What are fat dissolving enzymes? A guide to injectable fat reduction

October 12, 2025 •

4 min read

In 2015, the FDA first approved deoxycholic acid, a synthetic form of a naturally occurring enzyme, for treating moderate-to-severe fat below the chin. These injections use specially formulated enzymes to break down stubborn fat cells that are resistant to diet and exercise, offering a non-surgical alternative to procedures like liposuction.

Quick Summary

This article explains how injectable fat-dissolving enzymes work to target and destroy localized fat cells. It details treatments like Kybella, compares enzymatic lipolysis with surgical alternatives, and outlines the procedure, potential side effects, and what to expect from the process.

Key Points

FDA-Approved for Double Chin: Kybella, a brand of deoxycholic acid, is the only fat-dissolving injection approved by the FDA, and it is specifically for the area under the chin.
Not a Weight Loss Solution: Fat dissolving injections are intended for body contouring by targeting small pockets of stubborn fat, not for significant weight reduction.
Multiple Sessions Required: Unlike a single surgical procedure, most fat dissolving injection treatments require several sessions, spaced weeks apart, to achieve optimal results.
Works by Destroying Fat Cells: The primary mechanism involves injecting a cytolytic agent, such as deoxycholic acid, that permanently destroys fat cell membranes; the body then clears the cellular debris naturally.
Common Side Effects are Temporary: Patients should expect temporary side effects like swelling, bruising, and numbness at the injection site, which typically resolve within days or weeks.
Choose a Qualified Professional: To minimize risks like infection, nerve damage, or scarring, it is crucial to receive injections from a trained and licensed healthcare provider and to avoid unregulated online products.

Understanding Fat Dissolving Enzymes

Fat dissolving enzymes, more accurately referred to as injectable lipolytic agents, are substances used in cosmetic procedures to break down localized pockets of fat. The term "enzymes" is often used broadly, but the most well-known and scientifically validated compound is deoxycholic acid. This is a naturally occurring molecule in the body that helps break down and absorb dietary fat. When synthesized and injected, it acts as a cytolytic agent, disrupting and destroying the membranes of fat cells (adipocytes) in the treatment area. The body's natural metabolic processes then gradually clear the destroyed cells over several weeks.

These injections offer a non-surgical solution for those bothered by small, stubborn fat deposits that persist despite a healthy diet and regular exercise. Unlike weight loss treatments that shrink existing fat cells, these injections permanently destroy them. However, it is not a weight loss solution for significant fat reduction, but rather a body contouring procedure for targeted areas.

How Deoxycholic Acid (Kybella) Works

Kybella is the brand name for the FDA-approved injectable deoxycholic acid. Its mechanism is based on cytolysis, the process of breaking down cells. When a trained professional injects Kybella into the subcutaneous fat under the chin, the deoxycholic acid molecules disrupt the fat cell membranes. This causes the cells to burst, releasing their contents, which are then cleared by the body's lymphatic system. This triggers a gradual inflammatory reaction, and macrophages (specialized immune cells) remove the cellular debris. Over time, this process leads to a noticeable reduction in the targeted area.

The Role of Other Compounds in Lipodissolve

Another common approach, often referred to as Lipodissolve or mesotherapy, involves injections containing a mix of compounds, sometimes including phosphatidylcholine (PPC) and deoxycholate (DC). Phosphatidylcholine is a soy-derived substance that assists with the digestion of fat cells that have been broken down by deoxycholate. While this method has been used for years, it is important to note that many such formulations are not standardized or FDA-approved, unlike Kybella, which only uses deoxycholic acid. The FDA has specifically warned against purchasing non-approved injections online, citing risks of infection, scarring, and other serious complications.

The Procedure and Recovery

Receiving fat dissolving injections is a relatively straightforward process performed in a healthcare provider's office. A consultation is first required to determine if you are a suitable candidate.

The treatment process generally involves:

Consultation and Marking: The provider will assess the area and mark a grid pattern on the skin to guide the injections.
Numbing: A topical anesthetic cream or ice pack is often used to minimize discomfort during the injections.
Injection: A series of small injections are administered into the targeted fat pocket. The number of injections and sessions depends on the area's size and treatment goals.
Post-Treatment: Patients can typically resume normal activities quickly, as downtime is minimal. It is common to experience temporary side effects.

Potential Side Effects

Common, temporary side effects include swelling, bruising, pain, redness, and numbness at the injection site. These usually resolve within a few days or weeks. Swelling, in particular, can be significant for the first 24-48 hours. Less common side effects can include small lumps or nodules under the skin, which typically fade over time.

Rare but serious risks include:

Nerve injury in the jaw area, which can lead to a temporary uneven smile or facial weakness.
Difficulty swallowing.
Skin ulceration or infection if injections are too superficial or administered improperly.
Permanent scarring.

Choosing a qualified, licensed professional is crucial to minimize these risks.

Areas Treatable with Injections

FDA-approved deoxycholic acid (Kybella) is specifically indicated for submental fat (double chin). However, some off-label uses and non-FDA-approved treatments claim effectiveness in other localized areas, such as:

Bra fat
Lower abdomen
Inner and outer thighs
Knees
Arms

Fat-Dissolving Injections vs. Traditional Liposuction


Feature	Fat-Dissolving Injections	Traditional Liposuction
Invasiveness	Minimally invasive, involving only injections	Surgical procedure requiring incisions
Anesthesia	Local anesthetic or numbing cream	Local, sedation, or general anesthesia
Downtime	Minimal; usually 1-2 days of swelling and bruising	Weeks-long recovery, with activity restrictions
Fat Volume	Treats small to moderate, localized fat pockets	Removes large fat deposits in broader areas
Results	Gradual over weeks or months, as the body processes the fat	Immediate and dramatic, once swelling subsides
Sessions	Multiple sessions (e.g., 2-6+) are typically required	Usually a single procedure per area
Cost	Lower initial cost per session, but multiple sessions add up	Higher initial cost for the single surgical procedure
Risks	Temporary swelling, bruising, and rare nerve injury	Higher risk of bleeding, infection, and contour irregularities

Conclusion

What are fat dissolving enzymes? They are a non-surgical option for reducing small, localized fat deposits, primarily using injections of synthetic deoxycholic acid or other lipolytic agents. The most well-known example is Kybella, which is FDA-approved for treating the double chin. The treatments work by destroying fat cells, which are then naturally eliminated by the body over time. While less invasive and with minimal downtime compared to surgery, they require multiple sessions and produce more gradual, subtle results. Patients should be aware of potential side effects, from common temporary reactions like swelling and bruising to rare but serious complications. For the safest and most effective outcome, it is essential to consult a qualified medical professional, especially since some non-FDA-approved products carry significant risks.

For more information on deoxycholic acid, you can visit the MedlinePlus Drug Information page.

Frequently Asked Questions

When administered by a qualified healthcare professional using an FDA-approved product like Kybella for its intended use, the procedure is generally considered safe. However, non-approved products and improper administration carry significant risks, including infection and permanent scarring.

The main active ingredient in the FDA-approved injectable is deoxycholic acid, a naturally occurring molecule in the body that aids in the breakdown of dietary fat. Other unapproved mesotherapy or Lipodissolve formulations may use a combination of compounds like phosphatidylcholine.

Results are gradual. You may begin to see noticeable improvements a few weeks after treatment, with full results becoming apparent several months after the final session. The body needs time to process and eliminate the destroyed fat cells.

The only FDA-approved use for deoxycholic acid (Kybella) is for moderate to severe fat under the chin. Other, non-FDA-approved treatments are sometimes used for other areas like the abdomen and thighs, though with unverified safety.

Yes, once the fat cells are destroyed by the injection, they are permanently eliminated from the body. However, remaining fat cells can still expand if you gain weight, so maintaining a healthy lifestyle is key for long-term results.

The number of sessions varies depending on the treatment area and the amount of fat to be dissolved. For FDA-approved Kybella, many patients see results in two to four sessions, though up to six may be administered.

Fat dissolving injections are minimally invasive, require multiple sessions, and are best for small, targeted fat pockets with minimal downtime. Liposuction is a surgical procedure for removing larger volumes of fat in one session but has a more involved recovery period.