This shampoo is for anyone with blonde, silver, or gray hair, natural, highlighted, balayage, or fully color-treated, dealing with warm, brassy, or yellow undertones, across hair textures from straight to coily (1–4c). It suits people already familiar with toning shampoos, since amika recommends adjusting how often it's used based on how the hair's tone responds, rather than using it as a plain daily cleanser.

People with naturally dark or brunette hair that's been lightened should expect to need it more often, since amika notes darker natural hair tends to pull warmer tones back faster.

The main differentiator is that it's positioned as a repair shampoo first and a toner second: instead of relying only on violet pigment to mask brassiness, it pairs that pigment with a bond-fortifying complex, quinoa protein, and plant butters aimed at the hair's strength and hydration. amika reports clinical testing, as a system with the matching conditioner, showing 2.2x stronger hair, 86% more repair, and 55% less breakage after a single use, a stronger repair claim than a standard toning shampoo typically makes.

amika suggests patch-testing on a small section at the nape of the neck before settling into a regular routine, then adjusting frequency based on hair type and how quickly brassiness returns.

• Apply to wet hair, massage through, and rinse; follow with the Bust Your Brass conditioner for the full system.
• Natural (non-color-treated) blondes: use every other wash, more often in summer months when brassiness tends to increase.
• Platinum or color-treated blondes: use every other wash, increasing to every wash if brassiness reappears; the Bust Your Brass mask can replace conditioner once a week for extra toning.
• Gray hair: use every wash, or alternate with amika's Kure system.
• If hair starts pulling too cool or slightly violet, cut back on frequency for a week or two.

• Pro: Combines toning for brassiness with a bond-repair conditioning base in one shampoo step, rather than requiring a separate toner and treatment.
• Pro: Free of sulfates, parabens, phthalates, mineral oil, and petrolatum.
• Pro: Works across a wide range of textures (1–4c), with amika giving separate usage guidance for platinum, natural, highlighted, and gray hair.
• Con: As a purple/violet-pigmented shampoo, overuse can push cooler-toned or fine hair too far toward an ashy or violet cast, which amika itself warns to watch for.
• Con: Best results are demonstrated when used with the matching Bust Your Brass conditioner as a system, not necessarily as a standalone shampoo.