Updated: Feb 10, 2022
What makes a bar of soap special? The way it smells; the way it looks; the feel of it in your palms as it lathers and turns; how it leaves your skin feeling when you’ve put it away and dried your hands.
Its power to clean things makes soap very special indeed. Soap molecules are made of two parts: shaped like a pin, they have a hydrophilic (simply, water loving) ‘head’, and a hydrophobic (water hating) ‘tail’ which bonds with oils and fats (lipid molecules) and is repelled by water.
Soap works by bonding with the oils on your skin that dirt and germs have mixed in or stuck to, and also bonding to the water that the soap molecules are suspended in.
The need to either bond with or avoid water is so strong that soap molecules can destroy the types of viruses and bacteria which have a lipid membrane, wedging their tails into and breaking the membrane apart but keeping the pieces in the water, so that when you then rinse your hands, the pieces are washed away. This is why the simple act of washing your hands thoroughly is such an important part of fighting the spread of the Corona virus, and why it continues to be the foundation of personal hygiene and health.
The main purpose of soap is to clean, and your skin should look and feel clean when you’re done using it, but it shouldn’t feel tight and dry. While washing away dirt, soap shouldn’t also strip away all the natural oils in your skin which protect it and keep it healthy, by maintaining its acid mantle (skin is naturally slightly acidic) and sebum layer, which forms a barrier locking in your skin’s natural moisture.
Standard soaps have a different pH to skin, being more alkaline, and this breaks down the acid mantle, leading to dryness. Most soaps also contain some levels of surfactants, but these harsh additives (the most recognisable being Sodium laurel sulphate and Sodium laureth ether sulfate) while great for your washing, make soaps over efficient and encourage the soap molecules to bond with oils deeper in the sebum layer, breaking it down.
I say ‘standard’ and ‘most’ because there are soaps that are closer to the natural pH of skin, and which don’t contain chemical additives. These, of course, are homemade, artisan bar soaps with a short list of easy-to-understand ingredients, that clean because of their nature and don’t need additives to make them more efficient.
People who make small batch, artisan soaps don’t put any thing in them that they wouldn’t use on their own skin, and so you can be sure that what you’re getting is good for you. The natural oils and butters that go into handmade soaps put back the moisture that is lost through the cleaning process, and are often chosen for their nourishing properties, which are not lost in the process of soap making.
Adding to those benefits are other skin-friendly ingredients, including botanicals such as seaweed, flower petals and herbs, fruits and vegetables (carrot, cucumber, raspberry powder), and natural colourants like clays.
If your skin feels uncomfortable, tight and dry after washing your hands or bathing, you should consider changing your soap, not only for what it doesn’t contain, but for what it does.