Olaplex Numbers Explained: What Each One Does (UK Guide)

May 23, 2026 Thomas Strangwood

Olaplex is the most talked-about professional haircare brand in the world, but the numbering system can be genuinely confusing. There are at least eleven different products in the range, all numbered, and the numbers don't run in a perfectly logical order. If you have ever stood in front of a shelf of Olaplex products trying to work out what you actually need, you are not alone.

This guide walks through every Olaplex product number, what each one does, who it is for and which combinations actually make sense to buy together.

The short version

If you only ever buy two Olaplex products, make them No.3 Hair Perfector and No.4 Bond Maintenance Shampoo. That combination gives you the weekly bond-building treatment and the daily wash that maintains the results. Everything else in the range adds layers on top of that core. If you bleach your hair regularly, add No.5 Bond Maintenance Conditioner as well.

How the numbering system actually works

Olaplex products are split into two groups. The first group — No.1 and No.2 — are professional in-salon treatments used during chemical services like bleaching, colouring and perming. The second group — No.0 and No.3 to No.9 — are at-home products designed to maintain and extend the repair work between salon visits.

The numbers are not a strict order of importance or strength. They were added over time as the range expanded, so the order roughly reflects when each product was launched rather than a hierarchy. Think of them as a system of complementary tools, not a ranking.

Olaplex No.0 Intensive Bond Building Hair Treatment

Olaplex No.0 is an intensive pre-treatment that primes the hair to absorb more of the No.3 that follows. It is a liquid that you spray onto dry hair, leave for ten minutes, and then apply No.3 directly on top without rinsing in between. Used together as a two-part system, No.0 plus No.3 delivers significantly more repair than No.3 alone — Olaplex's own clinical data shows 68% more repair and 3x stronger hair when the two are used in combination.

Best for: anyone with severely damaged or heavily bleached hair who wants the maximum at-home repair impact.

Olaplex No.1 Bond Multiplier and No.2 Bond Perfector

These are the original Olaplex products and remain professional-only treatments used in salons during chemical services. No.1 is added directly to bleach, colour or perm formulations to protect the hair during processing. No.2 is applied after the service to seal in the repair before the hair leaves the salon.

You can buy these at home, but they are designed for stylists to use as part of a colour or chemical service. We stock the Olaplex Stand-Alone Treatment with No.1 and No.2 in a single-use professional system and the larger Olaplex Salon Intro Kit with No.1 and 2x No.2 for stylists and professional use.

Best for: hairdressers and professionals. Not typically recommended as a starting point for at-home users.

Olaplex No.3 Hair Perfector (and No.3 Plus)

Olaplex No.3 Plus Complete Repair Treatment is the most popular Olaplex product and the one almost everyone starts with. It is a weekly pre-shampoo treatment that you apply to damp hair, leave for at least 10 minutes (longer is fine), then shampoo and condition as normal.

The "Plus" version is an updated formula that Olaplex launched as an improvement on the original No.3 Hair Perfector. It delivers more repair, smoothness and shine in the same application time. If you are buying No.3 today, this is the version to buy.

Best for: anyone with damaged, chemically processed, bleached or colour-treated hair who wants one product that will make a noticeable difference. This is the entry point to the Olaplex system.

Olaplex No.4 Bond Maintenance Shampoo

Olaplex No.4 Bond Maintenance Shampoo is the everyday shampoo in the Olaplex system. It is sulphate-free, gentle enough for daily use, and continues the bond-building work of No.3 every time you wash your hair.

There are also two variants worth knowing about. No.4 Fine is formulated for fine or flat hair that needs the same repair benefits without any added weight. No.4C Clarifying Shampoo is a deep-cleansing version for when product or mineral build-up is a concern.

Best for: anyone using No.3 who wants to maximise the results. Pairs naturally with No.5 conditioner.

Olaplex No.4P Blonde Enhancer Toning Shampoo

No.4P is a purple toning shampoo that combines the bond-building benefits of the Olaplex system with violet pigments that neutralise yellow and brassy tones in blonde, bleached and grey hair. We cover this product in much more detail in our dedicated post on Olaplex for bleached hair.

Best for: anyone who bleaches their hair regularly and wants a toning shampoo that also strengthens.

Olaplex No.5 Bond Maintenance Conditioner

Olaplex No.5 Bond Maintenance Conditioner is the daily conditioner that pairs with No.4 shampoo. Like the shampoo, it is sulphate-free, vegan, suitable for all hair types and continues the bond-building work with every wash.

Best for: anyone using No.4 — they are designed to be used together. Using one without the other works, but you get noticeably better results from the pair.

Olaplex No.6 Bond Smoother

No.6 Bond Smoother is a leave-in styling cream that smooths, reduces frizz and adds shine while continuing the bond-building work. It is applied to damp hair before blow-drying and gives a polished, smooth finish to the hair. A small amount goes a long way.

Best for: anyone with frizz, flyaways or unmanageable hair who wants a smoothing leave-in that also strengthens.

Olaplex No.7 Bonding Oil

No.7 is a lightweight bonding oil applied to damp or dry hair as a finishing product. It adds shine, smooths flyaways and provides heat protection up to 230°C. Unlike many styling oils, it is genuinely lightweight and does not weigh hair down.

Best for: anyone wanting a styling oil that also gives heat protection and bond support. Pairs well with No.6 — apply No.6 to damp hair, blow-dry, then use a drop of No.7 on dry hair to finish.

Olaplex No.8 Bond Intense Moisture Mask

No.8 is a deep-conditioning mask with a higher concentration of moisture-binding ingredients than the regular conditioner. Used once a week as an intensive treatment, it boosts hydration and shine alongside the bond-building benefits.

Best for: dry, dehydrated hair that needs an intensive moisture boost on top of bond repair.

Olaplex No.9 Bond Protector Nourishing Hair Serum

No.9 is a leave-in serum that protects the hair from environmental damage, including UV and pollution, while delivering bond-building and moisturising benefits. It is applied to damp hair before drying.

Best for: anyone who is regularly exposed to sun, chlorine or high pollution and wants to add a protective layer on top of the standard routine.

Which Olaplex products to buy first

If you are new to the Olaplex system, the order to build up your routine is:

Start with No.3 Plus — the at-home treatment that delivers the most noticeable single-product result
Add No.4 shampoo and No.5 conditioner — daily maintenance that makes the No.3 work harder
Add No.0 if your hair is severely damaged — combine with No.3 for maximum repair
Add styling products (No.6, No.7, No.9) based on your hair's needs — frizz, shine, protection
Add No.8 mask for intensive weekly moisture — especially useful for dry hair

If you want the system in one purchase, the Olaplex Best of the Bond Builders Kit covers the four core products (No.0, No.3, No.4 and No.5) in one bundle and is genuinely good value compared to buying them individually. We cover the gift sets and bundles in detail in our Olaplex bundle guide.

Our take from the salon

In our Codsall salon we use the professional Olaplex system (No.1 and No.2) during bleaching and colour services as standard. The difference in hair condition immediately after a colour service that includes Olaplex versus one that does not is genuinely visible — clients with damaged or fragile hair leave the salon with hair that feels noticeably stronger and looks healthier.

For at-home use, the products we recommend most often are No.3 Plus, No.4 shampoo and No.5 conditioner. That core trio is what almost every Olaplex client should start with, and it is what delivers the consistent results that have made the brand the global phenomenon it is. The more advanced products (No.6 to No.9) are great additions for people who want to optimise further, but they are not where to start.

Item added to your cart