Blue vs. Purple Shampoo: What’s The Difference?

Blue and purple shampoos aren’t your regular cleansers; they’re toning products meant to neutralize unwanted tones in your hair. When you step outside, sun exposure, chlorinated water, and even regular washing can turn your locks brassy or yellow. That’s where these formulas step in. Blue shampoos are crafted for brunettes to combat orange or red tones, while purple shampoos keep blonde hair from turning yellow or brassy.

Choosing between blue vs. purple shampoo depends largely on your hair color and the result you’re aiming for. It all boils down to basic color theory. On the color wheel, blue and purple sit opposite to orange and yellow, respectively, which means they can cancel out the unwanted tones when applied.

With an array of products flooding the market, making an informed choice can save your hair from potential damage. Ahead, we’ll take a deeper look into how these shampoos target different hair colors, the science involved, and how to use them effectively for vibrant, true-to-color locks.

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Meet the experts:

Rachel Valentine is a color specialist based in Wimbledon. She provides hair tips and tricks for everyone, including beginners and novices.

Sarab is a hair educator and licensed hair stylist based in Brampton. Across her social media platforms, she shares hair hacks and everyday styles that you can create in the comfort of your home or at a salon.

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Target Hair Colors

Blue shampoo, primarily aimed at brunettes, helps in neutralizing the brassy tones that often develop in brown hair over time. Whether it’s natural or dyed, brown hair can start showing unwanted red or orange hues due to various factors such as sun exposure or harsh water. By using blue shampoo, brunettes can keep their color looking fresh and cool-toned, as the blue pigments work to neutralize the brassy red and orange tones.

On the flip side, purple shampoo is the go-to for blondes, whether natural or dyed. Blonde hair has a tendency to pick up yellow or brassy tones, which can make the color look dull and lackluster. The purple pigments in these shampoos help to counteract the yellow tones, keeping blonde hair looking bright and ashy.

“When our hair fades to yellow, we’re gonna want to use a purple shampoo. However, the keyword in that is to neutralize, not to brighten. When we think of neutral colors, they’re actually quite dull and flat,” Valentine explains. “What will happen when you use it on your blonde hair is it will neutralize the yellow, making it a flatter color, which, in the short term, may appear brighter.”

Underlying Science

The principle underlying the effectiveness of blue and purple shampoos is rooted in color theory. On the color wheel, colors positioned opposite to each other are known to neutralize one another. In this scenario, blue is opposite to orange, and purple is opposite to yellow. When these shampoos are applied, the colored pigments are deposited onto the hair shaft, where they work to neutralize the unwanted tones, bringing the hair color back to its desired shade.

“Blue shampoo is used to counter any orange in the hair. It’s made for brunettes rather than blondes. It’s not really made to counter any yellow; it’s mostly to counter orange,” Sarab shares. “You can use it once a week after you use another sulfate-free color-safe shampoo on your hair.”

At a molecular level, these shampoos work by depositing pigment molecules onto the outer layer of the hair shaft. Over time, environmental factors and chemical treatments can erode the natural color molecules in hair, leading to the emergence of undesired brassy or yellow tones.

The pigments in blue and purple shampoos act as a temporary fix, masking these unwanted tones every time you wash. This doesn’t alter the internal structure or color of the hair but provides a surface-level solution to manage undesired color changes between salon visits.

Benefits and Limitations

Blue and purple shampoos provide a convenient and cost-effective method for maintaining color-treated or natural hair at home. They help to extend the life of your color between salon visits, saving both time and money. Besides, they are straightforward to use and can be incorporated into your regular hair care routine for continuous color management.

However, they come with their set of limitations. Overuse can lead to color over-correction, leaving a blue or purple tint in the hair. Additionally, these shampoos can be drying, as they often contain higher levels of sulfates and alcohol compared to regular shampoos. It’s essential to follow up with a hydrating conditioner to maintain hair health. They are a temporary fix and not a replacement for professional color correction when needed.

Application Techniques

For achieving the desired results, it’s crucial to use blue or purple shampoos correctly. Start by wetting your hair thoroughly, apply the shampoo evenly, and leave it on for the recommended time on the product label, usually between 3 to 5 minutes, before rinsing. This allows the pigments to deposit onto the hair shaft and neutralize the unwanted tones.

Common mistakes to avoid include overusing the product or leaving it on for too long, which can lead to unwanted tinting of the hair. Also, not all blue and purple shampoos are created equal; some may require more frequent use, while others might be more potent and require less frequent application. It’s advisable to follow the instructions on the product packaging and consider consulting with a hair professional if unsure about which product is suitable for your hair type and color.

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