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pH drift with Gluconolactone and sodium benzoate
Hello! I am brand new here and so please forgive me if I ask something completely stupid. I know this is what you people do for a living and you are very busy. I only do this for myself. I have no intention of selling. This is all personal use for me. I have been doing this off and on for years and doing a lot of online research, but I’m no chemist
I have googled the crapola out of this and realize I may need to get another ingredient to fix this. I just need sound advice so I don’t do something harmful. I recently started using GSB as my preservative. I make 20 oz batches or less (yes, by weight, I have a scale), keep the bulk in the fridge and only take out a bit here and there, so I tend to go light on preservatives. Maybe tmi, but my skin has been all over the place since perimenopause and I never know when, why, what it’s annoyed by. Things I have done forever with no problem, can purely randomly be a problem, just as an fyi.
Case in point I made the below lotion a month or two ago and my skin loved it. Totally fine. In fact, I was so excited that I found a formula that seemed to hydrate enough (live in dry Nevada) and that the preservative didn’t bother me. Used it for about 3 or 4 weeks. Made a second batch, same formula. Then I noticed my skin seemed to be a bit tingly, subletly burny (for lack of a technical term), and seemed to get a wee bit blotchy red sometimes, but it would calm down later. I check the pH and noticed it was a 4. Usually my lotions in the past have been around 5-5.5, maybe 4.5 as the lowest. So I made another small batch without the preservative GSB and it’s pH is about a 5.5-6.
I have tested all my ingredients by themselves many times and individually nothing has been a problem. But I think my skin is having a problem with a pH of 4, because it has just become more sensitive in general.
So my question is (sorry that was a lot of preamble) how can I buffer it a wee bit? I have sodium lactate, but I realize it may not be strong enough, and I don’t like the skin feel of sodium lactate for some reason (just personal preference). I don’t have sodium citrate and don’t know if that can be used alone to help buffer or if it drastically changes the feel of things…?
I like the how the gluconolactone in the preservative seemed to subtly exfoliate my skin gently the first time I used it and would like to be able to continue with it. I know there are a bazillion preservatives out there, but I would like to try to work around this one, so any advise on the pH would be great. Then I can see if I still have irritation, before trying to change things too much.
And yes, I know the Olivem1000 is low in the formula below, but I like it a bit runny. And yes, a lot of oils. Again this is just for me and I live in the desert so need more oils to go with my glycerin
.Thank you so much in advance if anyone has time to help. I just don’t want to hurt my skin, and I have read about this particular ingredient having a pH shift and had seen something about using sodium citrate to help adjust. It’s just a wee out of my league not doing this for a living. I just don’t understand why it didn’t bother me at all the first time I made this.
Thanks again! Kim
Olivem1000 - 2.5%
Beeswax - .5%
Avocado oil – 6%
Borage oil – 6%
Meadowfoam – 6%
Pomegranate oil – 8%
Glycerin – 5%
Allantoin - .5%
Beta Glucan – 5%
Glycine betaine Beet sugar extract – 3%
Syn-col - 2.5%
Pumpkin seed extract (Cucurbita pepo (pumpkin) seedcake) – 4%
Chamomile EO - .5%
Neodefend – 1% (gluconolactone and sodium benzoate)
Distilled water -
6 Replies
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@Kimluow I’m currently waiting for a sample of GSB for testing, but I’ve heard that it helps to heat GSB to 70C in the water phase. I don’t know if this is simply to prevent emulsion issues or if it helps with the pH drift (or both). I think sodium citrate would be a good buffer, but I don’t know how much you would need.
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@thebrain… Thank you. I will try heating it, which I have not done before, as well as, order some sodium citrate to have on hand. I may have to play with how much sodium citrate and try to find more online about buffering with it. Thanks so much for your reply. Good luck with your testing
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The reaction you are experiencing is probably from the Sodium Benzoate + Low pH. Gluconolactone + Sodium Benzoate does tend to cause a pH shift. Your skin may now be sensitized to the Sodium Benzoate … it can cause a flushing reaction and it sounds like that is what is happening to you.
You can purchase Gluconolacctone separately and switch to a preservative that does not contain sodium benzoate. Try Benzyl Alcohol (0.8%) or Caprylyl Glycol (1%) + 1,3-Propanediol (3%) … that should do the trick
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@ MarkBroussard… Thank you. I was wondering about the sodium benzoate and do have gluconolactone by itself and I was going to test with just it to see if IT was bothering me at all. Sorry to ask another question, but if the Gluconolactone should cause the pH to be too low, would the sodium citrate be an appropriate way to buffer?
I don’t have those other preservatives yet, but can get some. Right now, which I have not tried (it came as a sample), I have EPE 9010 Ethylhexylglycerin + Phenoxyethanol. Do you know anything about that one? If I should go with your other suggestion first or if you think this one would be safe enough to try since I already have it?
Thank you again so much. I apologize for the additional questions. Just don’t want to obliterate my skin if at all possible
. I so appreciate it. You guys on this site are great!
Kim -
Yes, the Euxyl PE9010 should work just fine. Try it with Gluconolacctone as a solo ingredient and see if that solves your problem. Yes, you can try Sodium Citrate … don’t know if that will work as a buffer, but certainly give it a try.
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@MarkBroussard. Thank you for your quick reply! Cheerios! We’ll see how it goes. Have a good one.
Kim
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