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Sodium cocoyl isethionate (SCI) cleansing bar OEM/ODM manufacturing
Sodium Cocoyl Isethionate (SCI) Cleansing Bar · Syndet Bar · OEM/ODM
Sodium cocoyl isethionate (INCI: Sodium Cocoyl Isethionate, SCI) is an ester of coconut fatty acids with sodium isethionate, a synthetic anionic surfactant that, according to Sun et al. (2003), had been the predominant ingredient of syndet bars for more than thirty years. A "syndet" (synthetic detergent) bar uses synthetic surfactants instead of soap: soap is the alkaline salt of fatty acids made when oils react with alkali, so its solution is always alkaline, whereas a syndet bar can be adjusted to neutral. What needs to be said plainly: "can be" does not mean "is". In a survey measuring 10% solutions, 8 of 14 syndet bars on the market were still alkaline and none was acidic (Khan et al., 2024). On mildness, in repeated tests on people SCI irritated less than SLS, but a sulfosuccinate ranked lower than SCI, and the CIR Expert Panel concluded that isethionate salts are safe "when formulated to be nonirritating". This page therefore focuses on what is specific to an SCI facial bar: solid raw material forms and dust at weighing, the binder framework of the bar, a mix – mill – extrude process that has to be set on pilot batches, pH measured on the bar itself, wear, mush and cracking in use, and claim limits. Handmade soap and the anhydrous body lotion bar have their own pages. Butter-C offers turnkey OEM/ODM manufacturing, from formula development and testing to labeled finished goods and the notification dossier.
Formula base
SCI as the framework, with a binder phase and fillers
A syndet bar has no water as a solvent the way a liquid cleanser does, so surfactant makes up a much larger share of the bar and a "binder – plasticizer" phase is needed to turn surfactant powder into a solid block. The sources read give no standard use level for SCI (the abstract of the 2017 CIR report states no concentrations), so every level below is set by test batches and calculated as % active from the COA.
Sodium Cocoyl Isethionate: primary surfactant and "framework" of the bar
Commercial material is solid: powder, flakes, granules or noodles; active content follows each grade's technical data sheet, and the INCI label lists every component of the raw material according to its COA. SCI is a mixture of fatty acid chain lengths, so it has no single molecular formula (CAS 61789-32-0). Its water solubility is limited (Sun et al., 2003): in a bar this makes it dissolve gradually, but it can leave undissolved particles when washing with cold water.
Fatty binder – plasticizer phase
Stearic Acid, Cetearyl Alcohol, optionally Butyrospermum Parkii Butter: they melt and recrystallize to bind the surfactant particles, make the mass plastic enough for extrusion and slow down wear; too much reduces lather (formulation experience). The fatty acid is kept in its free form: if it is neutralized with alkali, that part becomes soap and the bar becomes a "combar" (combination bar), no longer a pure syndet.
Fillers
Zea Mays Starch or Oryza Sativa Starch, Kaolin: add bulk and adjust hardness. In a crossover hand-washing trial in 72 healthy volunteers, the syndet bar with more wheat starch caused less itching and redness (Korting et al., 1992), but the two bars differed in SCI, sulfosuccinate and starch at the same time, so the role of starch alone cannot be isolated. Natural powders carry a microbial load: require a microbiology COA for each batch; wheat starch contains gluten, so it is used only with your agreement and the correct INCI.
Humectants, secondary surfactants
Glycerin plasticizes the mass and reduces cracking, but it attracts moisture: too much makes the bar mushy and "sweat" in hot, humid climates. Liquid Cocamidopropyl Betaine can be added to tune lather, but it brings in water and softens the bar, so its level is limited by bar hardness (formulation experience).
pH adjustment, preservation
Citric Acid brings the bar solution pH into the agreed range (measured at a fixed dilution). A syndet bar usually has a near-neutral pH (it still has to be measured) and relies mainly on low water activity to limit microbes, so whether a preservative is needed is decided by a written microbiological risk assessment for each formula (ISO 29621 framework); if one is needed, it must be listed in ASEAN Annex VI.
Key technical points
Five things specific to an SCI facial bar
These are the points where a syndet bar differs from both a liquid cleanser and a soap bar; each is settled with raw material documents or tests on samples.
Syndet is not soap, and it does not automatically have "skin pH"
Soap is the alkaline salt of fatty acids, so its solution is alkaline: all 37 soaps in the survey by Khan et al. (2024) were highly alkaline. Isethionate-based syndet bars can be formulated at neutral pH (review by Petter, 1984; the author worked for a surfactant manufacturer), yet the same survey found 6 of 14 syndet bars neutral, 8 alkaline and none acidic; 9 bars labeled "balanced" measured neutral in 6 and alkaline in 3. The abstract does not name each bar's surfactants, so the results are not attributed to SCI specifically: pH must be measured on the bar itself.
pH within the stable range of the ester bond
Isethionates are prone to hydrolysis at high (> 8) or low (< 5) pH (Petter, 1984); hydrolysis splits the ester into fatty acid and isethionate. The finished product pH is set within the stability range stated by the supplier and confirmed by stability testing, measured in a solution prepared at a fixed ratio written into the method (the Khan survey used 10% solutions). A lower pH is not automatically milder; see the reasoning on the amino acid facial cleanser page.
Shaping: mix – mill – extrude – cut – stamp, set on pilot batches
The usual route for syndet bars is heated mixing so the binder phase melts and wets the particles, milling through several rolls to homogenize, extrusion through a vacuum chamber to remove air, then cutting billets and stamping the shape (practical knowledge). We have not found published extrusion parameters for syndet bars, so temperatures, speeds and pressures come from raw material and equipment suppliers' documents and are set on pilot batches; before accepting an order, Butter-C confirms suitable bar-forming equipment for the specific formula. The same formula can give different bars on two lines, so batch records capture temperatures, number of milling passes and vacuum level.
Lather, wear, mush and cracking: defects specific to bars
A bar that dissolves too slowly gives little lather and a squeaky feel; one that dissolves too fast is used up quickly. Lots of humectant, a porous bar and hot water increase wear; a bar left in a puddle develops a mushy surface; wet – dry cycles and deep stamped patterns cause cracks (formulation experience). Because SCI solubility is limited, lather and leftover particles are tested at the actual water temperature of the target market.
Dust during weighing and mixing
We have not found respiratory data on SCI dust in PubMed (ingredient article, searched 25/10/2026); surfactant powder is still handled as a dust source: prefer granules, noodles or flakes over fine powder, weigh under local exhaust ventilation, charge into a closed mixer, and give workers respiratory protection, goggles and gloves. Dust control is also cross-contamination control between batches.
Three formulation directions
Three types of SCI facial bar
Basic syndet bar
SCI as the framework, Stearic Acid and Cetearyl Alcohol as binders, corn or rice starch as filler, little glycerin; an opaque, firm bar with creamy lather. For normal and combination skin; fragrance-free for a short ingredient list.
Syndet bar with a fatty conditioning phase
Add Butyrospermum Parkii Butter and slightly more fatty phase for a softer after-wash feel; excess fat reduces lather and slows dissolution, so wear is rebalanced. A dry-skin positioning becomes "no tight feeling" only with sensory testing of the finished product.
Combination bar with soap (combar), only if you accept it
Part soap combined with SCI gives faster lather at lower cost (formulation experience); pH is intermediate between soap and syndet depending on the soap share (background knowledge, measured on the finished product), so the product can no longer be described as "soap-free". Sodium and potassium hydroxide have their own entry in ASEAN Annex III (Ref 15a, use as pH adjuster: pH < 11), with no specific entry for soap; how it applies is confirmed by the regulatory team when the dossier is prepared. This page defaults to a pure syndet.
Packaging and tray are designed with the formula
A paper box needs a bar surface dry enough that oil and fragrance do not seep through; shrink film keeps moisture in better, but a glycerin-rich bar "sweats" easily in a sealed wrap. A draining tray can be included, or directions printed to let the bar drain between uses.
Parameters we monitor
What our R&D lab measures on every sample
These are the parameters Butter-C monitors during formula development and scale-up. Most are in-house methods for solid formats; specific limits are agreed with you on the approved sample and then written into the product's in-house specification.
- Appearance & cross-section
- Color, odor, pattern, cracks, spots; the bar is cut across to check the core for air holes or layering, against a retained reference sample.
- Weight & moisture
- Each bar weighed; moisture or loss on drying under fixed conditions, linked to hardness, mush and microbial risk. Bars lose weight as they dry over time, so the labeled weight is fixed after the stabilization period.
- Bar solution pH
- Measured in a solution prepared at the fixed ratio written into the method, 25°C; only results at the same ratio are comparable. Tracked across stability time points because the SCI ester bond hydrolyzes outside its stable pH range.
- Hardness or breaking force
- Needle penetration or breaking force at a fixed sample temperature and time after production; used to compare batches.
- Wear, mush, cracking
- Wear: the bar is rotated in water a standardized number of times, dried and weighed. Mush: part of the bar is soaked for a fixed time, the soft layer scraped off and weighed. Cracking: soak – dry cycles to an in-house protocol, photographed.
- Lather
- Foam height and stability of a solution at a fixed ratio, in water of specified hardness, at the expected use temperature; with sensory assessment.
- Moisture uptake & stability
- Unwrapped samples stored at high relative humidity to check "sweating" and a sticky surface; samples in commercial packaging stored at several temperatures and humidities, tracking appearance, weight, hardness, pH and odor.
- Microbiology & raw material COA
- Microbiological testing at a GLP / ISO 17025-accredited laboratory; a written microbiological risk assessment, with a challenge test when the assessment cannot rule out risk. The SCI COA states form, % active and pH; starch and kaolin COAs state microbiology and heavy metals.
- Skin tolerance & eye irritation
- Tolerance testing on volunteers before claiming "gentle" or "no tight feeling"; the ingredient article found no eye data specific to SCI, so eye irritation is assessed on the finished product if any eye-related wording is wanted.
Claims
Claims for an SCI facial bar
A facial bar is a rinse-off product; SCI is a surfactant, not a skin-conditioning ingredient. Evidence for SCI mildness is limited: the micelle-size mechanism is an in vitro study on pig skin (Ghosh & Blankschtein, 2007); on people, the irritancy ranking changed with the test method (Tupker et al., 1999: one-time occlusive test scored visually, soap ≥ SLS ≥ SCI; repeated tests, SLS > SCI ≥ soap; the sulfosuccinate ranked below SCI in every method); data on syndet bars belong to the whole formula. Appendix 03-MP of Circular 06/2011/TT-BYT lists claims that go beyond cosmetic scope; Butter-C reviews label and marketing wording when preparing the notification dossier.
Cleanses dirt and excess sebum from facial skin
Instead of: skin detox, deep pore cleansing, claims to act on bacteria.
Soap-free syndet facial bar; sulfate-free (ingredient description)
"Soap-free" only when the formula contains no fatty acid salts; "sulfate-free" only when it contains no alkyl sulfates or alkyl ether sulfates. Instead of: sulfate-free and therefore gentle, "toxic sulfates", chemical-free.
Bar pH (state the figure and dilution when measured on the finished product)
Instead of: pH-balanced, pH 5.5, physiological pH without measurement; many syndet bars on the market are still alkaline.
Gentle cleansing, no tight feeling (with finished-product test results)
Instead of: the gentlest, non-irritating, non-drying, gentle for every skin type, for sensitive skin without testing.
Creamy, fine lather (once lather and sensory feel are measured); surfactant based on coconut fatty acids (source description)
Instead of: skin-nourishing lather, coconut extract, all-natural; SCI is the product of a chemical reaction.
Warnings and directions
Avoid contact with eyes; if contact occurs, rinse immediately with plenty of water; stop use if redness, itching or burning occurs. Let the bar drain on a draining tray between uses and do not share it (practical directions). People with damaged skin or a history of irritation from cleansers should consult a dermatologist; pregnancy and breastfeeding: not enough data, ask a doctor if in doubt. Instead of: safe for every skin, suitable for children.
Manufacturing specifications
How we proceed
- Formats
- Syndet bar based on sodium cocoyl isethionate; combination bar with soap (combar) on request.
- Shaping
- Depends on equipment and order size: the usual route is mix – mill – extrude – cut – stamp; suitable bar-forming equipment is confirmed and parameters are set on pilot batches of the specific formula before an order is accepted and production is quoted.
- Pack types
- Square, rectangular, oval or custom-shaped bars; weight fixed when the mold is made. Paper box, shrink film, optional draining tray.
- Minimum order quantity
- Agreed per order, depending on the mold, pack type and pilot batch results.
- Testing
- Tested at a GLP / ISO 17025-accredited laboratory, with a certificate of analysis for every batch.
- Documentation
- Product Information File (PIF) and cosmetic product notification dossier prepared by Butter-C, with the SCI raw material COA stating form and % active, and the microbiological risk assessment.
- Packaging
- Label design, printing and packing run in parallel with formula development.
Suggested product concept
Fragrance-free SCI syndet facial bar for normal and combination skin
A concept to help you picture the product, not a ready-made product for sale. The actual formula is built around your brand positioning and price range.
Granular or noodle SCI as the framework
A low-dust grade; % active from the COA; "soap-free" and "sulfate-free" can be stated as ingredient descriptions.
Stearic Acid, Cetearyl Alcohol, corn starch
Binder phase and filler set by wear, mush and hardness tests on pilot batches.
Solution pH measured and recorded
Set within the hydrolysis-stable range of SCI; the figure goes on the label only once measured on the finished product.
Fragrance-free, paper box printed with directions to let the bar drain
Fragrance-free removes one source of allergens from the ingredient list and avoids softening the bar; draining directions reduce mush and wear.
Customization options
What you can specify
The same product type can target very different customers. Tell us your requirements in the areas below and our pharmacists will build the formula accordingly.
Lather level and bar life
Quick lather or a long-lasting bar: the two pull in opposite directions and are balanced through the binder, filler and humectant levels.
Filler
Corn starch, rice starch or kaolin; wheat starch only if you accept an ingredient list that contains gluten.
Fatty conditioning phase
Shea butter or plant oils for a softer after-wash feel; liquid oils soften the bar, so hardness and wear are retested.
Fragrance and color
Fragrance-free or lightly scented; liquid fragrance softens the bar and can cause "sweating"; colorants from the ASEAN colorant list, and water-soluble colors bleed when the bar is wet.
Shape and logo stamping
A mold to your brand's design; deeply stamped patterns or lettering crack easily, so wet – dry cycling is tested before the mold is fixed.
Cleansing set
Paired with a liquid facial cleanser (for example based on sodium cocoyl glycinate or amino acid surfactants) for users not used to bars; each product has its own dossier and tests.
Further reading
Related knowledge
Sodium cocoyl isethionate (SCI) in cosmetics
Powder forms, solubility, pH and hydrolysis, mildness data, the CIR conclusion and ASEAN regulation (in Vietnamese).
Classification of foaming agents
The four surfactant classes and why "sulfate-free" is not automatically mild (in Vietnamese).
Sodium lauryl sulfate (SLS) in cosmetics
The anionic surfactant often used as the irritancy benchmark in studies on SCI (in Vietnamese).
Handmade soap OEM/ODM manufacturing
Soap bars made by saponification: different chemistry from a syndet bar, alkaline pH.
Facial cleanser OEM/ODM manufacturing
General principles of surfactant systems, conditioning phase and pH; this page focuses on the SCI bar format.
Solid body lotion bar OEM/ODM manufacturing
An anhydrous leave-on bar, not a cleanser: entirely different formula and claims.
How we work
From idea to finished batch
Eight steps and three milestones signed off by both sides: approved sample, notification number, finished batch. Step-by-step details →
Get started
Tell us about the product you plan to launch
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