[jeremien]

@Perry and @vitalys, I totally agree with the fact that the cosmetic industry is very marketing and sometimes claims are not based on real science. However, in the case of peptides, there are many studies showing effects on specific receptor of cells, and the use of biologic mimetics peptide  is well documented (not just for skin). Regarding the dose, there are some pharmaceutical formulations based on peptides where only a few milligrams allow a pharmaceutical effect to be obtained for months, after a single parenteral injection.

The main problem, as said before, is the bypass of SC, and this can be achieved with a adequate delivery system. Looking quickly through the peer-reviewed literature, I find these two articles, but I’m sure you can find many more:

 
- Gazitaeva ZI, Drobintseva AO, Chung Y, Polyakova VO, Kvetnoy IM. Cosmeceutical product consisting of biomimetic peptides: antiaging effects in vivo and in vitro. Clin Cosmet Investig Dermatol. 2017

- In Vitro and in Vivo Studies of pH-Sensitive GHK-Cu-Incorporated Polyaspartic and Polyacrylic Acid Superabsorbent PolymerShilpa Sharma, Mohammad Faiyaz Anwar, Amit Dinda, Maneesh Singhal, and Amita Mali ACS Omega 2019 4 (23), 20118-20128 DOI: 10.1021/acsomega.9b00655
 
Just as a comment, working for many years in the academic, pharmaceutical and cosmetic industry, I could tell you that the cosmetic industry is full of very good scientists, and there is a huge knowledge of the skin and its biology… the problem is at some point, commercial use of this knowledge.

[jeremien]

@Graillotion, you can access the sederma website and download a technical dossier with all the tests carried out.

@pomelo22 peptides are very effective at very low doses, and you don’t really need to use them at high concentration. However, as stated in this chat, to be effective they must bypass the outer SC layer of the skin,

[jeremien]

@Perry in vitro studies on col 1, 3 and elastin, this study has been repeated many times and the effect appears to be reproducible in 2D cell culture model and 3D skin looking to gene expression and protein quantificaation, and the corresponding anti-wrinkle effect observed in clinical studies.

[jeremien]

@Graillotion GHK- Cu has many studies proving its efficacy. @Pharma is right to point out the penetration issue, as the peptide need to reach living cells, and bypass the stratum corneum. There are some delivery system available encapsulating peptides that allow them to penetrate the skin and target specific cells.

[jeremien]

Thanks to both of you! especially @Pharma, it makes a lot of sense! The use of oil, which, depending on the solubility of the active ingredient, can enhance or hinder penetration.

[jeremien]

Thank you all! What I understand is that in Europe there is only this opinion, but there is no regulation  (Retinol is not in Annex III of the cosmetic regulation). So until the opinion enters the regulation, the concentration can be push over 0.3%

[jeremien]

I am in Europe, but I would like to know the limitation of concentration in different geographical areas. I am mainly interested in face cream! Thanks for your help!

[jeremien]

what are the conclusions? no way to formulate retinol withour BHT?

[jeremien]

https://www.cosmeticsandtoiletries.com/research/methodsprocesses/Sticking-it-to-Hair-Damage-Delivery-Duo-Protects-and-Repairs-Inside-and-Out-494523421.html

[jeremien]

O/O emulsion interesting concept. I already know about  W/W emulsions.. 

[jeremien]

Thanks @Microformulation  and @ngarayeva001 for the recomendations. I will try these options

 

[jeremien]

Thanks!

[jeremien]

In my opinion the ratio surfactant/oil phase is very
high. Not enough dispersed phase to expect the emulsion to be viscous. You
could add some polymer to increase the viscosity. 

[jeremien]

Also be aware that caprylhydroxamic acid have some regulatory restrictions in China and others countries  if used as preservative or in special use cosmetics

[jeremien]

Emulsion are thermodynamically unstable… so of course it will follows a destabilization pathway with time. You need to be sure that your especification are not too strict. Maybe flocculation, if it is weak flocculation is not a “no go”  after 1 month at 40ºC.

[jeremien]

@Belassi

you refere to
Spectrastat™ G2-N? el Caprylhydroxamic Acid puede
ser considerado como natural? Solo bajo la norma NSF/ANSI 305-2012?

[jeremien]

Emulsion science is all about amphiphilicity and how surfactant
behaves at the interface. HLB is very simple system that give a number to the surfactant
and not to the system, without taking into account interaction with other
ingredients of the formulation that interfere with interface such as alcohols,
electrolytes, polarity of the disperse and continuous phase, and phase behavior
components such as composition and temperature (that last condition explain why
HLB fails for ethoxylated surfactants)… that why it will only give partial
indication on the selection of the surfactant, and in many case it fails … This
will be the case if you only calculate the required HLB and match it with the
HLB of the surfactant, nevertheless, there is experimental method to determine
the required HLB that are maybe more accurate. Calculating is a good starting
point when you have no idea. 

We can start a new study to have a statistical result
to know what give better results HLB or intuition. Since I believe in science, I
believe HLB, even as simple it is, there is science in the concept.  I also believe that luckily intuition (you may
refer by intuition to experience?) do a good job because nowadays they is very
great and efficient surfactants system on the market

Other concept take into account more interaction of the system,  that
is the case of the HLD (Hydrophilic Lipophilic Difference) developed by Salager
and PIT (for ethoxylated surfactants) developed by Kunieda. Unfortunately the application
of these concepts is more complex, and discourages many formulators in their
daily work.

[jeremien]

@ ngarayeva001 why do you consider W/O more difficult?

[jeremien]

what about ingredient companies? there is no such monopoly isn t it?

[jeremien]

@DAS I completely agree with you

[jeremien]

@mikethair  In the last issue of C&T there is thsi article dealing with labelling and the author go in that way of reducing the labeling to only the sexy ingredients: 

https://www.cosmeticsandtoiletries.com/regulatory/claims/Why-We-Should-Shorten-Cosmetic-Ingredient-Labeling-503856641.html

[jeremien]

@em88 , i see, in that case polarizers are great to follow crystal formation… the hot stage can allow you to predict stability at high temperature 

[jeremien]

In the case of gel, i m not sure that microscopy can
help you… to see something you need contrast between two phases

[jeremien]

There are 3 important brands: Olympus, Leica and Zeiss… Leica and Zeiss, have very nice optics, but are also more expensive.
For emulsion observation it is quite important to equip the microscope with polarizers
to observe liquid crystalline phases, and a hot stage can be useful too.
Differential interference contrast filter (DIC) is also a good option to
increase the contrast of your images

If you need to take images, there are many cameras, and
price vary a lot. 

Image processing software can be useful if you want to
determine the droplet size distribution. 

[jeremien]

Tretinoin is a drug and cannot be used in cosmetic isn’t it?