Kybella vs Aqualyx: One Has a US Label, One Has None

Two injections sold for the same purpose share an active ingredient. Deoxycholic acid dissolves fat cell membranes, and it is what does the work in both Kybella and Aqualyx.

That is where the sameness ends. One of them is a medicine approved for a single area of the body, with two phase 3 trials behind it and a nerve-injury warning on its label. The other has no American approval at all, and a published literature of five papers.

What each product is actually licensed to do

The CE mark named in that table is a European conformity marking, and it is not an American approval or its equivalent. It certifies that a product meets European requirements for its category, which is a different test from the one a medicine passes to reach a US label.

The right column is a description of a regulatory gap, not a finding about danger. The distinction is the whole point of this comparison, and the article returns to it below.

Kybella: one area, six treatments, and a warning about the smile

Kybella's American prescribing information is specific about where it may go. The approved indication is "improvement in the appearance of moderate to severe convexity or fullness associated with submental fat in adults", and the label states that it is not approved for use outside the submental region.¹ Submental means under the chin.

The dosing is equally bounded. Each injection is 2 mg in 0.2 mL. A single treatment may use up to 100 mg across a maximum of 50 injections, and a patient may have no more than six treatments, at least a month apart.¹ The label was revised in September 2026, so this is current, not historical.

Two warnings carry over from the trials. Marginal mandibular nerve injury, which shows up as an asymmetric smile or facial muscle weakness, occurred in clinical trials; all reported cases resolved without treatment, over a range of 1 to 298 days and a median of 44.¹ Difficulty swallowing occurred in 2 percent of treated patients, resolving in a median of 3 days.¹

The evidence behind that approval is two trials of nearly identical design. REFINE-1 randomised 506 adults and reported that 70.0 percent of treated patients achieved at least a one-grade composite improvement against 18.6 percent on placebo, with at least a two-grade improvement in 13.4 percent against none on placebo.⁶ REFINE-2 randomised 516 and reported 66.5 percent against 22.2 percent, and 18.6 percent against 3.0 percent.⁵

Read those numbers as a patient rather than as a regulator. The common outcome is a one-grade improvement on a five-point scale, not the disappearance of a double chin, and roughly a third of treated patients did not reach even that. REFINE-1 also reported marginal mandibular nerve paresis in 4.3 percent of treated subjects, mostly mild and transient.⁶

Aqualyx: five papers, two of them case reports

A search of PubMed, the National Library of Medicine's index of biomedical literature, returns five records for Aqualyx.² That is the entire indexed literature, and it is worth listing.

The largest is a four-year retrospective review of 186 patients, which reported mild swelling and redness resolving within days and stated that "no major complications or side effects occurred, such as necrosis".² A prospective study of ultrasound-guided injection to the inside of the knees found reduced circumference in 71.42 percent of its patients, and had seven of them.⁷ A third paper treated 17 lipomas and achieved complete removal in 70.59 percent.⁴

The remaining two are case reports of harm. One describes skin necrosis after injection of an adipocytolytic solution.⁸ The other describes chronic infection, painful nodules and purulent lesions after deoxycholate injection administered by untrained personnel.⁹

The same literature cannot agree on what kind of product Aqualyx is. A 2015 paper in Aesthetic Surgery Journal calls it "A CE-Marked Drug Used for Localized Adiposity Reduction".² A 2019 paper by an overlapping author group calls it "a Class III CE-marked device".⁴ Drug and device are different regulatory categories with different evidence requirements, and the difference is not cosmetic.

What the American label database says, and what it does not

Querying the label service run by the National Library of Medicine returns one record for Kybella and none for Aqualyx.¹³ A query for Kabelline, one of the Korean-made products sold on the same promise, also returns nothing.¹⁰

That absence has a precise meaning and no more. It means no approved indication exists, so no body area has been authorised. No approved dose exists, so no maximum applies. And no labelled warning exists, so nothing has to be disclosed to a patient in the way Kybella's nerve-injury paragraph does.

It does not mean the product is more dangerous than the approved one. Nobody has run the trial that would establish that either way. This is where most comparisons of these two products go wrong, and they go wrong in both directions. One error treats a European marketing authorisation as equivalent to an American approval. The other treats an absence of American approval as evidence of harm.

The price gap is partly a gap in what was tested

Prices are where patients start, so it is worth putting them next to the evidence.

One price aggregation across 21 American clinic price lists gives a median of 600 dollars per Kybella vial, with the middle of the range between 500 and 736 dollars.¹¹ Most patients need two to four vials a session and two to six sessions.

A London and Cheshire clinic group's 2026 guide prices Aqualyx at about 150 to 400 pounds a session for a small area such as a double chin.¹² Abdomen, flanks or thighs run 250 to 650 pounds or more, and a small-area course 400 to 1,100 pounds. Many patients need two to four sessions.

So a course of the approved product runs into thousands of dollars and a course of the unapproved one into hundreds of pounds. Part of that difference is the cost of two phase 3 trials, a submission and a label. Part of it is that the cheaper product is being offered for body areas no regulator has authorised any deoxycholic acid injection to treat.

Notably, the Aqualyx price guide says nothing at all about regulatory status, licensing or who may lawfully inject it.¹² Neither does it have to.

Abroad, the ladder is visible on one page

A Turkish clinic aggregator's 2026 guide prices all of these products in one table, which makes the structure of the market unusually easy to see.¹³

The same page puts a session in the United States at 600 to 1,800 dollars, the United Kingdom at 300 to 600, and Turkey at 200 to 500.¹³

It also names Kybella as approved by the US Food and Drug Administration and gives no regulatory information at all for the other three.¹³ That is the omission this article is about, stated by a seller rather than about one: the one product whose approval status is advertised is the one that has an approval to advertise.

What the quoted price leaves out

Who is allowed to hold the syringe. In the United Kingdom, a treatment requiring a prescription requires a prescriber. One local authority's guidance for non-surgical aesthetic procedures states that "for treatments which require a prescription, a face-to-face consultation must be performed by a suitably qualified prescriber", naming doctors, dentists, prescribing nurses and pharmacists.¹⁴ A remote form is not that consultation.

The rules are being tightened while these prices are being quoted. In August 2025 the Department of Health and Social Care announced restrictions on the highest-risk non-surgical procedures.¹⁵ Only qualified healthcare professionals working for providers registered with the Care Quality Commission will be allowed to perform them, with a licensing scheme and training standards for lower-risk treatments. Fat-dissolving injections were not named in that announcement, which is worth knowing before assuming the category is covered.

The case report names the mechanism of the worst outcome. The chronic-infection case describes injection by untrained personnel.⁹ That is a claim about who injected, not about which brand was in the syringe, and it is the variable a price comparison never shows.

Nobody is following these patients. There is no registry for fat-dissolving injections in any of the markets discussed. The five papers on Aqualyx are what exists, and two of them exist because something went wrong badly enough for a surgeon to write it up.

How to use this before booking

Ask which product, by brand name, and ask for the body area it is licensed or approved for. If the area you want treated is not that area, you are the evidence base.

Ask who will inject it and whether they can prescribe. In the United Kingdom that means a face-to-face consultation with a prescriber before anything is supplied.

Ask what the maximum dose per session is and where that maximum comes from. For Kybella the answer is on the label: 100 mg, 50 injections, six treatments. For an unapproved product there is no published answer, and the honest version of that reply is that the clinic sets it.

Compare courses, not sessions. Two to four vials across two to six sessions is the unit that matters for the approved product, and two to four sessions for the other.

And treat the absence of a label as a missing document rather than a verdict. It tells you what has not been established, which is exactly the information a price per session is not carrying.