogens in unpreserved, unrefrigerated, homemade hair gel.©Science-y Hair Blog 2013

If you want to preserve your flax-based or gum-based gels, there are some safe, easy ways to do this. I have tested some preservatives, and my data have been added to by some other people with preservatives I have not yet tested. I began with 2 bases, one was flaxseed gel with agave nectar and hydroxyethylcellulose, the other had olive oil added as well. For each gel, one sample was refrigerated and one was left at room temperature. I did a un-preserved control too. I used a Gram-stain test to detect bacteria in the gels as they were. This is a different method than used by cosmetics companies - but it gives us a rough idea of how our preservatives are working.©Science-y Hair Blog 2013

Preparation Notes: Even if you’re refrigerating your gels, it’s best to use distilled water to prepare them (no chlorine or minerals) and to wipe down all your utensils and nearby surfaces with rubbing alcohol. Remember, this isn’t just "cooking," you’re planning to keep using this for longer than a week – you need to be careful! Put your gel in a bottle with a lid. If it’s in a cup where you’ll be sticking your fingers into it, you dramatically increase the potential for contamination. And spilling (trust me about the spilling bit).©Science-y Hair Blog 2013
Why are preservatives given as percentages? That's the best way to measure. If you need 0.5% (half of one percent) preservative, that is 0.5 grams per 100 grams. Or 1.25 grams per cup (250 grams). 1.25 grams is one full quarter teaspoon (1/4 tsp) per cup of gel. You will have a much more accurate preserving experience if you weigh your gel, do the math, then weigh your preservative accordingly. It is difficult to weigh out grams on an inexpensive kitchen scale - you need one that reads at least "0.00" or gives you 2 decimal places. 
Here is the math: weight of gel in grams x % preservative recommended by manufacturer in decimals. For example, your gel ends up weighing 236 grams and you're using 1% preservative. Multiply 236 x 0.01 = 2.36 grams. 
If you must "fudge" and use measuring spoons (approximate measurements, you will probably not get exactly this percent using a measuring spoon):
1/4 teaspoon per full cup =  0.5%
1/2 teaspoon per full cup = 1%
Ideally, we subtract the weight of each additive from the total when formulating products (add one gram preservative, subtract one gram gel). If your product goes funky because the measuring was off - don't say I didn't warn you. Just don't use it! And if you make a product to give a friend or family member - please use a preservative. Friends don't let friends use contaminated hair gel.

©Science-y Hair Blog 2013

The scorecard (hits, misses, and so-so):

Hit!

Preservative: Refrigeration: Regardless of the additive (agave nectar, oils, protein, thickeners), refrigeration for up to 2 weeks prevents or effectively inhibits the growth of bacteria and fungi to the point at which they are scarcely present. If you don't use up a batch of gel in 2 weeks and you're not using a commercial preservative, freeze half.

So-so (at room temperature):

Preservative: Citric acid (1/8 tsp), potassium sorbate (0.2%), vitamin E (0.2-0.3%): This may work for you, but when I tested it for bacteria, I found small quantities of bacteria and lesser amounts of fungi at 2 weeks time. The gel had begun to look cloudy. The citric acid discourages some species of bacteria, the potassium sorbate inhibits fungal (mold) growth (and you could double the amount of potassium sorbate). But this won’t preserve for a long time. If refrigerated, this preservative combination is perfectly adequate.

Hit!©Science-y Hair Blog 2013

Preservative: Citric acid (1/8 tsp), potassium sorbate (0.2%), vitamin E (0.2-0.3%), EDTA (disodium or tetrasodium EDTA) at 0.2%: This appeared to have very good preserving qualities with virtually no bacterial or fungal contamination at 2 weeks at room temperature or refrigeration. EDTA is not only an antioxidant, but it inhibits cell wall formation in bacteria. 2013 update: The pH of this may be a bit low, start with much less citric acid, adding a little at a time and use pH strips to make sure the pH is above 4.5.

Miss©Science-y Hair Blog 2013

Preservative: Cosmocil CQ (Polyaminopropyl biguanide, 0.5%) and potassium sorbate (0.2%): A very mild (to the skin) preservative which must be paired with another preservative to inhibit fungi (mold). Not a good result. The preservative made the gel look cloudy and thicker from the beginning, and there was a film over the surface at 2 weeks in the un-refrigerated sample which appeared to be mold. I was not able to identify what sort of mold. No bacterial growth was evident, and the percentage of potassium sorbate could be increased – but this preservative made an aesthetically and texturally unpleasing product from the start, thus is was a “miss.”

Hit!©Science-y Hair Blog 2013

Preservative: Sodium Hydroxymethylglycinate (0.5%) and citric acid to balance the pH:

There was no evidence of bacterial or fungal contamination in the refrigerated or unrefrigerated samples. The gel was crystal-clear and the preservative did not change the texture or thickness.

A word of caution: this preservative is a potential formaldehyde releaser and may irritate skin which is sensitive to formaldehydes. I can tolerate it, although I cannot tolerate other formaldehyde releasers, so to each their own. This preservative raises pH and it is necessary to bring it back down with citric acid so that it is not damaging to the hair.

Hit!©Science-y Hair Blog 2013

Preservative: Optiphen Plus (Phenoxyethanol, Caprylyl glycol and Sorbic acid, 0.5%):

This preservative may not work well if you use hydroxyethylcellulose in your gels (it may be rendered less effective). I have not tested this for bacteria yet, I am sensitive to this preservative. I have used it in other products and I know of another person who used it in a complex flaxseed gel mixture with no evidence of contamination after almost a month. Contaminated flaxseed gel has the advantage of becoming cloudy at low contamination levels. Optiphen Plus makes thick polysaccharide gels like flaxseed gel slightly less stringy (alters viscosity when added). It is a broad-spectrum preservative effective against bacteria and fungi.

Other preservatives I have not tested (that gets expensive!) which should be compatible with homemade gels so long as you are not adding any commercial conditioners (and possibly cellulose derivatives) are: Tinosan, Phenopip, Germall Plus, Germaben, and Geoguard Ultra.

If your homemade natural hair gel becomes cloudy, changes color, changes odor or viscosity (thickness, texture), throw it out!

On the Go: If you are away from home, no matter how well you’ve preserved your product, it should not be left in a hot car or in the sun. An exception would be putting a single-use of gel in a small bottle in a gym bag or purse to use that day. My travel tip is to bring along a cooler and stash the gel in there (along with food – hey, I travel cheap)! If you are flying or taking a train, you can stop at a store at your destination and purchase a small cooler (even a large, insulated coffee cup will do if you pack some ice around your bottle of gel).©Science-y Hair Blog 2013

A note about additives and grapefruit (seed) extract:

If you use ingredients such as prepared protein additives, these are pre-preserved. But don’t count on the preservative in there to protect your product. It may help a little, but it’s not enough.

Grapefruit seed extracts have not been demonstrated to be true preservatives. Sometimes they work because of the preservatives added to the grapefruit seed extracts to keep it from going bad (said preservatives are usually not on the product label), but don’t trust these products to keep yours from becoming home to colonies of bacteria and fungi. If you want to use grapefruit seed extract, buy it from a cosmetics-ingredient supplier so you are getting a concentrated product meant for preserving cosmetics. If the bottle says it's safe to ingest, it is probably not going to preserve your hair products for very long.©Science-y Hair Blog 2013

Clean Bottles!
When you’re done with your gel, if you wish to re-use the container, wash it well with soap and water (and a bottle brush if you have one), then use diluted bleach or rubbing alcohol (or un-diluted white vinegar) to sterilize. Pour a little in the bottle, cap it, and shake it up. Leave the bleach or alcohol in there for 20 minutes, shaking several times during the interval. Run some disinfectant through the cap if it’s a flip-cap. Then empty and rinse.
Here is a link to a post about cleaning bottles for your homemade gel.

Preservatives Which Can Itch

Preservatives are a common source of skin irritation or allergic reaction in cosmetics and hair products. This is a short list of common offenders to suspect if a product causes problems for you:

Benzyl alcohol

Imidazolidinyl urea

Diazolidinyl urea

Sodium Hydroxylmethylglycinate

Methyl, Propyl, Butyl, and Ethyl Parabens

Phenoxyethanol

DMDM hydantoin

Quaternium-15

Methylisothiazolinone©Science-y Hair Blog 2013

Those in italics are formaldehyde releasers. Formaldehyde is an excellent preservative, but can be commonly irritating to skin and is dangerous to breathe (carcinogenic).©Science-y Hair Blog 2013

Amino Acids in Hair Products

Updated: March 2019.

What Are Amino Acids:

Amino acids are very small molecules, they’re not even “proteins” on their own, they’re the constituents of proteins formed from an amine group (nitrogen-containing, and all things proteinaceous contain nitrogen), a carboxylic acid group (carbon, hydroxide or “OH” and oxygen) and a side chain with a varied number of carbons, nitrogens, hydrogens, occasionally sulfur. To have a protein, you put these amino acids together.©Science-y Hair Blog 2013

Where Are They:

In hair, there are many amino acids (one source I have lists 20). The cuticle of hair – it’s multi-layered outer coating of “scales,” contains more amino acids than in the inner parts of the hair fiber - partly because proteins break down into amino acids and there is always protein being broken down at the cuticle. The outermost layer of cuticle (which can be missing at the ends of very long or damaged hair) contains more cysteine forming cross-links with other proteins – creating a strong, resilient outer cuticle. Cysteine is a sulfur-rich amino acid. I imagine this like “cuticle glue.”  Also in high amounts in the cuticle are glutamic acid, proline and valine.

In the epicuticle (a protein-heavy, lipid-rich covering over the cuticle) there are large amounts of glutamic and aspartic acids and lysine.©Science-y Hair Blog 2013

Amino acid content in hair increases with exposure to UV light and to bleaching chemicals or “retexturizing” (permanent waves, chemical relaxers) – as breakdown products from the hair proteins resulting from these processes.

Do Amino Acids Stay on My Hair?©Science-y Hair Blog 2013
You may have heard that amino acids simply rinse away when they are included in a shampoo or conditioner. This is not entirely true. If you apply amino acids to hair mixed in only water, hair will take up as much as it can (there is a point at which the hair will stop adsorbing amino acids when it reaches equilibrium with the solution into which you’ve placed it). But if amino acids are present in a formula (like a conditioner) including cationic surfactants, adsorption of amino acids becomes more difficult because they interact with the other ingredients. In general, studies have shown that the addition of amino acids to a formula helps damaged hair regain it’s hydrophobicity or it’s water-repellent quality which means that amino acids help fill in porosities (gaps in the cuticle). Healthy, undamaged hair is also hydrophobic/water repellent. Amino acids can also strengthen and moisturize the hair because of their water-attracting habit.

Which Amino Acids Work Well (or “should” work well):©Science-y Hair Blog 2013

Of those tested, arginine was strongly attracted to hair. Histidine and phenylalanine improved the strength of hair, but only histidine, phenylalanine, glutamic acid, arginine, alanine, and isoleucine, were studied in the reference I am using. Many were left out!

Usually one finds amino acids listed as “silk amino acids” or "methionine" or “wheat amino acids.” Which should you look for?

Here is what I can find from manufacturers’ descriptions of amino acid additives regarding their constituent amino acids which are present at the highest percentages (they do contain a variety of other amino acids). The italics refer to amino acids which occur in high amounts in the cuticle and epicuticle of hair.©Science-y Hair Blog 2013

Silk amino acids: alanine, glycine and serine

Wheat amino acids: cysteine, glutamic acid

Oat Protein and derivatives: glutamic acid, aspartic acid, proline, alanine

Soy protein and derivatives: phenylalanine, tyrosine, leucine

Keratin amino acids: cysteine, serine, glutamic acid

Cysteine - check out those sulfurs!

Interior or exterior of hair? Amino acids tend to have molecular weights less than 200 g/mol. This is small enough to penetrate into the cortex of hair (and into skin as well). Amino acids can move into the hair's cuticle to help retain moisture for good hydration.cience-y Hair Blog 2013

Other notes: If you are allergic to any of these ingredients (like wheat) or have an intolerance which causes severe physical symptoms, you may also need to avoid the hydrolyzed versions of the proteins. 13

Does it really work to try to “replace” amino acids in the hair with amino acids from an outside source? Difficult to say. Whether it is because the amino acid from a hair product takes on a functional role (literally replaces that which was lost and starts playing the same role) or just plays a supporting role, they are effective moisturizers and therefore do have benefits in rinse-off and leave-in products.

Sources:

Journal of Cosmestc. Science, 58, 347-357 , 2007

Hair and amino acids: The interactions and the effects

E. Oshimura, H. Abe, and R. Oota

Chemical and Physical Behavior of Human Hair 

Robbins, 1994. 3^rd Ed. Springer-Verlag, New York