No, ANUA Azelaic acid serum isn't a scam
A cosmetic chemist on neutralised azelaic acid: why it's not a scam, and what it can't do.
Many, many questions about Anua Azelaic Acid and similar Korean azelaic acids being a scam, on account of the fact that they use pH neutralisation as a strategy to deliver azelaic acid into your skin.
Two things you should know before we start, Complexions. I’ve worked with Anua before. I’ve also made plenty of TikToks about what this serum can’t do, and they’re all still up. And the shopping list at the end is affiliate, I earn a commission if you buy through it.
Neither of those changes the chemistry one bit, but you get to weigh them however you like.
What I can’t do is stay silent when people in the comments call it a scam. It isn’t. It’s unfair to compare these serums to prescription-strength products. That’s a separate conversation. Neutralising the azelaic acid to create a very skin-friendly solution does not mean it’s ineffective.
Let me walk you through why…
The accusation
The argument goes like this.
Azelaic acid is the active ingredient. Neutralise it with something like sodium hydroxide or tromethamine and you turn it into a salt, for example sodium azelate. And a salt, they say, is a different thing from the acid. It isn’t bioavailable. It doesn’t carry the same benefits as free azelaic acid. So the 10% on the label is misleading. You think you’re buying azelaic acid, and what you’re getting is a salt that doesn’t do what azelaic acid does.
Well, the chemistry works differently.
Why anyone neutralises it in the first place
Neutralisation is not an Anua trick. It’s a normal, sensible way to formulate this ingredient.
Azelaic acid barely dissolves in water. Only about 0.24% at room temperature, which is nowhere near enough to be useful, so in its raw form, it sits as gritty crystals.
The prescription 15 to 20% products get around this by suspending it. And people treat suspension and solution as though one of them has to be the loser. They don’t work like that.
A suspension is doing something clever. Only dissolved azelaic acid can cross your skin, so those undissolved crystals look like dead weight sitting there. They aren’t. They’re a reservoir. Every time a bit of dissolved acid slips into the skin, a bit more crystal dissolves to take its place, so the solution stays saturated the whole time it’s on your face. And saturated is the hardest a solution can push. You cannot do better than that.
So prescription strength isn’t brute force. It’s a format that holds itself at full pressure for as long as you’re wearing it.
But it can come at a cost. In Finacea gel's own trials, burning, stinging or tingling hit 29% of users and itching another 11%, mostly in the first weeks. Though that's the vehicle as much as the strength: the 15% foam is the same azelaic acid, same suspension, and reports a fraction of the sting. Skinoren at 20% is stronger again.
And a clear, light serum can’t lean on suspension anyway. So you solubilise instead, and one standard route is to neutralise. The salt dissolves where the free acid won’t. That’s what neutralisation buys you: a smooth, wearable serum rather than a gritty, stingy paste.
That’s not cutting a corner. It’s basic pharmaceutics.
And really, holding a 15 to 20% prescription medicine up against a 10% cosmetic serum is a daft comparison to begin with. They aren’t the same category of thing.
The salt isn't a different ingredient
Sodium azelate isn't a different ingredient from azelaic acid. It's azelaic acid with a couple of bits removed.
Picture azelaic acid as a long chain with two ends, and a little proton parked on each. Neutralising it just lifts those protons off. That leaves the chain with two negative charges, so sodium ions drift over to balance them out, stand-ins keeping things even. That's all the salt is. Same chain, protons gone, sodium keeping the books.
What decides whether the protons are on or off is one thing only: pH.
Think of pH as how crowded the surroundings are with spare protons. Somewhere acidic is packed with them, so azelaic acid happily keeps hold of its own. Somewhere less acidic is emptier, so it lets them go. Same molecule the whole time, just reading the room.
Because it has two ends, it can let go of one proton or both, so you always have a mix. In a neutralised serum, most of it has dropped both. That’s why the bottle is mostly salt.
And none of it is stuck that way. Swapping protons on and off is about the fastest thing that happens in water. Constant, instant, no enzyme, no waiting. So a neutralised bottle isn’t a bottle of some separate, lifeless compound. It’s azelaic acid with its protons off for now, ready to snatch them back the instant the pH drops. Which is what your skin should do to it.
So Anua isn’t lying to you when it says 10%. That figure is the total azelaic acid content, whatever state it’s in. The salt doesn’t subtract from the dose. It's the same azelaic acid, counted honestly, just with its protons off while it sits in the bottle.
The half that's true
The fair part of the criticism is: in the bottle, yes, it’s mostly the salt. And the salt on its own isn’t the form that crosses your skin most easily. True.
What matters more than the form azelaic acid takes in the bottle is delivering it to the target in the skin.
So how does that happen, if the salt itself can’t cross the skin?
The chemistry happens over the few minutes the serum is on your face, and in that time, your skin turns some of the salt back into free acid. And that’s the form that gets in.
None of this is unusual. Plenty of medicines are made as sodium salts, so they dissolve and keep well, then cross into the body as the free acid. Naproxen sodium. Diclofenac sodium. Nobody says those don’t work, because they obviously do. Azelaic acid from a salt is the same idea.
So does it actually get in
Fair question. If most of it is the charged form in the bottle, does enough actually get into your skin to matter?
Yes, because the pH in the bottle is not the pH at the point of entry.
Your skin surface is acidic. On healthy skin, the acid mantle sits around 4.7, and the pH climbs the deeper you go, up toward your body’s neutral 7.4 in the living layers. Azelaic acid’s two acid groups flip over at roughly pH 4.5 and 5.5. So as the film’s pH falls towards those numbers, more of the uncharged form appears.
How far it falls is the honest gap in all of this. Your serum has its own buffering holding it up, your skin has its own pulling it down, and nobody has measured who wins on a real face. So take what follows as what the chemistry predicts, not as something that’s been watched and measured.
The real point of restriction for this molecule is solubility. How much of it is dissolved and ready to go.
And yes, there’s a trade-off. To slip through skin, azelaic acid does best uncharged. But to be there in useful amounts, it has to dissolve, and it dissolves far better when it’s charged. So the two things it needs pull in opposite directions.
pH is the dial between them. Go very acidic and almost nothing dissolves, so there’s barely anything to get in. Go less acidic and plenty dissolves, but hardly any of it is uncharged, which is the form that crosses most easily. Around pH 5 you get both at once: a good amount dissolved, and a good share uncharged. That’s about where your skin sits, so it meets the serum right at its best delivery pH.
And it keeps feeding. As azelaic acid is absorbed, more dissolves to take its place, and the salt takes protons back from your skin to top the uncharged share up. Nothing is locked away. Most of it just waits its turn as the salt, feeding the surface for as long as the serum sits on your face.
If the film’s pH really does drop towards 5, the serum makes far more free acid than plain water could ever hold. Well past its solubility. So it shouldn’t stay dissolved at all. It should come out as fine solid, right there on your face. That’s the same trick used to purify azelaic acid in a factory: acidify the salt, and the acid drops out.
Which means a neutralised serum may quietly build itself into a suspension on your skin. The same format the prescription arrives in, assembled where it counts instead of ground into a paste first.
But that’s what the chemistry predicts, not something anyone has watched happen. The glycols in this formula hold more free acid in solution than water would, so where that threshold actually sits, I can’t tell you. But the direction is right.
Once it's inside.
Follow it a little further, because the story doesn’t end at the surface.
As azelaic acid travels deeper into the skin, the pH climbs. Down in the living layers, it's close to your body's own neutral pH, nothing like the acidic surface. So the molecule lets its protons go again and turns back into the charged form.
But being charged doesn’t mean finished. Which form does which job once it’s inside isn’t something I can tell you with any confidence, and I don’t think anyone can. What I can tell you is that being charged doesn’t take a molecule out of the game.
And that’s how loads of medicines behave. Ibuprofen, aspirin, statins, all charged at the pH inside your body, all working perfectly well like that. Charged doesn’t mean switched off. It just means charged.
So your skin gives azelaic acid an acidic surface to slip in through, and more neutral layers underneath. Same molecule the whole way down, just reading each room as it gets there.
Where the format does matter
I’m answering a chemistry question, not cheerleading the Anua serum. I’ve made plenty of TikToks about this product and its limitations.
Because delivery format matters a lot. It changes how much you get in and how fast, not whether it can act once it's there.
A suspension carries its own reservoir, so it holds itself at saturation for as long as it's on you. A neutralised serum starts fully dissolved and has to make its own free acid as the pH drops. Cyclodextrins are a third route, and they don't wrap the molecule up and release it like a parcel. They hold it in a loose grip that's forming and letting go constantly, which keeps more of it dissolved. Get the ratio wrong and the grip wins, and you deliver less. Buffering decides how long any of it keeps going.
These are real levers, and they're why two 10% products are not automatically equal. But every one of them is a question of dose delivered.
What I'm NOT saying
I’m not claiming a neutralised 10% matches the prescription stuff. It DOESN’T.
Prescription azelaic acid is 15 to 20%. A 10% serum is lower to start with, and how well it works depends on the whole formulation, not on whether it’s neutralised. And nobody, me included, has the penetration data for this exact serum. So I’m not telling you it’s proven potent.
What I am telling you is narrower. The claim that neutralisation turns azelaic acid into a dead, non-bioavailable salt is wrong. The salt isn’t a separate, permanent thing. Some of it reverts to free acid on your skin. And charged doesn’t mean dead anyway.
So, is ANUA Azelaic acid serum a scam?
No.
It's not a scam. Some of the salt turns back into free acid on your skin, so it gets in. And being charged deeper down doesn't take it out of the game.
Whether any given 10% serum is as effective as you’d like is a real question, and it depends on the full formulation and, honestly, on data most of us don’t have.
Which brings me to you, Complexions. Have you tried the Anua azelaic acid, or another neutralised one? Did it do anything for your skin? I want to hear the real-world side, because that’s the part the chemistry can’t answer for me.
And if you're shopping, here's my running list of OTC azelaic acids worth a look (LINK). Read the note on each one, because they are not all equal. Not in strength, not in formulation, not in what they are actually for.
Bye now, M x
Such a brilliant deep dive. It will clear a lot of things up for many! I used this serum briefly before switching to Regimen Lab Azelaic. I did like it. Just wanted something stronger personally 💚
Thank you for explaining the chemistry so clearly. I use Anu's formulation and it is clearly helpful for my roscea. I use it right after ascorbic acid in my routine and get good results.