Peptides used on the skin fall into four groups: signal peptides, neurotransmitter-inhibiting peptides, carrier peptides and enzyme-inhibiting peptides. The best studied in human trials are palmitoyl pentapeptide-4, which in a 12-week study of 93 women smoothed wrinkles more clearly than placebo, and Argireline, which reduced wrinkle depth by up to 30 percent in 30 days. GHK-Cu, the copper tripeptide found in human plasma, stimulates collagen synthesis and speeds up healing.
What are cosmetic peptides?
They are short chains of amino acids, much smaller than skin proteins such as collagen and elastin. How exactly a peptide differs from a protein is broken down in the article on peptides versus proteins. In skincare one thing matters: a peptide can pass a signal to a skin cell that the protein itself cannot.
With age the skin makes less collagen and elastin, and what it has breaks down faster. Peptides are meant to shift that balance, each group in a different way. The division into four groups by mechanism of action comes from the 2009 review by Gorouhi and Maibach.
What are the four groups of peptides in skincare?
| Group | What it does | Example |
|---|---|---|
| Signal | stimulate fibroblasts to make collagen | palmitoyl pentapeptide-4 |
| Neurotransmitter-inhibiting | relax the muscles of facial expression | Argireline |
| Carrier | deliver copper to skin cells | GHK-Cu |
| Enzyme-inhibiting | slow the breakdown of collagen | plant peptides |
Signal peptides
Fibroblasts are the cells of the dermis that produce collagen and elastin. Signal peptides tell them to get to work. The best studied is palmitoyl pentapeptide-4, known by the trade name Matrixyl: five amino acids with palmitic acid attached.
A 2005 study enrolled 93 women aged 35 to 55. For 12 weeks each applied a cream with the peptide to one half of the face and the same cream without it to the other. On the peptide side, wrinkles and fine lines decreased clearly more than on the control side, and the skin tolerated it well.
Neurotransmitter-inhibiting peptides
Expression lines such as crow's feet come from contractions of the facial muscles. Argireline is six amino acids designed to interfere with the SNARE protein complex, which is needed to release the signal from nerve to muscle. Botulinum toxin works the same way, only much more strongly.
In a study published in 2002, a cream with 10 percent Argireline reduced wrinkle depth by up to 30 percent after 30 days of use. The authors noted that the peptide inhibits signal release about as strongly as the toxin, but its effect is much smaller. It is a choice for someone who wants a gentler route than an injection.
Carrier peptides and GHK-Cu
The most important member of this group is GHK-Cu, the tripeptide glycine-histidine-lysine bound to a copper ion. It occurs naturally in human plasma, saliva and urine, and its level falls with age. Copper is needed by the enzymes that build collagen.
A 2015 review collects what is known about GHK. It stimulates the synthesis of collagen and proteoglycans, draws immune cells to a wound and speeds up skin healing in animals. In cosmetics it improved skin firmness, density and elasticity and reduced fine wrinkles. Most of the data on its mechanism come from laboratory and animal studies.
In the shop, GHK-Cu is available as GHK-Cu copper tripeptide 100 mg by Bio-Peptide for 40 EUR. It is research material in the form of a lyophilisate, not a finished cream.
Enzyme-inhibiting peptides
With age and sun exposure, the activity of enzymes that break down collagen rises in the skin, among them the matrix metalloproteinases. Peptides in this group, most often obtained from plants, are meant to slow that breakdown. Of the four groups, this one is the least described in studies.
What is the main obstacle for peptides on the skin?
The outer layer of the epidermis, the stratum corneum, is fatty and holds back molecules that like water. According to the rule described in 2000 by Bos and Meinardi, a substance needs a mass below 500 daltons to pass through the skin. Most peptides are heavier.
Manufacturers deal with this in two ways. The first is attaching a fatty acid, as in palmitoyl pentapeptide-4, which makes it easier to cross the fatty barrier. The second is carriers such as liposomes, which protect the peptide and help it get deeper.
Which skin peptides are in the shop?
The skin and longevity peptides category has three products by Bio-Peptide: GHK-Cu 100 mg for 40 EUR, glutathione 1000 mg for 30 EUR and NAD+ 1000 mg for 75 EUR. Shipping from Poland costs 30 EUR paid in advance or 80 EUR cash on delivery. How to prepare a solution from the lyophilisate is described in the article on reconstituting a peptide with bacteriostatic water.
Frequently asked questions
What types of cosmetic peptides are there?
There are four: signal, neurotransmitter-inhibiting, carrier and enzyme-inhibiting. The group says more about what a peptide does than the trade name on the pack.
What is GHK-Cu?
It is a copper tripeptide that occurs naturally in human plasma, and its level falls with age. It stimulates collagen synthesis and speeds up skin healing in animal studies.
How long does it take to see the effect of peptides on the skin?
Weeks, not days. Argireline showed a result after 30 days, and palmitoyl pentapeptide-4 was studied for 12 weeks.
Can peptides replace botulinum toxin?
Not fully. Argireline works on the same mechanism, but it is applied to the skin and its effect is clearly smaller than that of an injection.
Sources
- Gorouhi F, Maibach HI. Role of topical peptides in preventing or treating aged skin. International Journal of Cosmetic Science, 2009, 31(5): 327-345. https://doi.org/10.1111/j.1468-2494.2009.00490.x
- Robinson LR, Fitzgerald NC, Doughty DG et al. Topical palmitoyl pentapeptide provides improvement in photoaged human facial skin. International Journal of Cosmetic Science, 2005, 27(3): 155-160. https://doi.org/10.1111/j.1467-2494.2005.00261.x
- Blanes-Mira C, Clemente J, Jodas G et al. A synthetic hexapeptide (Argireline) with antiwrinkle activity. International Journal of Cosmetic Science, 2002, 24(5): 303-310. https://doi.org/10.1046/j.1467-2494.2002.00153.x
- Pickart L, Vasquez-Soltero JM, Margolina A. GHK Peptide as a Natural Modulator of Multiple Cellular Pathways in Skin Regeneration. BioMed Research International, 2015: 648108. https://doi.org/10.1155/2015/648108
- Bos JD, Meinardi MM. The 500 Dalton rule for the skin penetration of chemical compounds and drugs. Experimental Dermatology, 2000, 9(3): 165-169. https://doi.org/10.1034/j.1600-0625.2000.009003165.x