This Japanese treatment uses heat to restructure the cuticle so it lies flat, giving you glossy, pin straight hair hair that doesn't require blow-drying.

Who has done it:
Julianne Moore

Works best for: Untreated or minimally colored (highlights or single process) Caucasian hair. The irons are too damaging for most African-American hair and for Caucasian hair that has been double processed or permed.

How it works: First, hair is chemically softened with a solution that is milder than a standard relaxing solution. Then, individual 1/4 - inch sections of hair are straightened with irons heated to 180 degrees. Some salons will blow-dry hair first, so steam from damp hair has no chance to burn your scalp; others keep it damp to minimize trauma to the hair. Afterward, a neutralizing formula is smoothed onto the hair close to the cuticle.

How long it takes: The relaxer sits on the hair for only 20 to 25 minutes, but the whole process takes about four hours, including ironing each 1/4 - inch section for three seconds.

How long it lasts: Six to 10 months. Thermally reconditioned hair will never be curly again; you won't have to repeat the process until new hair grows in.