Soap vs Detergents

by Catherine Haug, January 28, 2011

At the suggestion of our audience (at our recent gathering on Making Soaps at Home, with Kathy Mansfield), I promised to write a post on how to tell a soap from a detergent on an ingredient list.

2015 update: I just found a very helpful website, regarding deciphering the ingredient list on personal and body-care products: Terre Essentials: Ingredient Guide (for personal and body-care products).


Soaps are made from fats and oils, which are made up of fatty acids and glycerol (glycerine). Typical fats include tallow, suet, and shea butter; typical oils include olive oil, coconut oil, and palm oil.  Examples of fatty acids include lauric, stearic and palmitic acids. (see my post, Fats for Soapmaking for more).

Soaps are naturally antimicrobial and do not require the addition of preservatives.

Many soaps lather well, are non-drying, and some are moisturizing. Soap doesn’t rinse away as well as one would like, but an acidic rinse (diluted vinegar or lemon juice) resolves that problem.

Soaps can exchange minerals with those in hard water, creating calcium or magnesium soaps, for example, which are insoluble in water and leave a “soap ring.”

(* NOTE: there can be soaps of other minerals, for example calcium laurate, but these are not soluble in water and precipitate out (think soap ring), so are not used in manufacture of soap).

Soap names

Soap names are relatively simple and do not require abbreviations (like TEA, DEA, EDTA or PCA) in their name. To be a soap, its name is always two words:

  • the first being a mineral: ‘sodium’ or ‘potassium’ * and
  • the second being the derivation from the fatty acid, ending in ‘ate’. The part before the ‘ate’ is the ‘root’ name of the fatty acid. For example, a soap from lauric acid is called sodium laurate.

NOTE: the ‘sodium’ could be ‘potassium’ or vice versa; the fatty or fatty acid root is in blue:

  • sodium laurate (from lauric acid, such as from coconut oil or goats milk)
  • potassium myristate (from myristic acid, such as from coconut oil)
  • sodium palmitate  (from palmitic acid, such as from palm oil)
  • potassium stearate (from stearic acid)
  • sodium linoleate (from linoleic acid, such as from olive oil)
  • potassium cocoate (from all the fatty acids in coconut oil)
  • sodium tallowate (from all the fatty acids in tallow, or beef/sheep fat)

Soap products don’t usually list the specific fatty acid names on the label, because they are made from the whole fat comprised of many different fatty acids. Instead, they will say something like “saponified coconut oil and palm oil”, or “tallowate” indicating it is a soap of all the oils in tallow.


Detergents can be related to soaps, but are a much broader class of surfactants (surface cleansers). They are not necessarily antimicrobial and so often contain preservatives.

Most detergents lather very well, but are drying, and non-moisturizing; the application of moisturizer after using detergents on hair, scalp and skin is recommended. Detergents are more soluble in water than soaps, and rinse away better than soap. They do not typically form insoluble scum, even in hard water – the main reason why they have become popular.

Unlike soaps, detergents are not typically made from the whole fat but rather fatty acids synthesized from petroleum. Detergents and their additives are often toxic and cause sensitivity problems, both on the skin and internally.

You cannot make most detergents in your kitchen; the process requires high heat and pressure that can be obtained only in an industrial setting.

Detergent names

The names of individual detergent substances may also include the root of the fatty acid name in the ingredient, but their names are more complex (more than 2 words, or include abbreviations). For example (the root is in blue):

  • sodium laureth sulfate
  • lauramide DEA
  • cocoamide DEA
  • TEA cocyl glutamate (note, the ‘glutamate’ is from glutamic acid, which is an amino acid, not a fatty acid)
  • cocamidopropyl betaine (‘cocamid’ is an amide of all the fatty acids in coconut oil, but is not a soap)
  • Sodium cocoyl isethionate
  • Sodium laurylglucosides hydroxypropylsulfonate
  • Sodium Lauroyl sarcosinate
  • sodium PCA (sodium pyrrolidone carboxylate); even tho carboxylate would indicate a soap, the insertion of the pyrrolidone, which is not a fatty acid, makes this something else. It is a humectant (moisturizing agent) in skin, but is likely made synthetically and may be an endocrine disrupter.

Sample soaps and shampoos, and their ingredients

To learn more about individual ingredients and their toxicity, refer to the Environmental Working Group website on cosmetic ingredients: (Thanks to Kathy Mansfield for this link).

Locally-Made Handcrafted products

Grizzly Mountain Soaps (from Polson, MT) contains superfatted soaps and scents:

  • Pure buffalo tallow
  • Mountain river water
  • Coconut oil
  • sodium hydroxide
  • scent
  • olive oil

Snowbunny Lemon Verbena Soap (from Kalispell, MT) contains superfatted soaps and scent (superfatting simply means adding more fat than needed to react with the alkali):

  • superfatted olive and coconut oils
  • saponified shea butter (shea butter soap)
  • essential oil
  • lemon verbena

Commercial products

Keligreen Laundry Detergent: (Montana Made)

  • Distilled water
  • Tea tree and castile soap
  • Plant-based solubilizer
  • Plant-based surfactants
  • Aluminum-free baking soda
  • Citric acid
  • Sea salt.

Dr Bronner’s Pure Castile Soap (liquid soap), contains soaps that are pH balanced with citric acid and preserved with vitamin E:

  • Water
  • Saponified Organic Coconut (fair trade)
  • Organic Palm Oil (fair trade)
  • Organic Olive Oil w/Retained Glycerin (fair trade),
  • Organic Hemp Oil,
  • Organic Jojoba Oil
  • Essential Oils
  • Citric Acid
  • Vitamin E

Kirk’s Original Coco Castile bar soap contains true soap and other natural ingredients:

  • Coconut soap
  • Water
  • Coconut oil
  • Vegetable glycerine (from fats)
  • Natural fragrance

Bee & Flower Chinese Soap bar contains true soap and other ingredients (from eVitamin This was my preferred soap, until handcrafted soaps became widely available:

  • Tallow & Vegetable Oil (78% min)
  • Perfume (1.58-2.50% min)
  • Free Alkali (0.05% max)
  • Sodium Choride (0.7% max) [refined table salt]
  • EDTA-4Na & EHDP (0.06% max) [a synthetic amino acid that allows other ingredients to penetrate the skin into the blood stream]
  • Pigment (trace)
  • Moisture (balance)

Grisi Donkey’s Milk Moisturizing bar soap contains soaps, detergent and other ingredients:

  • sodium tallowate (a soap from beef or sheep tallow)
  • sodium cocoate (a soap from coconut oil)
  • zea mais (corn) starch
  • sodium lauryl sulfate (a detergent, known as SLS, usually made from petroleum)
  • mineral oil (from petroleum)
  • beeswax (from bee hives)
  • shea butter
  • fragrance
  • decyl glucoside (non-ionic surfactant – not a soap)
  • tetrasodium EDTA (known toxic salt of a synthetic amino acid that allows other ingredients to penetrate the skin into the blood stream)
  • milk
  • titanium dioxide (a pigment)
  • citric acid (used to balance pH)

Softsoap (R), a liquid handsoap

  • water
  • sodium C14-18 olefin sulfonate (detergent)
  • lauramid DEA (detergent)
  • Glycol stearate (an ester -neither soap nor detergent, with some toxicity)
  • sodium chloride (table salt)
  • cocamidopropyl betaine (detergent)
  • citric acid (pH balancer)
  • fragrance
  • DMDM hydantoin (antimicrobial, works by releasing formaldehyde)
  • polyquaternium-7 (antimicrobial)
  • aloe barbadensis leaf juice
  • tetrasodium EDTA (known toxic salt of a synthetic amino acid that allows other ingredients to penetrate the skin into the blood stream)
  • glycerin
  • dydrolyzed silk (protein)

Avalon Organics Shampoo (liquid shampoo) contains detergents, botanicals, natural fragrances, protein and preservatives

  • Aqua (Water),
  • Aloe Barbadensis Leaf Juice,
  • Cocamidopropyl Betaine (a detergent)
  • Sodium Laurylglucosides Hydroxypropylsulfonate (a detergent)
  • Glycerin
  • Sodium Cocoyl Isethionate (a detergent)
  • Stearic Acid (fatty acid)
  • Sodium Lauroyl Sarcosinate (a detergent)
  • Various flower, resin, peel, and root extracts (depends on specific shampoo)
  • Arginine (an amino acid)
  • Bisabolol (a natural alcohol)
  • Hydrolyzed Wheat Protein
  • Sodium Citrate
  • Sodium PCA (moisturizing agent and may be an endocrine disrupter)
  • Panthenol (a provitamin of B5)
  • Tocopheryl Acetate (synthetic vitamin E)
  • Guar Hydroxypropyltrimonium Chloride, a salt made from guar gum, is used as a conditioner
  • Alcohol
  • Benzyl Alcohol (a preservative)
  • Potassium Sorbate (a preservative)
  • Sodium Benzoate (a preservative, that, when combined with citric acid/citrate included above, forms benzene, a known carcinogen)
  • Coumarin, Limonene, and Linalool (natural fragrances)

Trader Joe’s Herbal Shampoo (liquid shampoo) contains detergents, botanicals, protein, carbohydrate, fragrance, preservatives, and pH balanced with citric acid

  • Extracts of various flowers and herbs
  • sodium laureth sulfate (SLS, a detergent)
  • sodium lauryl sarconsinate (a detergent)
  • cocamidopropyl betaine (a detergent)
  • cocoamide DEA (a detergent)
  • inositol (a carbohydrate)
  • hydrolyzed wheat protein
  • wheat germ oil
  • annato (natural color, from anchiote tree)
  • citric acid
  • methylparaben and proplyparaben (preservatives known to have estrogenic activity and may be carcinogenic)
  • diazolidnyl urea (a preservative that works by releasing formaldehyde, and may be allergenic)
  • fragrance

See also:

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