Natural soap: what it is, what’s in it and how to choose

The EU Cosmetics Regulation (EC) No 1223/2009 does not define ‘natural’. Claims must still be truthful, supported and not misleading under Regulation (EU) No 655/2013, so a soap sold as natural should be able to justify the word.

Two reference points help to put the term into context:

• ISO 16128 sets out how to calculate the share of natural and naturally derived ingredients in a formula. It is a calculation guideline, not a seal or a certification.
• Private standards such as COSMOS or NATRUE define their own rules for natural and organic cosmetics and certify products that meet them.

Without either, ‘natural’ describes a concept rather than a checked standard. That is not a problem in itself – it simply means the label deserves a closer look.

Typical building blocks of natural soap bars:

• Oils and butters: olive, coconut, shea, castor or palm oil. Each gives the bar different properties – coconut oil lathers quickly, olive oil gives a dense, mild-feeling lather.
• Alkali: sodium hydroxide for bars, potassium hydroxide for soft and liquid soaps.
• Water, most of which evaporates while the soap matures.
• Optional additions: fragrance (‘Parfum’) or essential oils, plant extracts, clays, colourants such as iron oxides.

A label might read Sodium Olivate, Sodium Cocoate, Aqua, Glycerin, Parfum, Limonene. Fragrance allergens such as Limonene or Linalool must be named above set concentrations. How olive oil soap in particular is made, matured and classified is covered in our olive oil soap guide.

Glycerin is a natural by-product of saponification. In cold-process soap it remains in the bar; in some industrial production it is separated off and sold on.

Transparent glycerin soaps are a different product. To make them clear and meltable, manufacturers add ingredients such as sorbitol, propylene glycol, sugar or alcohol, and some bases also contain surfactants such as Sodium Laureth Sulfate. That does not make them bad, but it changes the character of a soap sold as ‘natural’.

The INCI list shows which type you are holding.

Whether soap feels drying depends on the skin, the water hardness and the formula. The alkaline pH of soap and how it reacts with hard water are explained in detail in our olive oil soap guide, so here are just the practical points:

• Natural soap for face: lukewarm water, a little lather, rinse thoroughly and follow with a cream.
• Body: a bar is an alternative to a natural shower gel. Both clean the skin; the choice is mostly about feel, scent and packaging.
• Fragrance: unscented bars contain fewer potential allergens than heavily scented ones.

Cosmetics do not treat skin conditions. If you have eczema, acne or psoriasis, ask a doctor or pharmacist which cleanser is right for you.

‘Natural soap and shampoo’ is a common search, and two different products sit behind it:

• Soap-based hair bars are saponified oils, just like body soap. In soft water they can work well; in hard water insoluble calcium soaps form, which can make hair feel heavy and look dull. Some users follow with an acidic rinse, such as diluted cider vinegar.
• Solid shampoo bars are often not soap at all but compressed mild surfactants such as Sodium Cocoyl Isethionate, with a pH closer to that of skin.

For regular hair washing, a liquid or solid natural shampoo made for the purpose is usually the more practical choice. 2-in-1 bars for body and hair exist, but they are a compromise for travel or camping rather than an everyday solution.

Products sold as ‘natural soap for men’ usually differ in three ways:

• Scent: rosemary, cedarwood, vetiver or citrus instead of floral notes. Unscented bars suit everyone.
• Shaving soap: formulated for a dense, stable lather, often with stearic acid and a mix of sodium and potassium soaps. It is used with a brush and is not the same as a body bar.
• Beard and body: a mild bar can clean the beard; a beard oil or a lotion afterwards keeps the skin underneath comfortable.

Soap is also a classic gift, often paired with a shower gel or body lotion – see our natural skincare gift sets.

Real soap cannot be made without lye: sodium or potassium hydroxide reacts with the oils and is used up in a correctly made bar. Phrases such as ‘chemical-free’ or ‘no additives’ are marketing language, not a legal category.

More useful questions when buying natural soap bars:

• Is it saponified soap (Sodium Olivate, Sodium Cocoate …) or a base with synthetic surfactants?
• Does it contain fragrance (‘Parfum’), and which allergens are declared?
• Are there colourants (CI numbers) or preservatives?
• Are the manufacturer’s or Responsible Person’s name and address on the pack?

Specific ‘free from’ statements such as ‘without fragrance’ are helpful when they are true and do not disparage other products. Our guide to reading an INCI list explains the order and names on the label.

We do not publish recipes, but two points are worth knowing before you start:

• Safety: a lye solution heats up strongly, gives off fumes and must be kept away from children and pets. Fresh soap is still caustic and needs several weeks to mature before use.
• Selling: handmade soap sold in the EU must comply with Regulation (EC) No 1223/2009 – a Responsible Person, a cosmetic product safety report by a qualified assessor, notification in the CPNP portal, good manufacturing practice and complete labelling. This applies to small makers too.

If you want soap under your own brand without your own production, you can work with an established manufacturer instead. Seda Pura offers olive oil soap for wholesale and private label; details are provided on request.