How long does vitamin c take to turn yellow w/ expose to air
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free skin care · Wed Apr 05, 2006 7:41 am

I know this sounds like an odd question, but before I start using this vitamin c serum I made, I'm testing to see if this is real ascorbic acid that I bought from this store because I have my suspicions maybe it isnt. I have had it in a cup filled with half pure colorless aloe vera and some ascorbic acid powder for like a day and a half now completely exposed to air and everything else with no lid and it still hasn't turned the slightest yellow. Should it have turned by now or does it take a few days??

free skin care · Wed Apr 05, 2006 9:06 am

Hi Mermaid,

Um ... does the Aloe Vera have a preservative in it? Mine does ... and any preservative, even the small amount in the aloe vera will extend the life of the l-ascorbic acid.

Why do you suspect that the crystals/powder you purchased isn't "real" ascorbic acid. Or do you doubt that it's not l-ascorbic acid?

I know of one woman who mixes her l-ascorbic acid with plain distilled water ... and it lasts her two weeks in amber glass sitting on her bathroom counter.

It may take several days for it to begin to turn colour ... but that's not what's important really. What's important is that within a very short time of air exposure, the l-ascorbic acid content begins to degrade.

If you begin with a 10% l-ascorbic acid serum ... after a day, you may only have, say a 5% l-ascorbic acid concentration ... because with exposure to air, the l-ascorbic acid becomes d-ascorbic acid.

Now, as an experiment, I put a few drops of my homemade 10% serum on one side of an apple cut in half. It took two or three days for the apple side with the serum to turn brown ... so I'd expect that sort of result with your experiment.

Also ... did the crystals/powder fully dissolve in the aloe vera? If not, you're not going to get the same result. The powder/crystals have to dissolve.

I don't know what you should expect from this experience ... nor do I quite understand why you selected that particular means of testing it.

Why not contact the manufacturer and ask?

Mary

free skin care · Wed Apr 05, 2006 10:36 am

I'm assuming the crystals desolved because I shake my bottle every morning and when I put the drops into my hand and apply to face it feels watery not like gritty. So does that mean they disolved??

Are you saying that when you mix your vitamin c serums at home, your getting 10% the first day and only 5% the second day even when stored in a light resistant bottle??

The reason I did this was to determine if there is actually Ascorbic acid in the container I bought. I know they are a pretty reputable company but they sell their vitamins very cheap (not just the ascorbic acid crystals) so it just made me wonder. I know I'm just being paranoid, but I figure better know for sure before I keep applying this stuff to my skin because making my own is soooo much cheaper - like 100% cheaper than buying even the least expensive c serums and not knowing that they are full potency when you get them.

free skin care · Wed Apr 05, 2006 1:12 pm

Hi Mermaid,

No ... if you have your Vitamin C serum in an amber glass bottle ... your concentration does not reduce to 5% within a day.

What that was illustrating was if you left it in the open air ... it would degrade much faster.

I also said that I know a woman who mixes her crystals with only distilled water ... and hers is effective for two weeks in an amber bottle just on her bathroom counter. It would last longer in the refrigerator.

The less water you have in your serum the more stable the vitamin C is ... but the l-ascorbic acid needs water to dissolve.

In your aloe vera gel, there is less water [although it's largely water itself] ... but most natural aloe vera gels have some kind of preservatives in them ... so that will also extend the life of the serum.

L-ascorbic acid crystals/powder is very cheap. I think my bottle costs about $2 ... and makes quite a few serums.

Mary

free skin care · Wed Apr 05, 2006 4:41 pm

Thanks Mary.

I should try the distilled water with C crystals. I wonder if it would be drying on the skin though. Well maybe I'll try that next time. My aloe vera gel actually doesnt come with any preservatives in it. It says no preservatives on the bottle but the company says its good for 10 years so guess I'm safe.

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