Settings Comparison Coolglide => GentleLase

Hair Removal Methods Laser hair removal
1

Ok, I’m going to ask my laser doc to switch me back from Coolglide to GentleLase. Right now the hairs are getting finer, and the pain/side effects : kill ratio is just not worth it on the Coolglide anymore.

On the Coolglide, I think I was at 55J/cm^2. This was very painful.

I’m wondering what comparable settings would be on the GentleLase? (This is for the face, light skin, dark hair).

I’m also wondering what the minimum settings that are usually effective would be [I realize this is variable, but do you know of an average?] /w GentleLase?

What do most people treat with?

I’d like nominally painful (if I take some ibuprofin first) treatments with no cuts/scars, which still kill at least 20-30% of the viable hairs they treat. Is this possible?

On the Yag it seems like we were getting 50-90% kill rates depending on the area, but the pain was very intense, and I have 3 scars on my chin as a result (and the recovery time was always at least a week before the swelling came down to a reasonable level).

In the end, I’m ready to switch to Electrolysis, but alas, no electrolysis in China or most of Asia for that matter, so I just want less painful, less dangerous laser treatments for now.

Thanks in advance for any info you guys might have =)

Layla

Ps. I tried to search on this topic, but I didn’t find much of relevance…

2

What kind of “scars” are you getting from your Coolglide treatments? Are you getting burned? Are you getting pigmentation? Is all the hair you’re treating coarse? 55 joules is just one metric. There is also a spot size and pulse setting which you didn’t provide, which make a big difference. It’s hard to judge with just joules on their own as info.

On GentleLASE, there are adjustable spot sizes and joules, and pulse is stable at 3ms. Usually, it’s best to treat at larger spot size and highest joules. On largest 18mm spot size, 20 joules is max. On 15mm, 30 joules is max. In general, treating at least with 14-16 joules at 18mm to start is good if your skin can handle it without burning. If you don’t burn at 20 joules, even better.

However, you should consult with your clinic on settings. They can see in and your skin in person and should know what settings to use. With proper treatment, you should not be getting ANY side effects, i.e. no burns, no scars (not sure what this even means in your case), no pigmentation, etc. If any of these are happening, something needs to be adjusted.

In terms of pain, if it’s working, it’s going to be painful, especially if the hair is coarse and dense. You can take ibuprofen and ice the area before and after to ease the pain, but you can’t eliminate it unless the settings are so low, they’re ineffective.

3

Well, my face has been swelling to the point that the skin breaks on my chin to allow fluid to drain (despite my icing to keep the swelling down), and then these cuts have been leaving scars after the scabs fall off :frowning:

I’m pretty sure that you would classify this as burning.

The doctor is Chinese and she’s possibly a bit too aggressive in her treatments, I think.

My hair is mostly all coarse. But I have both white and black hairs. The white ones can’t be killed by the laser, so recently I started plucking them until I can get to electrolysis to kill them. It makes life a lot easier not having so many coarse hairs regrowing everyday!

On 18mm, 20 Joules is max allowed by the machine?

4

Yes, on GentleLASE it is max. You should not be having those side effects. Start at 14 or 16 joules on 18mm on GentleLASE and see how you handle that setting.

5

The new GentleLase Deluxe that they have in China has a max of 24J/cm^2.

They treated me on 22J/cm^2 today. pulsewidth=1.5, two other settings were 50 and 40.

I assumed one of them was treatment time in ms, not sure about the other. I didn’t see the spot size.

I took a 500mg tylenol and then used the topical anesthetic.

I felt absolutely no pain. At moments, I felt what could be described like a small pin prick or someone pulling a hair, but it was so brief and painless compared to the ND:Yag that it might as well have been nothing. On a scale of 1 to 10, the GentleLase was barely a 1, the CoolGlide was about a 58!!! Really!!

I did feel some swelling and stuff twards the end, and I was smelling the burning. I’m not sure how much of this was due to the tylenol+anesthetic and how much was due to the active cooling of the GentleLase + the differences between treatment from Alexandrite @ 22J/cm^2 vs ND:Yag @ 55J/cm^2?

Anyway, the doctor was able to treat the areas around my chin much more effectively, because I wasn’t in pain. I actually felt her thouroughly cover the whole area. With the yag, she usually just hit spots here and there because I was in so much pain in those areas I think she was afraid to keep pushing.

We’ll see how the results are. She’s still under the impression that the Yag has better results than the GentleLase, but even if I only get 50% of the clearance I was getting from the Yag, the difference in pain, swelling, etc. would be, in my mind, WELL worth it for me to take it slower by using the GentleLase!!!

By the way, even with the glasses on, and my eyes closed, I saw bright red flashes of light each time she applied the laser. I imagine they were red because eyelid skin is red, but it also could have been from the red tinted goggles. The thing I’m wondering is, does this thing really let off THAT much diffuse light in all directions that through my eyelids, I’d be seeing it? That doesn’t make much sense to me, since lasers should be focused pulses. I don’t see why they would let off diffuse light in other directions at all. It almost makes me wonder if it wasn’t actually somehow that I was seeing pain instead of feeling it or something? Like nerve impulses firing in my occular nerves when the laser was applied? Has anyone else experienced this? It was quite weird!!!

Anyway, I can’t wait to see how the result is! I’m elated that this treatment was so easy and painless! After 6 months of the worst pain of my life and a week of horrible swelling and soreness after each time, this is SOOO refreshing to have such an easy treatment!!!

Best,
Layla

6

So little pain either means the settings were too low or you didn’t have coarse dense hair as you did on your last treatment, which hurts most.

The settings don’t make a lot of sense. ‘ms’ is usually the pulse, and on GentleLASE it’s usually stable at 3ms. 1.5ms would be too low. Don’t know if any machines goes that low. 40-50 sounds more like the pulse, if this is a new machine where the pulse is adjustable unlike previous GentleLASE machines with constant 3ms. Spot size is very important here. Generally, the only way to go higher than 20 joules on GentleLASE is by reducing the spot size. I would ask them for exact settings: joules, pulse and spot size. It’s hard for us to judge otherwise.

Overall, to me, it sounds like she is better trained on the Coolglide and just doesn’t know how to use the GentleLASE to get results, i.e. it’s not the machine, but rather her lack of knowledge of how to manipulate this machine in terms of settings to get results.

7

Are you sure that this was a Candela machine and not something else. I know of no Gentlelase Deluxe. There is a new GentleMax that is dual Alex/YAG.

For a Candela machine the settings you describe do not fit the Alexandrite. First, the 1.5 is the hertz rate, number of pulses per second. The 40-50 sounds like the pulsewidth which would be the YAG not the Alex because the Candela machine is fixed at 3 ms pulsewidth. If this is the YAG, then it is easy to understand why you didn’t feel much at 22 joules.

Finally, a 100 watt lightbulb is a pretty bright light. It puts out 100 kilowatts in an hour. This is 100,000 watts in an hour. Divide that by 3,600 seconds/hour and you get 27.7 watts per second. The Gentlelase pulse is 3 milliseconds long. In 3 milliseconds, the wattage of the lightbulb is 27.7 *3/1000 or 0.08 watts. Now compare that to a Candela Alex which can put out up to 50 watts in a single pulse.

100 watt lightbulb = 0.08 watts
Candela Alex = 50 watts

Candela Alex is 625 times brighter.

Wattage is really a function of the number of photons. With this many photons, is it surprising that you may “see” a few through your closed eyes? No not really. But as long as you are wearing goggles that protect your eyes, you are fine.

8

The machine clearly said Candela on it. Gentlelase Deluxe.

She said this is a new machine, that the old machine was 20J/cm^2 max and the new one was 24. I assume it has a better power supply, allowing it to use higher settings.

I’ll try to find out the spot size, but I don’t understand why this is important? Can someone explain to me how energy density @ a given spot size is in some way supposed to be related to treatment effectiveness? J/cm^2 is a measure of energy over an area. Spot size sounds to me like the size of the area being treated by a single pulse from the laser. If you can fix the energy density to some value, then changing the spot size should have no effect on energy delivered to a point on the skin… If you choose 12J/cm^2, then each cm^2 will get 12J, no matter if the spot size is 12mm or 18mm or whatever, no? The only thing that would change is the ammount of energy required of the power supply driving the laser (Because a larger spot size will require more energy at the same engery density, because your adding more points at the same engery, so total energy consumption goes up [12x24 < 18x24!]). So I can see why they might have limits on maximum energy density at a given spot size, corresponding to some maximum limits of the powersupply of the machine or the diode itself…

I don’t understand why everyone is always talking about treating at different spot sizes and different settings for that spot size… it seems to me you would select spot size based on the area you were treating (smaller for the face, bigger for an area like the legs where you don’t have obstacles like the lips to worry about working around and want to work more quickly).

If I’m mistaken, someone please tell me. But it seems to me that if I’m mistaken, there must be some abuse of the terminology going on…

About the flashes of light:
If it’s due to the laser putting out lots of light, then please explain why I haven’t seen ANY flashes of light at all in any previous treatments with other lasers then? A 55J/cm^2 pulse from a YAG should have a similar energy content, no? I’m not talking about seeing a “few” photons. I’m talking about flashes brighter than staring at the sun. There’s really this much laser going other places than the treatment area?

About it possibly being a YAG:
I’m very sure this was not the YAG, as the doctor advised me against using it because it was an Alexandrite and she is of the opinion that YAG lasers have better results.

About the hair thickness:
The hair has not changed THAT much since my last treatment. Something that might have helped was that I plucked all the white/clear hairs from my face, but they shouldn’t be absorbing that much energy anyway, due to the nature of them reflecting most of the light energy that hits them. Besides, most of the pain previously was coming from the skin, not simply from the places there were hairs. The skin was being burned, and it hurt like hell! This time, the skin was not being burned, but I still smelled the hairs cooking. Seems to me like what a laser treatment SHOULD be like (the theory about laser reflecting off the white skin, and targeting the black hair---- it seems the YAG was having as much influence on my skin as it was on my hair).

Elaboration about the pain:
The difference, was like comparing someone pinching you gently to someone cutting through your face with a flaming scalpel. Truly a world of difference. Yet, I could notice that I did turn a bit red in some spots and had some swelling. It seems that there would have been some pain if not for the anesthetic and the 500mg of ibuprofin.

My feelings 1.5 days post-op:
We’ll have to wait and see to judge how effective the treatment was, but I already have some pepperspots, so it couldn’t have been that ineffective. I see the signs that look like a lot of hairs will fall out in the coming days.

Thoughts? Questions?

Thanks for reading, and I look forward to any insights =)
Layla

9

Spot size is very important. It determines how energy is delivered to the skin. Most importantly, it plays part in the depth of the beam penetration. SSLHR has explained this in the past several times if you run a search on this forum. Here are two:

http://cosmeticenhancementsforum.com/forum/viewtopic.php?t=4257&highlight=spot+size+penetration

http://www.hairtell.com/forum/ubbthreads.php?ubb=showflat&Board=36&Number=37853&Searchpage=1&Main=7905&Words=sslhr+spot+size&topic=0&Search=true#Post37853

Without the spot size and pulse setting, it’s really impossibly to determine how high your settings were. For example, on an alex, 20 joules on 18mm with 3ms is very high, but 20 joules on 8mm and 50ms is very low, i.e. you will really feel the first one and barely feel the second one.

Also, alexandrite will always be more effective than a Yag at similar settings (they would have to be converted of course) especially once the hair gets finer unless the hair is very deep and requires 1064nm, which is rare and is almost never the case on a woman’s face. Alex is a more powerful laser. Like I said before, it just sounds like they are very familiar with their Coolglide Yag and just haven’t figured out how to use the new machine to get similarly good results on the coarse hair and better results on finer hair.

10

I thought you said the pulse was stable at 3ms… how could you set it to 50ms? I think it was at 1.5ms on the new machine.

11

See the post by SSLHR. GentleLASE has a stable pulse at 3ms. We’re not sure that this is the machine that’s being used on you. 3ms wouldn’t show up on the screen and no laser hair removal laser has a 1.5ms pulse. We’re thinking that the 50 setting you saw may have been the pulse, if on this machine the pulse is adjustable. As far as we know, and SSLHR communicates with the manufacturer Candela Corporation often, there is no GentleLASE machine with non-stable pulse. Their new machine is GentleMAX, which is both an alex and a YAG and has adjustable pulse, so we’re thinking this may be what is being used on you.

Were you trying to figure out the settings yourself by looking on the screen or did you ask them for the settings? If you didn’t ask, it would be best to ask to find out. Otherwise, there is no way for you to know what spot size was used.

If you Google btw, nothing comes up for “GentleLASE Deluxe” except this post. And it’s not on the Candela website either.

12

Could it have been “GentleLASE Plus” perhaps rather than deluxe?

The 50 and 40 could have been referring to the spray and delay on the cooling.

13

A couple of quick points. Let’s assume that you are on an alex. Candela does not make a 24 joule (max setting alexandrite). Their laser maxes out at 20 joules at 18 mm spot and 30 joules at 15 mm spot. Given that this is in China, I don’t know what to say. But what you are describing may be some Chinese copy. I don’t know. I am meeting this Saturday with the national sales manager of Candela in Dallas. I’ll ask him about a GLase Deluxe.

Why is spot size important? You did a great job of going through the concept. But you are making a big error. You are absolutely right that at a point on the skin, the energy density is the same regardless of the spot size. But we are not treating the skin. We are treating a structure buried relatively deep into the dermis. And that is why spot size makes a difference. I’ll leave that for you to think through. If you think about it, it will eventually make sense.

About the flashes of light. First, I am assuming that you are wearing goggles designed for the laser. If so, you should not see a flash brighter than staring at the sun. Make sure that the goggles state on them that they provide 5+ (or more) diopters at 755 nanometers. Diopters of reduction.

But assuming that you are using good goggles, there is also a very simple reason why you saw more light this time than the last time when you used a ND-YAG. The alex uses 755 nm which is visible to most people while the YAG uses a 1064 nm pulse which is invisible.

Finally, the pain. Most people think the YAG hurts more. Probably because it penetrates a little deeper and has more (relative) absorption by blood.

14

Now that it’s mentioned, that makes a lot of sense about 40 and 50 being related to cooling. It fits with what I saw on the screen. I’ll go back and find out if it was Max or Plus and not Deluxe as I had thought.

The pulse length is variable on the Candela YAG (in the MAX), but only down to 2.5ms; and the spot size is variable down to 1.5mm – but I doubt she was using a 1.5mm spot size, or she would’ve had to use a lot more pulses on my face than she used during the session.

In any case, if indeed it is the MAX, would the Candela yag be better than the Coolglide they have in the other room if I were to choose a yag to be treated by? The Cryogenics cooling seems like it’s a good technology, especially since she’s not big on icing before she starts treating, only after.

Assuming she was using the Alex @ 22J fluence and a reasonable spot size, with 3ms pulse fixed, what could explain the lack of pain?

Assuming she was using the Yag by accident? (I doubt it since as the last poster mentioned, I could SEE the laser light this time, and 1064nm is outside the visible spectrum), then we’d agree that 22J is just too low with a yag, right?

Regarding spot size and depth of penetration (which makes some sense after thinking about the lens optics a bit more – shorter focal length, shorter depth of penetration, smaller spot size):

"The considerations regarding the use of large diameter spots in order to increase the depth of these lasers are interesting from a theoretical point of view but clash with experimental measures. Z. Zhao and P. Fairchild have directly measured the depth of penetration into the skin and have shown, in “Dependence of Light Transmission Through Human Skin on Incident Beam Diameter at Different Wavelengths”, SPIE Proceeding, Vol. 3254, 01.98, two important aspects concerning the increase in the size of the diameter of the laser beam.

The first is that even increasing the diameter over a certain size the laser beam does not reach the deepest areas (for example, for the ruby laser and the alexandrite laser this saturation is obtained at 10mm with white skin). Moreover, the depth of these wavelengths, at 10mm, is the equivalent of that of the Nd:YAG laser at 7mm. For dark skins the equivalence for 10mm is 5mm of the Nd:YAG laser."

15

By the way, as to a probable reason why Candela limits the lower bound on their lasers to around 3ms:

"Since it is preferable to treat the follicle in a selective way without damaging the surrounding tissue, the energy needs to be released in pulses of a length that is less than or equal to the thermic relaxation time of the target structure. The thermic relaxation time (TRT) is the time it takes for the structure that has absorbed the laser radiation, and is therefore at a certain temperature, to lose 50% of the heat stored. In order to destroy the follicle it is necessary for the pulse duration to be about the same as its TRT. Pulses with a longer duration would only have the effect of heating the follicle at lower temperatures because it would have time to cool down in the meantime. Since the epidermis is the first to be exposed to the laser beam, it is extremely likely to be damaged by the energy of the laser pulse if the duration is shorter than its TRT.

Therefore, in order to hit the follicle the laser energy must be released in a pulse whose duration is longer than the TRT of the epidermis (estimated at a few milliseconds) and shorter or the same as the TRT of the follicle (a few tens of milliseconds)."

On that note, I noticed that the Coolglide goes down to 1ms. I think I remember seeing 1 or 1.5ms on the screen back when I was being treated with that laser. That might go a long way to explaining the horrible burns I was experiencing. (In addition to overtreatment in the spots that scared.)

16

Not having read this particular study I don’t know what to say about it. I question exactly what they measured and how they measured it. The question is not how deep a particular photon will travel but at what depth the heat released reaches the threshold at which the diffusion due to scatter is greater than the increase due to volume and this forms a three dimensional boundary. This is a much more difficult thing to measure. Think of it this way, how do you measure a weather front? You can only measure it by taking hundreds of measurements and then plotting them on a map. In this case we are essentially measuring a temperature boundary (front). To understand where the boundary occurs (and it is not a saturation) in an experimental design requires taking many many measurements and plotting them in 3D. This is not trivial to do. It can’t be done over multiple pulses, it has to be done during one pulse. Every study I have seen on this topic has measured the diffusion of laser energy and then applied that diffusion in a mathematical model to determine what the overall effective depth of penetration. I tend to be cynical about whether they measured this directly or just made some measurements that they then applied in a model. If you happen to have a link to the article, that would be appreciated.

As far as real life, according to this ideas in this paper we should not see a difference in effectiveness between 10 mm and 15 mm and 18 mm on the alex. Nor should we see a difference between 7 mm and 15 mm on the YAG. Yet we do. In fact, the differences are substantial. And it is not just me but everyone with experience who sees this difference. Again, the research in this article doesn’t really jive with observations. One tends to believe experimental evidence over observations, unless the observations are substantial and the experimental evidence is weak. I see the experimental evidence from this study being questionable given the intrinsic difficulties in actually measuring it.

We could talk more about the theory and thoughts about this, but until I can read this article, I don’t have the ability to say more about it.

The reason the alex has a fixed pulsewidth of 3 ms (by the way, saying that " Candela limits the lower bound on their lasers to around 3ms" is not technically correct. In fact, I am not exactly sure what that means.) rather than a variable pulsewidth is because 1) the Gentlelase was designed for Laser hair removal only and you are right about the TRT and having to be above that of skin. 2) The Gentlelase used cryogen spray from the beginning when all the competitors were using cold gel and therefore they could get away with a lower fixed pulsewidth. Competitors using cold gel had to have variable pulses so as to increase safety. 3) A fixed pulsewidth is simpler to design and engineer and makes the system more reliable.

The reason the Coolglide goes down to 1 ms or 0.5 ms is because it is also designed to be used on veins and you need far lower pulsewidths for blood vessels.

17

(by the way, saying that " Candela limits the lower bound on their lasers to around 3ms" is not technically correct. In fact, I am not exactly sure what that means.)

They limit it to 3ms on the GentleLase and 2.5ms on the GentleYag (which is variable). Thus, I said about 3ms. Lower bound meaning the lowest setting you can apply.

Taking your experience with applying LHR to a lot of clients, I’m inclined to believe what you say about the spot size observations not jiving with that experiment. I’m also inclined to believe that the relationship between penetration depth and spot size is not linear to the ideal in practice (The photons are passing through skin, not say space or air, afterall). I imagine that the falloff would be dependent on the laser, the lens, the properties of the skin, etc. It’s possible that they modeled this, and didn’t take enough variables into account to come up with something that matched reality (But they did claim to have measured it, so if they half-measured, then modeled, they weren’t being honest. I closed that page over a week ago now, so I’ll have to do some searching again to try to locate it for a link).