Understanding Hair Butters and Oils- Natural Hair

Tonya McKay writes;

Butters, oils, and waxes all come from fats that are derived from plants or animals, and have two basic components; fatty acids and alcohols. The difference between butters and oils is primarily whether or not they are solid at room and/or body temperature. Although they are both composed of groups of fatty acids, there are differences in the molecular composition and structure of butters and oils that are responsible for these differences in melting points.

Factors that determine melting point of lipids
  • Molecular weight – lower-molecular-weight fatty acids have a lower melting point, so that they are liquid at room temperature or body temperature. Higher-molecular-weight fatty acids form crystalline structures that persist to higher melting points, and so they are usually solids at room temperature and higher.
  • Saturated molecular structure — longer-chain fatty acids without any double bonds are straight chain molecules (like long snakes) that are able to closely pack next to one another This close-packing induces crystallization, which requires more energy to break apart than molecules not packed together into a crystalline or semi-crystalline structure. For this reason, the melting points of these types of fatty acids are much higher. This means the “oil” will exist in a solid state at room temperature or even body temperature.
  • Unsaturated molecular structure — unsaturated molecules have at least one double bond somewhere in their structure. This creates a kink or branching effect in the geometry of the molecule. This prevents unsaturated fatty acids from getting too close to one another, thereby preventing crystallization. These molecules have lots of space between themselves, which allows for more mobility of the molecules and results in a lower melting temperature. These oils may be liquid at room temperature or melt upon contact with skin.
  • Stearic acid, a saturated hydrocarbon molecule with 18 carbons (relatively long-chain fatty acid) has a melting point of 69.6°C (157.28°F). Oleic acid, a monounsaturated hydrocarbon molecule, has a double bond in it that creates a kink in its geometry, which makes it more difficult for adjacent molecules to pack tightly next to one another. It has a melting point of 10.5°C (50.9°F). Polyunsaturated acids, such as linoleic and linolenic, have multiple kinks in their chains and are liquid at very low temperatures (melt point = -5°C (23°F) for linoleic acid).
  • Linolenic acid, polyunsaturated fatty acid.
  • Linoleic acid, polyunsaturated, omega-6 fatty acid.
  • Oleic acid, monounsaturated fatty acid.
  • Stearic acid, saturated fatty acid.

The Buzz About Honey

CurlChemist Tonya McKay writes;

If you peruse the CurlTalk discussions, you’ll see honey mentioned on numerous threads.

This should come as no surprise, given honey’s long history as a health and beauty ingredient.

The use of honey has been documented throughout human history, with mention found as far back as in various Sumerian tablets. The practice of cultivating bees for the purpose of harvesting their honey was an integral part of ancient Egyptian culture. Honey was widely used in Egypt and Babylon as a hair and skin treatment, in cosmetic mixtures, for medicinal purposes, and as a bath component. Through trading, honey gradually found its way into the lives of humans all around the globe.

During the post World War II era, many natural ingredients typically were replaced by lab-synthesized chemicals, which were touted as being superior to nature and were valued for being “modern.” Recently natural ingredients are experiencing a renaissance. This has driven the cosmetic industry toward the development and marketing of products containing natural ingredients such as honey.

There are many hair and skin-care products being marketed that highlight the inclusion of honey. There are also many recommendations for the use of honey in recipes for home conditioning treatments and rinses for curly hair.

So what’s the real story on honey? What sorts of things should one be aware of when using honey in a hair-care routine?

Read on...

What's the Scoop on Silicones?

CurlChemist Tonya McKay of NaturallyCurly writes;

We always get lots of questions about silicones, as they are in so many products and are of ongoing concern to many curly-haired consumers. I thought this month we could tackle a couple of those questions in a quick, practical manner (hopefully) to aid in the seemingly never-ending process of ingredient scrutiny and product selection.

Q: Is there any way to rank silicones in order of their water solubility and also recommend the best surfactants to remove each category?

A: It is difficult to actually rank the silicones in order of water solubility, simply because they are usually either soluble or not. Most silicones are water insoluble due to being non-polar, but there are a few that are chemically modified in order to render them more compatible with water. The following table lists the main types of silicones found in hair care formulations. It also indicates whether or not they are water soluble and includes which surfactants can be used to ensure good removal of the silicone from the hair. Studies done by Dow Corning have found that the water-insoluble silicones show no appreciable buildup when a shampoo containing one of the recommended surfactants was used.

Read on...

What is pH and What Does it Have to do With Hair?

“pH” is an abbreviation for “potential hydrogen” and is a scale used for ranking the relative acidity or alkalinity of a liquid solution. The precise mathematical definition of pH is the negative logarithmic value of hydrogen ion (H+) concentration in the solution. pH = – log [H+]

A scale of zero to fourteen is used for pH, with 7.0 being a neutral solution (water). A number below 7.0 is considered to be acidic, with a lower number being more acidic, and anything above 7.0 is considered to be alkaline or basic, with 14 being the strongest alkaline value. Due to the logarithmic nature of the pH scale, a solution with a pH of 2.0 is ten times more acidic than one with a pH of 3.0. Human hair is a solid material, a composite of protein molecules with three distinct layers. The central portion called the medulla is not present in every hair and is usually just made up of air. The surrounding layer, known as the cortex, is composed of bundles of fibrous coils made of keratin protein molecules that supply the hair strand with its strength and elasticity. The cortex also contains particles of melanin, which impart color to the hair strand. The outer layer is comprised of multiple layers of overlapping, keratinized scales and is called the cuticle, which acts to protect the cortex and medulla. Hair and skin are both covered by a very thin fluid layer comprised of oil, salt and water, called the mantle, which is slightly acidic (pH = 4.5 – 5.0). This acid mantle is very important in maintaining the proper moisture balance in our hair and skin. It is also instrumental in making the cuticle scales lie flatter against the surface of the hair shaft, which makes hair smoother and shinier as the flat scales reflect light more coherently. Scales that lie more snugly against the hair shaft also prevent moisture loss more efficiently, which helps hair to be stronger and healthier. With the normal exposure to the environment as well as washing and styling, this acid mantle can become contaminated or removed and must be restored with the use of properly pH-balanced products.

The Truth About....

Sodium Lauryl/Laureth Sulfate- the cleansing agent in many commercial shampoos.

I ran across this article in a thread on Naturallycurly.com and asked JC to do her thang! The article claims that "soaps and shampoos containing sodium laureth sulfate can lead to direct damage to the hair follicle, skin damage, permanent eye damage in children and even liver toxicity". Find her response below:

This article is yet another example of poor interpretation of science. Here are the facts. SLS (both laureth and lauryl) is a foaming detergent. It is used to create the suds that people like in shampoo and toothpaste. It is a cheap and effective cleanser.

It is an irritant(this is why you don't want shampoo in your eyes). The tear-free formula shampoos and shower gels for kids generally do not contain SLS (not always but often). It is not carcinogenic but has sometimes been found to be contaminated with a different carcinogenic chemical. A small number of people are sensitive to SLS and it can cause dermatitis (inflammation of the skin).

It is often reported that SLS shampoos can dry hair and break it. Yes some people find SLS to be drying, this is usually fixed by following up a shampoo with a conditioner so that you can correct the charge on the hair and help the cuticle to lie back down. SLS specifically lauryl sulphate is used in the lab to break down proteins. You would however need a significantly concentrated amount than what you get in a shampoo bottle or 20.

Lastly the article says SLS mimics oestrogen in the body. Now my head was spinning and I couldn't quite grasp this. What? How? What kind of chemistry? At the risk of my computer shutting down on me for sheer madness, I decided to push all my reservations aside and look for any scientific paper that says this. Needless to say, I didn't find any ( I did find 10 similar sites though to this which all state this as a fact without any references). Interestingly, there were topics about adding SLS (in an active concentration) to help fight HIV infection which is new to me, so my search was not entirely fruitless.

In the end, you can choose to use SLS-free shampoos if you are concerned or have experienced sensitivity or dry hair. These cleansers are perhaps not always as effective as SLS but they are available and may be gentler to your hair. If you have an SLS shampoo, you are using one of the most researched cleansers out there.

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