Doreen
Forum Replies Created
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@zaidjeber
I agree with Bob on the sunscreen, hope it will help you, good luck! -
@em88
A BHA exfoliant with 1% salicylic acid. I have gotten a few tips I’ll start working on (also keep it out of the fridge). To be continued!
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Serum should be composed of many active ingredients.
I totally agree with this.
This is also why I don’t understand the suggestion of @mikethairWhy not just use a blend of oils and leave the other gunk out?
How can you call a simple blend of oils a serum and skin actives ‘gunk’?
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Tocopherols in higher % are also sticky. With BHT present, maybe you can leave it out?
(I can imagine the sticky feeling to be experienced as ‘oily’)
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10% glycerin is a lot, you can lower it as you already have 2% dexpanthenol. Glycerin above 5% can cause it to be sticky, an unpleasant feeling. I don’t think any polysorbate will help with this.
The darkening of skin: does the skin feel warm, like when you’re blushing? This can be due to the potassium sorbate. It has vasodilating properties, not everyone has problems with it, but I have it too, even in a % of 0,2%. Perhaps you can lower the potassium sorbate and raise the sodium benzoate a bit?
Personally, I don’t have any problems with 0,05-0,1%. From 0,2% I’m getting red like a lobster. Thanks to help on this forum, I found out what was causing it.I don’t know if 0,2% tea tree is too much. It is a common skin irritant. Just like fragrances, can be irritating too.
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Hire a formulator?
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@MarkBroussard
I keep most of my skincare products in the fridge, to inhibit microbial growth. I’ll try your suggestion and keep it at room temperature!@Belassi
Good idea! Glad I still have a microscope. Thanks!
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btw the sticky residue is also there when I leave out the oil phase.
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Hi @MarkBroussard ,
I measure the tare weight of the beaker for water loss during heating, put the water in, heat it to 70C and add the ingredients that aren’t heat sensitive individually. Adding the buffer to the mix really speeds it up.
I will definitely try your suggestion, thanks.
Can you tell me how I should adjust the pH with a buffer present?
I would like to lower it a bit, but it seems useless because of the buffer resisting pH changes. Don’t want to add an awful lot to lower it.p.s. Maybe this is also important, forgot to mention it: I keep it below 7C, in the fridge.
Crystals start ‘growing’ on the bottom of the bottle in some sort of sticky residue. The particles are tiny shards, shaped evenly. -
@DRBOB@VERDIENT.BIZ
There is only one supplier here that sells propanediol, 108 euro’s (about 130 dollars) for only half a litre, it’s just absurd… -
@Zink
I know this is an old discussion, but very relevant to me.
How have your experiments with differents solvents for the salicylic acid been going?I tried 20% propylene glycol with 1% sodium citrate as buffer at a pH of 4.0 - 4.2 (to 75% water). No such luck. Precipitation starts within about 5 days when I keep it in the fridge.
Edit: I see you use castor oil and ethanol in an anhydrous system. You had no problems with it so far?
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As long as I can’t get better solvents, i’m thinking of adding 2% ethanol to the formula.
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@EliseCortes
Thanks for you suggestion, but can’t get it where I live. Just like octyldodecanol etc. -
This is the reason why I will never use unfiltered, cold pressed shea butter again. The smell is simply unbearable!
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I melt substances au bain marie, with a simple bottle warmer. It’s cheap, it can hold my 250 ml beakers and it has a max of about 80C, which is high enough.
About the toxicity of ceteareth-25, have you read the safety data sheet?
https://worldaccount.basf.com/wa/AP~en_GB/Catalog/Cosmetics/info/BASF/PRD/30274706 -
You would also need to have a seperate working area in your house. A kitchen (where most homecrafters prepare) is most definitely not according GMP if you intend to sell.
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@Bill_Toge
Even more?! I really need another solvent… Wish I could get methyl gluceth-20 here. -
I wish I was living in the USA… Here we have to do with lousy suppliers that 1. hardly sell anything 2. have absolutely no knowledge of cosmetic science so they give terrible ‘advice’ and you can’t ask them substantive questions…
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Thanks @Belassi and @Bill_Toge
The problem is almost certainly the salicylic acid…
Someone sent me this link, if I interpret the graph of table 2, to dissolve 1% salicylic acid I would need at least 40% of PG in a binary solvent system with PG and water!
(f1= 1.0 = 100% water, f1 = 0.0 = 100% PG) -
This is the formula (pH 3.5):
Distilled Water Q.S. Sodium Lactate 3% Panthenol 1% Glycerin 1% Ferulic Acid 0,5% Polysorbate 80 * 1% d-Alpha Tocopherol * 1% Sodium Hyaluronate (RMW) 0,2% 1,3-Propanediol 30% L-Ascorbic Acid 15% Preservative(s) Q.S. @MarkBroussard
LOL I see your formula is a real hit, keep seeing this everywhere!.
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https://link.springer.com/article/10.1007/s11746-002-0433-6(Quote: “For example, the optimal concentrations for α-tocopherol and γ-tocopherol were ∼100 and ∼300 ppm, respectively, whereas δ-tocopherol did not exhibit a distinct concentration optimum at the levels studied (P<0.05). The optimal concentration for the natural tocopherol mixture ranged between 340 and 660 ppm tocopherols (P<0.05)”.)
So their verdict is: 0,01% is the optimum concentration for alpha- and gamma tocopherol before it becomes pro-oxidative; 0,03-0,06% is the optimum dose for mixed tocopherols.
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@zaidjeber
You’re welcome!@DRBOB@VERDIENT.BIZ
Interesting article, thanks!
I don’t know what happened with the L’Oreal patent request from 2010. I’ve been reading some LOI’s on their self-tanners, but haven’t found dehydroascorbic acid or a derivative so far… -
You’re welcome!
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@DRBOB@VERDIENT.BIZ
It’s strange though… a lot of studies about ascorbic acid in skin, but hardly any information on this.
I can’t imagine it hasn’t been noticed when they did their double blind researches on collagen synthesis etc.
Edit: It has been noticed. I see L’Oreal has even asked a patent on dehydroascorbic acid for use as a self-tanner. A ‘new DHA’, but the same horrid smell.