zetein
Forum Replies Created
-
@DaveStone Post was talking about acidic or neutral-as-water cleansers based on synthenic surfactants. Alkaline fatty acid soaps should never be recommened as it directly neutralize intercellular lipids and also leave scums onto skin and cause irritation.pH7 products won’t do this. And their effect on the pH balance of skin is negligible because it’s the same as that of tap water in the rinsing process which is an inevitable despite the acidic cleanser you might use. -
The zein test is a very sketchey ex-vivo test that uses dead vegetable proteins and the duration can be hours. It doesn’t really apply to how surfactants was used in practice. Also the results can be conflicting sometimes. IMO shouldn’t be taken too seriously on its own.This article should interest you:Also take note of this sentence belowFrom our previous work (
, we know that in the presence of the ammonium ion, the zein test underestimates the irritation. -
@vitalys In practical terms I am going to rinse with tap water which is pH 7-8 anyway. So the pH only affect the washing/lathering process, afterwards, hardly. The rinsing would bring up the pH of post-wash skin to ~7 regardlessly.
-
The pH of Dove bar is ~7 and they actually published an article that the pH ~7 bar is milder than pH 4-5 bars, debunking the low pH cleanser myth.The theory behind this is that neutral pH makes keratin less positively charged, therefore less interaction between skin and anionic surfactant.
-
@Pharma Thank you. Seemingly not-prone-to-hydrolyse is more of another marketing gimmick.
-
Using sugar alcohol to dissolve salicylic acid is quite novel. Would you mind sharing your experience?
-
The original one commercialized by Nikko Chemicals in 1996 goes by inci Ascorbyl Tetraisopalmitate, and you can see hexyldecanoyl- drawn in their research.So I think none of the two inci names are really percise, and the correct should be Ascorbyl Tetrahexyldecanoate.The name Tetrahexyldecyl Ascorbate would be suggesting it’s made by esterfying 4mol hexyldecanol with 1mol ascorbic acid, which wasn’t to happen. Not sure why it exists, could be patent risk management?
-
@Abdullah The table says ammonium lauryl sulfate is harsher for both.
-
The Draize test says otherwise though.
-
Could also be cationic guar, polyquaternium-10 and the like.
-
Yes, and it comes into conclusion with that moisturizers smell good, feel good, make skin look soft and supple, good to touch etc. but they are as temporary as a makeup fundation and don’t really help with skin function as some would advertise.Interestingly, a aesthetically better skin may not be a physiologically better skin.
-
@chemicalmatt @vitalys There are a couple studies discussed paraffin and silicone oils and it’s quite interesting:VPJ neither forms nor acts like an epicutaneous impermeable
membrane; instead, it permeates throughout the SC interstices, allowing
normal barrier recovery despite its occlusive properties.Apparently petrolatum does get in touch with SC lipids. But instead of disrupting them, it replaces them and their function, and gives good result. Not sure about long-term use.
—Conclusion: Both oil types remain in the superficial layers of the SC (0-20% of the SC thickness). Skin treated with mineral- and plant-derived oils shows significantly higher disordered lateral and lamellar packing order of ICL in these layers of the SC compared to intact skin. Plant-derived oils significantly changed the ICL ordering in the depths of 30% and 70-90% of the SC thickness, which is likely due to the penetration of free fatty acids in the deeper layers of the SC.Mineral oil affected here but not as intense as triglycerides.
—With the exception of dimethicone 100, cetearyl iso-octanoate and caprylic/capric acid triglycerides, all vehicles showed characteristic alterations of the phase-transition temperatures and enthalpies of the stratum corneum lipids. Mineral oil and isopropyl myristate caused a reduction of the enthalpy and a decrease of the phase-transition temperatures. These two vehicles are thought to fluidize the lamellar-gel phase of the stratum corneum lipids, and possibly partially dissolve the lipids. Dibutyl adipate and caprylic/capric acid triglycerides containing 5% phospholipids decreased the phase-transition enthalpy only, probably due to dissolution or extraction of the stratum corneum lipids.Not so sure. Mineral oil had similiar effect with IPM, a known penetration enhancer. Dimethicone seems to be as inert as emollients can be. And the phospholipids-containing oil did solublize inherent lipids here, but the vehicle itself didn’t ????. This one was on isolated skin though.
-
The ascorbic acid product in the market often direct to use only a few drops one time. Salicylic acid - enough to soak a cotton pad usually.
-
@Pharma Could be palm kernel oil? However, Sodium Palm Kerneloyl Isethionate is a legit INCI name. Not sure why it weren’t used instead.
-
It’s also one of the most common rodenticides.????
-
Caprylyl Glycol and Hexylene Glycol are barely innocent.
-
It was banned.
-
@PhilGeis Can the cationic surfactant in conditioner be relied on for anti-microbial? If yes, what should the concentration and pH be?
-
@Pharma Does it worth the hype?
-
I would buy.
-
@Pharma But wouldn’t the insolubility of the active make it almost impossible to diffuse inside the vehicle, after the frontline get absorbed?Ultimately, only the first few lucky guys get into skin thanks to petrolatum, and all the others get blocked out by the petrolatum left by the lucky ones.
-
Why are there waterphase stabilisers in SkinCeuticals’ A.G.E. Interrupter and Pond’s Cold Cream, the example of modern and traditional w/o cream respectively?water, propylene glycol, dimethicone, hydroxypropyl tetrahydropyrantriol, cyclohexasiloxane, isohexadecane, glycerin, synthetic wax, dimethicone/peg-10/15 crosspolymer, aluminum starch octenylsuccinate, ci 77163 / bismuth oxychloride, phenoxyethanol, magnesium sulfate, ethylhexyl hydroxystearate, salicyloyl phytosphingosine, acrylates copolymer, methylparaben, ethylparaben, disodium edta, vaccinium myrtillus extract / vaccinium myrtillus fruit extract, parfum / fragrance, butylphenyl methylpropional, coumarin.mineral oil, water, ceresin, beeswax, triethanolamine, behenic acid, phenoxyethanol, cetyl alcohol, ceteth-20, fragrance, carbomer, disodium EDTA, methylparaben, iodopropynyl butylcarbamate
-
Is salicylate here adequate against gram-negetave bacteria?
-
I found that L’Oréal, the whole company, around the world, uses Coco-Betaine instead of Cocamidopropyl Betaine in shampoo and face wash. Not sure why, could be they are manufacturing their own amphoteric surfactant.
The only pro I can think of for Coco-Betaine is that it eliminates dimethylaminopropylamine, which is considered a sensitizer and part of the reason why CAPB gets a bad reputation.But this seems irrelevant to your thread since Coco-Betaine wasn’t used either.Regarding your question, I remember it was answered once and it was down to the called “structured surfactant system”, something I don’t comprehend as a civilian and would call for an Explain Like I’m Five from the real chemists.It was barely mentioned in this talkboard and I got a blank search result for the word “spherulite”, could possibly due to that everyone hates oil in shampoo here and structured surfactant system stands out for their oil holding/delivering ability. -
see page 5According to the super sketchy ex-vivo test in this ad, CAPB works better lowering irritation of anionic surfactant than APG.But like I said, it’s super sketchy, and there are some obvious BS in this ad too, so don’t mind me. :#