What are peptides in cosmetics? Episode 55

Have you ever wondered about peptides in anti-aging products? What are they and how do they work? Listen to today’s show to get the scoop on peptides.   

Show notes

Question of the week: What are peptides in cosmetics? 

Paulette asks…I was wondering about peptides: what they are, what they do and how long do you have to use them to get results?

What are peptides?

The term “Peptide” is actually common in the world of biochemistry and is the generic name given to a small string of amino acids. Amino acids, remember, are the so called building blocks of life. They are very small molecules that have both an amine group (which means it contains a nitrogen) and a carboxylic acid group (which means it contains a carbon double bonded to an oxygen.)

Amino acids can be linked together because the amine group of one amino acid can connect to the acid group of another.  Two connected amino acids are called a dipeptide, a chain of three is called a tripeptide, and so on. When a bunch of them are strung together the result is called a polypeptide. As a rule of thumb, if there are 50 or fewer amino acids hooked together, the chain is called peptide. If there are more than 50 it’s called a protein. Proteins can be VERY large and are organized in such a way that they have biological properties (for example proteins are components of hair and skin.) Some peptides occur naturally in your body and others are made synthetically to mimic the function of natural peptides.

What do naturally occurring peptides do in skin?

Peptides are naturally occurring in skin. (They’re not exactly the same as the peptides used as cosmetic ingredients, which we’ll explain in a minute.) These naturally occurring peptides come from some of the structural proteins in the epidermis and dermis which are broken down by enzymes. These protein fragments perform multiple functions in the skin.  They can regulate hormonal activity, activate or deactivate immune responses, communicate between cells, and activate wound healing. Maybe the simplest way is to think of peptides as “messengers” between skin cells.

According to at least one theory, your body has a feedback loop that tells it when to produce fresh collagen. It goes something like this:

Collagen has a natural life cycle and it eventually breaks down. When it breaks down it release little protein fragments (which are peptides). Some skin cells have receptors for these peptides which work like a little lock and key. When then peptides “turn the lock” it triggers the cells to produce fresh collagen. Then when that collagen is worn out it breaks down and those little broken pieces trigger more new collagen production and so on.

The problem is that as you age your body becomes less effective at this process of triggering new collagen. So by adding synthetic peptides, you can send a signal that “wakes up” these cells so they start producing more collagen again.

Now let’s talk about the 4 different kinds of peptides used for anti-aging.

Types of peptides used in cosmetics

Neurotransmitter inhibitors  are “wrinkle relaxers.” 

These peptides inhibit acetylcholine release by a variety of chemical interactions. The most extreme neurotransmitter include the poison curare and the botulism toxin (Botox). Less invasive versions have been developed for use on skin and the hypothesis is that they relax the muscles of facial expression so they don’t contract as much which causes wrinkles to relax.   These neurotransmitter inhibitor peptides have been shown to reduce certain types of wrinkles by approximately 30% (in in vivo studies.)

Signal peptides are “collagen boosters.” 
These peptides stimulate skin fibroblasts to produce more collagen, elastin, and other proteins in the matrix of the dermis.  Boosting these “scaffolding” proteins makes skin look firmer and fuller. GHK is an example of a signal peptide and it was one of the first peptides discovered – it was originally isolated from human plasma in the early 1970s and its wound healing properties were first observed in the mid 80s- which goes to show that this technology is relatively new.

Carrier peptides act as “delivery agents.”
These peptides deliver trace elements, like copper and magnesium, which help with wound repair and enzymatic processes. These trace elements have been shown to improve pro-collagen synthesis, elasticity of skin, and overall skin appearance. For example,  a copper complex (called Lanin gel) which is made of amino acids glycine, histamine, and lysine ]is used in the treatment of diabetic neuropathic ulcers. This type of peptide is sometimes called a “penetrating peptide” or a “membrane transduction peptide.”

Enzyme inhibitor peptides are ‘breakdown reducers.” 
These peptides, as the name implies, interfere with enzyme reactions. This is important because some enzymes (such as MMP or Matrix Metalloprotease) degrade structural proteins like collagen. Therefore, by inhibiting enzymes these peptides can preserve your natural collagen and keep skin looking younger.  Soy proteins work this way – I suspect the mechanism is similar to how hormone disruptors work.

Paulette asked how long you have to use peptide products. The answer is: a long time. Unlike something like an AHA or a retinol that starts to work right away. But because of the way these peptides work you have to use for at least several weeks and probably up to a few months, to see much of an effect.

Naturally occurring vs synthetic peptides

Peptides sound good, don’t they? You just smear some natural peptides on your skin and look you younger. However, there’s a catch. Peptides aren’t always stable in water solutions, and because of their amino-acid functionality, they are charged in such a way that they don’t easily penetrate skin. And even if they do penetrate skin, they can be broken down by enzymes which render them inactive.

To overcome these problems, scientists have figured out that attaching a “fatty” carbon chain to the peptide can stabilize it and increase skin penetration. This non polar carbon chain allows the peptide to penetrate better, sometimes up to 5x better. The most effective peptides are modified this way to make them more effective.

Making sense of peptide names

As we explained, peptides are made up of long chains of amino acids. Often the number of amino acids shows up in the peptide name.

For example:

Pentapeptide has 5 amino acids
Hexapeptide has 6 amino acids

For every peptide chain of a given length many peptides can be formed because there are so many different amino acids. Therefore, the peptide name typically includes a number at the end of the name which gives the chemist additional information about its structure.

For example:


Now, for peptides which are bonded to a fatty acid group the name of that fatty acid appears usually at the beginning of the name.

For example:

Palmitoyl Tripeptide-5
Acetyl tetrapeptide-8

It’s kind of tricky but now you understand it, right? Wrong! It gets worse.

Peptides are sometimes named using the IUPAC (International Union of Pure and Applied Chemistry) convention which may or may not be the same as INCI.

For example:

Acetyl glutamyl Heptapeptide-1  = Acetyl octapeptide-3
Palmitoyl Pentapeptide-4  = Pal-KTTKS
Hexapeptide-11 = Peptamide 6 (Peptamide is also good to take if you have an upset stomach.)

So, yes, this is confusing but now you’ve got it? Right?  No you don’t.

Peptides can also go by the brand name given to them by their company which is totally made up word. For example:

The most well known brand name is probably Matrixyl  which is actually Palmitoyl Oligopeptide.

Acetyl tetrapeptide-5 =“Eyeseryl”
Tripeptide-10 citrulline = “Decorinyl”

To be consistent we will try and use the name official INCI name which is what would appear on the ingredient list on the back of the package.

And speaking of the INCI name, there’s one last thing you need to watch out for when reading about peptides. The names may change from time to time:

For example:

Acetyl hexapeptide-3  is now called Acetyl hexapeptide-8

So depending on what information you’re looking at on what website can be very difficult to understand which peptide you’re looking at.

Which peptides really work?

Given that there are dozens of different peptides and that there are so many different ways that they can be named, you can imagine how difficult it is to track down definitive information on how each one works.  Which means…to learn which peptides really work you’ll have to wait a little while. We’re still research them and we’re planning on putting together an information product for you guys in the near future. So stay tuned. 

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