At many aesthetic clinics, HPL and fat-dissolving injections are commonly offered as body-contouring treatments.
Names vary from clinic to clinic, and some emphasize trademarks (brand names).
Acu injections / Egg injections / V injections / “Quick-Slim” injections / “Slim-Down” injections / “Girl-Group” injections…
With so many types, have you ever wondered what the ingredients are and how their mechanisms differ?
In this article, we’ll organize and explain the main ingredients, how they work (mechanism), and possible side effects.
HPL? Fat-Dissolving Injections? — Ingredients and Types
What is HPL?
HPL (Hypotonic Pharmacologic Lipo-Dissolution) is a procedure that uses a hypotonic (low-osmolarity) solution to cause fat cells to swell and rupture, with the goal of reducing volume.
It began to spread in the United States around 2002.
Source: Lipoplasty with Hypotonic Pharmacologic Lipo-Dissolution, Steven M. Hoefflin, MD (2002)
Mechanism: A solution with lower osmotic pressure than fat cells (typically saline under 0.45%) is injected to draw water into the cells, causing them to swell and rupture.
Key point: The core principle is to inject “water that is hypotonic compared to body fluids.”
Other ingredients serve mainly as supporting agents—they help establish the osmotic gradient and aid in dissolution and diffusion of the solution.
Source: Lemon Bottle (reference formula)
Recently, many clinics have adopted “upgraded versions” of HPL that include additional ingredients such as caffeine, vitamin B, alpha-glycerylphosphorylcholine (alpha-GPC), and aminophylline.
Are fat-dissolving injections the same as HPL?
While both aim to reduce body volume, their formulas and mechanisms differ.
Each clinic or weight-management center uses its own brand names and ingredient combinations, but the underlying principle remains the same.
Most formulations include vitamins and metabolic activators, but the core component is steroids.
Mechanism: This utilizes one of the pharmacological effects of steroids—soft tissue atrophy—a mechanism also applied in keloid treatment and other therapies.
Source: Keloid scar
Common auxiliary ingredients used in major network clinics (examples):
Lidocaine: A local anesthetic that also acts as a solvent to facilitate the diffusion of other ingredients.
Pentoxifylline: A phosphodiesterase inhibitor that increases cAMP levels, promoting adipocyte apoptosis and improving microcirculation.
Multivitamin (especially B12): Aims to improve connective tissue quality. When vitamin B12 is included, the solution takes on a pink to reddish hue.
L-Carnitine: Supports fat metabolism when combined with caffeine and aminophylline.
Caffeine & Aminophylline: Modulate intracellular signaling in adipocytes by blocking adenosine receptors and inhibiting phosphodiesterase.
Side Effects of Steroid and HPL Injections
The idea that “steroids = bodybuilding drugs” is a misconception — their safety and effect depend entirely on how and how much is used.
Unlike high-dose intravenous or oral steroid therapy, localized microinjections are generally within a safe range.
However, excessive dosing in a single session can increase the risk of adverse effects.
Representative side effects:
Because estrogen and steroids have similar structures, injecting a large dose at once can lead to changes in the menstrual cycle and breakthrough bleeding (this occurs more often than you might expect).
Those who wish to become pregnant or who are breastfeeding should avoid body-contouring treatments.
In clinical practice, it’s standard to manage and limit the total daily steroid dose, but there are cases where commercial formulas aren’t fully disclosed to the on-site physician, creating a risk that the practitioner doesn’t know the exact ingredients being injected.
Skin depressions (indentations)
In body-area treatments, large injection volumes are often required.
If the injected solution pools under the skin or the local steroid concentration becomes too high, it may cause subcutaneous tissue atrophy, leading to visible skin depressions.
Source: Google Image Search
Other Possible Side Effects
Bruising, bleeding, or small hematomas from large-gauge needles are relatively common.
Some patients may feel lightheaded immediately after treatment,
so it’s recommended to stay lying down for a short time before standing up.
What kind of clinic should you choose?
In most cases, the difference lies in the mixing ratio rather than the ingredients themselves — the underlying pharmacologic principle is quite simple.
If you rely solely on injections to force fat volume reduction, the skin can lose elasticity, leading to sagging or cellulite, much like a deflated balloon.
Rather than repeating expensive fat-dissolving injections, patients often achieve better long-term satisfaction through a combined program that includes GLP-1 treatments (like Saxenda), oral weight-control medication, exercise, and diet management.
Technique makes the difference
Understand how much volume reduction is realistic and design the plan to avoid unwanted indentations.
Choosing the correct injection layer (depth) is critical.
With aging, deep fat pads decrease—which can hollow the cheeks—while superficial fat tends to persist and sag.
Therefore the primary target is the superficial fat layer; do not inject fat-dissolving agents into the deep fat pad.
If deep fat is reduced, side effects like cheek hollowing may occur and fillers could be needed later.
Summary (Key Points)
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HPL and fat-dissolving injections differ in both ingredients and mechanism.
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HPL: Uses a hypotonic solution to create an osmotic gradient → cell swelling → rupture.
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Fat-dissolving injections: Steroid-centered, inducing soft-tissue atrophy (+ auxiliary agents).
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Because their side-effect profiles also differ, it’s essential to avoid overdosing and inject into the correct layer.
Watch for menstrual irregularities / breakthrough bleeding, indentations, and bruising.
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Avoid treatment if you are planning pregnancy or breastfeeding.
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For satisfaction and safety, choose a clinic that is reasonably priced and led by a seasoned physician who understands formulations and anatomy.
If you have questions, feel free to “Like” or leave a comment. We’ll respond carefully. Thank you.
Sources (as originally cited)
📍 Primi Clinic
52 Seongsuil-ro, Seongdong-gu, Seoul, South Korea (3F)
📍 Primi Clinic
서울특별시 성동구 성수일로 52 3F（Primiクリニック）
KR
JP
CN
