Red light therapy
A course of sessions under a laser A 635 nm laser is aimed at the body from a stand. Zerona is the best-known brand. The trials ran three sessions a week, for two to four weeks.
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Red Light Therapy vs CoolSculpting
Red light therapy is measured with a tape measure, not on fat. It is a short course of sessions under a 635 nm laser, and the panel you can buy online is a different product. CoolSculpting is measured on the thickness of the fat layer. It is a cold cup held against one bulge for 35 to 60 minutes.
At a glance
| The difference | Red light therapy | CoolSculpting |
|---|---|---|
| Cost | No dated figure has been published | $3,268 on average, from $750 to $8,800 |
CoolSculpting
Side by side
The differences that matter
What you actually do
Red light therapy
A course of sessions under a laser
A 635 nm laser is aimed at the body from a stand. Zerona is the best-known brand. The trials ran three sessions a week, for two to four weeks.
CoolSculpting
A cold cup, 35 to 60 minutes
A cooling cup draws a fold of tissue against a chilled plate and holds it there. One area takes 35 to 60 minutes. In the largest real-world review, the median was 4 cycles in a single visit.
How it works
Red light therapy
Light on the skin, fat cells left alive
Nothing is heated and nothing is felt. No clearance in this class describes destroying fat cells. One clearance in the same category says the light makes fat cells release their contents rather than die.
CoolSculpting
Cold that injures fat cells so they die
The cold injures the fat cells in the fold, and scavenger cells clear the dead ones over the following weeks.
What you can expect to see
Red light therapy
Centimetres off a tape measure
The largest sham-controlled trial reported a combined 3.5 inches off the waist, hips and both thighs. But the distance around a body part moves with posture, breath, tape tension, meals and fluid. No study reports how much that measurement wanders on its own.
CoolSculpting
A fat layer about a fifth thinner
FDA's pooled review put the mean drop in fat-layer thickness at 21% on ultrasound, across a range of 10% to 26%. An independent trial found about 14%. In most clearances the main test is whether blinded doctors can pick the "before" photo - a spot-the-difference test, not a measurement of fat.
More photographs
CoolSculpting
How long it lasts
Red light therapy
Some of it comes back within weeks
In the pivotal trial, 0.31 of the 3.5 inches had come back two weeks after the course stopped. Nobody has published a longer follow-up.
CoolSculpting
The fat layer thins over weeks
The trials measured their results at 12 and 16 weeks after treatment.
The downside
Red light therapy
Nothing to feel and nothing to recover from
The light is not felt, and the sessions are usually described as painless. No side effects were reported in the sham-controlled trials.
CoolSculpting
Numb, red and firm for days to weeks
Pain arriving a few days after treatment is common. One review found it lasted 3 to 11 days and cleared on its own. Numbness past 12 weeks happened in 4 of 30 patients in the arm study.
Cost
Red light therapy
No dated figure has been published
No published price covers this treatment on its own.
CoolSculpting
$3,268 on average, from $750 to $8,800
Self-reported by 1,928 RealSelf reviewers. It is priced per cycle rather than per session, which is why patient totals scatter so widely.
The at-home or drugstore version
Red light therapy
Panels and masks, sold for skin
Most panels sold online hold no clearance for circumference. A few consumer models do. The clearance belongs to the model, not to the colour of the light, so check the model number.
CoolSculpting
Not a cheaper version of the same thing
The result comes from holding a fold of fat against a cooled plate for a set time. A gel wrap warms up against your body straight away and does not hold the tissue still.
Who tends to be happy with it
Red light therapy
- Best for - Someone who wants no sensation, no recovery and no needles, and who is measuring with a tape.
- The mindset - A short course, a small number on a tape, and an honest look at a trial that found nothing.
CoolSculpting
- Best for - Someone near a stable weight with one defined bulge and fairly firm skin over it.
- The mindset - One area, volume only, and a two to three month wait.
The lump, and why it is the one thing to watch for
Red light therapy
None of that applies to red light therapy. There is no cooling and no cell death, so the risk does not arise.
Before you book
CoolSculpting
For CoolSculpting, three blood disorders rule it out. In each one, blood reacts badly to cold. They are cryoglobulinemia, cold agglutinin disease and paroxysmal cold hemoglobinuria.
The fine print
Red light therapy
"Red light therapy" covers two products: the 635 nm Erchonia and Zerona laser systems, which hold FDA clearances for reducing body circumference, and the panels and masks sold for skin and recovery.
FDA created the laser category on 24 August 2010 through a De Novo request, DEN090008, granted to Erchonia. Later clearances read some version of "reduction of circumference", naming the body area; the upper-arm clearance is K120257.
CoolSculpting
CoolSculpting was authorised the same day through De Novo request DEN090002, which created the FDA category for cryolipolysis. Its clearance covers the upper arm, bra fat, back fat, banana roll, thigh, abdomen and flank, at a body mass index of 30 or less. Under the chin and jaw are cleared separately. CoolSculpting Elite is K212707.
A 510(k) clearance is not a finding that a device works. It means FDA agreed the device is much the same as one already on the market. No red-light clearance names a fat bulge, and no CoolSculpting clearance names circumference.
A panel bought online is not cleared for fat or circumference unless that exact model holds a clearance. A few do: the Zerona Z6 OTC, the Zerona Z-Bed and the Contour Light CL-100.
Common questions
Questions Patients Ask
Does red light therapy actually burn fat?
Not in the sense most people mean. No device in this class is cleared to destroy fat cells, and none is cleared on fat-layer thickness. What the Erchonia and Zerona clearances cover is a reduction in the circumference of named body areas, measured with a tape. Three sham-controlled trials found circumference reductions and one independent trial found none.
Can I use my red light panel at home instead of paying for CoolSculpting?
Only if that specific panel holds a clearance for circumference reduction, and most do not. A handful of consumer devices do, including the Zerona Z6 OTC, the Zerona Z-Bed and the Contour Light CL-100. A panel sold for skin, sleep or muscle recovery is a different product, and using it will not do what the cleared laser systems were tested to do.
Which one has more evidence behind it?
CoolSculpting has more, and better-controlled, evidence for its own endpoint - a De Novo authorisation, thirteen subsequent 510(k) clearances, and an FDA-conducted pooled review of 4,792 treatments. The laser evidence is three positive sham-controlled trials, two of which were funded or co-authored by the manufacturer, and one small independent trial that found nothing. Neither body of evidence tells you what you personally will see.
Do the inches come back?
In the pivotal laser trial, some of them did. Two weeks after the six-session course ended, the treated group had regained 0.31 of the 3.51 inches they had lost. Nobody has published a longer follow-up of low-level laser circumference reduction. For cryolipolysis the fat cells are destroyed rather than emptied, but the entire long-term evidence base is two men photographed at 6 and 9 years.
Does either one hurt?
The laser sessions are not felt at all, and no adverse events were reported in the sham-controlled trials. CoolSculpting is intense cold followed by an uncomfortable thaw, then numbness and firmness for days to weeks. Pain that arrives a few days later is common and lasted 3 to 11 days in a review of 554 procedures.
Can I do both?
No published study has combined them, so there is no evidence either way on whether one adds to the other. They are cleared on different endpoints and measured differently, which also means there would be no clean way to tell which one produced any change you saw.
Will either one make me lose weight?
No. The FDA states that non-invasive body contouring "will not result in weight loss", and CoolSculpting's manufacturer says the procedure is not a weight-loss treatment. A pooled analysis of cryolipolysis studies found no significant change in body weight. These are treatments aimed at the shape of one area.
Safety to keep in mind
A centimetre off a waist and a millimetre off a fat layer are not the same finding, and neither converts into the other. The laser has never been asked to show it removed fat, and CoolSculpting has never been asked to show that a tape measure moved. Neither one is a weight-loss treatment, and FDA says so plainly.