What gives Shave Cream/Soap its lube properties?

In my quest to find good soaps/creams that are good for me, I am trying different kinds that have different ingredients. But is there one ingredient that stands out (more than others) that gives the product its lubricating properties? Or is it a combination of ingredients?

i.e. - tallow
glycerin
glycerin & ??? & ???
??? & ???, etc...

The one thing all creams and soaps have in common is, soap. Soaps are long molecules which stick strongly to both oils and water, this means that they will coat your skin easily and hold lots of water next to your skin to lubricate and cushion it. This is why modern gels and things don't really offer anything extra, when you get down to the basic chemistry soap is pretty much the ideal thing for the job.
The only major difference between different products are the types of oil used to make a soap, such as tallow (derived from animal fat) or any of the many different plant oils. Minor differences are the ratios of different types of soap. And there are other chemicals which may be added as an addition to soap, things like glycerine, or oils, or scents, or preservatives etc. But these are just personal preference, there is not one of these things that makes a difference for everyone.

What has me curious is that some creams/soaps will lubricate better than others and I am wondering what "chemical" is causing that or is it a chemical that is more pronounced in one product over another?
For example with EJ Sea Buckthorn SOAP has Glycerin as their 7th ingredient whereas TOBS Sandalwood SOAP, glycerin is the 5th ingredient. Not that I am stating that Glycerin is the main lube property; just wondering if the order of the ingredients is what makes one soap lube better than others. Of course a person's skin type plays a big role in this question also.

The Soph Gent said:

What has me curious is that some creams/soaps will lubricate better than others and I am wondering what "chemical" is causing that or is it a chemical that is more pronounced in one product over another?
For example with EJ Sea Buckthorn SOAP has Glycerin as their 7th ingredient whereas TOBS Sandalwood SOAP, glycerin is the 5th ingredient. Not that I am stating that Glycerin is the main lube property; just wondering if the order of the ingredients is what makes one soap lube better than others. Of course a person's skin type plays a big role in this question also.

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I don't think you will find any one "magical" ingredient. Beyond the ingredients is also HOW the soap is produced. The process (cold vs. hot, temperature, aging/drying/milling) will all affect the final product. I would go as far as to say that the processing and attention to detail probably affect the final product MORE than the ingredients themselves (within reason - using LARD - pig fat, or primarily olive oil, will NOT give a good shave lather), but when good quality, shaving soap "appropriate" ingredients are used, the manufacturing technique will account for a LOT of the properties of the final product.

The Soph Gent said:

What has me curious is that some creams/soaps will lubricate better than others and I am wondering what "chemical" is causing that or is it a chemical that is more pronounced in one product over another?

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It's impossible to say. The soap itself does most of the work, and hence has the most impact on the difference between different soaps. First of all there are a lot of different soaps which the product might be made from, for example there is stearic acid, oleic acid, palmitic acid and many others. Most products contain a blend of these, and the ratio of each product may effect performance. But remember that many products do not list these in the ingredients, they just list the source (i.e. tallow/palm oil etc.)
Also, not only the ratio of these chemicals but the purity will affect it as well. Two different soaps might both use the exact same ingredients, but get the ingredients from different places, and because things like tallow are from natural sources the actual composition can vary much more than a product synthesised in a laboratory.


You will never be able to find the right soap for you like this. The approach you should take is to group products by similarity rather than by specific ingredients. First choose between soaps or creams, then by glycerine or non glycerine. It means you have to try lots of different things but there isn't really a better way.

Cogwulf said:

It's impossible to say. The soap itself does most of the work, and hence has the most impact on the difference between different soaps. First of all there are a lot of different soaps which the product might be made from, for example there is stearic acid, oleic acid, palmitic acid and many others. Most products contain a blend of these, and the ratio of each product may effect performance. But remember that many products do not list these in the ingredients, they just list the source (i.e. tallow/palm oil etc.)
Also, not only the ratio of these chemicals but the purity will affect it as well. Two different soaps might both use the exact same ingredients, but get the ingredients from different places, and because things like tallow are from natural sources the actual composition can vary much more than a product synthesised in a laboratory.

You will never be able to find the right soap for you like this. The approach you should take is to group products by similarity rather than by specific ingredients. First choose between soaps or creams, then by glycerine or non glycerine. It means you have to try lots of different things but there isn't really a better way.

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I think you are right. Also, there is so much hype and advertising and cult following for the big names that personal experience of the category variety is the best idea. The same thing for brushes, for that matter, and probably razors and blades, too. (I've been shaving with Feathers mostly for a few weeks, and this morning tried a Derby. Now I remember why I stopped using the Derby.) Over time, your personal preferences surface, and the bottom line is what works, looks, and feels best on your skin that day. Accumulate a number of those days and you have the winner(s).

I would say some soaps and or creams have more glycerine added..some have less
Tallow=beef fat
MWF=sheeps fat

I don't think there is any single factor. The mechanics of dragging a sharp piece of metal over our face are too complicated. There's too many ways in which friction operates, and several other things we perceive as "smooth".

If shaving were as simple as in Mechanics 101 class, we'd simply use silicon or some other oil and be done with it. There are also atomic-level forces at work, where chemistry and properties such as wetting and adhesion (of the soap to skin) becomes important. Another factor is that the face isn't smooth. This causes the blade to hop and dig in. On the dips, the force "into" or perpendicular (normal force) with the skin increases, which increases the dragging friction. The cutting aspect of this digging-in also feels like a tugging, so while this aspect isn't technically friction, the distinction isn't really important for how a shave feels. One way to lower the friction on these surfaces is to fill in the gaps with a more or less viscous material, such as thick oil, gel, paste, or foam. Foams, particularly of soaps, have peculiar friction properties by themselves. Much like toothpaste, the viscosity of soap foam drops as you move faster. This means the friction is lower when you move faster. On the other hand, the friction or opposing force of cutting hair increses as you cut faster. And those factors don't quite complete the survey.

A few things do seem clear to me. Shaving is pretty complicated. Depending on one preference or choice, a person might come to an entirely different approach to shaving. When it comes to the shaving foam, one person might prefer a very thick tallow lather, while another might prefer a lighter, wetter foam laced with siicon particles. They might even change their preference in foam depending on how much hair is on the face. I know I do--preferring a wetter lather for later passes.

Isn't the magic ingredient just water?
I think I remember seeing a documentary on TV were they stated that water is the best lubricant there is, and shaving creams and soaps are just a way to make a thick layer of water stick to your face!
Makes sense to me.

Google 'superfatting' as a technique in soapmaking.

Water's a good lubricant for a very few things. It's good for cells inside the body, against earthquakes, and in certain kinds of turbine engines. It's pretty bad to completely useless for other things.

smalltank said:

I would say some soaps and or creams have more glycerine added..some have less
Tallow=beef fat
MWF=sheeps fat

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You sure about that? I was under the impression that Mitchell's Wool Fat = tallow soap + lanolin (aka "wool fat") rather than "sheep fat". However, on further investigation, tallow is a generic term that can include both beef fat and sheep fat, as well as others. that being said, I believe that beef tallow is more common than sheep tallow, so would be more likely in the soap.

That make any sense to anyone but me?

Isn't the magic ingredient just water?
.....and you still have VERY bright scientest working on just that. Water as a molecule is one complicated liquid...er, gas, solid..water tension...never mind.