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Ferulic acid turns yellow in anhydrous LAA serum
Whenever I add ferulic acid to my anhydrous L-ascorbic acid serum, it quickly turns yellow. I know it’s not the LAA because the solution containing LAA alone is still completely clear after a month. Why is the ferulic acid oxidizing so quickly?
Serum 1 - Still clear after 30 days
15% LAA
85% propanediolSerum 2 - Yellow in 5 days
15% LAA
1% ferulic acid
5% Sodium lactate
79% propanediol
* Heated to 50C to dissolve the ferulic acid -
20 Replies
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You really don’t need to heat the propanediol to get the Ferulic Acid in solution. It will dissolve in room temp propanediol with stirring. Ferulic Acid does have a yellowish tint to it. Try cutting the ferulic acid down to 0.5%
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MarkBroussard said:@DeedeeUkuleleYou really don’t need to heat the propanediol to get the Ferulic Acid in solution. It will dissolve in room temp propanediol with stirring. Ferulic Acid does have a yellowish tint to it. Try cutting the ferulic acid down to 0.5%
Thanks, will try at 0.5%. The problem is it starts out champagne-colored when fresh but turns an oxidized shade of yellow after just a few days. Maybe the ferulic acid I have is low quality? Because I really can’t get it to dissolve at room temperature at all.
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Ferulic Acid in neat Propanediol readily dissolves at room temperature with stirring and no heat.
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Just a side note: You’re not really anhydrous
. Especially not in a blend of a glycol with a hygroscopic salt and an open beaker. Also, there’s plenty of oxygen available… maybe store in a closed bottle?Furthermore, colour isn’t linearly correlated with concentration, the amount of degradation product could be very small. On the other hand, the yellow colour might as well be all LAA being oxidised.The issue with combining ascorbic acid with a phenol or some other stuff is the creation of an ‘electron sink’: Whilst plain LAA might not react with oxygen even in solution (or not to a visible degree) it easily does start to react if you add for example ferulic acid. Under others, because ferulic acid reacts first and then LAA reduces it back, ferulic acid oxidises again, more LAA reduces it back and all the while oxygen enters the bottle and keeps the cycle running until nothing is left… -
Thank you! That makes a lot of sense.
I have another LAA+FA sample stored in a closed bottle, the top is still oxidizing. I had planned to package this in airless pumps but I guess there’s just no avoiding the yellowing 🤷
RE: the “electron sink”, I had a sinking feeling (no pun intended!) the LAA and FA were just using each other up. And here I was with grand plans to throw in some resveratrol as well! Considering the LAA-only solution is doing okay so far, I probably won’t need co-antioxidants right? I was really hoping to have a great marketing story with the FA and resveratrol.
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Are you in the US? I see people working on these types of serums constantly, if they were taken to market are they not in violation of L’Oreals current patent?
https://patents.google.com/patent/US20050154054A1/en -
A: They mention glycol ether (which the products I’ve seen do not contain) and B: the patent is over 15 years old… wouldn’t it be expired?Also, that patent doesn’t seem right from a scientific angle. Sure, many things in cosmetics aren’t as we think they should theoretically be because theory only goes that far.Apart from that: Why do most not use an antioxidant which regenerates oxidised ascorbic acid and/or captures oxygen or a ‘suicide’ inhibitor of pigment formation?
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evchem2 said:Are you in the US? I see people working on these types of serums constantly, if they were taken to market are they not in violation of L’Oreals current patent?
https://patents.google.com/patent/US20050154054A1/enNot from the US but this doesn’t violate L’oreal’s patent. You can only infringe a patent when your product contains every element in the claim. For example, the infringing serum would have exactly the following:
5% to 20% L-ascorbic acid,
0.5% to 5.0% of a cinnamic acid derivative selected from the group consisting of p-coumaric acid, ferulic acid, caffeic acid, sinapinic acid, a derivative thereof, and a combination thereof,10% to 60% of a solvent comprising a glycol ether and an alkanediol;0.5% to 1.5% phenoxyethanol;0.3% to 1.5% panthenol;0.5% to 5.0% triethanolamine;0.05% to 0.3% sodium hyaluronate;1.5% to 5.0% surfactant; andwater to 100%,the composition having a pH of no more than about 3.5.This is why you see a lot of LAA+FA+Vit E serums in the market. Their workaround is pH higher than 3.5 or they don’t use ethoxydiglycol, etc. In my serum’s case, it doesn’t even have a pH.
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Pharma said:A: They mention glycol ether (which the products I’ve seen do not contain) and B: the patent is over 15 years old… wouldn’t it be expired?Also, that patent doesn’t seem right from a scientific angle. Sure, many things in cosmetics aren’t as we think they should theoretically be because theory only goes that far.Apart from that: Why do most not use an antioxidant which regenerates oxidised ascorbic acid and/or captures oxygen or a ‘suicide’ inhibitor of pigment formation?
20 years for a patent. In 2025, everyone’s gonna go crazy making LAA+FA+Vit E serums left and right!
I know nothing about chemistry, but a quick and superficial Google search led me to superoxide dismutase. Would that fit the bill?
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Removing hydrogen peroxide would remove one of the possible intermediates in one of the AA degradation pathways. However, there are some issues with that: For one, this won’t stop degradation and for another, you’d have to use a solvent which allows full activity of SOD (this usually means more water and some electrolytes).A thiol or sulfur based antioxidant would work. Also, use airless and lightproof containers, a good chelate and increase viscosity.
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Pharma said:Removing hydrogen peroxide would remove one of the possible intermediates in one of the AA degradation pathways. However, there are some issues with that: For one, this won’t stop degradation and for another, you’d have to use a solvent which allows full activity of SOD (this usually means more water and some electrolytes).A thiol or sulfur based antioxidant would work. Also, use airless and lightproof containers, a good chelate and increase viscosity.
@@Pharma
Great, I’ll keep this in mind. Thank you so much!
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DeedeeUkulele said:Whenever I add ferulic acid to my anhydrous L-ascorbic acid serum, it quickly turns yellow. I know it’s not the LAA because the solution containing LAA alone is still completely clear after a month.Serum 1 - Still clear after 30 days
15% LAA
85% propanediolSerum 2 - Yellow in 5 days
15% LAA
1% ferulic acid
5% Sodium lactate
79% propanediol
* Heated to 50C to dissolve the ferulic acidThe difference between those 2 formulas is not only ferulic acid, but also Sodium lactate. Try to take it out and see what happens. LAA quickly degrades in presence of electrolytes (which is Sodium, right?), although I am not sure if it applies in waterless solutions.
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toketsu said:LAA quickly degrades in presence of electrolytes (which is Sodium, right?), although I am not sure if it applies in waterless solutions.
Do you have any source for that claim? Sodium and lactate are both electrolytes… Anyway, it does degrade faster in presence of certain metal cations (mostly ‘redox active’ heavy metals).
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For the dumb people like me what is LAA? Assume L-Ascorbic Acid? If so are you just using L-Ascorbic acid powder? I have made myself a very basic 10% Vitamin C serum with Distilled Water, L-Ascorbic Acid Fine Powder 10%, Ferulic Acid 0.8%, Glycerin, Pentylene Glycol, Xanthan Gum Clear + another preservative and have in an Amber dropper bottle wrapped in foil - This was just a test for myself and after close to 3 months it is still the same color it was when I made it. I kept in fridge at 12 degrees for first month but since then is at room temp (my room temp is around 25 to 26 degrees). I intend playing around with the formula so always interested in what other people are doing on this forum and continuing to learn. Note that mine is for my own use only and not to sell. Cheers
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Pharma said:Do you have any source for that claim? Sodium and lactate are both electrolytes… Anyway, it does degrade faster in presence of certain metal cations (mostly ‘redox active’ heavy metals).
You are right, I mean metal ions. I’ve never seen a formulation with LAA and Sodium salts together, so I assumed Sodium is also speeds-up the degradation.
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Squinny said:For the dumb people like me what is LAA? Assume L-Ascorbic Acid? If so are you just using L-Ascorbic acid powder? I have made myself a very basic 10% Vitamin C serum with Distilled Water, L-Ascorbic Acid Fine Powder 10%, Ferulic Acid 0.8%, Glycerin, Pentylene Glycol, Xanthan Gum Clear + another preservative and have in an Amber dropper bottle wrapped in foil - This was just a test for myself and after close to 3 months it is still the same color it was when I made it. I kept in fridge at 12 degrees for first month but since then is at room temp (my room temp is around 25 to 26 degrees). I intend playing around with the formula so always interested in what other people are doing on this forum and continuing to learn. Note that mine is for my own use only and not to sell. Cheers
Yes, LAA is L-Ascorbic Acid.
Yes, L-Ascorbic acid is used as a powder.
The fact that your serum is still clear might not mean LAA is still non-oxidized. I heard (but I don’t claim it and would like to know if it is true) that brown color in serum is a reaction of LAA oxidation with aminoacids (the same way as fake tan reacts in skin). So if you have plain mix of LAA and Water you won’t see a color? Also, I’ve seen that there are several steps of degradation, so some products of degradation might not have a color?Also, the lower pH the more stable the acid. I don’t see any adjusters in your formula, so I assume it is very low ith 10% of LAA.
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toketsu said:…
The fact that your serum is still clear might not mean LAA is still non-oxidized. I heard (but I don’t claim it and would like to know if it is true) that brown color in serum is a reaction of LAA oxidation with aminoacids (the same way as fake tan reacts in skin). So if you have plain mix of LAA and Water you won’t see a color? Also, I’ve seen that there are several steps of degradation, so some products of degradation might not have a color?
…The first oxidation step results in a nearly colourless compound which can be reduced back to LAA. Higher amounts should be noticeable as a slight ochre hue. Further reaction steps lead to autopolymerisation and, as you mentioned, also to polymerisation with amino acids and other molecules. These polymers are usually red to brown. Yellow colour can either be shorter polymers or, such as the case with ferulic acid, are the oxidation product of ferulic acid (which is inrensely yellow, if I’m not mistaken).
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So if you have a product that you have made like mine and it hasn’t changed color why would you think it is oxidized? How else do you know it has oxidized besides a change in color? (ie. for the home formulator). If you bought a OTC product and it didn’t change color as a consumer you wouldn’t know if had oxidized either would you? You would assume stable? Just interested in everyone’s views. the pH of my product was 3.8 and no I didn’t put the total % of each ingredient in my post and any pH adjustments. Cheers
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Pharma said:toketsu said:…
The fact that your serum is still clear might not mean LAA is still non-oxidized. I heard (but I don’t claim it and would like to know if it is true) that brown color in serum is a reaction of LAA oxidation with aminoacids (the same way as fake tan reacts in skin). So if you have plain mix of LAA and Water you won’t see a color? Also, I’ve seen that there are several steps of degradation, so some products of degradation might not have a color?
…The first oxidation step results in a nearly colourless compound which can be reduced back to LAA. Higher amounts should be noticeable as a slight ochre hue. Further reaction steps lead to autopolymerisation and, as you mentioned, also to polymerisation with amino acids and other molecules. These polymers are usually red to brown. Yellow colour can either be shorter polymers or, such as the case with ferulic acid, are the oxidation product of ferulic acid (which is inrensely yellow, if I’m not mistaken).
Thanks Pharma I think that explains the color changes well, especially for a home formulator novice like me. Have a lovely weekend, Cheers
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Hi, DeedeeUkulele,
very interesting post regarding L-Ascorbic and Ferulic acid. Those two ingredients also bothering me.
Thanks to all for great comments, especially Pharma, so valuable info!!!
I must to add, that so the temperature is important. You have mentioned that heated up propanediol to 50 degrees to dissolve the ferulic acid, but LAA you added later or at the same temperature? This is crucial and speeds up ascorbic acid degradation - light and heat should be avoided with those ingredients ( me have tested creams with MAP at 40 C, so in that temperature they were getting yellow more quickly about 2-3 weeks as in room temperature could stand one year almost white color.
The other thing regarding oxidation and chemical changes even if could not be indicated by color is odor. Have the smell of serum changed in your case?
I have got not color changes in my serum, but the odor became so unpleasant and strong …like at dentistry cab.Please see my post here (its about MAP and Ferulic acid serum) https://chemistscorner.com/cosmeticsciencetalk/discussion/comment/69302#Comment_69302.
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