Olaplex No.3 was the bottle that taught a lot of people the phrase bond building. It began in salons and then moved to bathroom shelves as a pre-shampoo treatment, the take-home step of the original trio. Olaplex was founded in 2014 by Dean Christal, working with Dr. Craig Hawker and Dr. Eric Pressly, chemists at the University of California, Santa Barbara, around a patented molecule the brand says rebuilds broken disulfide bonds in hair. It launched as a trio: No.1 and No.2 for stylists to use in the salon, and No.3 to take home. In February 2026 the brand said the newer No.3PLUS is replacing the original No.3 Hair Perfector, so the one in this edit is the current version. Allure reports that the original sat on the hair for ten minutes, while the brand says No.3PLUS does its work in three. I wanted to walk the whole numbered shelf around it, because the numbers are a system, not a random list. Grid one is the treatments and masks, and No.3PLUS leads.

Grid two is the washing step, and the trick is to choose by hair type, not by the number. No.4P is a purple shampoo for blonds and grays that the brand says neutralizes brassiness. N°4CURL and N°5CURL are a matched shampoo and conditioner for coils, curls and waves, and the brand claims they cut frizz in half even in humidity. No.5 Fine is the conditioner for fine hair, which the brand says doubles volume at the root without weight. Christal's parents worked in salons and hair care distribution, per Business Insider, and you can feel that in a range so carefully split by texture. My tip for the purple is to go lightly the first time and watch the tone, since pigment builds quickly on lightened hair. Match the conditioner to how much hair you have, then see how it feels by the third wash.

The last grid is what stays in. No.6 is a leave-in styling cream the brand says controls frizz for up to 72 hours. No.7 is a weightless styling oil with heat protection up to 450 degrees, No.5L is a leave-in conditioner aimed at split ends, and Shape Set is a flexible hold hairspray. What I would skip is doing every step just because the shelf has a number for it. The brand itself says No.0 is not required with No.3PLUS, since the new formula is designed to do that job alone. I would also skip layering cream, oil and leave-in in one morning, especially on fine hair, because it reads as limp by noon. Pick one leave-in, one styler for heat or hold, and leave it there. If your ends are the problem, let No.5L be the only leave-in for a week.

The numbers are the point of Olaplex, and they are also its trap. It started as three steps, and it has grown into a shelf that can feel like homework. I would treat it like a menu. Start with the treatment, add whichever wash step matches your texture, and bring in a leave-in only when your hair asks for it. If you take the newer No.3PLUS for a three-minute trial run, you will know quickly how your hair responds. If you want to keep browsing, I also put together Hair Gel Has Been Holding Styles for 3,500 Years, So Choose Yours Well.