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The Science of Beauty

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I use beauty products and I am a curious scientist....so I will dig up some answers and try to make the world of beauty a bit more intellectually fascinating!

Do you want to learn how cosmetics such as lipstick, mascara and hair dye are made?

Go to How Products are Made,

scroll down a little and then choose from the alphabetical list. 

Fascinating! 

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Because I can't know all of this stuff on my own:

Check out The Beauty Brains 


View a lovely animation on the penetration depthsinto the skin by thevarious wavelengths of light at L'Oreal

Everything you EVER wanted to know about hair can be found at L'Oreal

 

 The Chemistry of Mascara

 I have some vague recollection of first learning about chemical bonds and hydrophobicity and hydrophilicity of molecules sometime in high school. Important chemistry concepts indeed. My curiosity about mascara (which is one of two MUST HAVES for me in the make-up department, the other is more crucial: under eye concealer) and especially my new affection for L'Oreal's Beauty Tubes Extend Lash provoked me to make a demonstration video about three different types of mascara: water soluble, water proof and the new Beauty Tubes. It's sort of long, but it is a real time demo/discussion. I wish I could say I was a polymer chemist, but I'm not...I know just enough to be dangerous!

 

Without turning this into a full-fledged chemistry tutorial, I will quickly quickly discuss various type of chemical bonds as this plays a part in how the various mascaras work. We can divide chemical bonding into two types: covalent and non-covalent.  Non-covalent then can be further subdivided into three different types: ionic, hydrogen and van der Waals.  Overall, covalent is a very strong type of bond formed primarily by sharing electrons (there can be single or double bonds, but we won't worry about that here). 

Before we go onto weaker types of bonding, let's quickly talk about polar vs. non-polar molecules: In a polar covalent bond, electrons are shared unequally, usually between two different atoms such as -O-H (oxygen and hydrogen) and -N-H (nitrogen and hydrogen) resulting inpartial negative charge on one side of the molecule and a partial positve charge on the other. We most certainly see this in water, and this sets up an opportunity for spontaneous electrical attraction and bonding.

On the other hand, the bond between carbon and hydrogen -C-H has the electrons attracted more equally by both atoms and is fairly non-polar. We will see the importance of carbon-hydrogen bonding in the formation of oils, waxes, lipids and plastics in a bit.

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Above is an image from Essential Cell Biology by Alberts, et al about Water as a solvent.  When a substance dissolves in a liquid, the mixture is termed a solution. The sugar in this image is the solute and the liquid that does the dissolving is the solvent.

For our discussion of mascara, we will focus on non-polar covalent bonding and the weaker hydrogen bonding.

Water is held together by hydrogen bonds. In each molecule of water, the two H atoms are linked to the O atom by covalent bonds. Again, without all the details, water is highly polar because of the imbalance of electrons between the O and the Hs. Two water molecules, when in close proximity to each other can establish a weak bond called a hydrogen bond. These can be broken by random thermal motions and each bond lasts only a short time.

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 Molecules such as alcohols or urea (see above image) that contain polar bonds and can form hydrogen bonds mix well with water. (molecules that carry positive or negative charges-ions-also dissolve readily in water). These molecules are termed hydrophilic, meaning that they are "water-loving"

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Hydrophobic molecules are generally uncharged, form few hydrogen bonds and do not dissolve in water. In these molecules, the H atoms are covalently linked to C atoms by nonpolar bonds.

Let's look at a few molecules from the water soluble (hydrophilic) mascara: (water, glyceryl stearate, ammonium acrylates copolymer, polyvinyl alchohol, alcohol)

The fact that the first molecule listed on the ingredients is water gives a clue that the next items are water soluble. The ammonium (contains Nitrogen) indicates that we have a molecule with a potential to be hydrophilic because it will most likely be in a polar molecule. Alcohol has the ability to dissolve both polar and non polar substances--a very good solvent.  Polyvinyl alchohol has many purposes, one being that it is a good adhesive to the lash.

And from the waterproof (hydrophobic) mascara (petrolum distillate,  polyethylene, caranuba wax, pentaerythrityl hydrogenated rosinate, tall oil glycerides)

If you see the word wax, or oil or fat, then you know you are dealing with hydrophobic molecules (all cell membranes have a long hydrophobic portion). These all are long hydrocarbons and must be dissolved in an oily substance (petroleum distillate) to be able to be in liquid/gel form in order to be applied to the lashes. The only way to dissolve these from the eyes is an oily make-up remover or a harsher solvent that can break the covalent bonds. We follow the rule "like dissolves like".

When looking at the formulation list for the Beauty tubes, I sense a more sophisticated polymerization (forming of long chains of molecules from smaller parts) and plasticizing process occuring there. This doesn't surprise me as I've never had flaking or smudging at all. The point of weak bonding is clearly between the polymerized mascara and the lash, hence when water is added, any bonding breaks at that point and the mascara comes off in a tube or string. I was looking at the list of step one and saw several waxes that melt easily in the presence of warm water. I can see this being able to support hydrophobic, non-polar polymers of the actual mascara, but allowing the interface to be weak enough to not require a solvent to remove, and warm water being sufficient to loosen the formed polymer.

Here is the link to L'Oreal Paris' so called "Science Behind the Beauty" for the Beauty tubes. Personally, it is not scientific enough for me, but may satisfy all you non-scientists out there! 

 

Why Hair Turns Gray!

From FASEB Federation of American Societies for Experimental Biology: H2O2-mediated oxidative stress affects human hair color by blunting methionine sulfoxide repair. February 23, 2009

Gray hair, according to new findings, is caused by a massive build up of hydrogen peroxide due to wear and tear on hair follicles. The peroxide winds up blocking the normal synthesis of melanin, your hair's natural pigment.

All hair cells make a tiny bit of hydrogen peroxide, but as you age, the amount increases. Essentially, you bleach our hair pigment from within, and your hair turns gray and then white.

Researchers made this discovery by examining cell cultures of human hair follicles. They found that the build up of hydrogen peroxide was caused by a reduction of an enzyme that breaks up hydrogen peroxide into water and oxygen.

They also discovered that hair follicles could not repair the damage caused by the hydrogen peroxide because of low levels of the enzymes MSR A and B, which normally serve this function. The high levels of hydrogen peroxide and low levels of these enzymes also disrupt the formation of tyrosinase, another enzyme that leads to the production of melanin in hair follicles.

 

Why Hair Volume and Shine are Mutually Exclusive

 You've all seen close up images of human hair (usually taken with a scanning electron microscope).  If you recall, hair is made of layers of scales of keratin, much like a stack of paper cups.  If those scales lie flat, the hair is smooth and reflects light, thus looking shiny.

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 If the scales separate from each other, the hair will look less shiny but will have more volume as the scales between individual hairs will push each other away.

Since we rarely want flat or dull hair, we need to make some compromises between volume and shine.  

Shine products, however, are great! They can allow some of the scales to separate and fill in leaving the hairs somewhat thicker but also smooth and shiny.

 

  
  

Flammability of Nail Polish

Why cold creams feel cold!  

It's evaporation!  Thanks to Beauty Brains Tweet for this.

 

The Science of Botox, a 25 minute tutorial split up into 4 separate videos. 

Keep following the links!

Why you should eat your moisturizer!

I teach students how to recognize mammalian tissues at the microscopic level. What I know from a few decades of looking at skin up close is that collagen (of which there are more than 20 subtypes) of the type found in the dermis is HUGE molecule--relatively speaking, that is.

It is true that we lose collagen and elastin as we age.  How to get it back and look youthful again?

NOT by simply placing collagen laden moisturizers on top of the skin!

Inexpensive hand moisturizers probably obtain their collagen cheaply and don't process it to be much smaller, so applying this to your skin will not be effective in adding to the collagen of your dermis. This is because your skin cells are held together to each other very closely by an aggregation of molecules that form what we appropriately call tight junctions.  And your epidermal cell membranes are fairly selective about what molecules can pass through. In the unlikely event that the first layer of cells decided to take in some collagen, it would need to be passed through a few more layers of cells to reach the dermis.

And that's not all.  There is one more barrier called the basement membrane between the epidermis and dermis.  This is a sheet of several molecules that also act as a barrier to prevent unwanted molecules and organisms from entering the underlying dermis (and possibly blood vessels).

For a moisturizer to replace collagen from the outside, we'd have to surpass all these barriers. I personally would think twice about a substance that can do that, meaning I could let just about anything into me!

But, since collagen is a protein, able to be broken down into constituent amino acids, consuming it could help your body produce more collagen if that is what it decided to do with it!

 

 

  
  

 

How Lip Plumpers Work!
 
From George Roman...The lips indicate how generous a person may be. Thick, full lips indicate spontanious (sic) generosity to friends and strangers and talkativeness (generous with words). Thin lips indicate selective generosity (only to those close) and conciseness (select with words). The thick lipped person might talk endlessly while the thinner lipped person wants to be brief.
 
Well, it seems I am a thin lipped, generous talker.  In other words, I am a thin lipped person with thick lips dying to get out. I have known, thanks to many wonderful make-up artists, how to use lip liner just right to make my lips look thicker (and not look like I just want to show off that I own lip liner--you've all seen these people!).  Small problem, I actually don't enjoy lipstick, but have been learning to tolerate lip gloss, and in particular, lip plumping gloss.  They work with a modicum of effectiveness.  I am just too far gone to have significant changes, but I've seen thick lipped people become impossibly large with them.
 
First generation lip plumpers like Lip Venom managed to torture you into believing your lips were thick.  I think that was its evil mechanism.  Severe pain, bringing you to your knees, begging for an ambulance and your mom all at once.  Through the blur of tears from your eyes, distorted vision can lead you to believe they looked thicker.  Again, thin lips have nothing to work with, so nothing much will happen.
 
How do they work, then?  There seem to be several mechanisms, but mostly, these products rely upon causing inflammation.  There are five cardinal signs of inflammation.  In Latin, they are : Rubor (redness), Calor (heat), Tumor (swelling), Dolor (pain) and functio laesa (loss of function).  The first three, I can tolerate.  The last two, not so much, especially for my lips.
Basically, the plan is to increase vasodilation (increased blood flow to the area) and induce changes in the capillaries so they leak out more fluids.  The active ingredients may include things like capsacin, which is the fiery ingredient in hot peppers.  Others claim to have substances that will build lips over time, but I am anecdotally stating, I don't think they work....just my personal experience.  Sigh.
 
  
  

expert science video host, science writer, speaker, and public outreach enthusiast

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