peptidi

[peterpan]

Non so se è il posto giusto per questo post o se ne avete già parlato ma volevo delle informazioni riguardo questi famosi peptidi di cui si sente dire meraviglie in cosmetica. Hanno a che fare con gli aminoacidi?

[tagliar]

Hanno a che fare con gli aminoacidi?

Biochimicamente parlando, i peptidi sono piccole proteine, quindi formati da aminoacidi.
Immagina di vedere una collana formata da diversi tipi di perle: la collana rappresenta la proteina o il peptide, mentre le perle sono gli aminoacidi.

[karitosa]

Io pure volevo sapere di sti peptidi, visto che fanno la differenza tra una crema da 60 euro e una da 200 !!
A parte la chimica, che effetti dovrebbero avere? Un ringiovanimento istantaneo e permanente, presumo, visto il prezzo...

[amarena]

Io pure volevo sapere di sti peptidi, visto che fanno la differenza tra una crema da 60 euro e una da 200 !!

Ma state parlando dei rame-peptidi di Pickart?

In caso contrario, ci sono anche creme economiche a base di peptidi (mi vengono in mente quelle Oil of Olaz, certamente non ecobio).

Ma ora chiedo: creme a base di peptidi e creme a base di proteine non sono la stessa cosa? e ancora, essendo gli aminoacidi più piccoli delle proteine, non è meglio utilizzare i primi per la maggiore penetrabilità?

[Lilli]

Dimentichi che un cosmetico, in realtà, non dovrebbe penetrare affatto...

[amarena]

Piccolo particolare che mi sfugge ogni tanto ... (sul non dovrebbe si era anche discusso tempo fa)!

Ma allora tanto vale che me li beva (gli aminoacidi)

[anto]

Discorso lungo ma al volo ti incollo un articolo tanto per incominciare ...

Scusate ma [no linguaggio sms] ho tempo di tradurre. Usate google

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Peptides used in skin care

Amino acids are the subunits (monomers) that make up a protein. Although there are many amino acids, only 20 are common in proteins. Amino acids can join each other in a peptide bond. Two amino acids joined in a peptide bond constitute a dipeptide, three a tripeptide, a few an oligopeptide, and many a polypeptide. A protein can be made up of just one or several polypeptides. A protein is a lot more than just a chain of amino acids: the function is intimately linked to its structure, and the structure tends to be extremely complex, with the chain folding in space and many interactions between amino acid groups that in the chain may look like they are far from each other but, as the chain fold in an intricate sculpture in space become neighbors. Protein structure and function is a field of study in itself, and one that becomes important as we try to change protein function in attempts to understand how cells change in response to hormonal influences, age or illness.

Peptides have become a fashionable ingredient in skin care, because they are perceived as high tech and because technological advances have made the synthesis of peptides economically advantageous. Like for everything else, some peptides make sense and others are just fluff. Below is my own classification for peptides used in skin care.

1: peptides that imitate natural molecules

The first use of synthetic peptides by the industry was of peptides imitating matrikins and copper peptide, which had clear roles well established by scientists. In some cases the peptides were slightly modified, supposedly to facilitate absorption but probably to help with the patent process.


Examples: Matrixyl, copper peptide



2: peptides that copy a portion of a natural protein

In principle, this is not a bad idea. A protein is a polypeptide that folds in space, and a particular function (i.e. the part that fits a receptor) may take just a few amino acid residues so having those amino acid residues in the right conformation may be able to mimic the function of that part of the protein, like keeping a receptor busy so that the actual protein can’t use it, etc.. But the amino acid residues involved in the relevant section may not be contiguous, but brought close together by the way the polypeptide chain folds in space. It is possible to study the structure of the protein (not all proteins are easily amenable to this kind of study) and years of research may be required to check that a particular synthetic peptide will be useful in replacing the native protein. Unless that research was done, the likelihood that a short peptide will replace the action of a native protein is zero.



Decorinyl (a.k.a. tetrapeptide-51 amide) imitates a very short sequence in an existing protein, and the claim is that this very short peptide (just 4 amino acids) can replace a natural skin protein called decorin (molecular weight more than 100,000, about 600 amino acids). Decorin, like everything else in the skin, decreases with age. According to this hypothesis, topical application of this peptide would increase collagen synthesis. This, however, is completely the opposite of what a biochemist (like me) would expect, because the presence of a short peptide would, if anything, compete with the real decorin, inhibiting the assembly of collagen.



Acetyl hexapeptide (Ac-EEMQRR-NH2, trademarked as Argireline) was the first attempt by the industry to imitate the effect of botulinum toxin (inhibiting the release of neurotransmitters) using a synthetic peptide. The makers of argireline made many peptides and chose the one that had some effect on the SNARE complex. This peptide resembles the N-terminal end of the SNAP-25, a membrane protein involved in the action of the botulinum toxin.





3. Synthetic peptides designed by marketing people

… or by somebody else but not by a protein engineer



SNAP-8 (a.k.a. Acetyl glutamyl heptapeptide), is argireline extended by a couple of amino acids. Argireline is now so common, something new was needed to excite buyer’s imagination.



Matrixyl 3000: a mixture of a tripeptide plus a tetrapeptide claim to do the same thing that Matrixyl does, but better, according to unpublished evidence.





4: peptides obtained by hydrolysis of natural proteins

These are extremely inexpensive as compared with synthetic peptides, especially when the raw materials are leftovers that would be used otherwise as animal feed. Soy, rice, wheat proteins are examples. There is nothing wrong with this class of peptides, except when they try to sell it to us like something really special. The use of hydrolyzed soy protein as a replacement for the “real” copper peptide is a shameless use of this class of peptides.

The peptides can be as short as two, and as long as about 30 amino acids length, up to molecular weight 5,000. Because of their relatively low price, you can use them in concentrations that will allow some of them to act as signals to the skin to make new collagen but also provide the skin the building blocks (amino acids) for protein synthesis. They will even help the skin retain moisture.



5 : peptides that nobody knows what the ϱϗ&* they are (please pardon my French)

Perricone neuropeptides: Peptide CLB-253, Peptide CLS-72, Peptide CL-835 etc. don’t exist in the scientific literature, so I can only guess what they are by reading the marketing material. They may be peptides in a bovine thymus extract, and nothing you would want on your skin. There is no possible reason to apply foreign neuropeptides on anybody's skin.

Leuphasyl: could not find the sequence anywhere, so no hope of finding out how it was designed, whether it works, anything. Marketing claims include something to do with enkephalins, a group of peptides that includes endorphins.



Syn-Ake , a synthetic tripeptide that, again according to unpublished data, imitates the effects of a peptide present in snake venom.



The "secret polypeptide # 153" in Amatokin is supposed to promote your own stem cells to create much younger-looking skin. Ha!



Neutrazen is a tripeptide that prevents and fixes neurogenic inflammation by binding melanocortin-1 receptor to modulate the production of UVB-induced inflammatory cytokines (see below).



My sincere hope is that these potentially dangerous ingredients, with no decent research behind them, are used in such low concentrations that they represent no real danger to the user.



6. Same thing with a different name

Regestril: Matrixyl 3000 with a couple of ingredients added.

[anto]

E questa che condivido in pieno:


The use of peptides in skin care started by imitating peptides that scientists found were relevant to skin biochemistry. It has now degenerated into a free for all, with new peptides that have no scientific support being added to creams every day. Because there are 20 amino acids and you can make peptides of any number of amino acids, we don’t have to be mathematicians to realize that there are millions of possible combinations. Although it is unlikely that these fashion peptides will hurt your skin, it is possible: just as there are peptidic messengers that will send a “good” message to receptors, others could be sending bad messages.

[amarena]

In buona sostanza e affidandomi al mio inglese: è un po' come mettere insieme l'alfabeto, potrebbe venire fuori la divina commedia ma anche un tema sgrammaticato.

Meglio -IMHO- usare pochi aminoacidi mirati senza pretendere d'imitare la natura.

[carla82]

Ma questi peptidi possono essere usati x spignattare creme in casa? Si riescono a trovare?

[anto]

Li trovi solo sui siti americani che io sappia.

Io avevo provato il Matryxyl ma con poca costanza onestamente ...

[Lola]

Posto questo studio (attivo contro placebo) su pelle maschile perchè è una delle molecole più in voga al momento e ho l'impressione venga percepita come un vero e proprio "cancellarughe".


The in-vivo study tested Matrixyl 3000 formulated at 4% on two panels of 24 men with a mean age of 45.5+/-6 years conducting half face daily application for two months. The ingredient was found to reduce the mean depth of the main wrinkle by -10.2% and its volume by -17.1%. Measuring an additional parameter, it was also found that as the wrinkle depth decreases its spread angle increases.

Considerando che lo studio è 'di parte' , che il matrixyl è stato usato al 4% (non aspettatevi questa percentuale nella maggior parte dei prodotti commerciali) direi che queste sono le % di riduzione delle rughe che nella migliore delle ipotesi potreste ottenere.

Insomma non aspettiamoci miracoli.

[lamia]

sapete dirmi dove poterli reperire?
secondo voi possono essere utili in un gel seno?
in caso possono essere momentaneamente sostituiti con altre sostanze? col collagene di AZ per esempio?
il link sopra a me non funziona :(

[Laura]

Non è questa la sezione per chiedere di reperibilià e sostituzioni.
Che funzione vorresti che svolgessero in un gel seno? Nel caso non sarebbero rassodanti nè peptidi nè collagene.

[lamia]

non ho ben capito la loro funzione allora
c'è chi li ha schiaffati nel loro gel seno e volevo capire il perchè

[Laura]

La questione è che il verbo rassodare è uno ma si estrinseca in maniera differente in base alla parte del corpo, la cute si può tentare di rassodare con i peptidi perchè dovrebbero stimolare il suo spessore/turgore, il turgore di un seno invece dipende dalla capacità dei muscoli di tenerlo su, e lì non ci sono peptidi che tengano.

[Leonard]

Mi sapete spiegare come mai negli attivi ricrescita capelli, vengono inseriti dei peptidi chiamati rame peptidi?
Quali sono le proprietà di questi peptidi?

[Lola]

Farti comprare il cosmetico a prezzo bello tosto.

[lamia]

Farti comprare il cosmetico a prezzo bello tosto.

e ma allora che se li tengano loro questi peptidi... Sul serio non hanno altre utilità?

[Lola]

Ma no, stavo scherzando. Sono adattissimi alle creme antirughe. Sui capelli la vedo un po' inutile.