Kybella and PCDC are both injections that dissolve fat with a detergent. The real difference is not the chemistry. It is whether anyone knows what is in the syringe. Kybella is an approved drug. One molecule, one strength, one label, one dosing table. PCDC is short for compounded phosphatidylcholine plus deoxycholate. A compounding pharmacy mixes it for the prescriber, and the recipe varies from one pharmacy to the next.
The FDA approved Kybella on 29 April 2015, under application NDA 206333, as a new molecular entity. It is man-made deoxycholic acid at 10 mg per mL. The label fixes the dose. That is 2 mg per square centimetre, 0.2 mL per injection, and injections 1 cm apart. No more than 50 injections or 10 mL in one session. Up to six sessions, at least a month apart. The label also carries a side-effect table built from 513 treated people. And it says, in those words, "Do not dilute or mix KYBELLA with other compounds."
Compounded PCDC has no approved label, no fixed strength and no side-effect table. When a clinic quotes you a percentage strength, that is the prescriber's own protocol. It is not an approved dose. Nothing makes two pharmacies mix it the same way. So the safety and result figures published for one recipe do not automatically describe another.
The phosphatidylcholine may not even be the part that works. Lab work published in 2004 tested an injectable phosphatidylcholine product against sodium deoxycholate on its own. It also tested two lab detergents. All three killed cells and broke open cell membranes to a similar degree. The authors concluded that sodium deoxycholate is the major active component behind that damage. That is why Kybella holds no phosphatidylcholine at all.
Nobody has ever compared the two head to head. No trial of branded Kybella against a compounded PCDC mixture has been published. The closest study is from 2009. It was a randomised double-blind trial of deoxycholate alone against a phosphatidylcholine-deoxycholate mix, under the chin. It has to be read for what it was: 42 people, compounded material, run before Kybella existed. It was scored on a 0-to-3 improvement scale that was not a validated tool.
There is no single PCDC product to point at. The recipe differs between pharmacies, and between the prescribers who order it.
Approved 29 April 2015 under NDA 206333. AbbVie now distributes it. The current label revision is dated October 2024.
There is no approved strength to check a batch against, and the recipe is not standard across pharmacies.
The deoxycholic acid is made in a lab rather than taken from bile. Each vial carries a hologram to guard against fakes. The label tells the injector not to use a vial without one.
The 2004 lab work called the effect non-selective. It damaged fat and muscle alike. The authors advised caution until there were proper safety data.
The label's whole mechanism section reads that the drug "physically destroys the cell membrane causing lysis." Fat is hit hardest because fat holds little protein and albumin, which otherwise soak up the detergent. That is relative selectivity, not a receptor.
FDA's consumer page on fat-dissolving injections, content current as of December 2023, names lipodissolve among unapproved products. It names phosphatidylcholine and deoxycholate as common ingredients in them.
The label goes further than silence about other areas. It says use outside the submental region "has not been established and is not recommended."
The submental one enrolled 42 people and reported minimal improvement from either arm. A split-body study in 37 women put the mixture on one side and deoxycholate alone on the other. Fat fell on both sides, with no significant difference between them. The abdominal trial most often cited as proof enrolled 13 people, and 7 finished.
The results are real and moderate. Pooled, 68.2% versus 20.5% improved by one grade on both the clinician and patient scales. Only 16.0% versus 1.5% improved by two grades. On MRI, 43.3% versus 5.3% reached even a 10% cut in submental fat volume after up to six sessions.
Tissue samples taken after PC/DC injection have shown scarring, small abscesses, panniculitis, and fat death with tiny calcium deposits and cysts. FDA says it has received reports of permanent scars, serious infections, skin deformities, cysts and deep, painful knots from unapproved fat-dissolving injections.
Beyond 30 days, 42% still had numbness, 20% still had swelling, 16% still had pain and 13% still had firmness. Nerve injury showing as an uneven smile happened in 4%. Every case cleared up by itself, over a range of 1 to 298 days.
In the trials the median number of sessions to a response was 3. The median was 27 injections per session, rather than the 50 allowed. And 59% of people went through all six anyway.
The American Society of Plastic Surgeons put it plainly in 2019. Combining the two makes a new drug that is not FDA-approved for any purpose. So its use "would NOT be considered 'off-label' use." Compounding for this purpose sits under sections 503A and 503B of the federal drug law. The society notes that doctors may face enforcement action if those conditions are not met.
Those are two different legal categories. The difference matters if you are working out what standard the product you are offered was held to.
Lipodissolve-type injections started with phosphatidylcholine. In the original European product, the deoxycholate was there as a solubiliser. Its job was to keep the phosphatidylcholine dissolved in water. It was described as an inactive ingredient rather than a drug.
The 2004 lab study turned that on its head: It compared the phosphatidylcholine product with sodium deoxycholate on its own, and with the lab detergents Triton-X 100 and Empigen BB. The tests ran in cell culture and in pig tissue. All of them killed cells, broke open membranes and damaged fat and muscle to a similar degree. The conclusion was that the product "works primarily as a detergent causing nonspecific lysis of cell membranes." Sodium deoxycholate was the major active component. The same group reported the same thing in patients the next year, in a small series treating lipomas. Deoxycholate, not phosphatidylcholine, was the active ingredient.
That is where Kybella came from. A pure man-made deoxycholic acid product, with no phosphatidylcholine in it, exists because of that finding.
The 2009 trial is as close as the published work gets, and it was not a comparison with Kybella. It split 42 people between compounded deoxycholate and a phosphatidylcholine-deoxycholate mix. Each had up to five treatments, four weeks apart. The injection was blinded, and photographs of 32 of them were graded blind. Mean improvement on a 0-to-3 scale was 0.8 for deoxycholate and 0.6 for the mix. The median was 0.5 in both arms. The authors reported no apparent difference in results or side effects from adding phosphatidylcholine. They were blunt about the size of the effect: the injections "produced minimal aesthetic improvement." They also said the question needed more study, with a validated grading scale and a better dose. That is, in effect, a description of the trial programme that later produced Kybella.
So the honest position is this. No trial has tested compounded PCDC against Kybella. The numbers from one cannot be read across to the other.
It changes three things at once. There is no approved strength, so a percentage you are quoted is a local protocol. There is no approved dose per area and no ceiling per session, so the volume injected is the prescriber's call rather than a labelled maximum. And there is no side-effect table from a controlled trial of that recipe. So how often any given problem happens with that mixture is simply unknown.
Kybella's own figures need one caveat too. The label's rates come from the two placebo-controlled trials. But the widely quoted median durations - swelling around 10 to 11 days, numbness 43 days, firmness 28 days - come from a later pooled re-analysis of those trials. The drug's developer funded it, and several authors worked for the sponsor. That does not make the numbers wrong. It does mean they are sponsor-generated, with no independent set to check them against.
On 7 April 2010 the FDA issued seven warning letters over the marketing of lipodissolve: Six went to US medical spas, and one to a Brazilian company running two websites. The spas were Monarch Medspa in King of Prussia, Pennsylvania; Spa 35 in Boise, Idaho; Medical Cosmetic Enhancements in Chevy Chase, Maryland; Innovative Directions in Health in Edina, Minnesota; PURE Med Spa in Boca Raton, Florida; and All About You Med Spa in Madison, Indiana.
The agency named several claims as unsupported. Those were that the products were safe and worked for removing fat, that they beat liposuction, and that they could treat male breast enlargement, lipomas and surgical deformities. The harms the agency said it had documented were permanent scarring, skin deformation, and deep painful knots under the skin at injection sites. Janet Woodcock then led FDA's drug centre. She said at the time that anyone thinking about the procedure should understand that "the products used are not approved by the FDA for fat removal."
The agency's current consumer position says the same thing. That page, content current as of 20 December 2023, states that fat-dissolving injections sold under names including lipodissolve are unapproved. Phosphatidylcholine and deoxycholate are common ingredients in them. The reports it has received include permanent scars, serious infections, skin deformities, cysts and deep painful knots.
An earlier FDA statement on lipo-dissolve, dated 2007, is cited in the plastic surgery literature. It can no longer be retrieved from FDA's own site. So it can only be treated as something the literature reports, not as a document you can go and read. The 2010 warning letters and the current consumer page are both on the record in full.
Ask for the name, strength and volume of what you are being injected with, and get the answer before the day: For an approved drug this is on the label. For a compounded mixture, only the prescriber and the pharmacy know it. It is a fair question.
Say in advance if you take a blood thinner or an antiplatelet medicine, or have a bleeding disorder: Bruising affected 72% of people in the Kybella trials. The label says to use the drug with caution in those situations.
Say in advance if you have ever had trouble swallowing: People with current or past swallowing trouble were kept out of the trials. The Kybella label says to avoid use in them.
Fullness under the chin is not always fat: The label tells the injector to check first for an enlarged thyroid and enlarged neck lymph nodes. It also says to think carefully before treating loose skin or prominent neck bands, where cutting fat may not improve the look.
Neither product should be injected into skin that is infected. That is the single contraindication on the Kybella label.
Trouble swallowing, or any trouble breathing
Fever or chills after an injection session
Redness spreading outward from an injection site hour by hour
Pus or discharge from an injection site
Trouble swallowing after these injections usually comes from swelling rather than nerve damage. In the trials it settled by itself, with a median of 3 days. It still needs to be checked the same day. Any trouble breathing is an emergency.
Your smile becomes uneven, or one side of your lower lip stops moving properly. This is the marginal mandibular nerve, and it affected about 4% of people in the trials
Any facial muscle weakness appears, or numbness gets worse rather than better
An open sore, ulcer or patch of dark, dead-looking skin appears at an injection site
A firm lump is still there more than a month after a session
A bald patch appears at an injection site. This is a labelled reaction, and the label says it may last
Swelling, redness or pain is increasing after day three instead of settling