Anyone with damaged or processed hair, from colour and lightening to heat styling, who wants a leave-in treatment that also handles frizz and shine. The overnight option suits people who prefer to treat their hair while they sleep rather than add another step to a morning routine.

It is a retail leave-in for home use and fits any hair type that tolerates a light serum.

Most bond-repair products live in the shower and are rinsed away within minutes. This serum stays on the hair, so the citric acid and Bonding Care Complex keep working while you go about your day or sleep, and it doubles as the finishing serum that tames frizz and adds shine. It turns the Acidic Bonding Concentrate routine into continuous care rather than a once-a-wash step.

1. Start with a quarter-sized amount for shoulder-length hair; use more for longer or thicker hair.
2. Apply to clean hair, damp or dry.
3. At night: distribute generously from mid-lengths to ends and leave in overnight.
4. By day: apply as needed for frizz control, conditioning and shine. Do not rinse.

Pros:

• Works as a daytime frizz and shine serum or an overnight treatment
• Absorbs quickly without leaving hair heavy
• Citric acid, squalane and polyglutamic acid in one leave-in step
• Designed not to leave visible residue on pillowcases

Cons:

• Contains silicones (dimethicone, amodimethicone), which some people prefer to avoid
• Too much on fine hair can look flat, so start with a small amount
• Contains added fragrance