CoolSculpting and DIY CoolSculpting (Cryolipolysis)

The commercial CoolSculpting® device.

CoolSculpting uses cold to reduce fat and it can be effective as long as you know the limitations; a similar effect can be achieved cheaply at home. This approach is marketed as CoolSculpting® or Cryolipolysis®. It works by chilling the skin, causing the underlying fat cells to naturally die off. This reduces the thickness of fat in the area treated, though the actual reduction is quite small. Typically, a single treatment will result in the loss of about 1.4oz/40g of fat and 7mm of thickness two months after treatment. While commercial CoolSculpting requires expensive equipment, I've found that a similar effect can be produced at home for almost no cost, though this DIY approach entails some risks. A safer approach is to use an authorized CoolScultping facility, and I'd recommend ensuring you're going to an authorized provider. (There are lots of cheap clones of the official CoolScultping machines on ebay.com, so check the machine is by ZELTIQ.)

Contents

1 What is CoolSculpting?

CoolSculpting uses an FDA approved device to chill the skin for up to an hour[1], with a session lasting one to three hours[2], producing a reduction in the fat thickness in the treated area. Animal and human studies have shown a reduction in fat thickness between 20% and 80% over 3 months following treatment[3]. The device sucks the skin and underlying fat into a cup[4]. More than one treatment can be used, but the results of the second treatment are not as dramatic as the first[5]. CoolSculpting is considered an alternative to liposuction[6], which is the one of the most common types of plastic surgery[7]. There are some initial indications that CoolSculpting may improve skin texture and laxity, with a tightening of the lose skin[8]. While promising, more studies on skin laxity are needed.

2 How Much Does CoolSculpting Cost?

The cost seems to vary quite a bit, and I couldn't find any recommended prices. However, self-reported costs seem to be generally between $1,500 and $4,000.

3 How Does CoolSculpting Work?

The device removes heat from the skin at a constant rate, rather than chilling to a particular temperature. (I suspect that simple icing is not used to ensure the technique is patentable.) While the underlying mechanism is unclear[3], the current theory is that chilling fat triggers inflammation of the fat cells (Panniculitis) and then triggers natural cell death in the fat cells (apoptosis). The inflammation starts 3 days after treatment, peaking at 30 days, with some residual inflammation seen after 90 days and the number of fat cells declining over the 90 day period[9].

4 How Cold is CoolSculpting?

CoolSculpting uses an approach of removing heat from the body at a constant rate, something they call Cooling Intensity Factor (CIF)[10][9]. This makes it tricky to understand the actual temperatures involved, though studies often quote figures of around -5c to -10c for the temperature of the paddles that are in contact with the patient's skin.

  • A study looked at the temperature of the skin surface and the fat at a point 1.5cm below the surface during a 60-minute CoolSculpting application set to -7c/19f[11]. The skin surface dropped in temperature steadily during the 60 minutes until it was at an average of 12.3c/54f (+/-2.6c). The underlying fat temperature dropped for the first 30 minutes to around 13c/55f then cooled more slowly for the final 30 minutes to around 10c/50f. It's interesting to note that the skin temperature was warmer than the underlying fat, and that even though the CoolSculpting device was set to well below freezing point, the skin never got close to that cold. The CoolSculpting setting was a "Cooling Intensity Factor" of 42 which has units of mW/cm2.
  • An animal study of two different machines that cooled showed a final skin temperature of 8.6c/47f and 5.8c/42f[12], which is similar to the human study.
  • Another study in 2017 evaluated two newer versions of the CoolSculpting device designed to go colder for a shorter period showed skin temperatures of -1.6c/29f and -7.1c/19f[13].
  • Further research by ZELTIQ looked at how isolated pig fat cells responded to chilling for an hour and then rewarming[14]. They found that chilling the fat cells to -2c, 0c or 2c caused the cells to die off (necrosis), while chilling them to 7c/45f caused some necrosis and some apoptosis (programmed cell death). Chilling the cells to 14c/57f, 21c/70f, or 28c/82f resulted in no necrotic injury and approximately the same apoptosis.
  • An early use of CoolSculpting used CIF of 42 mW/cm2 and produced -10c, or CIF of 34 mW/cm2 and produced -5c (both after 60 minutes.)[10].
  • Isolated mouse fat cells exposed to 8c/46f for 10 minutes showed some crystallization, with more crystallization seen after 25 minutes[15]. The crystal structures were still visible after 2 hours at 22c/72f.
  • Colder temperatures have been investigated. Most studies compare to the standard CoolSculpting as -10c/14f for an hour. One small study of 15 subjects used -12c for 45 minutes and -15c for 30 minutes, deployed under the chin area[16] (the fat reduction was less than 2mm). There's an abstract of a test using of 45 subjects using CIF of 50 mW/cm2 (-15c/5f) for 45 minutes on the flanks, resulting in 4.2mm (+/-2.6mm, range 10.7mm to 0mm) [17].
  • According to the FDA fillings, a version of CoolSculpting branded as "CoolAdvanatage" uses -11c/12f for 45 or 35 minutes[18].
  • Most images of patients after CoolSculpting show the fat has become semi-solid, which is sometimes referred to as the "butter stick". (Google for "CoolSculpting butter stick" for examples.) Some research from 1946 found that fat from 15 cadavers melted at various temperatures[19]. There was variation between individuals and between locations in the body. Subcutaneous abdominal fat melted around 31c-35c//88f-95f.
  • As another reference point, the most common fats in adipose (body fat) [20] are Oleic acid (~45%) with a melting point of 13-14c/55-57f, Palmitic acid (~22%) with a melting point of 63c/145f, and Linoleic acid (~12%) with a melting point claimed to be from -16c/12f to -5c/23f (sources differ.) This means that Palmitic acid is always going to be solid and Linoleic acid is always going to be liquid, so the "butter stick" effect seems to come from Oleic acid. Any solidification would suggest the fat has been chilled below 13-14c/55-57f.

All this research suggests that while relatively modest temperatures can result in the loss of fat cells, CoolSculpting may use lower temperatures and may have more impact.

5 How Much Fat Is Lost?

A 2014 study showed an average of 7mm reduction in fat thickness two months after a single treatment (about 1.4oz/40g)[21]. A 2012 study of CoolSculpting showed an average reduction of about 4mm after two months[5]. A second treatment had a lower reduction of an additional 1-2mm. Another study conducted between 2009 and 2012 of 518 patients showed an average of 23% reduction in fat thickness measured by calipers[22]. One patient showed a localized reduction of 2.2cm (nearly 1 inch) in fat thickness in spite of an increase of 0.1 Kg in overall weight. Note that the FDA clearance for CoolScuplting specifies a BMI of <=30 kg/m2[23].

6 What About frostbite?

A common concern is frostbite, or other damage to the skin. This should not be a problem if correctly performed, as you need far colder temperatures (-10c/14f) to cause that type of damage[24][25]. A study of mice showed the minimum time and temperature for cell damage is -4c/25f for 3 min[26], but this is actual cell temperature, not exposure to that temperature. CoolSculpting uses temperatures that do not immediately kill off the fat cells, but rather trigger the natural process of cell death (apoptosis). That's why CoolSculpting takes weeks or months for the full effect to be seen.

  • There is one case report of frostbite from commercial Cryolipolysis received at a beauty salon[27], but it's not clear if this was an official ZELTIQ CoolSculpting treatment or not.
  • There are reports of occasional frostbite in patients using a machine to pump ice/water to improve post-operative recovery[28]. These incidents are rare, with only 4 patients out of thousands having an issue, and the site of the frostbite is over the patella (kneecap) where blood supply may be a little more limited.
  • While there are reports of frostbite from gel packs[29], this appears to be surprisingly rare given the sales of gel packs.
  • A comparison of ice and gel packs showed that after 20 minutes ice reduced skin temperature to 10c/50f and gel packs to 13.6c/56f[30]. Another study using different amounts of ice showed that larger quantities of ice produced colder skin temperatures, with 0.6Kg/1lb producing an average of 6c/43f and a minimum of 4.4c/40f[31].

7 Risks and Side Effects of CoolSculpting

A 2015 analysis of the available research concluded that CoolSculpting "presents a compelling alternative to liposuction", "appears to be safe in the short term", and "results in significant fat reduction"[32]. However, there are a number of risks to CoolSculpting.

  • A common side effect is that the skin being treated goes red, with some bruising and numbness[3]. I suspect that the bruising may be because the CoolSculpting device sucks the fat against the cooling device[4]. These problems normally resolve within a week. The numbness is not associated with nerve damage[4].
  • While most patients find CoolSculpting uncomfortable, some suffer from "delayed onset pain." A study of 125 patients who underwent 554 treatments found 19 (15%) suffered from this problem[33]. The criteria for defining delayed onset pain was two of stabbing/shooting/burning pain, pain that disrupted sleep, or pain unresponsive to pain medication. The pain lasts 3-11 days, with no permanent symptoms.
  • Studies have shown no changes in blood lipid levels or liver function[1][34].
  • A study of 528 patients that underwent a total of 2,729 cycles showed only three cases of mild or moderate pain, which resolved within 4 days[6].
  • Another study of 518 patients showed 4% experienced severe pain during the first 5 minutes of treatment, with the remainder reporting mild to tolerable pain[22].
  • While "CoolSculpting" is a registered trademark of ZELTIQ, there are a variety of relatively cheap machines that claim to perform Cryolipolysis. Many even claim to be "ZELTIQ" even though they look nothing like the machines made by ZELTIQ and cost a tiny fraction of the cost of a genuine machine.
  • There is one report of frostbite from Cryolipolysis received at a beauty salon[27]. It's unclear if this was from an official ZELTIQ CoolSculpting treatment or not. The subject had two painful blisters arise within a few hours of treatment, but was advised against seeking medical help by the salon owner. The blisters deteriorated over the next few days until the subject went to the doctor. At that point there were two nasty 2" by 3" wounds (5x7cm) which were treated as frostbite.
  • The manufactures report that there have been a small number of patients (about 1 in 20,000 treatments) of a paradoxical increase in fat thickness[35]. However, another report suggests that the rate is much higher at 1 in 120 patients[36].
An example of a subject that had an increase in fat thickness due to Cryolipolysis. While rare (1:20,000), you can see this is a fairly dramatic increase in fat thickness.
An MRI shows that the increase in fat thickness is greatest on the edges of the treatment zone.

8 Weight Loss or Spot Reduction?

CoolSculpting reduces the fat thickness in the limited area that is treated rather than producing overall Weight Loss[3]. CoolSculpting does not seem to be effective in obese people, though it may simply be harder to observe the effects[3]. It's worth noting that CoolSculpting reduces the fat thickness in people who have a stable weight; in other words, you don't need to be on a diet for it to work.

9 How Long Does It Take to Work?

The effects of CoolSculpting should start within a few weeks, but the full effect may take 3-4 months[9]. Tests indicate that the changes are noticeable after 2-7 weeks (average 4 weeks)[5].

10 How Long Does It Last?

A case study of two early subjects of CoolSculpting were examined years later[10]. Rather unusually, the subjects opted to have just one flank treated, allowing for an ongoing comparison. The first subject had two cycles on left flank only, CIF of 42 mW/cm2 (-10c) for 60 minutes. The changes are clearly noticeable after 2 months, 2 years, and 6 years post treatment. The second subject had one treatment cycle with a CIF of 34 mW/cm2 (-5c) for 60 minutes, and the changes are again clearly visible after three months, five years, and nine years post treatment. I've had similar long-term changes with my DIY approach, as noted below.

11 CoolSculpting and Long-Term Weight Loss

There is evidence that long-term weight loss is it difficult to maintain, with many people regaining their lost weight over time[37][38]. There is growing evidence that weight loss changes the bodies weight regulation, creating a drive to regain the lost body fat[39]. One study found that the greatest body weight previously recorded is a linked to weight regain[40], and it's known that obesity can result in an increased number of fat cells (adipose hyperplasia))[41][42]. It's possible that the increase in fat cells may be a driver for weight regain[43], and there is some evidence that a number of fat cells will determine the weight loss or gain from exercise[44]. I wonder if the reduction in the number of fat cells from CoolSculpting might help with long-term weight maintenance. I should emphasize that I've seen absolutely no supporting evidence for this idea, but I hope we will see research to either support or refute the concept.

12 CoolSculpting and Massage

A 2014 study looked at CoolSculpting followed immediately by 2 minutes of massage, and compared the results with CoolSculpting alone[45]. Subjects received the CoolSculpting on both sides of their body, but massage only on one side, the other acting as a control. The study found that the addition of massage improved fat reduction by 68% after two months and 44% after four months. Samples of the fat tissue showed increasing inflammation, peaking at 30 days post treatment, with no signs of necrosis or fibrosis at any time (0-120 days). The massage and non-massage groups were similar, but quite small. The massage was described as "1 minute using a vigorous kneading motion followed by 1 minute of circular massage using the pads of the fingers."

13 CoolSculpting Compared With Cryosurgery

CoolSculpting is quite different to Cryosurgery, which uses cold to kill off tissue, such as tumors. Typically, cryosurgery uses far lower temperatures (-20c/-4f to -40c/-40f) and immediately kills off the living cells (necrosis) [46]. Cell damage is caused by temperatures below -10c/14f[24][25] and CoolSculpting does not go that cold.

14 Is CoolSculpting Just Thermogenesis?

Because the time frame of CoolSculpting is months, it seems extremely unlikely that the fat loss is due to the localized metabolism of fat to produce heat. The early research into CoolSculpting used Yucatan Pigs that are incapable of non-shivering thermogenesis[47]. While there is a recent study showing that as little as 30 minutes of icing can change the gene expression of fat cells to improve their fat burning capability[48], this is not what is typically meant by "Thermogenesis". Rather this is an increased thermogenic capability, and it could contribute to the fat reduction of CoolSculpting. (The study also showed that in lean subjects, similar changes naturally occurred in winter, but far less change occurred in obese subjects.)

Changes in fat burning capabilities due to 30 minutes of icing[48]. The markers represent each of the seven subjects.
Changes in seasonal fat burning capabilities of lean and obese subjects[48]. (A BMI of 30 was used to divide subjects.)

15 DIY CoolSculpting

Having reviewed the evidence for the commercial CoolSculpting, I wondered if it would be possible to replicate the effects by simply applying a bag of ice & water to the skin. An early animal study of Cryolipolysis showed a reduction in the fat levels from 10 minutes' exposure to temperatures of -1c/31f, though not as great a loss as colder temperatures[49]. A more recent study of humans using commercial CoolSculpting showed the skin surface temperature dropped steadily during the 60-minute treatment until it was at an average of 12c/54f[11]. There is evidence that applying ice to the skin produces an inflammation response in just a few minutes[1], so this approach seems viable. There are clearly risks to Cryolipolysis, but for me I decided they were acceptable.

15.1 Frostbite and Other Risks

Please use caution, and if you have any doubts you should talk to your doctor. Any issues with circulation or diabetes could make this dangerous, and mistakes can result in serious injury. Here's some things you can do to reduce your risk:

  • Making a mistake can cause serious injury. Even performed correctly, if you have circulatory issues or a susceptibility to frostbite[50], DIY CoolSculpting can be dangerous.
  • Using anything other than ice water can result in temperatures low enough to result in serious frostbite requiring hospitalization[51].
  • Never use any type of gel pack. These start too cold and can easily cause frostbite[52], and they warm up too quickly[53][30].
  • A mixture of ice and water will be about freezing point, but solid ice can be much colder, so don't use a solid block of ice. Make sure the ice is starting to melt slightly so that you have a mixture of ice and water. I've found that crushed ice in a Ziploc bag works well as it conforms to the shape of your body and starts melting quickly.
  • It's critical that you monitor your skin temperature closely (See below).
  • I repeat, don't use gel packs as they can cause skin damage and they'll warm up too quickly to be effective. Ice is cheaper and safer.
  • Let you skin rewarm slowly, as rapid rewarming can cause blisters. I cover up the area and let the skin warm up over the course of an hour or more. Don't take a hot shower or actively warm the area.
  • Err on the side of caution. Applying ice and water for shorter periods and building up over a few days is safer than more aggressive approaches.

15.2 Monitoring Skin Temperature

You should monitor your skin temperature closely, and if it gets too cold you should stop. Generally, I find my skin temperature doesn't drop below 2c/35.6f and is typically warmer than that. I've used several different technologies for skin temperature monitoring, each with their own advantages.

  • A thermocouple is a temperature sensor on the end of a wire, which allows you to continuously monitor your skin temperature, and I have one that supports four sensors at the same time and is only Error: Could not parse data from Amazon!. This is probably the most cost effective approach.
    This is the temperature monitor I use for checking skin temperatures.

    I tape the probes over the area I'm icing to check the temperature. Depending on the location, I may spread them out rather more than this.
  • A Thermal Camera is great as it allows you to see not only the temperature at one spot, but the pattern of temperature changes. The downsides are that you have to take the ice off to check the temperature, and the cameras are expensive. I'd use this with the above temperature sensor rather than instead of it. Of the two consumer-grade thermal cameras on the market, I prefer the FLIR, but it's discontinued and the new model hasn't been released yet. If you don't want to wait for the update, I'd recommend looking at the Seek Error: Could not parse data from Amazon!, but check out Thermal Camera for more details.
    An example image from my Thermal Camera showing the skin temperature.

15.3 Typical Skin Temperatures

I've made a number of tests, monitoring my skin temperature for up to three hours. The graph below shows three tests where I took temperature readings every 15 minutes, and it's fairly typical of what I see. The skin temperature initially drops fairly quickly, dropping to around 5-15c/40-60f within five minutes, and stabilizing around 5-10c/40-50f within 15-20 minutes. After that, the temperature tends to be reasonably stable, and most of the variation is down to how much the ice water is moved. If the bag of ice water is kept very still, the skin temperature will rise somewhat, but if it's actively agitated, then the skin temperature can drop. It takes some effort for me to get the skin temperature below 2c/36f, and obviously, the skin temperature never drops below freezing, as the ice water isn't that cold. This is broadly similar to research studies[30][54][31].

Skin temperature against time while icing.

Here are some other tests I performed, showing the variation you might experience, with temperatures rising and falling. Some of this variation is due to the body's natural responses, but quite a bit is due to how much I move the ice water around.

Various other tests of icing.

15.4 Testing 'DIY CoolSculpting'

So, I undertook a simple experiment and applied a bag of ice to the left side of my abdomen for 1-3 hours a day for two weeks. I generally did this in the evenings, applying the ice while watching TV or reading. While the ice is initially uncomfortable and cold, this sensation disappears in a couple of minutes. It also seems that after the first few times the ice is applied, the discomfort is far less.

15.5 Results of DIY CoolSculpting

At the end of the two weeks the fat thickness on the left side was noticeably thinner than the right side. The difference seemed to increase in the week following termination of the icing. It's hard to evaluate exactly how much change occurred in a few weeks, and I'm already quite thin (<10% body fat), so small differences are more noticeable than would be the case on someone larger. I used Skinfold Calipers to check my abdominal skinfold thickness and found a 2mm difference (measured 2 inches to the side of my navel). This is enough to be obvious to me, but not to show up well on photographs. Below are a couple of pictures that attempt to capture the resulting asymmetry.

The asymmetry resulting from icing the left side of abdomen using an oblique light to highlight the differences. The larger shadow on the right of the picture highlights the reduction in fat thickness in this area. You can also see larger bulges on the left side of the photo.
The asymmetry highlighted by taking the image from an oblique angle.

15.6 The Duration of DIY CoolSculpting Changes

The research into CoolSculpting suggests that it takes 3-4 months for the full effect. Because I applied the CoolSculpting more to the left side of my abs, it is possible to see how long the effects last. I used DIY CoolSculpting in May 2012 for a period of a few weeks. In the following five years, my weight fluctuated by around 15 pounds and I performed no more DIY CoolSculpting or icing of my abs during that time. Regardless of these fluctuations the slight difference in the two sides remained constant. This difference is slight, amounting to around 1-2mm, but is noticeable on inspection. This suggests that the effects of DIY CoolSculpting last for at least five years and probably much longer. Obviously, DIY CoolSculpting does not prevent overall weight gain, but it's unclear if it will limit this gain in any way.

15.7 How to perform DIY CoolSculpting

I iced for 1-3 hours most days, which is far more than CoolSculpting which uses a single 1 hour session. I have no idea if 'more is better' or if a single hour every couple of months is optimal. None of the research I found had any indication of the dose/response relationship. The latest research suggests that 30 minutes might be enough to induce changes, but I find 1-3 hours is convenient. I've tested and tried a wide variety of combinations of ice cubes, crushed ice, with/without water added, and lots of different bags. So far, the best option I've found is in this 3 Liter hydration pack letter bladder from a platypus: Error: Could not parse data from Amazon!. It's a nice size, and it's slimmer than most hydration bladders, so it's easier to cover a larger area. Unlike a cheaper Ziploc bag, it doesn't leak, and is a much better shape. If you want to use it for icing the back of your leg, buttocks, or back, you can use the hydration tube to release the pressure into a container under your seat.

The platypus bladder ready for use.
  • If you want to avoid the expense of the platypus bag, you can use a Ziploc bag, though I do find they tend to leak. You can use bags designed for ice cubes like Error: Could not parse data from Amazon! which you'll need to put inside a Ziploc bag, as with a are very thin and will pretty much always leak.
  • Fill up the bag most of the way up with ice cubes, then top up with chilled water. Don't fill up the bag all the way, but then squeeze the bag to remove all the air. You don't want the bag fully filled in order to have a little bit of movement, and it conforms to your body shape much better.
  • You can agitate the ice water in the bag for more effective cooling, but make sure you keep an eye on your skin temperatures when you're doing this.
  • You can put a thin piece of material between the bag of ice and your skin initially. This reduces the shock and allows the ice to start melting. I tend to have the bag in direct skin contact within a few minutes.
  • I generally find that the ice lasts more than an hour, but you may need to replace it depending on how quickly it melts.
  • Never, ever use a gel pack. They start off too cold and can cause frostbite, then warm up way too quickly. That makes them both dangerous and ineffective. By comparison, ice is safer, effective, and cheap.
  • Be careful, cautious, and if in any doubt, talk to your doctor. Mistakes can lead to serious injury and hospitalization.

15.8 DIY CoolSculpting Questions and Answers

Here are some of the questions I've been asked about DIY CoolSculpting along with my answers.

  • Is this a replacement for diet and exercise? Absolutely not. This approach will reduce the level of fat in a given area rather than producing an overall reduction in body fat.
  • Do you apply the ice directly or use a barrier such as a cloth? I normally apply the bag of ice directly to the skin. Sometimes I'll use a thin layer such as a tee shirt for a few minutes until the skin adjusts and then remove the layer. This prevents the sudden drop in temperature from making me squeal.
  • Is DIY CoolSculpting the same as drinking ice water? No, it's quite different. This approach triggers local removal of fat rather than changing the overall metabolism. (Drinking a gallon of ice water will only use about 70 Calories, so that is not a great solution to Weight Loss.)
  • Is DIY CoolSculpting like applying an ice pack as described in The Four Hour Body? No, the four hour body uses ice to chill the body overall rather than reduce the fat in a local area.
  • What happens to the fat that is lost? The absolute level of fat lost in this technique is not huge, so the calories made available from the fat is probably inconsequential.
  • ** A rough estimate is that each treatment covers around 10cm x 3cm and produces a 4mm fat loss, which is 12,000 mm3 or 12ml. 12ml is about 11 grams of fat, or about 100 Calories. Over three months that's about one Calorie per day. Treating multiple areas will increase this, but it appears most clinics would only treat 2-3 areas at a time.
  • How did you see results in two weeks when the studies say it takes several months? The animal studies of CoolSculpting showed that the process started after about 3 days, with the removal of the fat apparent between 14 and 30 days and from day 30 to 90 the process declined. Therefore, it is not unreasonable to see some results after two weeks. Also, CoolSculpting uses one hour long chilling, whereas I was chilling for 1-3 hours a day for two weeks, which is a lot more treatment.
  • Is there any corresponding skin tightening? In my experiment, there was not enough fat loss to make a difference to skin tension. Overall, CoolSculpting and DIY CoolSculpting are unlikely to produce the dramatic overall fat loss that would lead to sagging skin.
  • Is 'DIY CoolSculpting' the same as the real thing? No, the DIY approach of applying ice is different to CoolSculpting, which uses a single session applied for a shorter period.
  • Does 'DIY CoolSculpting' work the same way as Commercial CoolSculpting? It's hard to know for sure, but I believe the underlying mechanism is the same. DIY CoolSculpting could be burning more calories to keep the body warm, but that would produce an overall Weight Loss, not a spot reduction. Another mechanism, such as increased blood flow, could be behind the spot reduction, but that does not seem likely. Commercial CoolSculpting removes heat at a constant rate[49], where this DIY CoolSculpting uses the constant temperature of the ice, so the DIY version may not be as effective. However, the DIY can be applied far more frequently than the commercial approach.

16 References

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