Co-washing gets recommended constantly for dry or curly hair, but the research on whether it actually helps a dry scalp is more mixed than the trend suggests. Here's what co washing actually does, what dermatologists and cosmetic chemists say about it, and whether it's worth trying.
What Is Co-Washing?
Co-washing, short for conditioner washing, means cleansing hair and scalp with conditioner instead of shampoo. It's also known as "conditioner-only washing" or the "no poo method" (as in, no shampoo). Rather than lathering with a detergent-based cleanser, co washing hair relies on the conditioner's emollients to lift away some dirt and buildup while depositing moisture at the same time.
It's important to understand that what is co washing hair really means using conditioner on the scalp itself, not just the lengths as with a normal routine. This distinction matters, since conditioners aren't designed the same way shampoos are.
The Case For Co-Washing on a Dry Scalp
Traditional shampoos rely on anionic surfactants (strong detergents) that clean thoroughly but can strip natural oils in the process. A gentler cowash formula avoids this stripping action, which is why it's become popular for co washing curly hair specifically, where natural sebum struggles to travel down the length of the strand in the first place. This is really the core of co washing's appeal for dry or textured hair types.
• Reduces exposure to harsh sulfates that can worsen dryness
• Helps maintain moisture and hair elasticity between washes
• May be gentler on a scalp already prone to irritation
The Case Against: What the Research Actually Says ?
A peer-reviewed paper published on NCBI, "Pro and Contra of Cleansing Conditioners", offers an important, more cautious take: co-washing is suitable mainly for people with minimal product buildup, and cleansing conditioners are "not adequate scalp cleansers for individuals who regularly use hairstyling silicone-based products." Critically, the paper notes there is no scientific data on how frequently co-washing should be used or how safe it is for scalp health long-term, a genuine evidence gap worth knowing about.
Cosmetic chemist and Director of Research at TRI Princeton, Trefor Evans, interviewed by Prose, is more blunt: "Cleansing conditioners really are just conditioners, but you can argue that they give you a little bit of cleansing, it really is just a little bit," he says. "If you don't cleanse your hair and your scalp, then all of a sudden there's all the sebum and product buildup." He recommends everyone lather up with a real shampoo at least once a week, regardless of hair type or texture.
So, Is Co-Washing Good for a Dry Scalp Specifically?
Whether is co washing good for dry hair too depends on the same balance. The honest answer is: it depends on how you use it. Curl expert Ona Diaz-Santin, also interviewed by Prose, offers a more balanced middle ground: "Co-washing is a great method to use in conjunction with shampooing. It allows moisture to remain in the hair and not over shampoo. However, it does not replace a gentle shampoo."
Her rule of thumb is genuinely useful: if hair is dry and lacking moisture, shampoo less often; if hair tends to be oily, over-co-washing will just make things greasier. Buildup of product, sebum, and not keeping the scalp genuinely clean can, over time, contribute to dryness, irritation, and even hair loss, so co-washing works best as a supplement to occasional real shampooing, not a full replacement for it.
If You Want to Try Co-Washing
BBLUNT does not currently sell a dedicated cleansing conditioner formulated for co washing specifically, so a regular conditioner like the Intense Moisture Conditioner (built around Jojoba Oil and Vitamin E) isn't a true substitute for co-washing, since regular conditioners aren't designed to cleanse the scalp the way even a mild cleansing conditioner is. If you're set on trying the method, treat it as an addition to your routine rather than a replacement:
• Lather up with a real, gentle shampoo at least once a week to clear buildup
• Co-wash on the days in between if your scalp tends to run dry
• Massage the scalp thoroughly during co-washing, not just the lengths
• Watch for signs of buildup: flatness, dullness, or a scalp that feels coated rather than clean
• If you notice increased flaking, itching, or shedding, scale back and see a dermatologist
Conclusion
Is co washing good for a dry scalp? In moderation, as part of a routine that still includes regular shampooing, it can help. Used as a complete replacement for shampoo indefinitely, the evidence and expert opinion both lean toward caution: buildup accumulates, and a co wash conditioner alone isn't designed to prevent that. The most balanced approach to co washing is doing it between washes, with a real, gentle shampoo at least once a week.
FAQs
What is co-washing?
Co-washing means cleansing hair and scalp with conditioner instead of shampoo, relying on its emollients rather than detergents to lift away some dirt and buildup.
Is co-washing good for a dry scalp?
It can help in moderation, since it avoids the stripping action of harsh sulfates, but experts recommend still shampooing at least once a week to prevent buildup.
How often should you co-wash?
There's no established scientific guideline, but most experts suggest co-washing between washes while shampooing with a gentle formula once a week.
Can co-washing replace shampoo completely?
Most experts advise against it long-term. Cleansing conditioners provide only light cleansing, and skipping shampoo entirely can lead to buildup, dryness, or irritation over time.
