Fat-Dissolving Injection: Injection Lipolysis — Effects, Costs and Methods

The fat-dissolving injection — medically known as injection lipolysis or lipolytic therapy — is one of the most popular minimally invasive methods for targeted fat reduction. Anyone looking to eliminate stubborn fat deposits around the chin, abdomen or thighs without undergoing surgery will find injection lipolysis an effective alternative. Since the approval of Belkyra (known as Kybella in the United States) for the treatment of submental fat by the European Medicines Agency, this method has gained considerable importance.

In this comprehensive guide you will learn everything about how the fat-dissolving injection works, the active substances used, the treatment procedure, possible risks and expected costs.

What Is the Fat-Dissolving Injection? Definition and Fundamentals

The fat-dissolving injection refers to injection lipolysis, also called lipolytic treatment. Special active substances are injected directly into localised fat deposits to permanently destroy fat cells and allow the body to break them down.

Unlike conventional liposuction, injection lipolysis is a minimally invasive procedure requiring no general anaesthesia, no incisions and no hospital stay. Treatment is carried out on an outpatient basis in an aesthetic clinic and is considered a gentle alternative to surgical methods.

The basic principle is that the injected substances destabilise and dissolve the cell membranes of fat cells (adipocytes). Released fat molecules are transported via the lymphatic system and metabolised by the liver. The effect is permanent as long as body weight remains stable, because destroyed fat cells do not regenerate.

Ideal Candidates for Injection Lipolysis

Stubborn, localised fat deposits that do not respond to diet and exercise
Body areas where surgical liposuction would be disproportionate
Patients who do not wish or are not medically suitable for surgery
Corrections after weight loss where individual fat deposits remain

Active Substances: Phosphatidylcholine, Deoxycholate and Belkyra

Phosphatidylcholine (PPC)

Phosphatidylcholine is a naturally occurring phospholipid and a major component of cell membranes. In injection lipolysis it acts as a lipolytic agent, disturbing membrane integrity and initiating programmed cell death (apoptosis). It is derived from soy lecithin and is biosynthetically well tolerated.

Sodium Deoxycholate (Deoxycholic Acid)

Sodium deoxycholate is a bile acid naturally present in the body, involved in the emulsification of dietary fats. In aesthetic medicine it has proven to be the key substance for destroying fat cells. It acts as a detergent, dissolving the lipid bilayer of fat cell membranes and causing cell lysis. Released fat molecules are taken up by macrophages and transported to the liver for elimination.

Belkyra / Kybella: The Approved Product

Belkyra (European trade name) — Kybella in the US — is the only officially approved product for injection lipolysis in Europe. It contains synthetically manufactured deoxycholic acid as its sole active ingredient. EMA approval applies specifically to the treatment of moderate to severe submental fat (double chin) in adults. For other body areas, treatment is off-label use and patients should be informed accordingly.

Mechanism of Action: How Fat Cells Are Destroyed

Phase 1: Membrane Destabilisation

Immediately after injection, the active substance contacts fat cell membranes. Deoxycholate interacts with cell membrane phospholipids, disrupting structural integrity and increasing permeability.

Phase 2: Cell Lysis and Apoptosis

The destabilised membrane fails. Water and ions flow into the cell (osmotic lysis) and programmed cell death (apoptosis) is initiated — a more controlled process than pure lysis with a lower inflammatory response.

Phase 3: Fat Molecule Release and Breakdown

Triglycerides and free fatty acids from dissolved fat cells are taken up by macrophages and transported via the lymphatic and blood systems to the liver for metabolic processing and elimination.

Phase 4: Inflammatory Response and Tissue Tightening

A controlled local inflammatory response activates fibroblasts that produce collagen, contributing to tissue tightening. This side effect improves the cosmetic result and reduces the risk of loose skin after fat loss.

Treatable Body Areas

Body Area	Approval Status	Sessions Required
Double chin (submental)	Approved (Belkyra)	2–4
Abdomen and waist	Off-label	3–6
Inner / outer thighs	Off-label	3–6
Back rolls / flanks	Off-label	3–5
Upper arms	Off-label	2–4
Inner knees	Off-label	2–3

Areas unsuitable for injection lipolysis include deep visceral abdominal fat, areas with very thin subcutaneous fat layers, and areas with existing infections or skin conditions.

Treatment Procedure Step by Step

Step 1: Initial Consultation

Before treatment, a detailed consultation takes place with the treating doctor. Treatment goals, the fat deposit to be treated, medical history and contraindications are discussed. In some practices, an ultrasound examination is performed to measure fat layer thickness and determine optimal injection depth. Photographs are taken to document the baseline condition.

Step 2: Preparation on Treatment Day

The area is cleansed and disinfected. An anaesthetic cream (lidocaine) is applied 30–60 minutes before injection. For double chin treatment, a template marks injection points evenly to ensure symmetrical distribution of the active substance.

Step 3: The Injections

The doctor injects the active substance with a very fine needle (typically 30–32 gauge) into multiple evenly distributed points at a depth of 5–10 mm. Typical injection counts per session:

Double chin: 20–50 injection points
Abdomen: 40–100 injection points depending on area size
Thighs: 30–80 injection points

The injections are uncomfortable but well tolerated after prior anaesthesia. A brief burning and pressure sensation is typical and subsides quickly.

Steps 4 and 5: Aftercare and Recovery Timeline

Days 1–3: Maximum swelling, possible numbness and pressure sensation
Days 4–7: Swelling begins to subside, redness resolves
Week 2: Swelling significantly reduced; most daily activities resume
Weeks 4–8: First results become visible
Weeks 8–12: Further reduction in fat volume
Month 3: Final result of one session visible

Number of Sessions and Treatment Intervals

Sessions must be spaced at least 4–6 weeks apart to allow tissue to heal and metabolise released fat.

Double chin: Average 2–4 sessions (up to 6 for pronounced fat deposits)
Abdomen and larger areas: 3–6 sessions typically required

Costs Overview

Treatment Area	Cost per Session	Estimated Total
Double chin (Belkyra)	€600–€900	€1,200–€3,600
Abdomen	€400–€800	€1,200–€4,800
Thighs (per side)	€350–€700	€1,050–€4,200
Upper arms	€300–€600	€600–€2,400

Injection lipolysis is a cosmetic procedure and is not covered by health insurance. Costs must be borne by the patient. Many clinics offer financing options.

Comparison: Fat-Dissolving Injection vs. Liposuction vs. Cryolipolysis

Method	Invasiveness	Downtime	Best For	Cost Range
Fat-dissolving injection	Minimally invasive	3–14 days	Small to medium localised deposits	€600–€4,800
Liposuction	Surgical	1–4 weeks	Larger fat volumes	€1,500–€6,000
Cryolipolysis	Non-invasive	1–3 days	Graspable fat rolls	€600–€2,500

Risks and Side Effects

Swelling: The most common reaction; lasts 7–14 days
Bruising: At injection sites; resolves within 7–14 days
Numbness: May persist for weeks to months; usually resolves completely
Pain: Mild to moderate; controllable with ibuprofen
Skin irregularities: Rare with experienced practitioners
Nerve injury: Very rare; risk minimised by proper injection technique

Frequently Asked Questions

Is the result of a fat-dissolving injection permanent?

Yes. Destroyed fat cells do not regenerate. As long as body weight remains stable, the result is permanent. Significant weight gain can cause remaining fat cells to enlarge, which may require top-up sessions.

How long until results are visible?

First results appear after 4–8 weeks. The optimal result of one session is visible after approximately 3 months.

Is the treatment painful?

The injections cause a brief burning and pressure sensation, especially in the first few minutes. A topical anaesthetic cream significantly reduces discomfort. Most patients rate the treatment as tolerable.

Who is not suitable for injection lipolysis?

Contraindications include pregnancy and breastfeeding, clotting disorders, active infections in the treatment area, known allergy to the active substance, and very thin subcutaneous fat layers. Treatment must only be carried out by qualified medical practitioners.