jemolian
Forum Replies Created
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@Abdullah i think realistically you should have enough material to reduce TEWL, but at the same time balance the preceptive factors (skin feel / feeling after application) of the applied product. Some people might feel that it’s overly suffocating due to the amount of occlusives added. It’s hard to really reduce TEWL to a large percentage unless you are using petrolatum, which would be the cheapest material with 98% reduction with minimal 5% (https://www.researchgate.net/publication/303091758_Moisturizers_The_Slippery_Road), but you will have to balance the out the rest of the preceptive factors.
So far i’ve only seen that prolong occlusion induces skin damage, though i doubt using an applied material like an occlusive ingredient would be able to do the same inducing that a physical occlusive. could. https://pubmed.ncbi.nlm.nih.gov/10420139/
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@ngarayeva001 no problem. I only managed to come across it one day when looking at different books on moisturizers
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https://www.sciencedirect.com/science/article/pii/S2352647518300133Just some relevance for the table, but personally i think the TEWL percentage is mainly theoretical unless you have in vivo testing done. The main thing is that the TEWL reduction with occlusives should be designed based on the type of product you are formulating for the intended customer demographic. If the intended demographic don’t need a highly occlusive product, then there’s no particular need to really think too much about it. It’s more important to get the end user feedback.
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@Abdullah
the table is from the book called “Handbook of cosmetic science and technology”. You can find the PDF online or if you only want to see the chapter, it’s on google books here -> -
Butylene glycol for short term hydration is also less than glycerin. Isn’t it?
Yes, so normally for a higher short term humectancy, the combination can be used, but if your humidity is average of 52%, then butylene glycol won’t really make sense. You can take a look at the reference below, which is the normal table when you search for “humectant humidity” on google.
In terms of the 50+% humidity range, you can consider about 3% to 5% of glycerin. In my test, in an air conditioned room, at about 50% humidity, 2% glycerin USP isn’t that tacky.
Regarding the pH, it depends on your overall formulation, but there’s no issues with pH being at 4.5 - 5.5 to be honest. My preference is pH 5 - 5.5.
In this paper, The role of epidermal lipids in cutaneous permeability
barrier homeostasis:For example, the activities of both b-glucocerebrosidase and acidic sphingomyelinase are optimal at or below pH 5.5, which is very similar to the pH of the stratum corneum. Conversely, many of the proteases in the stratum corneum have a pH optimum of 7 or higher;
therefore, their activities are decreased at the usual stratum
corneum pH of 5.5. If the pH of the stratum corneum is
increased, the activities of b-glucocerebrosidase and acidic
sphingomyelinase are reduced and the extracellular processing of glucosylceramides and sphingomyelins to ceramides
is impaired, leading to abnormalities in the structure of the
extracellular lipid membranes and decreased permeability
barrier function (4, 41–43). Furthermore, increases in stratum corneum pH stimulate protease activity, resulting in increased corneocyte desquamation (4, 41, 42).Though, ultimately it’s up to you and your formulations requirements really.
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If you have to stick to one, then glycerin would be fine. Depending on the what you are trying to achieve and the suitability of the formulation, the choice can really be different.
For example, butylene glycol can make sense if you are intending to give a short term / up front impression that your product is very hydrating but mainly the long term hydrating function is sustained by glycerin. This would deal more with the customer’s perception.
Alternatively, other humectants like sodium lactate would likely be a good choice but if your formulation is not electrolyte sensitive. Assuming that you are cost saving, then it may not work out since you likely will use carbomer as part of the formulation for stability purposes.
The main issue with just using glycerin would be that it can be quite tacky depending on the percentage used and the humidity your intended users are at. In a high humidity climate, you don’t need that much glycerin, but at lower humidity, you can consider adding more. So a mixture of humectants can be used to create different skin feels as required.
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@Abdullah it depends on multiple factors really. If you don’t mind the natural/synthetic status, then the normal combination of butylene glycol + glycerin is fine enough in most cases, unless you want to use something more fanciful for specific purposes such as “natural derived” (eg, with propanediol or pentylene glycol), co-emulsification (eg, with pentylene glycol).
From what i’ve seen, butylene glycol normally boosts the humectancy profile for the first 1 to 2 hours, which is similar to the Figure above. Good thing about the glycols, they would help boost preservation to a certain extent.
Though just to mention, there’s also 1,2-Hexanediol.
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@Mel55 it’s like the skin feel of the emulsifier, you can look into the skin feel description they provide and if any of them fit your needs. Normally the BTMS has a powdery skin feel if i recall correctly?
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It’s better to do a combination since they have been shown to work better combined.
Here’s a screenshot from one of the test for a comparison done to compare individually.
Link from my dropbox (since i can’t find the PDF online strangely, please save if require in case i move it) ->
https://www.dropbox.com/s/4r009ugoq0k077a/Moisturizing%20Effects%20of%20Diglycerol%20combined%20with%20glycerol.pdf?dl=0
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@Abdullah i’m not too certain. I’ve not really looked into that yet.
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@abierose it will depend on the charge, so the anionic chelating agents won’t do. I’m not sure what charge sodium phytate is, but if it’s anionic but used in a small percentage, perhaps it would still be fine.
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It will turn out as a giggly marmalade look at about 1% when using normal ingredients.
Though you should just try it at 0.5% and 1% to see how much a loss of viscosity it would be due to the acid.
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It looks like a conditioner formulation. Though strangely some people also use BTMS for normal skin formulations, example the Cerave brand. A chelating agent may not be suitable for this case due to the BTMS.
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@Abdullah they do have quite many modules and structured formats for different formulas as different files. Will recommend dropping them an email to about about the book though, I believe they can be purchased separately. There should be info on their site on the ones available.
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@Paprik there shouldn’t be that many changes to the text i think.
It’s from this page https://www.dropbox.com/s/e3mor9eu436rtiu/Screen%20Shot%2006-24-21%20at%2008.43%20AM.PNG?dl=0
*I’ll delete it after a few days.
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@Abdullah it should be the text from the lipids module from Institute of Personal Care Science
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@emma1985 EWG had listed the 13 ingredients CNN mentioned in article since 2018, so i won’t be surprised if they took the list from them and gotten a quote.
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I saw there’s a post on reddit after seeing this thread, so here’s the study that the CNN article mentioned based on what the reddit commenters mentioned i guess?
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You will need to ask yourself if the combination makes sense in terms of your claims, frequency of use, packaging, and volume of product. It depends on how you intend your customers to use your products.
For example, are you intending to package it as
- a 30 pieces, 2ml ampoule for a basic LAA serum set for daily use
- a 12 pieces, 2ml ampoule for a LAA + GDL or SA, exfoliation set for thrice a week
The intention of use, frequency, and how you create the product set is very different, thus affecting the sales and prices of the products.
Alternatively, you can just use a willow bark extract for claims if the pH range is suitable.
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For the Krave, the US ingredients listing would likely be used fpr the EU.
For the Vit C serum, i think the chemist you work with is able to answer your questions regarding the technical portions, more so about the stability.
Personally, i’d expect to have the Salicylic Acid in a separate product, unless there’s a specific reason to be added into the serum. It would potentially increase the irritation that the a consumer might experience. Some people use a vit c serum twice daily, but a BHA product once per day or sometimes a few times only per week. You might be restricting your customers’ frequency of use.
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But as a consumer how do you know if they use 90% of a solution extract instead of 90% of raw extract ingredient?
Most consumers won’t really know much about the original form of the ingredients, so it’s easy to mislead them in that way. Though for the extracts you have listed
- Green tea is normally a solid powder extract. There can also be premade liquid extracts for easier use.
- Snail mucin can be a liquid extract since it’s a ferment, or uncommonly a powdered version
- Propolis is normally a solid extract, but may be liquid if solubilized
In regards to the Krave product, it’s common for korean companies to just add some oat extract (example in powder form) into a solution can call it an extract, then use that solution for label claims as 70+%. The previous examples i had mentioned are most of the time happening for asian products, more so happening with korean products.
You can see that the actual oat amount would be 2nd last in the list. If it were really 70+%, it would be the first ingredient. It is possible for extracts to be used in large amounts, for example in SK-II, where the ferment is the first ingredient, though we don’t know the actual solids or concentration, because it’s naturally a liquid extract in origin, where is can be ready diluted. Though normally for ferments, if you are looking at various ingredients, the use rates are only about up to 2%, sometimes 10% depending on use case. It’s hard to say for sure how much you are getting per say in any case unless the company mentions.
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So, can we put 15% of the oat solution (2%) in my serum and say that we have a 15% oat extract?
It depends on what your description is or how you market it.
In the case of some misleading marketing practices, some companies market their products as 90+% or up to 100% Hyaluronic Acid in serum form. While it is misleading since it refers to a 90+% Hyaluronic Acid solution being used, some people still fall for it thinking that it is “better” than one that list the raw material in the powder percentage, for example 1%. Same case as snail mucin.
15% of a 2% oat liquid extract is just 0.3% of oat extract (raw solids).
Though is there any cases where oat extracts are required in such a high percentage?
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Tremella is quite the premium humectant to use, so i’d recommend adding it only as a small percentage as a label claim ingredient unless you are using it in a higher percentage for specific purposes.
Based on patch testing at 0.1% or 0.2% powder (can’t really recall the actual amount), in the short term, i didn’t seem to do much for my skin.
You can take a look at my dropbox folder to see if you find anything interesting since there are some data from different manufacturers. You can download it to keep them in case i move them away in the future. https://www.dropbox.com/sh/kipeuwo1k67wi9y/AACm5tZN1Lx2nwaQvYE4Z8Voa?dl=0
Mine is the powder version from Shanghai Huiwen.
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One weird question i’ve seen lately on reddit is: Do i need to buffer with another product if i’m using a product that is of a specific pH?
Let’s say for example if they used a saponified / soap cleanser, then want to use a Ascorbic Acid serum. Do people need to use a pH balance toner before using the serum?
I’ve seen some people asking if they can find a low pH toner for that “purpose”.
Another basic question i guess will include: How long should people wait after low pH products (example chemical exfoliants, Ascorbic Acid) before moving on to the next product for them to be effective.