How to make your own ultrasound gel (which is also sterile and edible and environmentally friendly) **UPDATED--NEW RECIPE**
I have been doing lots of bedside ultrasound lately and realized how useful it would be in areas far off the beaten track like Haiti, for instance. With a bedside ultrasound (mine fits in my pocket) I could diagnose heart disease, kidney and gallbladder problems, various cancers as well as lung and intestinal diseases. Then I realized that I would have to take a whole bunch of ultrasound gel with me which would mean that I would have to check luggage, which is a real pain when traveling light to a place where luggage disappears. I heard that you can use water, or spit, in a pinch, or even lotion, though oil based coupling media apparently break down the surface of the transducer. Or, of course, you can just use ultrasound gel.
Ultrasound requires an aqueous interface between the transducer and the skin or else all you see is black. Ultrasound gel is a clear goo, looks like hair gel or aloe vera, and is made by several companies out of various combinations of propylene glycol, glycerine, perfume, dyes, phenoxyethanol or carbapol R 940 polymer along with lots of water. It is hard to find this information, but it is available in the material data safety sheets for the various companies that make it. The recipes are proprietary. Ultrasound gel is not super expensive, but it is not that easy to find in a store or in a developing country. It costs about $25 for 5 liters on Amazon, or $5 for a nice 8.7 oz squeeze bottle. It smells ever so slightly medicinal and leaves a sticky, then dry white residue as it dries.
There should really be some sort of powder that you mix up with water that makes ultrasound gel so we don't have to be shipping the water part of it, which is undoubtedly about 99% of the contents, long distances. But there isn't a powder. I have been looking. No instant ultrasound gel.
With a mixture of optimism and singularity of purpose I went to the kitchen and tried out 6 different recipes for an aqueous goo that would transmit sound waves. I thought that I could make ultrasound jam out of water and pectin, but that doesn't really work. Obviously there is something magic about fruit that makes pectin gel, maybe the acid or the sugar. Without fruit, even no-sugar pectin becomes about the consistency of spit. (I also tried spit, which does work, but has various obvious drawbacks.) I tried plain gelatin and water and got beautiful clear jello, which falls off the transducer, but kind of works, but is also messy. I tried corn starch and water, as if making extremely boring gravy. That was lovely and white, but the water wants to come out of it so it just slides off the transducer. I tried tapioca flour which I boiled with water, producing a nice clear, very mucoid gel which dries like glue on the skin and is very uncomfortable. I tried xanthan gum, a bacterial polysaccharide used to bind and thicken, boiled and cooled, and although it thickens the water it is slimy and falls off the transducer and makes a mess.
The recipe that worked (and worked great) is guar gum, salt and water. Guar gum has been used for a very long time in countries like India and Pakistan to thicken food and is now used often by people who can't eat gluten, to thicken gravies and make breads. Guar gum is the ground endosperm of the guar bean, which is very rich in a carbohydrate that avidly absorbs water. Guar beans are also eaten green and the pods are used as a vegetable ingredient after shelling out the beans. Guar gum is available in the flour section of many grocery stores and costs about $10 for a 220 gram bag. It is purported to be good for diarrhea, constipation, diabetes and lowering cholesterol. It has been added to infant tube feed formula in intensive care units to decrease stool frequency.
I messed with the recipe awhile and came up with a very nice slightly caramel tinged ultrasound gel this way:
1. Mix 2 teaspoons of guar gum with 1-2 teaspoons of salt. (The amount of salt isn't vitally important since it is just added to keep the guar gum from clumping. Using slightly less than a teaspoon of salt per 2 cups makes a gel with which is isotonic, which would be ideal for use near eyes or other mucus membranes or on open wounds).
2. Boil two cups of water.
3. Slowly sprinkle the guar gum/salt mixture into the boiling water while stirring vigorously with a fork or whisk.
4. Boil for about 1-2 minutes until thick and well mixed.
5. Cool before using. Save lives.
This is wonderful ultrasound gel (see photo above). I tried it and it works at least as well as the proprietary stuff, and probably doesn't dry out quite as fast. It wipes off easily and doesn't leave a sticky film. Even though it is not entirely transparent, there is no reduction in the quality of the ultrasound image compared with the standard clear ultrasound gel. It costs about 25 cents for a half pint, is sterile when you have finished making it and is completely non-toxic. The ingredients are available in many developing countries, not to mention the US. It is edible. It is not particularly bacteriostatic, though it could be made bacteriostatic with a little EDTA (but then it wouldn't be edible). It is probably best made and used for a couple or 3 days, then discarded if unused, though I kept some in a clean bottle at room temperature and it was stable and smelled fresh for over a week.
It is quite thick, like regular ultrasound gel, so it is a bit of a trick to get it into a squeeze bottle. A large bore funnel works, or the cooled gel can be squeezed into the bottle out of the cut end of a plastic bag. It can also be kept in a jar and used with a spoon.
This is kind of exciting. Now I will no longer be dependent on ultrasound gel manufacturers. If I was in Haiti, either I or someone at the house where I was staying could make up a batch of this the night before clinic and I would have fresh clean ultrasound gel with which I could be generous in my scans. The water wouldn't even have to be sterile since the stuff is boiled when it is made. Let there now be ultrasound in places that Amazon.com does not reach!
Here's a YouTube video of how to do it.
**This article has been very popular and readers have left all sorts of new good ideas as comments. In order to make good ultrasound gel it is really only necessary to have some kind of a powder that, when mixed with water, creates a mostly transparent gel which clings to the ultrasound transducer. Polysaccharides are good for this, and guar gum is one of the least expensive that is available worldwide. A reader, however, just told me that he used glucomannan powder in a proportion of 1/2 teaspoon to a cup of water. I just tried it and it is EVEN BETTER THAN GUAR GUM. It, like guar gum, is a thickener and emulsifier, it is used by dieters to decrease appetite and is safe both topically and internally. It is available online and probably in health food sections of grocery stores as a dietary supplement. Glucommanan is a cell wall component of many plants, including the roots of the Konjac plant. Unlike guar gum it does not clump and can be mixed in cold water then allowed to thicken over a few minutes. If it is mixed into boiling water its texture is smoother than when it is made with cold water, and of course it is also sterile, which is very useful. It is almost completely clear, has no flavor or smell and leaves very little residue. Thank you commenter who goes by the name "addedupon"!
***Recently an article has come out in PLOS 1 looking at making gel with different kinds of flour-type substances readily available in markets in resource poor settings. They recommend using cassava flour which is actually the same thing as tapioca flour. The problem with this gel is that it is very glue-like and when I tried to wipe it and even wash it off of my skin, the remaining residue was very uncomfortable. When I have done ultrasound in Africa there is usually nothing available except maybe some flimsy toilet paper to wipe ultrasound gel off of the patient. It is certainly worth experimenting with different combinations (they also mention sorghum flour which sounds promising) but it is important to use them on yourself to see what they feel like when they are incompletely wiped off, as is the usual case.
Ultrasound requires an aqueous interface between the transducer and the skin or else all you see is black. Ultrasound gel is a clear goo, looks like hair gel or aloe vera, and is made by several companies out of various combinations of propylene glycol, glycerine, perfume, dyes, phenoxyethanol or carbapol R 940 polymer along with lots of water. It is hard to find this information, but it is available in the material data safety sheets for the various companies that make it. The recipes are proprietary. Ultrasound gel is not super expensive, but it is not that easy to find in a store or in a developing country. It costs about $25 for 5 liters on Amazon, or $5 for a nice 8.7 oz squeeze bottle. It smells ever so slightly medicinal and leaves a sticky, then dry white residue as it dries.
There should really be some sort of powder that you mix up with water that makes ultrasound gel so we don't have to be shipping the water part of it, which is undoubtedly about 99% of the contents, long distances. But there isn't a powder. I have been looking. No instant ultrasound gel.
With a mixture of optimism and singularity of purpose I went to the kitchen and tried out 6 different recipes for an aqueous goo that would transmit sound waves. I thought that I could make ultrasound jam out of water and pectin, but that doesn't really work. Obviously there is something magic about fruit that makes pectin gel, maybe the acid or the sugar. Without fruit, even no-sugar pectin becomes about the consistency of spit. (I also tried spit, which does work, but has various obvious drawbacks.) I tried plain gelatin and water and got beautiful clear jello, which falls off the transducer, but kind of works, but is also messy. I tried corn starch and water, as if making extremely boring gravy. That was lovely and white, but the water wants to come out of it so it just slides off the transducer. I tried tapioca flour which I boiled with water, producing a nice clear, very mucoid gel which dries like glue on the skin and is very uncomfortable. I tried xanthan gum, a bacterial polysaccharide used to bind and thicken, boiled and cooled, and although it thickens the water it is slimy and falls off the transducer and makes a mess.
The recipe that worked (and worked great) is guar gum, salt and water. Guar gum has been used for a very long time in countries like India and Pakistan to thicken food and is now used often by people who can't eat gluten, to thicken gravies and make breads. Guar gum is the ground endosperm of the guar bean, which is very rich in a carbohydrate that avidly absorbs water. Guar beans are also eaten green and the pods are used as a vegetable ingredient after shelling out the beans. Guar gum is available in the flour section of many grocery stores and costs about $10 for a 220 gram bag. It is purported to be good for diarrhea, constipation, diabetes and lowering cholesterol. It has been added to infant tube feed formula in intensive care units to decrease stool frequency.
I messed with the recipe awhile and came up with a very nice slightly caramel tinged ultrasound gel this way:
1. Mix 2 teaspoons of guar gum with 1-2 teaspoons of salt. (The amount of salt isn't vitally important since it is just added to keep the guar gum from clumping. Using slightly less than a teaspoon of salt per 2 cups makes a gel with which is isotonic, which would be ideal for use near eyes or other mucus membranes or on open wounds).
2. Boil two cups of water.
3. Slowly sprinkle the guar gum/salt mixture into the boiling water while stirring vigorously with a fork or whisk.
4. Boil for about 1-2 minutes until thick and well mixed.
5. Cool before using. Save lives.
This is wonderful ultrasound gel (see photo above). I tried it and it works at least as well as the proprietary stuff, and probably doesn't dry out quite as fast. It wipes off easily and doesn't leave a sticky film. Even though it is not entirely transparent, there is no reduction in the quality of the ultrasound image compared with the standard clear ultrasound gel. It costs about 25 cents for a half pint, is sterile when you have finished making it and is completely non-toxic. The ingredients are available in many developing countries, not to mention the US. It is edible. It is not particularly bacteriostatic, though it could be made bacteriostatic with a little EDTA (but then it wouldn't be edible). It is probably best made and used for a couple or 3 days, then discarded if unused, though I kept some in a clean bottle at room temperature and it was stable and smelled fresh for over a week.
It is quite thick, like regular ultrasound gel, so it is a bit of a trick to get it into a squeeze bottle. A large bore funnel works, or the cooled gel can be squeezed into the bottle out of the cut end of a plastic bag. It can also be kept in a jar and used with a spoon.
This is kind of exciting. Now I will no longer be dependent on ultrasound gel manufacturers. If I was in Haiti, either I or someone at the house where I was staying could make up a batch of this the night before clinic and I would have fresh clean ultrasound gel with which I could be generous in my scans. The water wouldn't even have to be sterile since the stuff is boiled when it is made. Let there now be ultrasound in places that Amazon.com does not reach!
Here's a YouTube video of how to do it.
**This article has been very popular and readers have left all sorts of new good ideas as comments. In order to make good ultrasound gel it is really only necessary to have some kind of a powder that, when mixed with water, creates a mostly transparent gel which clings to the ultrasound transducer. Polysaccharides are good for this, and guar gum is one of the least expensive that is available worldwide. A reader, however, just told me that he used glucomannan powder in a proportion of 1/2 teaspoon to a cup of water. I just tried it and it is EVEN BETTER THAN GUAR GUM. It, like guar gum, is a thickener and emulsifier, it is used by dieters to decrease appetite and is safe both topically and internally. It is available online and probably in health food sections of grocery stores as a dietary supplement. Glucommanan is a cell wall component of many plants, including the roots of the Konjac plant. Unlike guar gum it does not clump and can be mixed in cold water then allowed to thicken over a few minutes. If it is mixed into boiling water its texture is smoother than when it is made with cold water, and of course it is also sterile, which is very useful. It is almost completely clear, has no flavor or smell and leaves very little residue. Thank you commenter who goes by the name "addedupon"!
***Recently an article has come out in PLOS 1 looking at making gel with different kinds of flour-type substances readily available in markets in resource poor settings. They recommend using cassava flour which is actually the same thing as tapioca flour. The problem with this gel is that it is very glue-like and when I tried to wipe it and even wash it off of my skin, the remaining residue was very uncomfortable. When I have done ultrasound in Africa there is usually nothing available except maybe some flimsy toilet paper to wipe ultrasound gel off of the patient. It is certainly worth experimenting with different combinations (they also mention sorghum flour which sounds promising) but it is important to use them on yourself to see what they feel like when they are incompletely wiped off, as is the usual case.
Comments
I work in East Timor as an obstetrician with very limited resources. I have been using water instead of ultrasound gel for my obstetric scans , with very poor results. Today I managed to source some guar gum from Australia and make my own gel and it was fantastic! Thank you so much for the advice
THANK YOU! I am a researcher, but not an expert in US gel, trying to develop a new simple hybrid optical-ultrasound method to detect and monitor TBI. Your article was very very helpful.
I really appreciate the work you did and the post here to serve as a starting place for people like me. Can you tell me if you have any experience with how long a batch of guar gum gel might last at room temperature before things start growing in it or it becomes a microbial hazard?
You.Are.Awesome.
Mix the guar gum with vegetable glycerin (just enough to wet it) before adding to the water (which can be room temperature which takes care of the issue of boiled water). This will prevent the gum from forming into balls and you don't need to blend it as much. If you do get air bubbles in your gel, just smack the container on your open palm and the bubbles will work themselves up to the surface. Glycerin is also a preservative to a limited degree, but should make the gel last a bit longer. I've never made ultra sound gel, just lots of other natural product, fyi.
why not use commonly available hand sanitizer gel? it's definitely not going to go sour, although you wouldn't want to get it in your eye. the active gelling ingredient is carbomer, a common cosmetic ingredient also used in aloe vera gel and hair gel. it also contains 50% alcohol and glycerin.
Thank you very much for this fabulous idea!
Would vaseline work? Could you try it and post your results? Thanks!
I tried using glucomannan powder (Puritan's Pride on Amazon) in Chad, Africa this past few weeks. 2 tsp per 2 cups water. The thickness is good because it doesn't run off the sides of a hot pregnant abdomen too easily.
I added the 1 tsp salt and then for a preservative I added 1/2 tsp boric acid (antibacterial and anti fungal) because everything gets infected here (110 degrees right now). So far so good.
I had no problem getting it into the dispensing bottle because I poured it from the sauce pan into the bottle fairly soon after all ingredients had gone into solution.
I did have bubbles as mentioned by our traveling resident but they did not interfere with imaging as I believe they are squished to the side by the application of the probe to the skin.
I estimate my cost of the two cups at just over 32 cents (US).
Apart from being allergic to formalin and denatured alcohol, I am, as MaryAnn Malecki, allergic to "something else" in ultrasound gel. After some exchanges with one manufacturer, propylene glycol seems to be the culprit. It appears that PG-free ultrasound gel can be found in the USA and Canada but not in Europe where I live.
I read your 2013 article with relief. I am about to make an appointment for a pregnancy ultrasound and will try your solution (hoping the ultrasound practitioner will accept). Before doing so, I have a couple of questions: you mention that after testing glucomannan, it works better because it is not clumsy. Glucomannan can be found under the name Konjac. I however noticed that Konjac products are not 100% Glucomannan but rather 80%. Is this a problem? Do you also add salt to Glucomannan or is this only for Guar gum?
And my 2 other questions are for my potentially skeptical or scared ultrasound practitioner: a) Over a scale of 100, 100 representing the screen clearness of an ultrasound performed using one of the main manufacturers gel, how would you rate your receipt? b) Do you think this home made gel (because of salt of whatever) could damage the ultrasound transducer?
One last very naive question to the practitioner you are: do you think that doing an ultrasound (with a regular gel) not directly on the skin but on a food plastic wrap placed on the skin could work?
Thanking you from France for your help!
https://www.bcfultrasound.com/product/ultrasound-gel-powder/