Sulfate-free shampoos now occupy a significant share of the hair care market. The category grew substantially after concerns about sodium lauryl sulphate (SLS) and sodium laureth sulphate (SLES) entered mainstream awareness. But "sulfate-free" describes what a product does not contain, not what it does. The relevant question is: what do the sulfates get replaced with, and does that replacement clean effectively?
What Sulphates Do
Sulphates, SLS and SLES, re anionic surfactants that have been the dominant cleansing agents in shampoo for decades. They work by reducing surface tension between water and oil, allowing sebum, product residue, and environmental deposits to be lifted from the hair and scalp and rinsed away.
They are highly effective cleansers, produce abundant lather, and are inexpensive to formulate with. They are also relatively harsh: SLS in particular can strip the scalp's acid mantle, disrupt the skin barrier, and cause irritation in sensitive individuals. SLES is milder than SLS but still classified as a moderate irritant for some scalp types.
Both are derived from petrochemical or palm oil sources and are excluded from the COSMOS standard on the basis of origin and processing requirements.
What Replaces Sulphates in Certified Natural Formulas
The performance of a sulfate-free shampoo depends entirely on which surfactants are used instead. The main alternatives used in COSMOS certified formulas include:
- Coco-glucoside and decyl glucoside, derived from coconut or corn glucose, gentle, low-irritation, biodegradable. Effective for normal to oily hair types.
- Sodium cocoyl glutamate, derived from coconut oil and glutamic acid, very mild, good for sensitive scalps.
- Sodium lauroyl sarcosinate, derived from lauric acid (coconut) and sarcosine (an amino acid), provides good lather and conditioning effect.
- Cocamidopropyl betaine, mphoteric surfactant from coconut oil, often used as a secondary surfactant to boost mildness and foam.
These surfactants clean effectively for the majority of hair types under normal washing conditions. The lather is typically less abundant than with SLS, foam is a cosmetic property, not a functional indicator of cleansing power, and the "squeaky clean" sensation after rinsing is usually absent, which some users initially interpret as inadequate cleansing.
Does It Actually Clean?
Yes, for most people under normal conditions. The surfactants used in quality sulfate-free formulas remove sebum, water-soluble product residue, and environmental particles effectively. They do this with lower irritation potential and without stripping the scalp's natural lipid layer as aggressively.
There are situations where mild sulfate-free surfactants may underperform compared to SLS-based shampoos:
- Heavy silicone or wax buildup from conventional products (a clarifying wash is needed first)
- Very high sebum production requiring more aggressive degreasing
- Hard water areas, where minerals can interfere with surfactant performance
For most people who are not using heavy silicone or wax products, the transition to sulfate-free shampoo produces effective cleansing with less scalp dryness and irritation.
The COSMOS Perspective
The COSMOS standard permits natural-derived surfactants that meet defined biodegradability and processing criteria. Petrochemical-derived sulphates are excluded on origin grounds. Palm-derived surfactants are permitted under COSMOS with sustainable sourcing requirements. All NUDA shampoos are formulated with COSMOS-approved surfactants, audited annually by ECOCERT.
Our BLOOM BATH Shampoo for fine hair and GLOSS BATH Shampoo for shine both use mild, coconut-derived certified surfactants rather than petrochemical SLS or SLES. For scalp-focused cleansing, DEEP MINT Scalp Scrub combines physical and chemical exfoliation. Full Volume and Body and Shine and Colour collections available.
Related reading
- Do COSMOS Certified Shampoos Contain Sulfates?
- How to Stop Colour-Treated Hair From Fading
- Silicones in Hair Care: What They Are and Why We Don't Use Them
- How to Get Glass Hair at Home
- Clarifying Shampoo: Do You Actually Need One?
Frequently Asked Questions
Will sulfate-free shampoo lather as much as regular shampoo?
Typically not. Lather volume is largely determined by the surfactant type and concentration. LS produces abundant foam, while milder glucoside-based surfactants produce less. Foam is a cosmetic property that affects perception but does not determine cleansing efficacy. A shampoo can clean effectively with minimal lather.
Do I need to wash more often with sulfate-free shampoo?
Not necessarily, though some people find their hair feels different initially. The scalp's sebum production adjusts to washing frequency and detergent strength over a period of weeks. Switching from aggressive SLS shampoos may cause a temporary adjustment period where sebum production feels higher before normalising to the milder cleansing routine.
Is sulfate-free the same as natural or organic?
No. "Sulfate-free" means the product does not contain sulphate surfactants, but says nothing about the rest of the formula. A sulfate-free product can still contain synthetic fragrances, silicones, PEGs, or other ingredients excluded from certified natural formulas. The claim describes one aspect of the formula, not the whole.
Can sulfate-free shampoo remove silicone buildup?
Generally not effectively. Silicones are hydrophobic and require stronger or sulphate-containing surfactants to break down. If you have significant silicone buildup from previous products, a clarifying wash with a stronger formula is typically needed before transitioning to a sulfate-free routine.
What is sodium laureth sulphate and is it different from sodium lauryl sulphate?
Yes. Sodium lauryl sulphate (SLS) is a more aggressive surfactant with higher irritation potential. Sodium laureth sulphate (SLES) is a milder version produced by ethoxylation of SLS, a process that makes it gentler but introduces ethylene oxide, a petrochemical byproduct, and potential trace contamination with 1,4-dioxane. Both are excluded from the COSMOS standard.