CBL-514 is an injectable drug that is being tested to shrink fat in one place, the abdomen, and the trial data so far do back that narrow claim. The version that circulates online, a peptide that hits visceral fat and fixes your metabolism, is not what the evidence shows.
Ask PeptideBlog about any peptide
The short version. CBL-514 is a small molecule, not a peptide. In randomized Phase 2 trials of adults with BMI under 30 or 35, up to four in-clinic abdominal treatments reduced subcutaneous (under-the-skin) fat versus placebo, measured by ultrasound and MRI, over follow-up of 8 to 12 weeks.[2][3] Visceral (deep abdominal) fat is a different tissue. The only human data on it are a small, sponsor-reported conference subgroup with no published statistics.[7] It is not approved anywhere, and the first Phase 3 trial began enrolling in 2026.[9] On this site’s evidence scale, the published trials are Tier 1 evidence from early-phase, sponsor-linked studies.
Research snapshot
| What it is | Investigational small-molecule injectable; not a peptide, antibody or hormone[1][2] |
|---|---|
| Developer | Caliway Biopharmaceuticals (New Taipei City, Taiwan) |
| Research focus | Local reduction of abdominal subcutaneous fat; also tested in Dercum disease lipomas and cellulite[4][13] |
| Strongest evidence | Three peer-reviewed Phase 2 trials in abdominal fat, one with MRI[1][2][3] |
| Visceral fat evidence | Preliminary, sponsor-reported, not peer-reviewed[7] |
| Development stage | Phase 3 (SUPREME-01, recruiting); SUPREME-02 not yet recruiting[9] |
| Regulatory status | Not approved. Sponsor-announced FDA orphan and Fast Track designations for Dercum disease[11] |
What CBL-514 is
Start with the label, because a lot of the internet gets it wrong. The papers describing the human trials call CBL-514 “a small-molecule injectable drug.”[2] A small molecule is an ordinary drug-sized chemical, far smaller than a protein, and a peptide is a short chain of amino acids. CBL-514 is the first kind. It turns up in peptide circles anyway, where it often gets labeled a peptide. I found no published structure and no international nonproprietary name in the sources I reviewed, so I will not describe its chemistry beyond what the developer has said.
It comes from Caliway Biopharmaceuticals and has been developed as a local injection, given in a grid of many small injections across the treatment area during clinic visits. The original aim was aesthetic: reducing stubborn abdominal fat without surgery. It has also been tested in small studies for painful fatty lumps in Dercum disease and for cellulite. Neither has a published controlled efficacy result that I could find.[4][13]
How it is proposed to work
The proposed mechanism is that CBL-514 pushes fat cells into apoptosis, the cell’s built-in self-destruct program, followed by breakdown of the stored fat. The 2022 paper contrasts this with the necrosis (messy, inflammatory cell death) it attributes to some other injectable fat treatments.[1]
Evidence level: proposed, mostly from unpublished sponsor data. In the 2022 Phase IIa paper, the developer reports its own nonclinical work: CBL-514 inhibits a cell-survival enzyme called DYRK1b, raises the apoptosis markers caspase 3 and Bax/Bcl-2 in a mouse fat-cell line (3T3-L1), and reduces local fat in rodents. It also reports that repeat-dose toxicology studies in dogs and rodents showed no necrosis around the injection site. The authors cite these as unpublished internal reports.[1] That means readers cannot inspect the underlying experiments. The same paper states that no biopsies were taken from participants, so apoptosis has not been directly shown in human fat in the papers I reviewed.[1]
Put plainly: cell and animal work, reported by the developer, suggests an apoptosis route. What the human trials demonstrated is the outcome, less abdominal subcutaneous fat. They did not demonstrate the route.
What the human studies measured and found
The abdominal-fat program is a series of Phase 2 trials run in the United States, Australia and Canada. Participants received up to four in-clinic treatment sessions and were then followed for 8 to 12 weeks. A rule that shows up in nearly every protocol: body weight had to stay stable, within about 3 kg, or the participant was withdrawn. That makes these local-fat studies, not weight-loss studies.[2][5][6]
Swipe the table sideways to see every column.
| Trial | Result | Design | Measure | Status |
|---|---|---|---|---|
| Phase IIa NCT04698642 | Top dose group (n=16): −23.13% at 4 weeks and −21.85% at 8 weeks after last treatment, versus its own baseline | 43 enrolled (39 analyzed), open label, three dose levels, no placebo | Ultrasound fat volume | Peer-reviewed 2022[1] |
| Phase 2 NCT04897412 | Versus placebo: −206.62 mL at 4 weeks (95% CI −276.09 to −137.16) and −216.28 mL at 8 weeks (−288.28 to −144.28). At 8 weeks, 69.6% (16/23) lost 150 mL or more versus 0% (0/16) | 76 randomized 2:1 to drug or placebo, single-blind | Ultrasound fat volume | Peer-reviewed 2025[2] |
| Phase 2b NCT05736107 | MRI at 4 weeks: −152.9 mL versus +5.1 mL (−20.3% versus +0.1%, P<.0001). At 12 weeks: −115.4 mL versus −3.5 mL (−17.3% versus +0.7%). Clinician-rated improvement of 1 grade or more at 12 weeks: 76.7% (23/30) versus 18.9% (7/37) | 108 randomized 1:1, single-blind, BMI over 18.5 and under 30 | MRI fat volume; clinician rating | Peer-reviewed 2026[3][5] |
| Phase 2b NCT06005441 | 4 weeks after final treatment: −166.6 mL versus +15.7 mL with placebo (−22.4% versus +1.8%); 54.2% reached a 20% reduction versus 0% | 173 randomized; placebo plus two other comparators (CBL-A1, CBL-A2); sponsor says double-masked | MRI fat volume | Sponsor press release only[6][7] |
Changes are from baseline in the treated abdominal area. Denominators shrink at later visits because participants dropped out, so percentages describe those who remained. The 2026 paper’s text and its flow figure give different analysis-set sizes, which the paper does not reconcile.
Read these numbers with the following in mind. Dropout was heavy: 49.3% of participants in the 2025 trial and 38.9% in the 2026 trial did not finish, often because weight changed or visits were missed.[2][3] In the 2025 trial, participants were blinded but investigators and the sponsor were not, and fat volume was estimated from ultrasound thickness at four points multiplied by a fixed 300 cm² area.[2] The 2026 trial added MRI, which is a better yardstick, though it was also single-blind.[3] All three peer-reviewed trials list Caliway employees among the authors, and Caliway took part in design and analysis in the 2025 trial.[2][3]
The fourth row deserves its warning label. The CBL-0205 results come from a company announcement, and I found no peer-reviewed publication or posted ClinicalTrials.gov results for NCT06005441.[6][7] Treat those numbers as sponsor claims that are consistent with the published trials, not as independent confirmation.
A different disease: Dercum lipomas
A 12-person, open-label Phase 2a study in Dercum disease, a rare condition of painful fatty lumps, reported median lipoma volume reductions of 45% to 59% and lower pain scores. It had no comparator, one site and 8 weeks of follow-up, and all 12 participants had at least one treatment-related adverse event.[4] A placebo-controlled follow-up, NCT06303570, is registered as completed with no posted results.[13] None of this tells us anything about abdominal fat in general.
Subcutaneous versus visceral fat
Your body stores fat in two main places. Subcutaneous fat sits under the skin, and it is what you can pinch. Visceral fat is packed around the organs deep inside the abdomen, and it is the type tied most strongly to metabolic disease. They share a belly but behave like different tissues, and treating one tells you little about the other.
Every peer-reviewed CBL-514 trial above measured subcutaneous fat in the treated area. The registered Phase 2b and Phase 3 protocols also exclude people with severe abdominal visceral fat.[5][6][9] That is not what you would expect from a program aiming to treat visceral fat.
The one visceral-fat dataset, and why it is thin
At the 2026 European Association for the Study of Diabetes (EASD) meeting in Milan, a CBL-514 analysis looked at visceral adipose tissue (VAT), measured by MRI at one level of the lower spine (L2 to L3). According to the sponsor’s version of the EASD press material, it covered a subgroup of two Phase 2 trials with usable MRI data: 41 people at baseline (23 drug, 18 placebo), 40 analyzed.[7] VAT changed by −12.01% with CBL-514 versus +5.68% with placebo at 4 weeks after the last treatment, and by −10.45% versus +11.76% at 8 to 12 weeks. The release reported no p-values, no confidence intervals and no safety data.[7]
Three reasons to hold that loosely. First, it is a post hoc subgroup, presented at a conference, with a Caliway author, and I found no peer-reviewed paper. Second, a trade-press account of the same presentation gave different counts and percentages (46 participants, and VAT changes of −10.9% versus +4.6% at 4 weeks) and did include p-values, so the figures are not settled.[8] Third, a large share of the between-group gap comes from placebo VAT rising. The presentation also did not report weight, blood pressure, cholesterol or any other metabolic outcome, and the comments linking visceral loss to health benefits were expectations from the speaker, not results.[7][8] No mechanism for how a subcutaneous injection would affect deep fat has been published that I could find.
So: subcutaneous fat reduction is supported by peer-reviewed trials. Visceral fat reduction is a preliminary signal that needs real data. Better metabolic health is untested.
How the research approach differs from systemic obesity drugs
Drugs such as semaglutide and tirzepatide act throughout the body, mainly on appetite, and are judged mostly by how much body weight falls. For that group, see our GLP-1 and obesity peptide guide. CBL-514 is aimed at a defined patch of tissue, is given in a clinic, and is judged by how much fat disappears from that patch while weight is held steady. The people studied were also different: BMI under 30 in the Phase 2b and Phase 3 designs, and use of weight-loss drugs, including GLP-1 drugs, was an exclusion.[5][9]
That means no efficacy comparison is possible, and none should be inferred. A 20% drop in the volume of a treated abdominal area is not a 20% drop in body weight. The sponsor is, however, now moving toward combining the two ideas: in August 2026 it announced FDA clearance of an IND for a Phase 2 study of CBL-514 with tirzepatide in about 120 adults with overweight or obesity, with MRI abdominal subcutaneous fat as the main outcome and body weight, visceral fat and lean mass as exploratory ones.[10] I did not find that study on ClinicalTrials.gov, and the sponsor’s rat data on combination and weight regain are unpublished. For another approach to the quality of weight loss, see bimagrumab and the BELIEVE trial.
Safety, limitations and open questions
Injection-site reactions are the story. In the 2025 trial, 98% of drug-treated participants had at least one treatment-related adverse event, almost all at the injection site (pain and redness 93.9% each), but placebo injections also produced high rates, 100% overall. Nine drug-treated participants (18.4%) had severe events, all injection-site pain, and two stopped for treatment-related reasons.[2] In the 2026 trial, any adverse event occurred in 96.2% versus 80.0%, severe events in 9.6% versus 3.6%, and 4 people on CBL-514 stopped for adverse events (hives in 3, pain in 1), compared with 1 on placebo. Injection-site hives occurred in 7.7% of drug-treated participants and none on placebo.[3]
Blood fats need a watching brief. Four participants in the Phase IIa trial and two in the 2025 trial had clinically significant lipid elevations, each with higher baseline values, and the 2022 authors could not rule out a drug effect from released fat. The 2026 authors describe their cholesterol and triglyceride changes as not clinically meaningful.[1][2][3] No serious events judged drug-related were reported in the peer-reviewed abdominal trials.
- Duration. Follow-up ended 8 to 12 weeks after the last treatment, so durability and long-term safety are unknown. A 12-month follow-up study is registered but not recruiting.[9]
- Who was studied. The earlier trials enrolled mostly women (69% to 94%) and mostly White participants (86% to 95%), and most designs capped BMI at 30.[1][2][5]
- Independence. There are no independent replications. Published trials involve the sponsor.
- Visceral and metabolic effects. Untested in a peer-reviewed trial.
Where development stands
As far as I could find, CBL-514 is not approved for any use. SUPREME-01 (NCT07140939, 320 adults, recruiting) is a placebo-controlled Phase 3 with up to four treatments given every 4 weeks. Its primary outcome is at least a 2-grade improvement on both patient- and clinician-rated abdominal fat scales, with MRI fat change as a secondary outcome. SUPREME-02 (NCT07526974) is registered with a similar design, a primary outcome that pairs a patient-rated 2-grade improvement with a clinically meaningful MRI reduction, and has not started recruiting.[9] A Phase 2b re-treatment study (NCT07608770) is also recruiting.[14]
Fat loss is only half of body composition. The question of lean mass versus fat mass in GLP-1 trials, and which drugs aim to protect muscle, is reviewed separately.
What you can reasonably conclude today
CBL-514 has real, if early, evidence for one thing: reducing abdominal subcutaneous fat volume in a treated area, in people who are not obese and who held their weight steady. The effect appears in three peer-reviewed trials, two of them placebo-controlled, and the peer-reviewed MRI trial showed an average drop of about a fifth at 4 weeks (20.3%) that was still present at 12 weeks (17.3%). It does not show weight loss, visceral fat reduction or better metabolic health, and the mechanism is a developer-reported proposal. The Phase 3 trials are the first real test of whether the effect survives bigger samples and a regulatory-grade analysis. Until then, the honest label is promising and unproven.
Frequently asked questions
Is CBL-514 a peptide?
No. The published trial papers describe CBL-514 as a small-molecule injectable drug. It is covered here because it circulates in peptide communities and is often mislabeled, not because it is a peptide. I could not find a published chemical structure or an international nonproprietary name for it.
Does CBL-514 reduce visceral fat?
That has not been established. The only human visceral-fat data are a small, post hoc MRI subgroup (about 40 participants) from two Phase 2 trials, presented at EASD 2026 and reported by the sponsor without p-values. It is not peer-reviewed, and other reports of the same presentation give different numbers. It says nothing about metabolic health.
Is CBL-514 a weight-loss drug?
The published trials do not show that. Participants had to keep a stable body weight, and the measured outcome was fat volume in the treated abdominal area. In the 2025 Phase 2 trial, mean body weight barely moved while local fat volume fell.
Is CBL-514 approved?
No approval for any use was found. Its lead program is in Phase 3 for abdominal subcutaneous fat, and the sponsor announced FDA orphan and Fast Track designations for Dercum disease, a separate rare condition. Because it is investigational, trial results do not transfer to any product sold outside a clinical study.
What side effects were reported?
Injection-site reactions were near universal: pain, redness, itching, swelling, warmth, bruising and discoloration. Severe events in the published trials were mostly injection-site pain, and a few people stopped treatment because of pain or hives at the site. Small lipid increases appeared in some participants in earlier trials. Follow-up so far has been short.
How long do the results last?
Not known. Published follow-up ends 8 to 12 weeks after the last treatment. A Phase 3b follow-up study (NCT07733947) is registered to track people for up to 12 months after their parent study, but it has not started recruiting.
References
- Goodman GJ, Ho WWS, Chang KJ, Ling YF, Sheu AY. Efficacy of a Novel Injection Lipolysis to Induce Targeted Adipocyte Apoptosis: A Randomized, Phase IIa Study of CBL-514 Injection on Abdominal Subcutaneous Fat Reduction. Aesthetic Surgery Journal. 2022;42(11):NP662-NP674. DOI | PubMed. Peer-reviewed; sponsor-affiliated authors.
- Gold M, Schlessinger J, Goodman GJ, et al. Efficacy and Safety of CBL-514 Injection in Reducing Abdominal Subcutaneous Fat: A Randomized, Single-Blind, Placebo-Controlled Phase II Study. Aesthetic Surgery Journal. 2025;45(6):611-620. DOI | PubMed. Peer-reviewed; sponsor-affiliated authors.
- Lorenc ZP, Gold M, Schlessinger J, et al. Randomized Phase 2b Trial of CBL-514 Injection for Abdominal Subcutaneous Fat Reduction With Clinician- and Patient-reported Outcomes and MRI Assessment. Aesthetic Surgery Journal. 2026 (published online 20 May). DOI | PubMed. Peer-reviewed; sponsor-affiliated authors.
- Herbst KL, Ling YF, Sheu AY, Schlessinger DI, Wu SY. Efficacy and safety of CBL-514 for Dercum disease lipomas: A randomized phase 2a study. JAAD International. 2025;25:1-4. DOI | PubMed. Peer-reviewed research letter; sponsor-affiliated authors.
- ClinicalTrials.gov. NCT05736107 (Phase 2b, abdominal subcutaneous fat; enrollment listed as 107, completed, no results posted). clinicaltrials.gov; NCT04897412 (Phase 2, stage 2) record; NCT04698642 (Phase 2a) record. Government registry. Records for NCT04897412 and NCT04698642 were matched to the 2025 and 2022 papers by dates, site count and enrollment, because the papers’ registration numbers did not display in the text I accessed.
- ClinicalTrials.gov. NCT06005441 (Phase 2b factorial study, 173 participants, completed, no results posted). clinicaltrials.gov. Government registry.
- Caliway Biopharmaceuticals. Announcement of CBL-0205 Phase 2b results (PR Newswire) and EASD 2026 visceral and subcutaneous fat press item (company site; also summarized by News-Medical). Sponsor-reported; not peer-reviewed.
- HCPLive. New Injectable Substantially Reduces Visceral Adipose Tissue in Obesity (EASD 2026 report). hcplive.com. Trade-press account of a conference abstract; figures differ from the sponsor’s.
- ClinicalTrials.gov. SUPREME-01, NCT07140939; SUPREME-02, NCT07526974; Phase 3b long-term follow-up, NCT07733947. Government registry; no results posted.
- Caliway Biopharmaceuticals. CBL-514 combination therapy IND clearance and SUPREME-01 enrollment announcement, 25 August 2026. PR Newswire. Sponsor-reported.
- Pharmacy Times. FDA grants orphan drug designation for CBL-514 to treat adult patients with Dercum disease (March 2024, based on a sponsor announcement). pharmacytimes.com. Secondary report of sponsor-announced designations; not checked against FDA records.
- ClinicalTrials.gov. Dercum disease: NCT05387733, NCT06303570. Cellulite: NCT05632926, NCT05836779. Government registry; no results posted.
- ClinicalTrials.gov. Phase 2b long-term re-treatment study, NCT07608770. Government registry.
Educational use only. This article summarizes published research and sponsor announcements and is not medical advice. CBL-514 is an investigational compound that is not approved for any use. Trial results describe groups of study participants and do not establish safety or benefit for any individual. Nothing here is a recommendation to obtain or use any experimental compound. Talk with a qualified, licensed clinician about personal health decisions.
