Which Olaplex Should I Use? A Simple Guide to Olaplex No.3, No.4, No.5 & More

If you've ever looked at the OLAPLEX range and wondered what all the numbers mean, you're definitely not alone. From No.3 and No.4 to No.6, No.7 and No.9, each product has a different place in your haircare routine.

The good news is that you don't necessarily need every Olaplex product. The best choice depends on your hair, how you style it and what you're trying to achieve.

In this simple guide, we'll explain some of the best-known Olaplex products, what they do and where they fit into your routine.

What is Olaplex?

Olaplex is a haircare brand best known for its bond-building approach to damaged hair. Hair can become damaged through colouring, bleaching, heat styling and everyday mechanical stress such as brushing and styling.

The Olaplex range includes treatments, shampoos, conditioners and styling products, so the numbers aren't different strengths of the same product. Each one has its own job.

Olaplex No.3 – the pre-shampoo repair treatment

Olaplex No.3 Hair Perfector is one of the products that made Olaplex famous.

An important thing to know is that No.3 isn't a shampoo or a conditioner. It's a pre-shampoo reparative treatment designed to help strengthen damaged hair.

It's particularly worth considering if your hair has been affected by colouring, bleaching, heat styling or other forms of damage.

Olaplex has also introduced No.3PLUS Complete Repair Treatment, the newer evolution of its repair-treatment step.

Best for: Hair showing signs of damage or breakage.

Where it fits: Before shampoo.

Olaplex No.4 – your shampoo step

Olaplex No.4 Bond Maintenance Shampoo is the cleansing step in the classic Olaplex routine.

It's a concentrated shampoo designed to cleanse while helping strengthen and nourish the hair. Unlike No.3, this is the product you'd use when actually shampooing your hair.

If you're looking to build a simple Olaplex routine rather than buying the entire range, No.4 and No.5 make a natural shampoo-and-conditioner pairing.

Best for: Cleansing while supporting stronger, smoother-looking hair.

Where it fits: Shampoo stage.

Olaplex No.5 – the conditioner

After No.4 comes Olaplex No.5 Bond Maintenance Conditioner.

No.5 is designed to condition, hydrate and strengthen while making the hair easier to detangle and helping improve smoothness.

Use it after shampooing, concentrating particularly on the lengths and ends of your hair.

Best for: Conditioning, hydration and easier detangling.

Where it fits: After shampoo.

Olaplex No.6 – for smoothing and frizz

Olaplex No.6 Bond Smoother moves us from washing and treating into styling.

It's a leave-in styling cream designed to smooth the hair, improve softness and help control frizz. It can be especially useful if your hair tends to become fluffy, frizzy or difficult to manage after washing.

Unlike No.4 and No.5, you don't rinse No.6 out. Apply a small amount to clean, damp hair and style as normal.

Best for: Frizz, smoothing and styling.

Where it fits: After washing, before styling.

Olaplex No.7 – for shine and heat protection

If you want a finishing product rather than another wash-day treatment, look at Olaplex No.7 Bonding Oil.

No.7 is a lightweight styling oil designed to add shine and softness while helping control flyaways and providing heat protection.

Because it's concentrated, you generally only need a small amount. It can be applied to damp hair before styling or used sparingly on dry hair as a finishing product.

Best for: Shine, softness, flyaways and heat styling.

Where it fits: Before or after styling.

Olaplex No.9 – the protective hair serum

Olaplex No.9 Bond Protector Nourishing Hair Serum is another leave-in styling option.

It's designed to smooth and protect the hair while helping with manageability and styling. If you regularly blow-dry or style your hair, No.9 can form part of your post-wash routine before styling.

Best for: Smoothing, protection and styling.

Where it fits: On damp hair before styling.

What's the difference between Olaplex No.6, No.7 and No.9?

This is where the numbers can become confusing because all three products are used around the styling stage.

• No.6 – choose this when smoothing and frizz control are priorities.
• No.7 – choose this when you want a lightweight oil for shine, softness and finishing.
• No.9 – choose this when you want a leave-in serum focused on protection, smoothing and styling.

You can also combine Olaplex styling products rather than choosing only one. For example, Olaplex itself recommends using No.6 and No.7 together as part of certain styling routines.

Which Olaplex should I use for damaged hair?

If repairing damage is your main goal, the pre-shampoo treatment step is the obvious place to start. Depending on the product available to you, that may be No.3 Hair Perfector or the newer No.3PLUS Complete Repair Treatment.

You can then follow with No.4 shampoo and No.5 conditioner to create a straightforward repair-focused wash routine.

Which Olaplex should I use for frizzy hair?

For frizz and manageability, No.6 Bond Smoother is particularly relevant because it's specifically designed as a smoothing styling cream.

No.7 Bonding Oil can then be used for additional shine and to help smooth flyaways.

Which Olaplex should I use for dry hair?

Dry hair often benefits from a routine that combines gentle cleansing with conditioning and styling products that improve softness and manageability.

No.4 and No.5 provide the basic wash-and-condition steps, while No.6 or No.7 can be added depending on whether smoothing or shine is your priority.

Which Olaplex should I use for coloured or bleached hair?

Colouring and bleaching can contribute to hair damage, so a repair-focused Olaplex routine may be useful for chemically treated hair.

A simple routine could start with a reparative pre-shampoo treatment, followed by No.4 shampoo and No.5 conditioner. You can then add a styling product such as No.6, No.7 or No.9 depending on your needs.

Do I need to use every Olaplex product?

No. One of the easiest mistakes to make when discovering Olaplex is assuming the numbered system means you have to purchase and use every number in order.

You don't.

Think about the range in stages instead:

• Repair treatment: No.3 / No.3PLUS
• Cleanse: No.4
• Condition: No.5
• Smooth and style: No.6
• Shine and finish: No.7
• Protect and style: No.9

A simple Olaplex routine

If you're completely new to the brand, you could keep things simple:

1. Use your Olaplex repair treatment when required.
2. Wash with No.4 Bond Maintenance Shampoo.
3. Condition with No.5 Bond Maintenance Conditioner.
4. Apply No.6 or No.9 to damp hair depending on your styling needs.
5. Finish with a small amount of No.7 Bonding Oil for extra shine.

Shop Olaplex at Cheap Beauty

At Cheap Beauty, we regularly stock Olaplex alongside other big-name haircare and beauty brands at lower prices.

Our stock changes frequently, so check the Olaplex products currently available below. Whether you're looking for a repair treatment, shampoo and conditioner or a styling favourite, you may find your next Olaplex product for less.

Product ranges and formulations can change. Always follow the instructions on the individual product you receive and check the packaging if you have specific sensitivities or requirements.