How to Choose Between OLAPLEX Nº.4P and Nº.4Curl Shampoo for Your Hair Needs

Selecting the right shampoo is one of the most important decisions in any hair care routine. With OLAPLEX’s innovative bond-building technology, you can repair and strengthen hair while targeting specific needs like toning brassiness or defining curls. Two standout options are the OLAPLEX Nº.4P Blonde Enhancer Toning Shampoo and the Nº.4Curl Bond Shaper Hydrating Curl Shampoo. Both deliver the patented OLAPLEX bond repair, but they are formulated for very different hair types and concerns.

If you’re wondering which shampoo is right for you, this guide breaks down the key differences, benefits, and ideal use cases. Whether you’re a blonde battling brass, a curly-haired beauty seeking definition and moisture, or someone with both concerns, we’ll help you make an informed choice. Plus, we’ll recommend complementary products from the OLAPLEX family to complete your regimen.

Understanding the Core Differences: Toning vs. Hydrating

The primary distinction between Nº.4P and Nº.4Curl lies in their intended function. Nº.4P Blonde Enhancer Toning Shampoo is a purple shampoo designed to neutralize unwanted yellow and brassy tones in blonde, silver, gray, or highlighted hair. It deposits subtle violet pigments while repairing bonds, making it ideal for color-treated blondes who want to maintain a cool, fresh tone without sacrificing strength.

In contrast, Nº.4Curl Bond Shaper Hydrating Curl Shampoo is formulated specifically for curly, coily, and wavy hair types. It focuses on hydration, curl definition, and frizz control while still delivering OLAPLEX’s bond repair. This shampoo cleanses gently without stripping natural oils, leaving curls soft, bouncy, and well-defined. If your primary concern is curl health and moisture, Nº.4Curl is the better fit.

Both shampoos share the same bond-building technology, but their secondary benefits—toning for Nº.4P and hydration for Nº.4Curl—determine which is best for your hair. For those with both blonde highlights and curly hair, you may need to alternate or choose based on your most pressing concern.

• Nº.4P: Best for blonde, silver, gray, or highlighted hair needing brassiness correction.
• Nº.4Curl: Best for curly, coily, or wavy hair needing moisture and definition.

Who Should Use Nº.4P Blonde Enhancer Toning Shampoo?

If you have blonde, platinum, silver, gray, or balayaged hair, Nº.4P is your go-to shampoo. It works by depositing violet pigments that cancel out brassy yellow and orange tones, a common issue for color-treated blondes. Unlike many purple shampoos that can dry out hair, Nº.4P incorporates OLAPLEX’s bond repair to strengthen and protect hair from further damage. This makes it ideal for those who lighten their hair regularly and need both tone correction and repair.

Use Nº.4P once or twice per week, alternating with a moisturizing or clarifying shampoo to avoid over-toning. For best results, follow with a conditioner like Nº.5 Bond Maintenance Conditioner or the Nº.5P Blonde Enhancer Toning Conditioner to maintain tone and softness. If you also have curls, you can still use Nº.4P on your roots and lengths, but you may need extra hydration afterward.

• Ideal for: Blonde, silver, gray, highlighted, or balayaged hair.
• Frequency: 1–2 times per week, or as needed to maintain cool tones.
• Pro tip: Pair with a deep conditioning mask if your hair feels dry after toning.

Who Should Use Nº.4Curl Bond Shaper Hydrating Curl Shampoo?

Nº.4Curl is designed for those with naturally curly, coily, or wavy hair who want to enhance their curl pattern while repairing damage. This shampoo uses a gentle, sulfate-free cleanser that removes buildup without stripping moisture. It’s enriched with ingredients that hydrate and define curls, reducing frizz and improving elasticity. The bond-building technology works to repair broken disulfide bonds, which are often more damaged in textured hair due to heat, chemical services, or manipulation.

For best results, use Nº.4Curl as your daily or every-other-day shampoo, depending on your curl type and oiliness. Follow with the matching Nº.4Curl Conditioner or a deep conditioner like Nº.5 Bond Maintenance Conditioner for added moisture. If you have color-treated curls, you can still use Nº.4Curl, but you may need to incorporate a toning shampoo like Nº.4P occasionally to manage brassiness.

• Ideal for: Curly, coily, wavy, or textured hair types.
• Frequency: Daily or every other wash, depending on hair needs.
• Pro tip: Apply a leave-in conditioner or curl cream after washing for extra definition.

Can You Use Both? Alternating for Multi-Concern Hair

Many people have hair that doesn’t fit neatly into one category. For example, you might have naturally curly hair that’s also highlighted blonde, or you might be a curly-haired individual who occasionally uses heat styling. In these cases, alternating between Nº.4P and Nº.4Curl can give you the best of both worlds. Use Nº.4P once a week to maintain your blonde tone, and use Nº.4Curl for the rest of your washes to keep curls hydrated and defined.

Another option is to use Nº.4Curl as your primary shampoo and incorporate a purple toning treatment or a clarifying shampoo like Nº.4C Bond Maintenance Clarifying Shampoo for periodic deep cleansing. This approach ensures your curls stay moisturized while your color remains fresh. Always listen to your hair: if it feels dry or brittle, reduce the frequency of toning shampoos and increase moisture-rich products.

For those who travel frequently or want to try both, consider the OLAPLEX THE HEALTHY HAIR TRAVEL SET, which includes mini versions of key products. This allows you to experiment with different shampoos without committing to full sizes.

• Alternate Nº.4P (toning) and Nº.4Curl (hydrating) for multi-concern hair.
• Use Nº.4C Bond Maintenance Clarifying Shampoo once a month for buildup removal.
• Travel-friendly sets like THE HEALTHY HAIR TRAVEL SET help you test products on the go.

How to Build Your Complete OLAPLEX Routine

Once you’ve chosen your shampoo, it’s time to build a full routine that maximizes repair and results. Start with your selected shampoo, then follow with a matching conditioner. For deep repair, incorporate OLAPLEX Nº.3PLUS Complete Repair Treatment once a week. This at-home treatment strengthens bonds from within and works well with any shampoo. After washing, apply a leave-in product like OLAPLEX Nº.7 Bonding Oil to seal in moisture and add shine.

If you have fine or thin hair, you might prefer lighter products, while thicker curls may benefit from richer creams. The key is to listen to your hair’s needs and adjust your routine accordingly. For a complete starter kit, the OLAPLEX THE HEALTHY HAIR DISCOVERY SET includes a curated selection of products to help you find your perfect match. Remember, consistency is crucial—bond repair takes time, but with regular use, you’ll see stronger, healthier hair.

• Step 1: Shampoo with Nº.4P or Nº.4Curl.
• Step 2: Condition with Nº.5 Bond Maintenance Conditioner or matching curl conditioner.
• Step 3: Weekly treatment with Nº.3PLUS Complete Repair Treatment.
• Step 4: Seal with Nº.7 Bonding Oil for shine and protection.

Choosing between OLAPLEX Nº.4P and Nº.4Curl comes down to your hair’s primary need: tone correction or curl hydration. Both deliver the bond repair that OLAPLEX is famous for, so you can’t go wrong. If you’re still unsure, start with a versatile option like the OLAPLEX THE HEALTHY HAIR DISCOVERY SET to sample multiple products and discover what works best for your unique hair. Your journey to stronger, more beautiful hair begins with the right shampoo—choose wisely and enjoy the results.