Cellulite is one of the biggest cosmetic concerns in women affecting 80-90% of women past puberty.  It usually appears on thighs, buttocks and abdomen as little dimples giving an “orange peel” or “cottage cheese” appearance. Cellulite is a localized skin condition and is found in women more commonly than men due to sex related differences in skin structure. Scientific evidence right there, it is hard being a woman!
Scientifically, cellulite has been an accepted gender predominant condition since 1978 when Nürnberger and Muller called it “an invented disease”  hinting on the fact that it is so common and natural. Nowadays, it is widely accepted that this is due to the perpendicular orientation of the walls between the female fibres (fibrous septa) allowing the fat to stand out, leading to the orange skin appearance as opposed to the oblique nature of those fibres in men.  However, cellulite is not a one-cause condition and there are other gender specific biological differences that contribute to this phenomenon as well.
To quote S. Luebberding et al. “Given the ubiquitous nature of cellulite, it is more appropriately thought of as a secondary sex characteristic rather than a disease. However, digitally altered photos in the media continue to not only alter the perception of beauty, but also to deceive the public about the true frequency of this condition that remains a major cosmetic concern for women”. Cellulite is so common that if you don’t have it you can consider yourself very lucky however, despite the fact that pretty much everyone has it, it somehow remains a major concern for women. As a result, there are a vast number of treatments available, even though cellulite is NOT a disease and perhaps the word treatment is not appropriate, from topical creams to mechanical stimulation, laser and light based therapies, radiofrequency treatments and even acoustic wave therapies.
But is there any scientific evidence as to whether such treatments have any effect in reducing cellulite?
The biggest challenge for scientific evaluation has been the quantification of cellulite. Since it is a very “visual problem” how do you establish whether a treatment had an effect or not, using any other way than simple visual inspection. Does it look better now? As you can imagine, this is not an accurate way of doing things at all. There have been some more valid techniques developed such as “skin topography” which is basically creating a map of the skin, a bit like creating a normal map where you have height differences of valleys and mountains for example. Such measurements though are usually very localized and are too small to represent the entire affected areas. 
Another common practice is to measure the before and after circumference of the affected area such as the thighs for example.  But as you might imagine this is also not very accurate at all, as you becoming thinner doesn’t mean you don’t have cellulite. To address a common misconception, thin women can also have cellulite, it is just less common or easy to see because naturally thinner women will have less fat. Other methods employed include the surprisingly more accurate than you think calipers,  magnetic resonance imaging MRI  and X-ray imaging . Let’s face it though you wouldn’t do an MRI or an X-ray to determine whether your cellulite is gone and as these are fairly expensive techniques that are more useful in actual disease research, they are not vastly employed in cellulite studies. Other skin characterization methods have been employed such as skin elasticity measurements, skin density, blood flow etc but neither of these factors have been proven to be directly affected by cellulite and therefore, cannot be accurately used to detect its presence. 
There are other methods reported as well but I think you get the point. Scientific quantification of cellulite can be subjective and the fact that it is most usually done on before and after imagery makes it even more so, as special equipment and lighting would be required to even take a clinical quality, representative image.
(a) Mechanical stimulation. This is usually done by a device or by hand, by delivering positive and negative pressure to the skin and tissue.  It is assumed that this causes damage to the fat cells forcing them to redistribute themselves when they heal and rebuild. As mechanical stimulation redistributes cells and are not therefore, all bundled up in the same place, the skin appearance smooths out. But bear in mind that this essentially just moves the fat cells around it doesn’t actually eliminate fat!
Such stimulation increases topical blood flow which can have a variety of beneficial effects such as bringing more nutrients in the area but can also drain the lymphatic system. Both these factors possibly also contribute to the improved appearance of the skin. 
Unfortunately, although there are some studies on the effectiveness of mechanical stimulation, including even just simple massaging or drainage of the lymphatic system, the results are not conclusive. The studies which focused specifically on mechanical tissue stimulation did indeed show improvement in cellulite appearance however, none of them compared their results to untreated participants and therefore there is no measure whether the effect was natural or due to the treatment or even how significant the effect was. 
(b) Topical cosmetics. There are so many of these, usually in the form of creams and gels that have extraordinary claims. Most of these products contain caffeine and retinol (Vitamin A) and other active ingredients such as botanical compounds.  These compounds work in a similar way as the mechanical stimulation, by facilitating lymphatic drainage, lipolysis of the adipose tissue (breaking of fat tissue) and reduction of any excess fluids around the area. Retinol specifically can also increase the thickness of the skin and therefore, potentially reducing the appearance of the cellulite bumps.  Perhaps the application of the cream by massaging it or working it into the skin also increases blood flow and introduces more nutrients into the site.
Sadly, despite what so many advertisements might claim, there is little to none evidence that such treatments reduce the appearance of cellulite. There are many research studies on topical creams, gels etc, with more than 600 participants, but none have concluded that topical cosmetics are particularly worth it.  Most studies did not include a non-treatment comparison and the ones that did found the difference to be very small. As a result, based on the scientific evidence so far, topical creams for cellulite are just not worth your money.
Personally, I have used a couple of cellulite products that I thought made a small difference in the appearance of my skin. However, when I run out of them and continued using a simple moisturizing body butter, I have found the effect to be very similar. This is actually a well known phenomenon, dehydration of the skin can make the appearance of cellulite worse so it could well be that some of the cellulite products improve the appearance of your cellulite simply because you are hydrating your skin. If you want my opinion and experience, buy a good body moisturizer, use it often and spend a couple of minutes massaging it into your skin. Eat healthy, exercise and drink lots of water. These are the best, cheapest and longer lasting ways to reduce cellulite appearance. And actually, if you work out you won’t just reduce the appearance but you might actually reduce cellulite after all. Such a typical suggestion but unfortunately, there are no quick fixes with this one.
(c) Acoustic wave therapy. This works by applying high energy acoustic waves on the skin and can potentially offer improvements by higher local blood circulation, increase in cell production of key compounds such as collagen and elastin fibres.[1, 10]
There are a couple of studies on acoustic wave therapy however, the results are inconsistent. Three studies concluded that this type of therapy improves the appearance of cellulite although the extent is unclear whereas two other studies concluded that there is no effect.  There is a definite need for more studies on acoustic wave therapy in order to make a solid conclusion.
(d) Laser and light based therapies. These therapies are quite popular and can be fairly expensive while requiring to attend many sessions. Scientific studies have not been able to pinpoint exactly how these work but it is speculated that it is through the stimulation of collagen production leading to thicker, healthier and more elastic skin.  Despite the fact that these are quite popular treatments, there aren’t that many scientific studies on the matter!
Two studies based on a 1064nm Nd:YAG laser have concluded that while the skin thickness did indeed increase, the appearance of cellulite remained the same. [12, 13] Other studies on a less invasive laser, 1440nm Nd:YAG. Two studies have shown significant improvement of the appearance of cellulite by reduced pimple appearance, smoother skin, higher skin elasticity and thickness however it is unclear where these results were of statistical significance as no deeper data analysis was performed. [14, 15]
Lower energy lasers also exist and can sometimes be preferred as they do not cause any heating on the tissue so they provide more pleasant treatments. They are said to work in a similar way, by increasing cAMP production which leads to breakdown of cell lipids and therefore cell collapse. They are also said to stimulate collagen synthesis.
Unfortunately, the results from such scientific studies also vary. A study using a 532nm laser showed improvements in cellulite appearance  whereas a study using a 808nm one did not show any significant changes . A third study using a 635nm laser showed improvements in fat thickness but no change in the appearance of cellulite. 
There are more studies but all conclude the same things. Some report beneficial effects but not improvement in cellulite appearance, some declare it a complete waste of time and others give results with no statistical analysis of which conclusions are very difficult to be drawn.
But what about light treatments? Is there any better evidence on those?
Infrared light is also meant to work in a similar way as the lasers. The heating on the skin is said to promote topical circulation, lymphatic drainage and collagen synthesis. Some studies report effective reduction in thigh circumference but no change in the appearance of cellulite. 
There are some treatments thought that combine both lasers, infrared light and even mechanical stimulation. Such treatments though are also plagued with inconclusive results with the exception of just two studies that reported statistically significant reduction in cellulite appearance. [20, 21]
(e) Radiofrequency treatments. These are very similar to the laser and light treatments and are supposed to have the same effects. Long story short, the same pattern is repeated here were some studies show improvement in some skin property such as thickness but no improvement in cellulite, others state cellulite improvement and others show no changes at all. 
(f) Weight loss. Overall, weight loss has been shown to improve the appearance of cellulite significantly unless the subjects were too overweight. In the latter cases the reduction in weight caused a lot of extra skin to be left loose which increased the appearance of cellulite.  Additionally, as I previously mentioned, cellulite is not an issue only for the overweight, there are also thin or normal sized women (and men but less often) with cellulite as well. Therefore, weight loss might not be a suitable method of action for everyone.
(g) Nutritional supplements. Believe it or not there are some supplements that are marketed as cellulite reduction products. They usually contain plant derived compounds such as Vitis vinifera, Ginkgo biloba, Centella asiatica, Mellilotus officinalis, Fucus vesiculosus, fish oils and more.  Such supplements are said to also work due to an increase in metabolism, collagen and elastic production while also inhibiting the oxidation of skin compounds (basically by keeping the skin healthy). Again, some studies support effects, some on cellulite some on just other skin parameters and some show that supplements give no effective results in cellulite reduction. 
(h) Other studies such as carbon dioxide therapy or combinations of some of the above also exist but again give inconclusive results.
In their review titled “Cellulite: An evidence based review” the authors conclude that such inconsistency in studies is due to the fact that they all chose different methods of evaluation, some analyzed their data for statistical importance whereas others did not, some included studies with control groups (people who didn’t have any treatment) whereas others didn’t.  The evaluation of cellulite and its presence has not been unified throughout all studies and perhaps that is the reason for such inconsistencies. A generalized, more standardized approach should be developed and used in future.
It is also possible that none of these treatments are actually effective at all (or enough) and require a very long time to give results. Otherwise, it is highly likely that no matter of what method of study was used, the results and effectiveness may have been more obvious.
Unfortunately, there is no solid scientific evidence as to any of the treatments working for cellulite. However, going through these research studies I have noticed that they all have a few things in common. Most treatments based their strategy on increasing collagen synthesis and redistributing or breaking fat cells and increasing topical blood flow. Collagen synthesis is a very important aspect of keeping our skin healthy and young and is something that we should perhaps focus on, in body creams as well. Why are body butters and creams so much simpler than face creams in terms of action and ingredients?
Make sure to hydrate your body skin and if you can, use products that will help with collagen synthesis as well like for example ones that include hyaluronic acid. Other ingredients of importance in keeping the skin healthy (and therefore thicker and more elastic meaning cellulite will not be as prominent) are vitamins C and E and other anti-oxidants that stop free-radicals from damaging processes and nutrients in skin. Retinol or vitamin A has also been employed in some of these treatments, however its effectiveness is still contested.
Try to keep your body skin as healthy as you keep your face skin and spend a few minutes massaging your lotions or creams into the body to increase blood flow. Keep hydrated not only by using moisturizers but also by drinking enough water and find an exercise regime that works for you. Unfortunately, for now, the only way that definitely gets rid off or minimizes cellulite is through exercise. Sweat it off ladies! And remember, sweat is fat crying!
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