Key takeaways
- Kybella is FDA-approved only for fat under the chin; jawline, jowl and body uses are off-label.
- Allergan reports at least one-grade improvement in 28% after 2 treatments and 72% after 6; the label allows up to 6, at least 1 month apart.
- A two-grade improvement was much rarer in the trials than a one-grade change: 13.4% and 18.6%.
- The label makes no permanence claim; "cannot store or accumulate fat" is Allergan's consumer-site statement.
How long until you see Kybella results?
Kybella (deoxycholic acid injection 10 mg/mL) is an FDA-approved prescription drug, first approved in the US in 2015, for improving the appearance of moderate to severe convexity or fullness associated with submental fat — the fat under the chin — in adults.
It is a cytolytic drug: the label describes it as physically destroying fat-cell membranes when it is injected into under-chin fat, causing the cells to break apart (lysis).
The change comes from fat cells breaking down rather than from anything placed into the tissue.
Alongside it, the trials measured the reaction the drug causes in the area.
In the two pivotal trials pooled, injection-site swelling or edema occurred in 87% of Kybella patients versus 43% on placebo, and injection-site pain in 70% versus 32%.
Reactions that lasted more than 30 days and occurred in more than 10% of patients were numbness (42%), swelling (20%), pain (16%) and hardness (13%).
Reactions lasting more than 30 days
Share of Kybella-treated trial subjects
Source: Kybella prescribing information
Against that background, the trials measured the outcome 12 weeks after each patient's final treatment: at that point, 70.0% and 66.5% of Kybella patients had improved by at least one grade on both clinician and patient ratings, versus 18.6% and 22.2% of placebo patients.
Allergan, the maker, says many patients see visible results in 2 to 4 treatments.
The label reports swelling in 87% of treated patients, and lists numbness and swelling among reactions lasting more than 30 days. The label gives no day-by-day swelling schedule, so a week-by-week timeline you see elsewhere is not label data.
How many Kybella treatments does it take?
The label allows up to 6 Kybella treatments, at intervals of no less than 1 month apart.
A single session is capped at 50 injections into the under-chin fat, up to a total of 10 mL.
Sessions are built from 2 mL vials, each holding 20 mg of deoxycholic acid, so a maximum session uses up to 5 vials.
In the two pivotal trials (514 treated patients), subjects received an average of 6.4 mL at the first session and 4.4 mL at the sixth, and 59% of subjects received all six treatments.
Improvement accumulated across the course.
Allergan reports rates of at least one-grade composite improvement of 8% after 1 treatment, 28% after 2, 43% after 3, 55% after 4, 66% after 5 and 72% after 6, against 2–22% with placebo.
At least one-grade improvement by number of treatments (Allergan; 2–22% with placebo)
| Treatments | Improved |
|---|---|
| 1 | 8% |
| 2 | 28% |
| 3 | 43% |
| 4 | 55% |
| 5 | 66% |
| 6 | 72% |
The course is what these figures describe: the label allows up to six treatments, 59% of treated trial subjects received all six, and Allergan's reported response rates rise from 8% after one treatment to 72% after six.
How many treatments and vials a course takes is covered in more depth in our Kybella guide.
Vials are the arithmetic behind a quote — a maximum session draws on up to 5, and the trials averaged 6.4 mL, a bit over 3 vials, at the first session — and how Kybella is priced explains the rest.
Is Kybella permanent?
How long do Kybella results last?
The honest starting point is the label, and the label makes no permanence claim.
The trials behind the approval followed subjects 4, 12 and 24 weeks after their last treatment.
What the maker says goes further.
Allergan's consumer site states that once fat cells are destroyed they "cannot store or accumulate fat", and that further treatment is not expected once you reach your desired aesthetic.
That statement is consistent with the mechanism the label describes: the drug physically destroys fat-cell membranes, causing the cells to break apart (lysis).
It is still Allergan's consumer-site statement, not a labeled outcome.
The FDA label itself stops short of saying results are permanent.
What the FDA label says
- No permanence claim
- Trials followed subjects 4, 12 and 24 weeks after the last treatment
- The drug physically destroys fat-cell membranes (lysis)
What Allergan's consumer site says
- Destroyed fat cells "cannot store or accumulate fat"
- Further treatment is not expected once you reach your desired aesthetic
- A maker's statement, not a labeled outcome
Scope matters for permanence claims too.
Kybella is not approved for fat outside the submental region, and the label says such use is not recommended — so jawline, jowl or body uses are off-label, and any result claimed for them is not the tested one.
The September 2026 label added a warning that serious adverse reactions have been reported after unapproved use outside the submental region, including blurred or reduced vision with use around the eyes, muscle or nerve injury (facial paresis, paresthesia), and nodules or masses that may not resolve.
Find Kybella for double chin providers near you
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Kybella reviews: is it worth it?
Start with what we could not read.
RealSelf's cost pages covering Kybella and other injectables returned a 403 bot challenge when we researched this page in October 2026, so no RealSelf averages appear here — and this page sticks to the trials and the label instead.
What the trials suggest about satisfaction is a matter of size of change.
The response the trials most often measured was a one-grade change: 70.0% and 66.5% of treated patients improved by at least one grade on combined clinician and patient ratings, but only 13.4% and 18.6% improved by two grades, versus under 0.1% and 3.0% on placebo.
Candidacy is part of the picture.
The label's only contraindication is infection in the injection area, and it tells providers to screen for other causes of under-chin fullness such as thyroid enlargement or swollen lymph nodes, and to consider whether excessive skin laxity or prominent platysmal bands would make reduction of submental fat look worse.
Then there is the commitment: up to 6 sessions at least a month apart, with swelling the most common reaction in the trials (87% of treated patients vs 43% on placebo), and 59% of trial subjects received all six.
For what changed at each point in the trials, see our Kybella before and after page.
Whether that trade is worth it for you is a question for a licensed provider who has examined the area — bring the response rates above and ask how many sessions they would expect in your case.
Frequently asked questions
Does Kybella work for everyone?
Not in the trials' numbers.
In Kybella's two pivotal trials, 70.0% and 66.5% of treated patients improved by at least one grade on both clinician and patient ratings 12 weeks after their final treatment, while 18.6% and 22.2% of placebo patients did.
A two-grade improvement was far rarer: 13.4% and 18.6%.
The label also tells providers to screen for other causes of under-chin fullness, such as thyroid enlargement or swollen lymph nodes, before treatment.
Can Kybella be used on the jawline or jowls?
Kybella is approved to improve the appearance of moderate to severe convexity or fullness associated with submental fat — the area under the chin — in adults.
The label states it is not approved for fat outside the submental region and that such use is not recommended, so jawline or jowl injections are off-label.
The September 2026 label added a warning that serious reactions have been reported after unapproved use, including blurred or reduced vision near the eyes, facial muscle or nerve injury, and nodules or masses that may not resolve.
Why do some Kybella reviews say it didn't work?
The measured size of change explains some of it: the trials counted a one-grade improvement as a response, and two-grade changes occurred in just 13.4% and 18.6% of treated patients — a one-grade change is a modest one.
Swelling and numbness can also outlast the treatment itself — numbness lasted more than 30 days in 42% of treated subjects and swelling in 20%.
The course matters too: in the trials 59% of subjects received all six treatments, and Allergan's figures show improvement climbing with each session.
And the label tells providers to consider whether reduction of under-chin fat may result in an aesthetically undesirable outcome in patients with excessive skin laxity or prominent platysmal bands.
How long does Kybella swelling last?
The label's pooled trials reported injection-site swelling or edema in 87% of Kybella patients, versus 43% on placebo.
Reactions lasting more than 30 days and affecting more than 10% of patients were numbness (42%), swelling (20%), pain (16%) and hardness (13%).
The label does not give a day-by-day swelling schedule, so ask your provider what to expect in your case.
Sources
Every number on this page comes from one of these sources and was checked against it.
- KYBELLA- deoxycholic acid injection, solution · DailyMed, U.S. National Library of Medicine
- FAQs · mykybella.com
Medical disclaimer. MedSpaStandard is for education only and is not medical advice. Talk to a licensed provider about your own health, and check any provider's license with your state board.