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What Is Eclairis Fat-Dissolving Injection? | A Doctor Explains the Effects, Costs, and Downtime
"My face line won't slim down no matter how much weight I lose."
"No matter how hard I try with diet and exercise, certain areas—my double chin, upper arms, thighs—just won't slim down the way I want."
"Liposuction has a long downtime, so I can't quite bring myself to do it."
"I want to look trim for an event or a wedding, but I'm looking for a body-contouring treatment that doesn't rebound easily."
Do any of these concerns sound familiar?
Hello. We are Smart Skin Clinic, a cosmetic dermatology clinic with over 24,000 annual injection procedures.
In this article, we explain, in clear terms from a professional standpoint, everything about the fat-dissolving injection "Eclairis" — its effects, how it differs from FatX Core, its downtime, and its side effects.
*If you already know what you are looking for, you can jump to the relevant section from the table of contents.
Group Chief Director, Smart Skin Clinic Group
Ishii Kota
Career
Graduated from Juntendo University School of Medicine
Worked at Tokyo Women's Medical University Hospital and affiliated facilities
Worked at a major aesthetic clinic in Tokyo
Affiliations / Qualifications
Board-certified specialist, Japan Surgical Society
Board-certified specialist, Japanese Society of Anti-Aging Medicine
What Is Eclairis?
Eclairis is a fat-dissolving injection developed by the Korean company TNS
Eclairis is an injectable solution developed by TNS Korea that contains "deoxycholic acid," a fat-dissolving agent, in a 1% formulation .
Another fat-dissolving injection, "BNLS neo," has a deoxycholic acid concentration of roughly 0.001-0.02%. Eclairis, by contrast, contains about 10,000 times more deoxycholic acid than BNLS neo, making it an injection that can be expected to offer a more powerful fat-dissolving effect.
The Main and Supporting Ingredients of Eclairis
In addition to deoxycholic acid, the star player in fat dissolution, Eclairis contains several supporting ingredients.
- Deoxycholic acid: the main ingredient, which physically breaks down the cell membranes of fat cells and reduces the fat cells themselves
- L-carnitine: an amino acid derivative that supports fat burning
- Oleic acid: an unsaturated fatty acid that promotes the elimination of broken-down fat
- Korean ginseng extract: a plant-derived ingredient expected to promote metabolism and provide anti-inflammatory action
- NAIS Complex anti-inflammatory ingredients: a combination of plant extracts and amino acids that help reduce post-treatment puffiness and swelling
The main ingredient, deoxycholic acid, is a pharmaceutical ingredient approved by the U.S. FDA (Food and Drug Administration) in 2015 under the name "Kybella" for the reduction of submental (under-chin) fat.
The combination of these ingredients means that the product is designed to do more than just melt fat—it provides comprehensive support, right through to the elimination of waste products from the body.
Why Eclairis Is Said to Be "an OEM of FatX Core"
When it comes to fat-dissolving injections, some may wonder how it differs from "FatX Core."
To put it simply, Ecliris is a new formulation that contains deoxycholic acid at the same high concentration (1.0%) as the fat-dissolving injection “FatX Core” . Since the concentration of the key fat-dissolving ingredient is the same, it is expected to deliver equally powerful results.
However, due to differences in the formulation ratios of auxiliary ingredients and adjustments to the anti-inflammatory components, Ecrilis tends to result in a slightly shorter swelling period compared to FatX Core. The appeal of Ecrilis lies in the fact that it offers “equivalent efficacy to FatX Core but with shorter downtime.”
The Mechanism by Which Eclairis Destroys Fat Cells Themselves
Deoxycholic acid, the main ingredient of Eclairis, has the action of physically breaking down the cell membranes of fat cells (adipocytes), known as focal adipocytolysis.
[How injected deoxycholic acid works]
- It interacts with the cell membranes of fat cells, destabilizing the membrane structure and dissolving the cells
- The dissolved fat cells are engulfed by immune cells (macrophages)
- Fibroblasts are then recruited, and collagen is produced
- Through a series of tissue responses, the broken-down fat is ultimately expelled from the body — as carbon dioxide via the breath, and as water via urine and other routes
In other words, Ecliris’s key feature is that it doesn’t just “temporarily reduce fat,” but rather “reduces the number of fat cells themselves” .
The details of the mechanism by which deoxycholic acid physically breaks down fat-cell membranes and ultimately reduces fat — through tissue responses such as macrophage infiltration and fibroblast recruitment — are reviewed in the following paper.
The Effects of Eclairis | Spot Slimming, Rebound Prevention, and a Slimmer Face
The biggest concern for those considering Eclairis is surely "Does it really work?" Here we explain, together with the scientific evidence, the mechanism by which Eclairis works and the specific changes you can expect.
- Spot slimming
- Rebound prevention | Because the number of fat cells themselves is reduced
- Firmness and tightening | Collagen production helps prevent skin sagging
1. Spot slimming
No matter how you diet or exercise, certain areas — under the chin, the upper arms, the thighs, the abdomen — are simply hard to slim down.
For example, someone with a small jaw may be affected by their bone structure, tending to develop a double chin from even a little fat. Or, even if the whole body slims down evenly, areas that had more fat to begin with can still stand out.
By injecting the product precisely into the area of concern and reducing the fat cells there, Eclairis makes "spot slimming" possible. It is an effective approach for localized fat concerns such as a slack jawline, a double chin, the upper arms, and the inner thighs.
2. Rebound prevention | Because the number of fat cells themselves is reduced
When fat is reduced through ordinary dieting and exercise, the fat cells simply shrink in size; the number of fat cells themselves does not change. That is why, when lifestyle habits slip, the cells swell again and rebound easily occurs.
On the other hand, with Ecliris, since the destroyed fat cells are expelled from the body, the number of fat cells in the treated area itself decreases. It is generally believed that once fat cells are reduced, they are unlikely to regenerate in that area, and as a result, the treatment is expected to help prevent weight regain.
Regarding the long-term durability of deoxycholic acid's effects, a 3-year follow-up study conducted in the United States reported that the fat-reduction effect of the treatment was maintained in 82.4% of subjects even after 3 years, as noted in the following paper.
3. Skin firmness and tightening | Collagen production helps prevent skin sagging
Some people worry, "Won't my skin sag if the fat is reduced?"
However, the tissue reactions that occur as deoxycholic acid breaks down fat cells—such as the mobilization of macrophages and collagen production by fibroblasts— help prevent sagging skin and can also be expected to provide firming and tightening effects.
With ordinary liposuction, the concern of "the fat is gone, but now there's excess skin that sags" tends to arise. Because Eclairis involves tissue remodeling through collagen production, however, it is a treatment with advantages from the standpoint of preventing sagging, too.
Guide to How Long Until You Feel the Effects, and How Many Sessions
Eclairis is not an immediate-result treatment; it is one whose effects appear gradually.
- Feeling the effects: changes begin to be felt from about 3 days to 1 week after treatment, and settle in after about 3 to 6 weeks
- Recommended number of sessions: about 3 to 5 sessions at 2- to 4-week intervals (individual differences apply, depending on the amount of fat in the area and the goal you are aiming for)
A particularly important point to understand is that "expecting a dramatic change from a single session is not realistic."
Since the breakdown and elimination of fat cells take time, the natural process is that by continuing with multiple treatments, fat cells will gradually decrease, and you will be able to notice a natural change.
We recommend planning from a long-term perspective, rather than being swayed by short-term changes.
Guide to the Areas Eclairis Is Recommended for and the Injection Volume (cc)
We introduce the specific areas that Eclairis can address, along with a guide to injection volume.
The diagram below summarizes everything in a single page.
*Please note that these are guidelines only.
Facial contouring / face-slimming treatment (double chin, jawline, cheeks, jaw angle)
Because the fat on the face lies beneath thin, delicate skin, it is an area where even a small injection volume can produce a noticeable change in impression.
- Cheekbone Area1 to 5 cc
- Cheeks / Nasolabial Folds1 to 5 cc
- Jawline Area1 to 10 cc
- Jawline Contour1 to 5 cc
- Submental Area / Under the Chin3 to 10 cc
*All figures are per side
*These are guidelines only
It is especially favored by those with concerns such as "I'm bothered by slackness under my chin," "I want to make a round face look sharper," or "I'm concerned about my profile."
Kybella, the FDA-approved drug, was likewise originally developed with the primary goal of improving submental (under-chin) fat.
Spot body slimming (upper arms, abdomen, thighs, calves)
For the body, a larger injection volume is generally required than for the face.
- Armpit Fat (Front)5 to 10 cc
- Upper Abdomen10–20 cc
- Lower Abdomen10 to 40 cc
- Flanks (Love Handles)20–40 cc
- Inner Thighs10–20 cc
- Outer Thighs10–20 cc
- Above the Knees5 to 10 cc
- Upper Arms10–20 cc
- Bra Bulge (Back)5 to 10 cc
- Upper Back (Shoulder Blade Area）10–20 cc
- Back10–20 cc
- Waist / Lower Back10–20 cc
- Under Buttocks (Banana Roll)10 to 40 cc
- Thighs (Both Sides)10–40 cc (both sides)
- Calves10–20 cc
- Ankles5–10 cc (both sides)
*All figures are per side
*Note: The maximum injection volume for body treatments is 100cc per area.
*These are guidelines only
Eclairis's strength is its ability to pinpoint areas that are hard to slim down even with exercise, such as "bat wings" on the upper arms, the "inner thighs," and a "protruding lower belly."
Regarding the effectiveness of deoxycholic acid on the body, the following paper shows that in a 12-week follow-up of deoxycholic acid injections into flank fat, improvement was confirmed in 86.7% of subjects.
Namakizadeh Esfahani, N., Khorasanizadeh, F., Ehsani, A., Nasimi, M., Mahmoudi, H., Kafi, H., Sabzvari, A., Gholami, H., Saeedi, K., & Balighi, K. (2025). Evaluating the Efficacy and Safety of Deoxycholic Acid Injection in Reduction of Flank Fat. Journal of Cosmetic Dermatology, 24(9), e70436. doi:10.1111/jocd.70436
However, because the body has more fat and requires a larger injection volume, downtime tends to be longer than for the face. The injection volume varies depending on the thickness of the fat and the goal you are aiming for.
Which layer is it injected into?
Injectable formulations vary in both their ingredients and intended purposes.
Therefore, it is extremely important to administer each formulation at the appropriate “depth” and “volume” to ensure optimal results.
With Eclairis, the primary injection layer is the "subcutaneous fat layer."
The skin is structured in layers, from the surface inward: the "epidermis," the "dermis" (comprising the superficial, middle, and deep layers), the "subcutaneous fat layer," and the "muscle layer," each of which plays a distinct role. The subcutaneous fat layer sits beneath the dermis and acts as a cushion between the skin and the muscle layer.
The subcutaneous fat layer is the layer where Eclairis's ingredients and intended effects can be harnessed most effectively, and this is the medical rationale behind our clinic's decision to inject this formulation into that layer.
Eclairis, FatX Core, Kabelline, BNLS | A Comparison of Fat-Dissolving Injections
Many patients ask us, "What's the difference between Eclairis and other fat-dissolving injections?"
Here we have listed the differences from the major fat-dissolving injections.
Fat-Dissolving Injections: A Comparison Table of Major Formulations
| Product name | Eclairis | FatX Core | Kabelline | BNLS neo |
| Deoxycholic acid concentration | 1.0% | 1.0% | 0.5% | 0.001 to 0.02% |
| Fat-dissolving effect | ◎ | ◎ | ○ | △ |
| Downtime | 3–7 days | 1 to 2 weeks | 2-5 days | 1-3 days |
| Number of injections | 3-5 times | 3-5 times | 3-6 times | 5-10 times or more |
| Injection site | Face & whole body | Face & whole body | Face & whole body | Mainly the face (small areas) |
| Supporting ingredients | L-carnitine, Korean ginseng, anti-inflammatory ingredients | Amino acids, plant extracts | L-carnitine, artichoke extract | Mainly plant-derived extracts |
The biggest difference is, of course, “the concentration of deoxycholic acid”. While a higher concentration of deoxycholic acid enhances fat-dissolving effects, it also tends to increase the risk of swelling and side effects. A concentration of 1% is considered the upper limit for ensuring safety, and both Ecliris and FatX Core are formulated with high concentrations specifically designed to reach this limit.
Three Reasons Eclairis Is Chosen Over FatX Core
The three advantages of choosing Eclairis over FatX Core, which has a comparable concentration, are as follows.
- It delivers the same high concentration of deoxycholic acid in a more refined formulation balance: adjustments to the anti-inflammatory ingredients tend to make the sensation of irritation milder
- Additional metabolism-supporting ingredients such as L-carnitine and Korean ginseng extract are included: comprehensively supporting not only fat dissolution but also elimination
- The swelling period tends to be shorter than with FatX Core: although it varies from person to person, it often settles within about 3 to 7 days
Those concerned about post-treatment swelling, or who want to reduce downtime for work reasons, tend to choose Eclairis.
How Is It Different from BNLS neo and Kabelline?
BNLS neo is a fat-dissolving injection whose main ingredients are plant-derived herbal components (such as licorice extract and carnitine), with a deoxycholic acid concentration of only about 0.001 to 0.021 TP3T. Its approach centers on “promoting lymphatic circulation and gently stimulating fat cells”; rather than aggressively destroying fat cells, it is characterized by the gentle promotion of metabolism through botanical ingredients. While one advantage is that it causes virtually no swelling, its fat-dissolving effect is mild, making it suitable for precise contouring and treating mild fat deposits.
Cabelin is a formulation containing 0.51 TP3T of deoxycholic acid. While its effects are milder compared to Ecliris and FatX Core, the downtime is relatively short—2 to 5 days—making it a recommended option for those receiving fat-dissolving injections for the first time.
It is important to select the optimal formulation in consultation with your physician, according to your lifestyle and wishes.
About Pain During Treatment
When they hear the word "injection," some people worry, "Will it hurt?"
The sensation during treatment varies by injection site and by individual, but it is generally described as follows.
- During injection: a pricking sensation as the needle enters, and a light feeling of pressure as the product spreads
- Immediately after injection: a sensation of heat or tingling at the injection site (subsiding within a few minutes to a few dozen minutes)
Because Eclairis in particular contains a high concentration of deoxycholic acid, the sensation of irritation upon injection may feel somewhat stronger than with milder formulations such as BNLS neo.
At our clinic, we consider anesthesia to be basically unnecessary for Eclairis. Local anesthesia can also be used on request (for an additional fee).
The Course of Downtime, Swelling, and Pain with Eclairis
While the downtime and side effects of Ecliris are relatively mild, they can vary from person to person. If you have important plans, we recommend scheduling your appointment so that there is a gap of about two weeks.
Guide to the Course from the Day of Treatment to 1 Week (Explained in Chronological Order)
Downtime for Eclairis generally follows the course below.
- Day of treatment: the peak comes right after injection. Mild swelling, redness, warmth, and a prickling pain are common.
- Next day to day 3: the period when swelling peaks and begins to subside. Bruising may appear. On the face, it is generally coverable with a mask or makeup.
- Days 4-7: swelling and redness gradually settle, and your appearance returns to nearly normal.
- From 2 weeks onward: little to no impact on daily life. This is the period when the elimination of fat cells progresses and you begin to feel the effects.
However, these are only guidelines. Downtime varies from person to person depending on the injection volume, the area, and individual constitution.
Guide to Downtime by Area
How readily swelling occurs and how long downtime lasts differ by area.
- Face (jawline, under the chin): about 3-7 days
- Upper arms, abdomen: about 5-10 days (tends to be longer than the face)
- Thighs, calves: about 1-2 weeks
Because the body has more fat and requires a larger injection volume, downtime tends to be longer than for the face. Please use this as a reference when considering the timing of your treatment around your work and schedule. It is best to avoid the period just before a wedding, graduation, or other important event, and to complete the treatment at least two to three weeks beforehand.
Aftercare to Reduce Swelling Quickly
To shorten downtime as much as possible, please keep the following aftercare in mind after treatment.
- Things to avoid: refrain from massage, strenuous exercise, alcohol, saunas, and long baths for about a week (they may increase swelling by promoting blood circulation).
- Cooling care: gently apply a cold pack through a clean towel.
- Hydration: drink water frequently to promote metabolism and support the elimination of waste products.
- Bathing: showering only on the day; baths are fine from the next day.
- Makeup: fine from the next day.
Being mindful of how you spend your time after treatment will help you get through the downtime more smoothly.
Possible side effects
The typical side effects of Eclairis are as follows.
- Transient numbness, itching at the injection site
- Rarely: induration (lumps), skin puckering, pigmentation
- Extremely rarely: nerve damage, infection, allergic reaction
In the unlikely event that symptoms such as severe pain, unusual swelling, or fever appear after treatment, please contact our clinic immediately, as treatment is required. With prompt care, most symptoms can be expected to improve.
Regarding the safety of deoxycholic acid, the following paper shows that a systematic review and meta-analysis combining multiple randomized controlled trials concluded that "side effects are within an acceptable range and manageable."
Three Drawbacks of Eclairis
When considering Eclairis, there are three drawbacks worth understanding in advance.
- It is hard to feel a dramatic change from a single session
- It takes time for the effects to appear
- It is self-pay treatment, not covered by insurance
Eclairis assumes multiple sessions. Also, because destroying and eliminating fat cells takes time, this treatment is not suited to those who "want to slim down right away," "cannot take any downtime at all," or "want to finish in a single session."
We ask that you weigh your wishes against the realities and consider it carefully.
Those Who Cannot Receive Eclairis Treatment
Those who fall under the following cannot receive Eclairis treatment.
- Women who are pregnant or breastfeeding
- Those with severe cardiac, renal, or hepatic disease
- Those with a bleeding tendency (including those taking anticoagulants)
- Those allergic to deoxycholic acid or to any ingredient contained in the formulation
- Those with an infection or inflammation in the area to be injected
- Those with an infection or skin condition at the treatment site
If you have any concerns about your health condition, or are currently taking any medication, please be sure to inform your physician during the consultation.
The Eclairis Treatment Process
You can easily make an appointment using your smartphone. You can book a date and time that works for you via our online appointment system at
or by phone. Whether you’re a new or returning patient, you can make an appointment 24 hours a day.
When you arrive, simply give your name at the reception desk for a smooth check-in. First-time visitors will be asked to complete a brief medical questionnaire.
During your consultation, please feel free to raise any concerns. Rest assured, there is no pushy sales. Next, we assess the thickness of the fat and the condition of the skin through palpation, ultrasound examination, and the like, and determine the appropriate injection volume and sites.
After disinfection and marking, cooling is performed as needed. We carry out the injection while checking in with you throughout.
We will provide detailed instructions on how to care for the treated area and what to keep in mind in your daily life.
In addition, with a focus on prevention and maintenance, we recommend appropriate home care products—such as oral medications and skincare products—that can help alleviate your concerns.
You may experience some swelling or puffiness immediately after the procedure, but you can resume your daily activities right away. You can apply makeup starting the next morning.
If you have any concerns, please feel free to contact us at any time.
Frequently Asked Questions About Eclairis
- Is Eclairis effective after just one session?
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Fat cells are reduced even after a single session, but to clearly feel a slimmer, more refined appearance, we recommend continuing for 3 to 5 sessions.
- How soon can I feel the effects?
-
Changes may be felt as early as about one week, but the broken-down fat is expelled from the body and the final result settles in about three to six weeks later.
- How much does it hurt?
-
There is a slight sting at the moment of injection and a heavy, dull ache afterward. In principle, anesthesia is not necessary, but if you would like local anesthesia, there is a separate charge of 5,500 yen (tax included) per session.
- Can I wear makeup, take a bath, or exercise on the day of treatment?
-
These are possible from the next day. On the day itself, please limit yourself to showering, and refrain from long baths, saunas, and strenuous exercise for about a week, as they can prolong swelling.
- Does Eclairis cause rebound?
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Because the treatment reduces the actual number of fat cells, rebound is generally unlikely. However, in the event of extreme weight gain, the remaining fat cells may enlarge.
- Can it be used together with diet medications?
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It depends on the type of diet medication. Regarding concurrent use with oral or injectable drugs such as GLP-1 receptor agonists, drug interactions and your overall condition need to be checked, so please be sure to consult your physician.
- How long do the effects last?
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Once fat cells are destroyed and expelled, they do not regenerate, so the effects can be considered semi-permanent.
- Can I receive treatment while pregnant or breastfeeding?
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Because its safety has not been established, this treatment cannot be provided to those who are pregnant or breastfeeding.
- Can I have this treatment on the same day as other aesthetic procedures?
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Depending on the treatment and area, some cases allow same-day treatment while others are not recommended. For specific combinations, please discuss this with us during your consultation.
For Eclairis, choose Smart Skin Clinic
Eclairis is one of the leading options for those who want "spot slimming without surgery."
Our clinic offers formulations that have been meticulously selected by the director himself. We also have a track record of performing over 24,000 injection procedures annually. Furthermore, consultations are conducted directly by the doctors, which helps reduce unnecessary costs.
The design of how much to inject, in which areas, and over how many sessions varies greatly depending on each patient's individual fat volume and lifestyle. Whether you're wondering if Eclairis is right for you, or weighing it against other treatments, please start with a free consultation at our clinic.
Details
| Treatment Time | Approximately 10 to 15 minutes (excluding consultation) |
| Recommended Number & Frequency of Treatments | ・Basically about 3 to 5 sessions at 2- to 4-week intervals ・Because intervals vary by area, please consult your physician |
| Downtime | ・Redness, swelling, and, in rare cases, bruising ・Several days to about one week (varies by area) |
| Treatment on the day of counseling | Available |
| Makeup | Recommended from the following morning onward to help prevent infection |
| Skincare | Possible right after the treatment |
| Shower | Possible from the same day |
*Results vary from person to person.
Reference
Clinic List
Jimbocho Clinic
〒101-0054
3-16-1 Kanda Nishiki-cho, Chiyoda-ku, Tokyo, EX Kanda Nishiki-cho Building 8F (general reception) / 7F
Hours: Mon–Fri 11:00–20:00 / Sat & Sun 10:00–19:00
Yokohama Clinic
〒221-0835
TS Plaza Building 2F, 2-23-2 Tsuruya-cho, Kanagawa-ku, Yokohama-shi, Kanagawa
Hours: 10:00–19:00
About the physician supervision of this site
This site is operated under the supervision of a Smart Skin Clinic supervising physician.
This page was produced in accordance with the Medical Advertising Guidelines Medical Advertising Guidelines revised and enforced in June 2018, under which we produce and provide this information.
- Scope of supervision: treatment descriptions, risks and side effects, price display
- Last supervision date: June 26, 2025