OldPerry
Forum Replies Created
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Well, that preservative works best with a pH of 5 or lower so try to keep it below 5.
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That really depends on the exposure conditions (length of time, what else it’s paired with). But hair conditioners might have a pH as low as 3.0. Shampoos are around 4.5 - 6.0 or baby shampoos are around 7.0. Hair relaxers go up to pH 12+ but you don’t want those to stay on your scalp for too long.
So, it depends.
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@Abdullah - Henna as an additive for shampoo. Maybe I just liked the fragrance we used.
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@grapefruit22 - Here is the full study you referenced. What is it that you find compelling?
I read the paper and find it lacking. While 16 subjects is pretty small (30 should be the minimum), that isn’t even what I have the most problem with.
Consider…1. They compared two completely different formulas. 5% L-ascorbic acid (La Roche Possay, France) or
4% hydroquinone water–oil emulsion (Stieffel, Coral Gables, FL,
USA). So maybe an ingredient other than vitamin C is responsible for the effect?2. Their primary measurements were subjective and the scale they used is terrible and leading. They asked rate your skin improvement (mild, moderate, good, and excellent)? This automatically forces the subject to say there was a positive improvement. Where is the “made skin worse” option? or the “no change” option?
3. Look at the before and after pictures. They don’t even control for lighting! The person’s lips are much darker in the before compared to the after picture. This is just terrible work. It’s the kind of thing that goes in beauty magazine or long sales pages on websites. This isn’t serious science.
Why didn’t they have a dermatologist rate the sides using a standard rating scale? This seems like it would be standard practice especially since the study was conducted by 3 dermatologists?
If they wanted a proper control in this study they only needed 24 participants which would allow for 16 half face sides for each treatment plus the control. It would have been easy enough to do.
At the end of the day, I don’t find this evidence compelling.
I will add that when these studies are done they actually pay volunteers to participate and scientists to conduct them. If a company had developed a great super hero ingredient the cost of testing would be tiny compared to the profit they could make.
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Ah sorry, I remembered it backwards. PQ 10 after surfactants. See this article for an explanation why. Basically what you have is PQ 10 is a cationic and it needs micelles to already be formed to prevent that clumping.
However, what you might do is pre-mix the PQ10 in water then add that solution to the surfactant solution. That way the powder disperses more easily.
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@Mondonna - I don’t doubt the results you’ve posted but I guess it is a step away from the claim that “glycerin is the superior humectant”. It’s humectancy as measured as a solution on Guinea pig skin. What I’m talking about is using glycerin as a humectant in a skin lotion on human skin. Even when compared to something like Urea as in this study, the best they could say is Sodium PCA was “equally
effective as a similar established product with a different humectant system (urea).”@grapefruit22 - The problem with the study you posted is that it doesn’t demonstrate Sodium Lactate and Sodium PCA are better. What is shows is that if you take a formula that includes 3% glycerin and then you add additional Sodium Lactate or Sodium PCA, then you get better scores using a corneometer. One has to wonder, why didn’t they do the additional test where they just increased the level of Glycerin and see how much additional scoring they would have gotten.
The cosmetic industry is awash is badly designed studies on all kinds of technology. And that is primarily because the studies are done by or funded by motivated researchers. There is no benefit to anyone in verifying that Glycerin is the best humectant for a skin care product. It’s cheap. It’s effective. There is no financial benefit to showing Petrolatum gives anti-wrinkling effects as good or better than active ingredients like ceramides or vitamins or any other ingredient of the day. So, this is why I’m highly skeptical of most any “research” that conflicts with what has been accepted fact in the cosmetic industry for decades. I’m not closed minded, but the studies better be robust.
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I’ve always been a fan of jojoba oil and henna.
And I really want to like Tea Tree oil but it’s hard to get over that odor. -
I’ve found adding it to water before the surfactants most effective.
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@toketsu - I don’t believe Vitamin C would work to “stain” the skin in the way that say Dihydroxyacetone (DHA - fake tan) would.
Ascorbic acid supposedly works by interfering with different biochemical steps in the melanin synthesis process. So, in theory, it stops the production of melanin which would steadily reduce the amount of pigment in skin at the spot where it was applied. This wouldn’t be staining the skin as suggested.
But like I said, while the theory is reasonable, I don’t find the evidence of it working from products compelling.
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@grapefruit22 - before I respond I want to sincerely thank you for participating in the forum. I very much appreciate you including links and making good arguments for your position. I don’t wish to come off as combative but it is easy to be misunderstood in text.
Alright, as to your response…
“The second article had 70 references to publications, none of them was convincing?“
I haven’t gone through all 70 references but certainly all 70 references are not relevant to the question at hand. For example, the first 2 references are simply related to the question of whether skin naturally contains Vitamin C. Of course I find this convincing. But this tells us nothing about whether applying Vitamin C topically is beneficial.Which of the 70 references did you find most compelling? As @toketsu points out, many of the referenced studies cite animal and mouse studies that may not be applicable to human studies.
“The huge popularity of vitamin C products is definitely more than marketing given the high prices of these products.”
Popularity is not a good measure of whether something works or not. It is a good measure of whether a brand’s marketing works but does not say much about the product. Having been a formulating chemist in the industry, I know that the price of a product has very little to do with how much it costs to make it. A 1 ounce serum that costs $125 likely costs about $2 or $3 for the company to make it. And the majority of that cost is the packaging. The reason the product costs that much is because of the brand positioning more than anything else.“you can read thousands of reviews of consumers who appreciate this effect of Vitamin C“
When a consumer reviews a product, they are assessing the entire product from application, packaging, price, odor, etc. This says very little about how effective the Vitamin C in a product is. Maybe they just like how it moisturizes skin?
“They cannot assess the photoprotection or the anti-wrinkle effect, but for sure they are able to notice improvement of skin tone.“
Again, I’ve been involved in enough consumer home research tests to come to the conclusion that consumers are terrible at noticing small improvements. The assessment of whether a product works or not is much more related to the amount of money they paid for the product rather than how it actually works. Many consumers are always looking for the next great new thing. Why? Because the thing they have been using doesn’t make any noticeable difference. And that’s because most products will moisturize and make skin feel good, but that’s about all a consumer really notices.
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@grapefruit22 - any individual’s experience is not necessarily generally applicable to everyone. There is nothing about sulfate formulas that makes them necessarily drying for everyone’s skin.
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I’ve always thought the research on topical vitamin C is sketchy and not terribly convincing.
Studies purporting to show a benefit to vitamin C typically are poorly designed and they don’t get to the heart of the matter for what consumers would really care about. That is, what is the best technology to use for treating wrinkles? (or whatever other characteristic you are measuring)
The studies are designed to be useful for marketing stories, not useful for determining what is true.
For example, the first study you link uses a small samples size and they had a huge number of people who dropped out. Started with 28 but only 19 were analyzed at the end? This is dubious as far as science goes. Then they didn’t just compare a placebo vs a placebo spiked with Vitamin C. Rather they looked at the placebo vs one spiked with Vitamin C, Zinc, and tyrosine. So, even if this study was correct in its findings, it says nothing about how vitamin C works but how Vitamin C in the presence of zinc and tyrosine works. From this study we do not know whether it was the vitamin C, the zinc, the tyrosine or some combination of the three.
The second study is more a review of what is out there but again, it’s not very compelling to me. The research just does not answer the main questions consumers would want to know.
For example, they claim vitamin C provides photoprotection. Ok, but there are vastly better ingredients that provide photoprotection (e.g. sunscreen drug actives). Why use an inferior technology? They claim vitamin C provides antiwrinkling. Ok, but why not use an occlusive agent like Petrolatum that works even better?
Overall, I find the claims of vitamin C to be nothing more than marketing stories. I have not seen any symptom that topical vitamin C would improve better than some alternative technology. I’m always open to new information so if anyone has better studies that they find impressive, I’d love to read them.
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I don’t know for certain but here is my hypothesis. It all comes down to the price and profit of the materials.
There isn’t a big difference in performance as the conditioning comes from the Behentrimonium portion and not the Chloride/Methylsulfate portion. So, big companies are going to use what is least expensive. That would be the Chloride version. They buy up huge quantities of the stuff and get huge price breaks.
Small companies buy their raw materials from chemical distributors. And really small companies buy them from repackers like makingcosmetics.com. Repackers and distributors buy a certain quantity of a raw material from the supplier then break it up into smaller portions to sell for a higher profit to small companies.
So, the repackers will have to compete with the big companies for a chemical like Behentrimonium Chloride. This drives prices down and makes the ingredient much less profitable for the repacker. On the other hand there is much less competition for a less frequently used (by the big companies) ingredient like Behentrimonium Methylsulfate. Repackers can buy that up and sell it for a better profit than they can the chloride versions.
That would be my guess anyway.
It also gives the small companies a point of differentiation because they can say their formulas are different than what the big companies make. That doesn’t mean they are better but many consumers don’t know that.
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Cyclomethicone is added more for its in-use effect than for its after-use hair feel. I personally don’t think cyclomethicone makes sense for a rinse out product.
As far as evaporating goes, the speed of it depends on the system but if the cyclomethicone is tied up within the bar, I don’t think it will just evaporate off too quickly. It evaporates more slowly than water.
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It’s difficult to guess because none of the ingredients are particularly well known to cause sebum production. So, perhaps a better explanation is that people think their hair feels or looks like it is oily and they think that is because of sebum. When in fact, that could be a result of just the condition in which the shampoo leaves the hair.
If that is the case then it is either the Guar or the Amodimethicone.
If there really is some drug effect then that would most likely come from a component of the fragrance.
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@Paprik - I don’t think mixing fragrances is a particularly good idea. It’s twice as challenging to get a matching scent from batch to batch.
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@PhilGeis - I heard they did this because the company they bought (Helene Curtis) had a resident microbial biofilm in the Suave shampoo filling lines which required Kathon to kill.
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Try adding to cold water
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You need to list all of the ingredients.
25% + 20% = 45%. What is in the other 55% of your formula? -
I suppose it depends on what your definition of “natural” is.
You have to ask the supplier what they mean.Some might mean that they make fragrances only using ingredients obtained from natural.
But some might mean they use ingredients that are chemically identical to ones found in nature.
Still others might just mean the fragrance smells like a fragrance you’d get from nature.
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You could try another solubilizer like Oleth-20 or 40. It may not thin out your formula the same.
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Yes that is not unexpected. Solubility of one fragrance oil is not the same as every other one. You often have to find a different solubilizer for a different fragrance. Polysorbate 20 works well but not with every fragrance.
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You simply have to look at the molecular formulas/structures of the ingredients for your answer.
DMDM Hydantoin - C7H12N2O4
Diazolidinyl Urea - C8H14N4O7
Imidazolidinyl Urea - C11H16N8O8 -
First, it’s helpful to understand why apples turn brown in the first place. Basically, enzymes (polyphenol oxidase - PPO) oxidize phenolic compounds in the apple which then react with amino acids and proteins to make a brown color.
PPO has a pH range at which it works optimally - pH 5.0 - 7.0. Below pH 3.0 it is inactivated. So, anything that is going to reduce the pH of the surface of the apple will significantly reduce the browning reaction.
LAA can work but so can citric acid, hydrochloric acid, acetic acid, glutathione, etc. It is a demonstration that can be easily fooled. Really, it is less a demonstration of the activity of the LAA and more a demonstration of the pH of the skin cream.
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Room temperature. We added about 25% of the water for the cool down