A tier · strong
The branded product carries FDA approval supported by two large, double-blind, placebo-controlled phase 3 trials with MRI-verified endpoints and three-year follow-up, but the indication is narrow, effect sizes are modest, and unlicensed copies sold online share the molecule without sharing any of that evidence.
deoxycholic acid
Deoxycholic acid is an endogenous bile acid that, when injected into fat, disrupts adipocyte membranes and causes localised fat cell lysis. As the branded formulation ATX-101 it is approved for submental fat with replicated phase 3 evidence; the unlicensed 'fat dissolving' products marketed under other names have not been through that process.
the explanation
This is a bile acid that dissolves fat cell membranes where it is injected. The branded version was properly tested and approved for fat under the chin, but the cheap online versions sold under other brand names are not the same thing and regulators have warned about them.
regulatory status
Approved (branded) — unapproved copies widely marketed
Approved by the FDA in April 2015 as Kybella and marketed as Belkyra in several other territories for moderate-to-severe submental fat convexity in adults; use outside the submental region has not been established. FDA separately names Aqualyx, Lipodissolve, Lipo Lab and Kabelline as unapproved fat-dissolving injections, and in April 2025 the UK General Pharmaceutical Council warned pharmacies against selling Lemon Bottle as an unlicensed, unregulated cosmetic product.
how it works · proposed mechanism
The molecule works by physical membrane disruption rather than by any receptor-mediated metabolic signal.
Detergent adipocyte membrane lysis
Deoxycholate is amphipathic and above its critical micelle concentration solubilises the phospholipid bilayer of adipocytes, causing immediate cell rupture. The effect is local and dose-limited to the injected tissue volume.
Protein binding self-limitation
Free deoxycholate is rapidly bound and inactivated by protein in surrounding tissue, which is why fat, being relatively protein-poor, is preferentially affected. This same property is why misplaced injection near the marginal mandibular nerve or dermis produces injury.
Macrophage clearance and fibrosis
Lysis is followed by a neutrophil and macrophage influx that clears cellular debris and released lipid over subsequent weeks. Septal thickening and dermal tightening during resolution contribute to the observed contour change beyond simple volume loss.
what’s reported
evidence shape
6 sourcesThe composition of the cited literature by study type. This describes the shape of the evidence, not its quality — and it does not by itself set the grade.
⚠ the catch
Everything positive in this entry belongs to one specific approved formulation studied at one specific anatomical site, and none of it transfers to unlicensed vials of sodium deoxycholate or phosphatidylcholine sold online under cosmetic branding. Regulators in the US, UK and Switzerland have all issued warnings about those products, with reported harms including permanent scarring, abscesses, cysts and necrosis.
key published findings
- Human trial: REFINE-2 (n=516, 258 per arm; Humphrey, JAAD, 2016) — composite 1-grade-or-greater improvement on clinician and patient scales in 66.5% of ATX-101 vs 22.2% of placebo (risk ratio 2.98) and 2-grade-or-greater in 18.6% vs 3.0% (risk ratio 6.27), both P<0.001, with MRI-confirmed submental volume reduction (P<0.001).
- Human trial: REFINE-1 (n=506; 256 ATX-101 / 250 placebo) — 1-grade composite response 70% vs 18.6% placebo and 2-grade response 13.4% vs 0%, with MRI responders more than eight times more frequent (46.3% vs 5.3%, P<0.001).
- Human trial: three-year follow-up of REFINE participants (n=224; Aesthetic Surgery Journal, 2021) — among those responding at 12 weeks, response was retained by 86.4% vs 56.8% at year 1 (P<0.001), 90.6% vs 73.8% at year 2 (P=0.014) and 82.4% vs 65.0% at year 3 (P=0.03).
- Official (safety): the FDA label reports marginal mandibular nerve injury in 4% of treated subjects (20/513) versus under 1% on placebo, all resolving spontaneously over a median 44 days (range 1-298), and dysphagia in 2% (10/513), median 3 days; local injection-site reactions occurred in 84.3% of ATX-101 recipients in REFINE-1.
- Official (unlicensed products): the FDA states Kybella is the only FDA-approved fat-dissolving injectable and links unapproved phosphatidylcholine/deoxycholate products to permanent scars, serious infections, skin deformities, cysts and deep painful knots; the GPhC warned on 10 April 2025 that Lemon Bottle is unlicensed with limited or no clinical safety data, noting Swissmedic had stated in March 2024 that it has no medicinal effect.
limitations of the evidence
- The controlled evidence covers only the submental region in adults; efficacy and safety at other body sites are not established by the phase 3 programme.
- Composite response thresholds are one- and two-grade shifts on ordinal rating scales, so a statistically robust result can still correspond to a modest visible change, and placebo response rates were substantial.
- The three-year follow-up enrolled a subset of the original trial population and was open-label for durability, which limits inference about long-term comparative maintenance.
documented safety signals
- Marginal mandibular nerve paresis causing asymmetric smile or facial muscle weakness in 4% of treated subjects in the pooled trial population, all spontaneously resolving but with a reported range extending to 298 days.
- Dysphagia in 2% of treated subjects in the trial programme.
- Injection-site ulceration and necrosis, particularly with superficial or dermal placement — the label specifically warns against superficial dermal injection.
- Contraindicated where infection is present at the intended injection sites.
- For unlicensed 'fat dissolving' products: regulator-documented reports of severe bruising, infection, abscess formation, cysts, deep painful knots, skin deformity and necrosis.
identity
| full name | Deoxycholic acid injection (ATX-101) |
| category | Cosmetic |
| modality | small molecule |
| formula | C24H40O4 |
| molar mass | 392.6 g/mol |
| cas | 83-44-3 |
laboratory handling
| storage | The approved 10 mg/mL formulation is stored at 20-25 C with excursions permitted between 15-30 C; it is supplied as a clear, colourless sterile solution in single-use vials and is not refrigerated or frozen. |
| solubility | Deoxycholic acid is poorly soluble as the free acid but its sodium salt is freely water-soluble and surface-active; the injectable is a buffered aqueous solution, and the molecule forms micelles above its critical micelle concentration, which is the basis of its lytic action. |
| co-studied with | Regulatory and trial evidence exists only for the single-agent formulation; combination vials pairing deoxycholate with phosphatidylcholine, lidocaine, bromelain or plant extracts — the composition of most unlicensed products — have no controlled efficacy data and are the specific formulations regulators have warned about. |
Handling information describes laboratory practice for a research reagent. It is not a preparation guide for use in humans.
the receipts
6 citedU.S. Food and Drug Administration · 2015 · official
U.S. Food and Drug Administration · 2023 · official
Pharmacy Magazine (reporting General Pharmaceutical Council statement) · 2025 · official
Journal of the American Academy of Dermatology · 2016 · randomized
Dermatologic Surgery · 2016 · randomized
Aesthetic Surgery Journal · 2021 · observational
others in Cosmetic