[Bluebird]

I heard that after HA, it’s best to hydrate it with a mist or a moisturizer, and then seal it with a thin coat of vaseline or something like that.

[Bluebird]

Certain pressure cookers, but not all pressure cookers, can be used as autoclaves. Pressure >120psi, 20min.

[Bluebird]

You could try adding NoOH to the solution before adding chitosan, maybe.

• This reply was modified 1 month, 1 week ago by  Bluebird.

[Bluebird]

It’s a very watery toner/serum type formulation. No oil or sugar.

I can’t use a chelator because I may have to add a zinc salt in one of the formulations so that won’t quite work with a chelator, I’m thinking.

Package won’t be as invasive as a finger-in-cream type; it will be most likely a spoid-type dropper dispenser, which does have a chance of contamination form users.

As for glycol I can increase it a bit in some formulations. Would, say 10% propanediol significantly help preservation instead of 5%?

[Bluebird]

My surfactant is coco glucoside. For shampoo, the percentage is higher (ex, 20%) but for face wash, I use a much lower rate: ~5%. Do you think mold risk is still low if I preserve it with sodium benzoate, say 0.5% and keep it at pH ~4.5? Even without EDTA?

[Bluebird]

Do you reckon polyquaternium 10 would reduce the foaming ability of coco glucoside by a lot?

[Bluebird]

You are right. I asked the manufacturer why this was not oil soluble and was rather water miscible, and asked whether there was any solubilizer in it. The answer you gave was exactly right, so it’s a pleasant surprise to come back here and read it, too.

• This reply was modified 1 month ago by  Bluebird.

[Bluebird]

Thank you.

[Bluebird]

Thanks. But I wonder. When I did test it on microbial testing, they actually killed Gram positive and negative bacteria (cap+1,2 hex) in broth full of bacterial food. And a product I used for over a year in the bathroom, preserved with only low percentage of the above, did not have any bacterial growth (0 CFU) when I tested. But I’m aware that they are mentioned as preservative boosters commonly; I wonder why.

[Bluebird]

These should be compatible with coco-glucoside as the surfactant (nonionic) and lowish pH (~5), right? 🙂

[Bluebird]

I’m thinking of pH 4.7-5.5 and anti-bacterial and anti-yeast preservatives are caprylyl glycol and 1,2 hexanediol. I suppose I can add sodium benzoate.

[Bluebird]

Thank you!

[Bluebird]

thank you!

[Bluebird]

Oh, got you. Thank you!

[Bluebird]

How about Sodium benzoate + 1,2 hexanediol then, for low pH (ex, 4-5)?

[Bluebird]

Rancid due to oxidation, yes. I did try vitamin E but that did not help. Though another antioxidant may work, I doubt it because the smell lasts a long time once applied (ex, a week or more) even after washing and it seems the original oil pulls out metal from hair/scalp and the metals kind of sit there despite washing, and then continue to react not with the original oil that was used, but with human sebum. People have higher metal contents due to various reasons. Some lack certain vitamins (esp. vitamin B) that help the process of removing heavy metals from the body. Others may be continuously using some products or eating food that have higher metal contents. I personally did one of these hair/scalp metal test and found aluminum was higher than normal/average. And I of course reacted rather badly with this oil as well.

[Bluebird]

Not to protect the product, but rather there is a specific oil I want to use that are good for a certain skin condition, but for an individual who has high metal contents in hair or scalp, but this oil is suspected to react fast (within hours) with metals and create funny smell; hence I wondered whether there was any oil soluble chelators to capture metals on scalp once this oil was applied.

[Bluebird]

Hi, there is no chelating agent.

Currently I’m testing with 0.5% of (caprylyl glycol and 1 2 hexanediol mix); the manufacturer recommends 0.5% but does not disclose the proportion of cap glycol and hexandiol, unfortunately. I am thinking of perhaps adding a bit more of hexanediol on top of this to be safer.

[Bluebird]

I have of course tried it already and I have not found the answer to my question still

[Bluebird]

Though this one is not from EU, I guess that has to do with dosage concern.

Here, apparently Canada regulates it, too, in cosmetics,

https://www.canada.ca/en/health-canada/services/consumer-product-safety/cosmetics/cosmetic-ingredient-hotlist-prohibited-restricted-ingredients/hotlist.html

List of Ingredients that are Prohibited for Use in Cosmetic Products

“Average daily absorption must be equal to or less than 25 µg per day.”

Still haven’t found the exact details of the restriction deal in EU.

canada.ca

Cosmetic Ingredient Hotlist - Canada.ca

The Hotlist is used to keep the cosmetic industry aware of substances that are restricted or prohibited in cosmetics

[Bluebird]

I’m talking about vitamin D ban in cosmetics, not as oral supplement!

[Bluebird]

Can you share where you found that EU bans only particular brands’ vitamin D?

From my search, they ban vitamin D2 and D3, which are final forms of vitamin D, not vitamin D from any brand in particular.

They do allow pro-vitamins, which are not truly vitamin D in their final forms.

• This reply was modified 7 months, 2 weeks ago by  Bluebird.

[Bluebird]

So sensitization= allergic contact dermatitis, then.

Earlier you mentioned neither PD nor PG is a skin sensitizer.

And yet there are people whose allergy patch panel test shows as positive to PG for a fact

(PG is tested in several concentrations in a patch test).

So am I interpreting it right that when you said PG was not found as a skin sensitizer,

you meant it’s not an ingredient that commonly causes allergic contact dermatitis?

(That allergy is rare?)

[Bluebird]

Thanks, these papers are nice to have.

I’m mostly wondering about allergy, not sensitization/irritation, though I did mention all of those words with regards to anecdotes and that could have clouded my meaning.

I’m wondering whether someone who tested positive in a patch allergy test to PG is likely to be also allergic to PD. This is not really in the realm of chemistry as it’s about allergens and immune reactions. I am asking in case folks long in the cosmetics industry have heard about it either way.

[Bluebird]

Is this how it works, though?

When you lower pH of the salt of an organic acid, wouldn’t you still expect higher solubility than its organic acid counterpart in low pH, because there is the balancing counter ion?

Ex, sodium benzoate solubility in water is high even in low pH;

but apparently the benzoic acid solubility in water is low, less than 0.2%.