Co-Washing: What It Is, How to Do It & Who It's For

What Is Co-Washing?

Co-washing — short for "conditioner washing" or "conditioner-only washing" — is a hair cleansing method that replaces sulfate shampoo with a silicone-free conditioner product. Instead of lathering up with a detergent-based shampoo, you apply conditioner directly to your scalp, massage it in like a shampoo, and rinse.

The method is a central pillar of the Curly Girl Method and has been discussed in the peer-reviewed literature. A 2019 review in Skin Appendage Disorders (published in PubMed Central) specifically examined the pros and cons of cleansing conditioners and confirmed their mechanism: these products primarily use cetyl alcohol — a fatty, nonionic surfactant — as the cleansing agent, rather than anionic sulfate surfactants. Cetyl alcohol has "very low cleansing ability" relative to sulfates, which is precisely why co-washing is gentle; it lifts only light buildup rather than stripping all scalp oils.

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How Co-Washing Works: The Science

Standard shampoos rely on anionic surfactants (sulfates) that aggressively reduce the surface tension between water and oil, emulsifying sebum and pulling it off the scalp and hair shaft. This is effective but indiscriminate — sulfates remove all surface lipids, including those that maintain the hair's hydrophobicity and softness.

Co-wash products rely on nonionic surfactants — primarily cetyl alcohol, stearyl alcohol, and sometimes added cationic conditioners — that interact more gently with scalp oils. They provide enough surface-active action to lift light buildup and sweat residue, but leave behind enough natural lipid to maintain softness and shine.

This trade-off makes co-washing suitable for hair that:

• Produces relatively little sebum (curly and coily hair types, which have difficulty distributing scalp oil along the curl's path)
• Is chronically dry or prone to frizz from sulfate stripping
• Is not exposed to heavy silicone product buildup between washes

And less suitable for hair that:

• Produces significant sebum (oily scalp types)
• Uses heavy non-water-soluble silicone styling products
• Needs stronger cleansing after exercise, swimming, or environmental exposure

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Who Should Co-Wash

Co-washing is best suited to:

The AAD advises that people with curly hair should choose "a moisturizing shampoo formulated for curly hair" when washing, and recommends washing "a minimum of every 2 to 3 weeks" for coily hair. Co-washing can be used in between those washes — or as the primary cleanse for those with very dry curl types.

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How to Co-Wash: Step-by-Step

See the steps below for the complete technique. Co-washing is not the same as conditioning — the scalp massage and distribution method are specific.

What You Need

• A silicone-free co-wash product (labeled "cleansing conditioner" or "co-wash"). Look for products that list cetyl alcohol, cocamidopropyl betaine, or sodium lauroyl methyl isethionate early in the ingredients — these provide the mild cleansing action. Avoid products with dimethicone, cyclopentasiloxane, or any ingredient ending in "-cone" unless it is PEG-modified (water-soluble).
• Warm water — slightly warm water helps open the cuticle and allows the surfactants to work more effectively.
• A regular silicone-free conditioner for post-cleanse conditioning (separate from the co-wash product).

Common Mistakes

• Using a standard conditioner instead of a co-wash product: Regular conditioners do not contain enough surfactant to cleanse. You need a product specifically formulated as a "cleansing conditioner" or "co-wash."
• Applying to dry hair: Co-washing works with water-solubilized surfactants — the product must be applied to soaking-wet hair and scalp.
• Only applying mid-shaft: The scalp is where cleansing is needed. Skipping the scalp massage defeats the purpose.
• Not rinsing thoroughly: Co-wash residue left on the scalp contributes to the buildup problem the method is meant to avoid.
• Never clarifying: Without occasional clarifying, co-washing gradually accumulates product residue under the cuticle scales.

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Choosing a Co-Wash Product

Look for these marker ingredients:

Good surfactant choices in co-wash products:

• Cetyl alcohol / cetearyl alcohol (primary nonionic surfactant)
• Cocamidopropyl betaine (mild amphoteric, adds lather)
• Sodium lauroyl methyl isethionate (gentle anionic)
• Disodium laureth sulfosuccinate (gentle anionic)

Ingredients to avoid in co-wash products:

• Dimethicone, cyclopentasiloxane, cyclomethicone (non-water-soluble silicones — build up without sulfate removal)
• Petrolatum, mineral oil (same build-up problem; require strong surfactants to remove)

Beneficial conditioning ingredients in co-wash:

• Glycerin, aloe vera juice (humectants)
• Shea butter (emollient, suits high-porosity hair)
• Hydrolyzed proteins (strengthen cuticle — use in moderation)

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Co-Washing Schedule

Finding the right frequency is personal and depends on scalp oiliness, activity level, and curl type:

• Type 4 coils, dry scalp: Co-wash every 7–14 days; deep condition with every wash; clarify monthly
• Type 3 curls, normal scalp: Co-wash every 5–10 days; clarify every 4–6 weeks
• Type 2C tight waves, normal scalp: Co-wash every 5–7 days or alternate co-wash with low-poo; clarify monthly
• Any type with oily scalp: Co-wash is insufficient as the only cleansing method — see CGM for oily scalp for a tailored approach

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The Buildup Problem: Why Clarifying Matters

The 2019 Skin Appendage Disorders review explicitly warns that co-washing "may lead to buildup due to residues under the cuticle scales." Hair with extreme buildup can develop "an oily and dull appearance" and dermatoscopic examination may show pseudo-casts and a plica cosmetica (a fold or coating along the shaft).

This is co-washing's primary drawback, and the fix is periodic clarifying — typically every 4–6 weeks — with a gentle sulfate-based or clarifying shampoo. A single clarifying wash removes accumulated buildup without setting back the moisture progress you have built with co-washing.

Some CGM practitioners use an apple cider vinegar (ACV) rinse (1–2 tablespoons diluted in 1 cup water, applied after cleansing, left for 1–2 minutes before rinsing) as a lighter alternative to a full clarifying shampoo between deep clarifying sessions. ACV's acidity (pH approximately 3.0) helps close the cuticle and can dissolve some mineral and product deposits.

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Co-Washing vs. Other Cleansing Methods

For a full comparison of co-washing and low-poo, see Low-Poo vs. Co-Wash. In brief:

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How Co-Washing Fits Into a Full CGM Routine

Co-washing is the cleansing step in a CGM routine, followed by:

1. Rinse-out conditioner (apply post-co-wash for added conditioning, then rinse)
2. Leave-in conditioner (applied to soaking-wet hair before styling)
3. Styling product — gel or cream applied to dripping wet hair

The full routine is detailed in the Curly Girl Method guide.