This is for anyone whose scalp gets oily or greasy between washes, or whose hair feels weighed down by styling-product buildup that a regular shampoo doesn't fully remove -- it's built to reset the scalp rather than to moisturize dry lengths.

It's suitable for color-treated hair since it contains no added colorant, but its glycolic-acid exfoliation may be more than someone with a dry, flaky, or sensitized scalp needs.

What sets this apart from a generic clarifying shampoo is that it treats the scalp like skin: glycolic acid chemically exfoliates buildup at the root instead of relying purely on stronger surfactants to scrub it away -- the approach Biolage built the whole Scalp Sync line around.

Massage into wet hair and scalp to lift oil and residue.

• Apply to wet hair, massaging into the scalp.
• Rinse thoroughly.
• Follow with a Biolage conditioner.
• Use as needed when the scalp feels oily or weighed down by product, rather than as your only everyday shampoo.

Pros

• Glycolic acid is formulated to exfoliate scalp buildup that a standard shampoo's surfactants alone won't fully lift.
• Fermented black tea extract is included to help offset irritation from the exfoliating acid.
• Vegan, cruelty-free, paraben-, silicone-, and mineral-oil-free, with no added colorant.

Cons

• Still built on a sodium laureth sulfate base, so it can be more drying on lengths and ends than a sulfate-free shampoo.
• The glycolic acid may be too active for a sensitive, flaky, or compromised scalp.
• As a clarifying formula it's meant for periodic or as-needed use on an oily scalp, not as a daily all-purpose shampoo for every hair type.