Sulfate free or salt free shampoo? Which one is better?

A shampoo can be sulfate-free but still contain sodium chloride, or be SLS/SLES-free while still using other cleansing agents such as sulfonates. A shampoo’s harshness is not determined by one ingredient alone. Performance depends on:

• total surfactant system and concentration
• pH
• conditioning agents
• polymers
• oils
• formulation balance.

A well-formulated sulfate shampoo can feel gentler than a poorly formulated sulfate-free shampoo. Likewise, some sulfate-free shampoos can still, depending on the alternative surfactants used:

• fade colour
• dry hair
• or cause irritation

Quick comparison

Claim	What It Excludes	Main Consumer Benefit
Sulfate-Free	All sulfate surfactants	Gentler cleansing, colour protection
SLS/SLES-Free	Only SLS and SLES	Avoids the harshest/common sulfates
Sodium Chloride-Free	Salt (NaCl)	Better for keratin, dry or treated hair

Why this matters for different hair types

	Best choice	Reason
Colour treated hair	Sulfate-free, preferably low foam and mild	Reduces colour stripping and helps toner last longer
Keratin / Smoothing Treatments	Sodium chloride-free, ideally sulfate-free too	Salt and strong surfactants can shorten treatment longevity
Oily hair	SLS/SLES free but with other mild sulfates or sulfonates	They remove oil more effectively, provide more foam for a deep clean feel.
Curly, dry or bleached hair	Sulfate-free with low detergent strength, with added moisturizing agents.

This is why an ingredient list analysis matters more than front-label claims.

Sulfate-free shampoo

A sulfate-free shampoo does not contain sulfate-based surfactants. Surfactants are cleansing agents known for strong foaming and deep cleansing.  Common sulfates include:

• Sodium Lauryl Sulfate (SLS)
• Sodium Laureth Sulfate (SLES)
• Ammonium Lauryl Sulfate
• Ammonium Laureth Sulfate

These ingredients are effective cleansers but can sometimes:

• Strip natural oils
• Fade hair colour faster
• Increase dryness or frizz
• Irritate sensitive scalps

So, to claim that a shampoo is sulfate-free, manufacturers sometimes use substituting ingredients such as Sulfonates.  Sulfonates are not technically sulfate but can still cleanse strongly and be very harsh on the hair and hair colour.

SLS/SLES-free shampoo

This means the shampoo does not contain 2 very specific sulfates:

• Sodium Lauryl Sulfate (SLS)
• Sodium Laureth Sulfate (SLES)

However, the formula may still contain other sulfates, sulfonates or other strong cleansing agents. So a shampoo can be SLS/SLES-free, but not truly mild. For example: A shampoo containing Sodium C14-16 Olefin Sulfonate could legally claim:

• “SLS-free”
• “SLES-free”
• sometimes even “sulfate-free”

but it may still cleanse quite aggressively.

“SLS/SLES-free” is often used for marketing to reassure consumers, or when brands want to avoid the most controversial sulfates specifically.

Sodium chloride-free shampoo

Sodium Chloride is simply salt.  In shampoo, it is commonly used as a thickener, to adjust viscosity, and sometimes to stabilize formulas. It can:

• Contribute to dryness in some hair types
• Reduce longevity of certain smoothing treatments
• Affect keratin-treated hair
• Potentially increase colour fading in highly processed hair

So, Sodium chloride-free shampoos are best for:

• Keratin-treated hair
• Chemically straightened hair
• Highly bleached hair
• Extensions
• Very dry or porous hair

Click here for a table containing a list of our shampoos, indicating for each whether they are sulfate, SLS/SLES or salt free.