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Fri Jan 26, 2007 3:29 pm  |
Has anyone attempted to test the efficacy of their antioxidant products with the sliced apple method? Take an apple, cut it in half, and place a layer of the antioxidant product on one half. When sliced fruit turns brown, that's due to oxidation. When the oil plugs in your congested pores turn black (--> blackheads), that's also due to oxidation (the color, anyway). If the antioxidants work, then it should appear as fresh-looking several hours later as when you first sliced it. Makes sense, right?
I don't know the fine details of how long you should be observing or how much of the product to use. I'm only paraphrasing what another forum member stated in a Vit C stability thread which I couldn't locate via google or forum search. I've been wanting to incorporate a new Vit C serum into my skincare routine, but which to choose? I figured this would be a good way to see how different products stacked against one another. Bah, now I'm sorry I tossed my last antioxidant serum. I've got to get some samples.
If anyone has results or even better methods of testing antioxidants at home, please submit them! |
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Fri Jan 26, 2007 4:14 pm |
Um...don't know if this is exactly what you mean, but....
My son's science project this year was on oxidation...spurred by the different methods we've used to keep his sliced apples fresh in his packed lunch.
I asked him to include my vit. c skin care...though I've never used it to preserve his lunch.
My MyChelle Perfect C came in 2nd to the air-tight container... (third was straight ascorbic acid, then O.J. then Vitamin water.) The Mychelle apple was actually the whitest...but it was very dry.
I've just ordered another Vit. C brand and plan on comparing them using apple slices. |
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Fri Jan 26, 2007 6:01 pm |
That test can't be used for actual comparison. Try just putting vasoline on an apple. It won't oxidize for a while either.  Is vaseline as good as vit-c serum for your skin? You be the judge. |
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Fri Jan 26, 2007 7:04 pm |
| Parentsaver wrote: |
| That test can't be used for actual comparison. Try just putting vasoline on an apple. It won't oxidize for a while either. Is vaseline as good as vit-c serum for your skin? You be the judge. |
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Fri Jan 26, 2007 7:57 pm |
Parentsaver wrote:
| Quote: |
| That test can't be used for actual comparison. Try just putting vasoline on an apple. It won't oxidize for a while either. Is vaseline as good as vit-c serum for your skin? You be the judge. |
Yeah, I see your point...I would add that a vit. C product compared with another vit. C product in this manner would be a primitive but reasonable home-grown test. Unlike vit. C, the vaseline would reduce oxidation because it would seal-off the apple, like an air-tight container, but two slices from the same apple both applied with a substance that works in the same manner, such as one form of vit. c versus another, would be apples&apples...not apples&oranges...so to speak...and valid. |
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Fri Jan 26, 2007 10:30 pm |
I tried that once with just my normal moisturiser on an apple and the apple didnt turn brown.
I also made some homemade vit c once and left the lid off to see how long it would take to go bad..2 weeks later it still hadnt turned so i tipped it out! |
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39, in Australia, using retin a, Skin actives I Bright and Antiaging Cream, change sunscreen regularly currently. |
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Sat Jan 27, 2007 12:05 am |
Is it an absolute certainty that color change in a C serum indicates to what level it's oxidized? I've always wondered about this, and there's evidently a lot of debate about it.
Carolb's post makes me wonder if color change is a reliable indicator, for surely two weeks of full exposure to air would cause oxidation, wouldn't it? |
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Sat Jan 27, 2007 12:15 am |
| m.april wrote: |
Is it an absolute certainty that color change in a C serum indicates to what level it's oxidized? I've always wondered about this, and there's evidently a lot of debate about it.
Carolb's post makes me wonder if color change is a reliable indicator, for surely two weeks of full exposure to air would cause oxidation, wouldn't it? |
m.april i did the test to see how quickly a c serum would go off when exposed to air and was really suprised when the colour didnt even change  Surely 2 weeks of constant air would oxidise it?? Yet an unopened sample bottle of Skinceuticals CE Ferulic (well i had opened a couple of times) turned a deep amber after 2 months so yeah im confused?? |
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39, in Australia, using retin a, Skin actives I Bright and Antiaging Cream, change sunscreen regularly currently. |
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Sat Jan 27, 2007 3:47 pm |
| Parentsaver wrote: |
| That test can't be used for actual comparison. Try just putting vasoline on an apple. It won't oxidize for a while either. Is vaseline as good as vit-c serum for your skin? You be the judge. |
No, I doubt Vaseline is as beneficial as a standard Vit C serum. Hmm, that's a good point. Vaseline is an antioxidant, then, since it prevents oxidation. A barrier effect? Better than nothing.
Purchasing something that I can only hope to benefit me in the long run is really a leap of faith. I know apples are apples and not human skin, sadly. Even if I can simply witness something preserving a piece of fruit, it makes it that much more substantial on a personal level. One can read all about the in vitro and in vivo tests performed with different antioxidants from PubMed and other places. Well, what does that have to do with the finished cosmetic product that one personally uses?
When Prevage first appeared, I wanted to know what the all the fuss was about and came across this article:
http://www.dermadoctor.com/pages/newsletter293.asp
I wouldn't have minded reading the whole antioxidant study myself if it hadn't cost ~$50. Bummer.
The part that remained with me most was this:
| Quote: |
| What about the real world? Who’s applying straight idebenone, or any of these other ingredients to the skin? In dermatology, a medication is only as good as its base; the active ingredient doesn’t function in a bubble. The pH of a formulation, the type of vehicle, the other actives present in the product and many other variables all ultimately play a role in product effectiveness. |
If all an antioxidant product has to do is fight off oxidation, how do you know it works? How do you know one leading product isn't 100% better or worse than another leading product? If anyone's got links to studies comparing full product formulations, that'd be welcome.  |
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Sat Jan 27, 2007 5:02 pm |
anysound you ask some very interesting questions....
Concerning the Prevage study, when they first started selling Prevage you could go to the Prevage website and read the entire study. I did read it but it was so long ago that I forget the specifics. I do recall that some of the results were based on in vivo testing. If I am not mistaken, the in vivo test had to do with sunburn cells and which antioxidant caused the least to form.
I would have to find it but such in vivo sunburn cell studies involving Vitamin C have also been done. It is possible that Skinceuticals has done these studies involving vitamin C, C+E and C+E+Ferulic.
As for specific forumlas this is also an interesting point. It would be good to know if a antioxidant serum has actual evidence of benefit. Not just if the "active" ingredinets have shown a benefit in an in vitro test.
This is an area where I would like to do more research. I use C serums mainly as a preventative measure and I would sure like to know if what I am spending is doing any good! I think that the evidence is there but I am going to look for it to be sure. I will let you know if I find anything..... |
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Sat Jan 27, 2007 5:35 pm |
| carolb69 wrote: |
| m.april wrote: |
Is it an absolute certainty that color change in a C serum indicates to what level it's oxidized? I've always wondered about this, and there's evidently a lot of debate about it.
Carolb's post makes me wonder if color change is a reliable indicator, for surely two weeks of full exposure to air would cause oxidation, wouldn't it? |
m.april i did the test to see how quickly a c serum would go off when exposed to air and was really suprised when the colour didnt even change Surely 2 weeks of constant air would oxidise it?? Yet an unopened sample bottle of Skinceuticals CE Ferulic (well i had opened a couple of times) turned a deep amber after 2 months so yeah im confused?? |
Some quick questions: Did you sniff the serum for a change of smell? Did you touch it to see if there was a noticeable change in texture? What was the manufacturing and/or expiration date of the sample bottle? Was it exposed to a lot of light or extreme heat? Was the bottle a pump or a dropper kind? Was the bottle clear or not? Like yayz 4 multiple factors.
| pbsadhaka wrote: |
As for oxidation, there is disagreement in the scientific community as to whether the color change (yellowing) is the l-ascorbic acid itself oxidizing, or the base substance (HA for example) becoming oxidized from the vitamin c. Also, studies have been done that show that even after the ascorbic acid has been exposed to an oxidizing agent, it can still retain up to 98% of it's efficacy for antioxidant action & dermal matrix stimulation.
So, some researches believe that the whole "stability" issue is really not that big of a deal. |
from http://www.essentialdayspa.com/forum/viewthread.php?tid=6801
| TheresaL wrote: |
pbsadhaka wrote:
Their stabilzation process consists mainly of 2 factors - pH and chelation. Ascorbic acid solutions are most stable at a low pH, and they are probably chelating the water with the zinc sulfate, which renders any trace minerals present unavailable to trigger oxidation. This is not new technology however, but is still effective nonetheless. Also, you may find this interesting, but even the oxidized form of ascorbic acid, dehydroascorbic acid, when applied topically is converted back into L-ascorbic acid in the skin. It is the presence of a specific amino acid in the skin, that has been found to recycle ascorbic acid from its oxidized form (dehydroascorbic acid) back into L-ascorbic acid. Hmmm......interesting! 
-Darren
Very interesting Darren! I had heard the part about pH and stabilization but not what you said about chelation. Is zinc sulfate the chelated form of zinc and how does adding this to water chelate the water? Does it sort of attach to the minerals and make them inactive to cause the oxidation? Also, I thought that it was the water itself that acted as a catalyst for oxidizing the ascorbic acid and that the presence of minerals/metals in the solution acted as a further catalyst for the oxidation process but even if you take the minerals "away" the water will still catalyze the oxidation, is this correct?
It is odd that you mention dehyroascorbic acid and the enzyme that will convert it back to l-ascorbic acid because I had just read this somewhere. I would guess that if enough dehydroascorbic acid is applied to the skin the enzyme would be reduced significantly and then would not be capable of doing the conversion sufficently. What do you think? I will provide the link to this article below but in it Dr. Pinnell states that the conversion process to l-ascorbic acid may happen or that the dehydroascorbic acid may just decay as the lactone ring irreversibly opens (no clue what that means!). So I guess there are several reasons why the dehydroascorbic acid would not be converted to l-ascorbic acid. Very interesting indeed!
http://www.revenirbeauty.com/distributors/files/CutaneousPhotodamage.pdf
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| TheresaL wrote: |
I think the confusion in this thread is over oxidized C serums and if they cause free radical damage or not. And even if they don't are they worthwhile to use.
I haven't made up my mind as to whether oxidized ascorbic acid causes free radicals. Here is a quote from smartskincare whom I consider to be a reliable source of information.
"In the presence of air or other oxidizing agents, vitamin C is easily converted to oxidized forms. The oxidized vitamin C is not only incapable of boosting collagen synthesis or scavenging free radicals but may actually promote free radical formation causing damage to vital molecules such as proteins and DNA. In poorly prepared or poorly stored skin care products, vitamin C may already be oxidized by the time you apply it to your skin."
"Furthermore, even stabilized vitamin C products may be at least somewhat oxidized by the time you use them. When vitamin C oxidizes, it eventually acquires a yellowish tint indicating an advanced stage of oxidation. Interestingly, some manufacturers add coloring to their vitamin C products, in which case it becomes hard to spot advanced vitamin C oxidation. Whatever the motives for adding color may be, we recommend avoiding vitamin C products that aren't colorless or white. Unfortunately, the lack of a tint does not, by itself, guarantee the lack of oxidation because the initial product of vitamin C oxidation (dehydroascorbic acid) is colorless. Only further oxidation produces a noticeable yellowish tint. Therefore, when selecting a vitamin C product it is important to pick a trustworthy source and be careful about the expiration date and proper storage."
http://www.smartskincare.com/treatments/topical/vitc.html |
from http://www.essentialdayspa.com/forum/viewthread.php?tid=19210
The latter site that TheresaL quotes is referring to L-ascorbic acid. Magnesium Ascorbyl Phosphate and Tetrahexydecyl Ascorbate are two popular examples of better stabilized Vit C. They oxidize less rapidly but they still do. Isn't this fascinating? :sigh: |
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