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Why Do These Products Clash? Any Scientific Minds Know About Ingredients? (Zinc Oxide Not Playing Well With My Aha)

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Hello all,

I was a member many years ago. Am having a raging return of various skin problems, which I'll cover another time in another topic - or this will get way too long.

For now, I'm just trying to understand why two (or three) products that I use do not seem to get along well.

What did work:

Since about 2004 I had been using cetaphil cream with Alpha Hydrox's oil free 10% AHA. No problems during all this time. They play very well together.

Where things started going wrong:

Only about a month ago, I began experimenting with adding plain zinc oxide powder to my cetaphil cream. It was pretty magical for me to see how it improved breakouts on my back, shoulder, and chest overnight. (I have other stuff for my face presently - long story.)

Here's the thing - I can apply the cetaphil cream / zinc oxide mix to my skin with no problems. There is no weird smell. It might smell barely medicinal, but I like that smell, it's clean smelling. It smells normal. It works nicely too.

However, anytime I put on my old AHA over top of where the zinc mixture had been the night before - or even when I put the AHA on after I've washed off the zinc mixture off (I know the zinc stays on my skin even after washing somewhat) - I can smell something like ammonia where the AHA seems to mix with what's left of the zinc oxide. The smell reminds me of when I was young and I would get my hair permed - that sort of ammonia smell - at least I think that's what it is.

This seems so strange.

  • Cetaphil cream is made to go well with everything - that's its purpose: to work well with various acne medications and be benign.
  • Zinc Oxide is used for the most bland and safe sunscreens that even babies are permitted to use.
  • The AHA says you're supposed to wear a sunscreen - so it seems to me it should work okay with a product containing zinc oxide.

HOWEVER, when I contacted the manufacturer of the AHA and asked them why the ingredients were clashing, they informed me that their chemists did NOT have a clue why, nor did they ever test their AHA with zinc oxide to see how it would react. They just said it sounds like a chemical reaction. Not comforting.

So I'm coming here - hoping someone with a scientific mind might know what's going on. It doesn't hurt my skin that I can see, but that smell can't be right. I am so eager to use it again - because it works so well on my breakouts - but I can't stand the idea that I'm poisoning myself with that ammonia like odor that gets produced.

What is it?

Here are the ingredient lists of the products:

Zinc Oxide - just pure zinc oxide powder - the white stuff - in a large micron size.

My AHA:

Water, Glycolic Acid, Ammonium Hydroxide, Sodium Lactate, Green Tea Extract, Carrageenan (Red Seaweed) (Sea Kelp Extract), Panthenol (Vitamin B5), Propylene Glycol, Diazolidinyl Urea, Methylparaben, Propylparaben, PVM/MA Decadene Crosspolymer

Cetaphil Cream:

Water, Petrolatum, Glyceryl Polyglycerylmethacrylate, Dicaprylyl Ether, Glycerin, Dimethicone, Glyceryl Stearate, Cetyl Alcohol, Prunus Amygdalus Dulcis (Sweet Almond Oil), PEG 30 Glyceryl Stearate, Tocopheryl Acetate (Vitamin E), Benzyl Alcohol, Phenoxyethanol, Sodium Hydroxide, Acrylates/C10 30 Alkyl Acrylate Crosspolymer, Dimethiconol, Disodium EDTA, Propylene Glycol

Help?

PS: I have ordered a body wash and shampoo with 14% glycolic acid called Aqua Glycolic - and am hoping and praying it might play better with the zinc. Am also hoping to order a plain zinc sunblock with fewer ingredients than the cetaphil cream in hopes that might help. Am getting desperate. I am 10 days from going somewhere very important.

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Okay so it took me a bit to figure this out but it's pretty interesting I think (tho I might be wrong).

I think the Zinc Oxide is forming a salt with the Sodium (in Sodium Lactate) because of the slightly basic condition of the solutions. This salt can react with the Hydroxide (in Ammonium Hydroxide) to form a Zinc Hydroxide, thus lowering the pH of the solution (making it more acidic). Under acidic conditions, Ammonium and dissociate with its extra hydrogen to form Ammonia, which is volatile. It's probably the Ammonia you're smelling.

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I could hug you for answering me so quickly. Thank you for wading through all the info.

Do you feel it is probably bad to continue using these at the same time, if they create this reaction? (I suspect it is.)

I don't want to pester you - but do these ingredients in the Aqua Glycolic Shampoo and Body Wash (14% AHA) sound like they might mix better with the zinc oxide? There's no sodium lactate in it - and it has ammonium glycolate instead of hydroxide.

Aqua Glycolic Shampoo and Body Wash ingredients:

Amino Methyl Propanol, Water (Purified), Glycolic Acid, Glycerin, Disodium Cocamphodiacetate, Ammonium Glycolate, Fragrance 4925, Propylene Glycol, Diazolidinyl Urea, Methylparaben, Propylparaben

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Hm, the glycolate is still acting as a base for the ammonium, and the disodium cocamphodiacetate still provides sodium for salt formation. It seems like you might get a similar reaction, although glycoate is a weaker base than hydroxide.

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Okay so it took me a bit to figure this out but it's pretty interesting I think (tho I might be wrong).

I think the Zinc Oxide is forming a salt with the Sodium (in Sodium Lactate) because of the slightly basic condition of the solutions. This salt can react with the Hydroxide (in Ammonium Hydroxide) to form a Zinc Hydroxide, thus lowering the pH of the solution (making it more acidic). Under acidic conditions, Ammonium and dissociate with its extra hydrogen to form Ammonia, which is volatile. It's probably the Ammonia you're smelling.

i'm quite sure i've fallen in love with u after this post.

lol! =p

i think using the sunscreen which lesser ingredients would be a better option.although am yet to find out if the zinc oxide there will have similar healing effect on it.

zinc oxide is said to be effective on fungal folliculitis.so may be ur bumps/zits were fungal after all.

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