Difference between Soap and Detergent

Often used in our daily lives as cleansing products, yet we don’t always know which one is best to use. By simply knowing their differences, you may have just improved your lifestyle.


Soap vs Detergent
All-natural soaps taken out from their molds

Soap – Soap as we all know it, is mainly used as surfactants (Surface Active Agents) for washing, cleaning, and bathing.  It is also used in textile spinning and is also considered to be an important component in lubricants. Soap can be made by treating vegetable or animal’s oils and fats with an alkaline solution called lye (liquid obtained by leaching ashes, or a strong alkali which is highly soluble in water). That being said, it is a naturally-made surfactant that is softer and less harsh on the skin than detergents.

Processes in Creating Soaps

  • Cold Process – With this process, soaps are made by cooling the lye solution to room temperature before adding the necessary oils. The oils are then melted and eventually cooled down to between 80° – 110° F (depending on the recipe formulation). The lye solution and oils will then be combined together and mixed until mixture thickens. Once the mixture has reached ‘trace’ (thickening of the mixture), other necessary ingredients (scent, color, herbs, etc.) are added to the mixture. Finally, the mixture is poured into molds for it to solidify.
  • Hot Process – With this process, the lye solution and oils are mixed together and then heated by an outside source to keep the temperature up. Also, it helps reduce the time required to finish the chemical process called saponification (chemical reaction of fat and sodium hydroxide). As with the cold process, the liquid soap produced will then be poured into molds and cool and become solidified.

Note: Soaps can be made either in liquid or solid form.

Detergent bars that have taken the shape of their molds

Detergent – Detergent is a surfactant with ‘cleaning properties in dilute solutions’. It is mostly known for washing clothes, and other uses such as a fuel additive and biological reagent. Detergent is a compound similar to soap, but is more soluble in water due to the other chemical reactions involved in the process. Like soaps, detergent also comes in liquid or solid form.

Classification of Detergents

  • Anionic Detergents – Typically a chemical compound called alkylbenzenesulfonates, with two varieties of alkyl groups (Branched and Linear).
  • Cationic Detergents – Similar to anionic ones, but having its quaternary ammonium as the polar end instead of the anionic sulfonate.
  • Non-ionic and Zwitterionic Detergents – These are based on polyoxyethelene or a glycoside and are characterized by their uncharged, hydrophilic headgroups.

Soap vs Detergent

What’s the difference between soap and detergent? While both may seem somewhat similar as both are cleaning surfactants, one would be of better use to specific uses than the other.

With their chemical differences, it does seem to be a bit complicated. A better way of putting it would be that ‘soaps’ are made out of naturally found alkalis, while  ‘detergents’ are synthetic (although some of their ingredients are natural). This would also imply that soaps are better used in bathing, hand-washing, or any cleaning/washing that involves the human body, simply because the ingredients are natural. It is also said that soap is much better for the environment than detergents. This is because detergents contain chemicals that are very toxic to wildlife, especially fish.

Common Soap ingredients: Palm kernelate, olivate, cocoate, tallowate, sodium or potassium palmate.

Common Detergent ingredients: Lauramide DEA, sodium cocoyl isethionate, disodium laureth sulfosuccinate, sodium olefin sulfonate, sodium laureth sulfate, sodium lauryl glucosides hydroxypropyl sulfonate.

Comparison Chart

Soap Detergent
Made from  natural ingredients Made from synthetic ingredients
Softer and less harsh on skin May cause mild to severe skin reactions
Recommended for bathing and washing part of the body Recommended for clothes, tiles, and other non-body surfaces
Won’t affect the environment Can be toxic to wildlife
Cheaper Usually costly
Requires more water on rinsing laundries Requires less water on rinsing laundries


Check out this interesting and fun video if you want to know more on how soap works.