pediaNatural soap is a cleaning product formed through the saponification reaction of vegetable oils with sodium hydroxide (NaOH) or potassium hydroxide (KOH), and it is not based on synthetic detergents. However, the term “natural soap” has no official definition in either Turkish legislation or EU regulations (EC/1223/2009)—a situation that allows the term to be used in various ways in marketing. This article examines what natural soap is and is not from the perspectives of ingredients, production methods, and legislation.
This article is intended for general informational purposes only. It does not contain any product promotion or therapeutic claims.
Saponification reaction: the chemistry of soap
Chemically, soap is the alkali salts of fatty acids. In production, vegetable or animal fats react with a strong base (NaOH—for bar soap; KOH—for liquid soap). This reaction is called saponification, and it results in two products: soap (fatty acid salts) and glycerin.
If we simplify the saponification equation:
Fat + NaOH → Soap + Glycerin
This reaction is irreversible—meaning the soap formed does not revert back to fat and alkali. When the reaction is complete, no free alkali (NaOH) remains in a properly calculated recipe; the fats are completely converted into soap, and natural glycerin is formed as a byproduct.
Glycerin: Soap’s Hidden Value
The glycerin formed during saponification is a natural humectant (moisture-attracting agent). In industrial soap production, this glycerin is typically separated out and sold at a higher price to the cosmetics industry. In cold-process soaps, however, the glycerin remains in the soap’s structure—this is the main reason why handmade soaps feel “more moisturizing.”
What “natural soap” is not?
To understand the concept of “natural soap,” it’s helpful to first clarify what it is not.
Detergent-based cleansers (syndet bars)
A significant portion of the products sold as “soap” on store shelves are not actually soap, but synthetic detergent-based cleansers (syndet = synthetic detergent). Instead of saponification, these products contain synthetic surfactants (typically Sodium Lauryl Sulfate — SLS, Sodium Laureth Sulfate — SLES, or Sodium Cocoyl Isethionate — SCI). Technically, they are not “soap” but are classified as “cleansing bars.”
The Limits of the “Natural” Label
A critical point: The term “natural” has no official definition in cosmetic regulations. Neither the EU Cosmetics Regulation (EC/1223/2009) nor the Turkish Cosmetics Regulation has established a legal definition or certification criteria for “natural soap.” This situation opens the door to the broad—and sometimes misleading—use of the term “natural” in marketing. Labeling a product as “natural” does not necessarily mean that all of its ingredients are of natural origin.
Independent Certifications for “Natural” Claims
To fill this definitional gap, independent certification bodies have stepped in: COSMOS (Cosmetic Organic and Natural Standard — Ecocert/Soil Association), NATRUE, BDIH, and USDA Organic. These certifications establish standards for “natural” and “organic” cosmetics—including permitted and prohibited ingredients, production methods, and labeling rules. However, obtaining these certifications is not mandatory and can be costly for many small-scale manufacturers.
Soap-making methods: Which is “more natural”?
The soap-making method directly affects the characteristics of the final product. The main methods are:
Cold process (CP)
Oils and an alkali solution are mixed at low temperatures (30–50°C), poured into molds, and left to cure for 4–6 weeks. The saponification reaction is completed in the mold and during the curing process. Glycerin remains in the soap. Essential oils and delicate ingredients are better preserved thanks to the low temperature. This is the most commonly used method for handmade natural soaps.
Hot Process (HP)
The reaction is accelerated by heating the oils and lye solution (typically to 60–80°C). Saponification is completed within a few hours. The curing time is shorter. The texture may be coarser and more rustic. The traditional kettle-cooking method (Aleppo soap, bıttım soap) falls into this category.
Melt-and-pour method (MP)
A ready-made soap base is melted, fragrance and color are added, and the mixture is poured into molds. Saponification is not performed by the manufacturer—a factory-produced base is used. Technically, this is not “soap making” but “soap shaping.” The bases may often contain synthetic surfactants (such as SLS).
Industrial continuous process
Production takes place in large factories at high pressure and temperature in continuous-flow reactors. Glycerin is separated out. Synthetic fragrances, colors, and preservatives may be added. Costs are low, and production capacity is high.
What should you look for when evaluating natural soap?
1. The INCI (ingredient list)
The most reliable starting point is the product’s INCI (International Nomenclature of Cosmetic Ingredients) list. The EU Cosmetics Regulation and the Turkish Cosmetics Regulation require that all cosmetic products display the “INCI” list on their labels. In the “INCI” list, ingredients are listed in order of concentration (from highest to lowest). In the INCI list for cold-process soaps, you will typically see the names of saponified oils such as “Sodium Olivate” (olive oil soap) and “Sodium Cocoate” (coconut oil soap).
2. Production Method Declaration
The manufacturer’s clear indication of the production method (cold process, hot process, etc.) is an important indicator of transparency. The term “handmade” alone does not define the method—melt-and-pour soaps can also be described as “handmade.”
3. Check for Synthetic Ingredients
If the INCI list includes synthetic ingredients such as SLS (Sodium Lauryl Sulfate), SLES (Sodium Laureth Sulfate), parabens (Methylparaben, Propylparaben), EDTA, and BHT appear on the INCI list, the product was likely not produced using the traditional saponification method or synthetic additives were added after production.
4. Source of Fragrance
The terms “Parfum” or “Fragrance” in the INCI list indicate the use of synthetic fragrance ingredients. For natural scents, you would expect to see the names of essential oils (e.g., Lavandula Angustifolia Oil, Melaleuca Alternifolia Leaf Oil). However, the term “Parfum” may sometimes be used for blends of natural essential oils as well—in such cases, you should refer to the manufacturer’s statement.
5. Color Source
Natural colorants: clay (kaolin — white, bentonite — gray, kaolin + iron oxide — pink), plant powders (turmeric — yellow, cocoa — brown, spirulina — green), activated carbon (black). Synthetic colorants: indicated by FD&C or CI numbers (CI 77891—titanium dioxide—is an exception; most are synthetic).
Natural Soap and Skin: Expectations and Realities
The pH Issue
All true soaps (products of saponification) are naturally alkaline in pH—typically in the pH 9–10 range. This is higher than the skin’s natural pH (4.5–5.5). The terms “pH-balanced soap” or “soap compatible with the skin’s pH” are technically not applicable to saponification products—these terms generally apply to syndet (synthetic detergent) bars. Healthy skin restores a temporary pH increase to the normal range within a short time (15–30 minutes) (“acid mantle restoration”).
Moisturizing Expectations
The primary function of soap is to cleanse—not to moisturize. However, in cold-process soaps, the natural glycerin content, the superfat (unsaponified oil) ratio, and the profile of the oils used directly affect how “tight” or “soft” the skin feels after washing. Therefore, the term “moisturizing soap” should be understood to mean that the soap does not actively moisturize the skin, but rather removes less of the skin’s natural moisture during cleansing.
“Natural ≠ safe”
An important note: “natural” does not automatically mean “safe” or “hypoallergenic.” Essential oils are powerful bioactive compounds and carry allergenic potential. Plant extracts can trigger contact dermatitis. Hazelnut oil may cause a reaction in individuals with tree nut allergies. When choosing a natural soap, it is recommended to check the list at INCI, be aware of your own allergy profile, and perform a patch test on a small area of skin when using a new product for the first time.
Regulatory Perspective: Turkey and the EU
In Turkey, soap is regulated under the Cosmetics Regulation. All cosmetic products (including soap) must be reported through the Ministry of Health’s ÜBİS (Product Notification System). The EU Cosmetics Regulation (EC/1223/2009) establishes mandatory labeling, the list of INCI, safety assessments (CPSR), and lists of prohibited and restricted ingredients (Annexes II–VI). This regulation does not provide a separate definition for “natural” or “organic”—this gap is filled by independent standards such as COSMOS and NATRUE.
Frequently Asked Questions
What is natural soap?
Natural soap is a cleaning product produced by the saponification reaction of vegetable oils with NaOH or KOH, and it is not based on synthetic detergents. However, the term “natural” does not have an official definition in the regulations.
What is the difference between natural soap and industrial soap?
Key differences include: production method (handmade cold/hot process vs. factory continuous process), glycerin content (retained in natural soap, separated in industrial soap), ingredient profile (plant-based vs. synthetic additives), and curing time.
Does natural soap have a high pH?
Yes—all true soaps naturally have an alkaline pH (9–10). This is a natural result of the saponification process. Healthy skin restores this temporary pH increase to normal within 15–30 minutes.
Is the term “natural soap” legally protected?
No—neither EU regulations nor Turkish legislation provide an official definition for “natural soap.” This gap is filled by independent certification standards such as COSMOS and NATRUE.
Is natural soap safe for everyone?
“Natural” does not automatically mean “safe” or “hypoallergenic.” Essential oils and plant extracts carry allergenic potential. It is recommended to check the list at INCI and test new products on a small area of skin.
References
1. EU Regulation (EC) No 1223/2009 of the European Parliament and of the Council on cosmetic products.
2. Turkish Cosmetics Regulation — Ministry of Health of the Republic of Turkey.
3. Spitz, L. (2009). Soap Manufacturing Technology. AOCS Press.
4. Cavitch, S. M. (1997). The Natural Soap Book. Storey Publishing.
5. COSMOS Standard — Cosmetic Organic and Natural Standard. cosmos-standard.org
6. Dunn, K. M. (2010). Scientific Soapmaking. Clavicula Press. doi:10.1007/978-3-319-52134-6