Kérastase Blond Absolu Anti-Brass Purple Shampoo (Bain Ultra Violet) – 250 ml

What it is and who it’s for

Kérastase Blond Absolu Anti-Brass Purple Shampoo is a toning wash designed for cool blondes and grey hair. On the page, it’s described as a product that neutralises brassy or yellow undertones with blue and violet pigments, helping highlight shades stay cooler for longer. It’s pitched as part of a routine that protects against daily oxidation and pollution while restoring shine and softness. If you’re aiming for cooler blond tones without drastic colouring, this shampoo is meant to be used once a week, alternating with another cleansing step in the same line.

How it works and key ingredients

The formula relies on blue and violet pigments to counteract warm tones. It’s complemented by notes of hyaluronic acid and edelweiss flower within the Blond Absolu range, which typically signals a focus on hydration and a gentle approach to colour maintenance. The idea is to leave hair instantly more luminous and nourished after use, with regular use offering ongoing anti-brassiness protection so highlights stay cooler for longer. It’s not framed as a daily shampoo but as a specialised weekly treatment in a broader routine.

What to like about it

If you prioritise cool, ashy blondes or want to maintain grey hair without yellowing, this product aligns with that goal. The weekly schedule can feel straightforward for those who prefer a clear routine and are wary of overtoning. The notion of incorporating a hydrating element (via hyaluronic acid) is a plus for hair that can be vulnerable to drying when using stronger toning agents.

Considerations and potential downsides

Because the formula relies on pigments to neutralise warmth, the effect may depend on your starting level of brassiness and your washing frequency. Some users report needing to adjust how often they use it depending on their natural or dyed shade, so it might not be a perfect fit for everyone if you have very fine or highly porous hair that reacts quickly to pigment deposits. Also, the instructions specify a leave-in time of 2–5 minutes, so if you’re short on time, you may want to combine it with a longer conditioning moment in the routine.

Who it’s best for

This shampoo is likely to suit those with cool-blonde or silver-grey tones who want to maintain brightness while avoiding yellowish undertones. It’s also a reasonable option for anyone who appreciates a higher-end salon approach to hair colour care and is already following a complementary regimen (such as a matching conditioner in the same line).

When it makes sense to buy

If you regularly see warmth creeping into your blonde or grey shades and you’re looking for a targeted way to keep tones cooler between salon visits, a weekly toning step could be worth trying. It may be especially appealing if you value a structured routine and want a product that claims to both neutralise brass and contribute to a luminous finish.

What to check before purchasing

• Ensure your current routine includes steps compatible with a toning shampoo (for example, a hydrating conditioner) to avoid over-drying.
• Consider whether you prefer a weekly toning ritual rather than daily use, and whether a long-term plan with the broader Blond Absolu line fits your needs.
• If possible, test how your hair reacts to pigment-based products, particularly if you have very light or porous hair.

Practical use case

Imagine washing your hair on a Sunday evening and leaving this purple-toned shampoo in for the full 3 minutes while you shower. The hair looks instantly more luminous as the brassiness retreats, and you follow with a conditioning step to lock in moisture. By midweek, you notice cooler tones in your blonde highlights that feel balanced rather than overly ashy, with a soft, manageable finish.

How it fits alongside alternatives

For those weighing options, a traditional daily shampoo may be enough if brassiness is mild or infrequent. If brassiness is persistent or you want a more deliberate toning approach, a dedicated purple shampoo used weekly—alternating with a cleansing step like Bain Lumière—offers a pragmatic balance between tone control and moisture.

Decision point: Is it worth it?

Is it worth it?

It makes sense if you want to extend cool-toned blondes between salon visits and are seeking a hydrating, pigment-based toning option.

FAQ

• How often should I use it? Typically once per week, as part of a routine alternating with another shampoo.
• Will it dry my hair? The inclusion of hyaluronic acid aims to support moisture, however, pigment-based toners can vary in effect depending on hair condition.
• Can I use it on grey hair? Yes, it’s marketed for cool blondes and grey hair to combat brassiness.
• Do I need to use a conditioner afterwards? The base description recommends completing the routine with a conditioner, such as Cicaflash, to finish with nourishment.