Fat-Dissolving Injections: Mechanism, Effects, Downtime, and Recovery

When researching procedures for managing facial contours, you'll often come across the term 'fat-dissolving injection' (yungwak injection). Because it's administered by injection without incisions, it may seem like an easy option to access, but in reality it's a procedure where the ingredients and mechanism of action vary by clinic, and the range of effects differs from person to person. This article summarizes neutral, informational content on how fat-dissolving injections work, what course and downtime they involve, and what to keep in mind for home care after the procedure.

What Is a Fat-Dissolving Injection?

Fat-dissolving injections are explained as a method that induces management of localized body fat volume by injecting substances known to act on fat cells into the subcutaneous fat layer. The expression 'melting fat' is commonly used, but it's more accurate to understand it as a process closer to fat cells being destroyed through cell membrane damage, followed by tissue reorganization.

Each clinic reportedly formulates its own mix of ingredients and ratios, which are generally categorized into: formulations using PPC (phosphatidylcholine) together with DCA (deoxycholic acid), formulations using deoxycholic acid alone, and formulations containing steroids (such as triamcinolone). The intensity of action and recovery course may vary depending on which combination is used.

Differences by Ingredient and Confirmed Facts

Among these ingredients, deoxycholic acid has reportedly been approved overseas as a cytolytic drug for improving moderate to severe convexity or fullness associated with submental fat (fat under the chin). However, this approval is limited to that specific area, and official materials reportedly state that safety and efficacy for other facial areas or other parts of the body have not been separately established.

Steroid ingredients used in some procedures are known to potentially create a change that appears to reduce volume in the short term, but there are mentions of possible side effects such as skin depression or atrophy with repeated procedures. In Korea, since such steroid injections were not originally approved for cosmetic purposes, there are no official standards for dosage or concentration, and it's pointed out that the method of administration is left to the practitioner's discretion in some respects. For this reason, it's necessary to sufficiently confirm with a specialist beforehand what ingredients and dosages will be used.

Effects, Duration, and Downtime

The effects of fat-dissolving injections vary depending on the treatment area and ingredients used, but changes are generally known to be maintained for several months (about 2 to 6 months) after injection. However, since the fat-reducing effect is often limited to a localized range, there are also indications that this procedure alone may not be expected to produce a dramatic change in facial lines, so it's helpful to set realistic goals and consult accordingly.

Immediately after the procedure, swelling, bruising, and stiffness or tightness in the treated area may occur, and these are known to last anywhere from a few days to as long as 1-2 weeks. Since the speed of swelling and recovery varies greatly depending on the ingredients used, the amount injected, and individual skin and constitution, it's advisable to check the expected downtime period and care methods with your practitioner beforehand.

Clinical data related to deoxycholic acid reportedly found no significant increase in blood cholesterol, triglyceride, or free fatty acid levels within 24 hours after injection, suggesting the impact on systemic metabolism is limited. However, this is a result observed under specific clinical trial conditions, and it's difficult to conclude that it applies equally to all formulations and all treatment areas.

Difference from Square Jaw Botox

When considering facial line management, fat-dissolving injections and square jaw Botox are often compared together. Both procedures are administered by injection and share the common goal of refining facial appearance without incisions, but they act on different targets.

Square jaw Botox works by regulating the movement of the chewing muscle (masseter), while fat-dissolving injections are often used with a focus on managing the condition of areas where fat is concentrated. If the cause of concern about facial lines is closer to muscle development, square jaw Botox may be discussed; if the concern is volume due to fat, fat-dissolving injections may be discussed. However, since both causes can sometimes act together in practice, consulting a specialist to accurately identify the cause should come first.

Post-Procedure Recovery and Home Care

After fat-dissolving injections, the skin in the treated area may temporarily become sensitive, and some may feel redness or dryness. During this period, skin can react more sensitively to stimulation, so rather than vigorous massage or strong exfoliation care, management aimed at minimizing irritation and stably maintaining the skin barrier is generally recommended.

During the recovery period as swelling or bruising subsides, maintaining adequate hydration can help manage skin condition, and it's safest to follow your practitioner's guidance regarding specific care methods and timing of product use. Since effects, recovery speed, and the occurrence of side effects vary greatly by individual, it's advisable to thoroughly consult with a specialist about any questions before and after the procedure.

Post-Procedure Recovery Is Shaped by Home Care

Immediately after the procedure, skin tends to become temporarily sensitive and prone to feeling tight or dry. During this recovery period, you might consider managing your skin's condition with products that are low in irritation and can help support skin barrier care. AVEZOO Cream is a 2-step product consisting of STEP1 Ultra Cera-Rich, focused on soothing and barrier care right after the procedure, and STEP2 Hydro Re-Boosting, for intensive hydration care during recovery, and can be referenced as one option for a post-procedure home care routine. However, this falls within the realm of supplementary home care, and the management of the procedure's own progress should always be discussed with your practitioner.

Medically reviewed by 아비쥬의원 의료진. (September 10, 2026)