Number 4 Hydrating Shampoo 8.5 oz

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Number 4 Hydrating Shampoo 8.5 oz — image 3
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80%
20%
91%
Moisture & Hydration
88%
Color Protection
86%
Scalp Comfort
63%
Lather & Cleansing Feel
58%
Value for Money
93%
Ingredient Quality
76%
Scent Experience
82%
Hair Shine & Appearance
79%
Manageability & Detangling
67%
Packaging & Dispensing
74%
Suitability for All Hair Types
83%
Residue & Buildup
94%
Ethical & Clean Credentials
More

Overview

The Number 4 Hydrating Shampoo 8.5 oz comes from Number 4 High Performance Hair Care, a brand that sits firmly in the salon-grade luxury tier — the kind you'd expect to find at a high-end stylist, not a drugstore shelf. It belongs to the brand's Hydrate Collection, built around deep moisture restoration for dry, brittle strands. The scent, L'Eau De Mare, carries a distinctly oceanic character that sets it apart from the typical floral or citrus options crowding the market. With four size choices ranging from a travel-friendly 1.5oz to a generous 64oz, it fits different routines. A 4.4-star rating across Amazon buyers puts it among the more respected options in its category.

Features & Benefits

What makes this hydrating shampoo stand out on ingredient grounds is its commitment to what's left out. No sulfates, no sodium, no parabens — the formula is built to clean without the collateral damage harsher shampoos can cause. That matters especially if you have color-treated hair, where aggressive cleansers noticeably accelerate fade. The formula also addresses dry, flaky scalp concerns without medicated ingredients, hydrating the scalp as it cleanses rather than drying it further. Worth knowing upfront: sulfate-free shampoos typically produce less lather than conventional ones, so a thinner foam isn't a sign it isn't working. It's also vegan and cruelty-free, with no gluten or shark squalene in the mix.

Best For

The Number 4 formula is a particularly strong match for anyone whose hair sees regular coloring, highlights, or chemical treatments. The gentle, color-safe cleansing keeps dye from washing out prematurely — one of the most practical things a shampoo can do for a salon-maintained look. People with dry or sensitive scalps will find it a good fit too; it hydrates without loading the scalp with heavy residue. If clean-label credentials matter to you, the vegan and cruelty-free certifications here are substantive, not just marketing language. The compact 1.5oz size is worth noting for travelers who don't want to check bags. Brittle, moisture-depleted hair across any texture should respond well to consistent use.

User Feedback

Buyers who use this sulfate-free shampoo regularly tend to highlight noticeable improvements in softness and a reduction in scalp irritation — two themes that surface consistently in positive reviews. Color retention is another point of praise, with dyed-hair users reporting their shade holds longer between salon visits. The price is the most common friction point; some buyers question whether the 8.5oz size offers enough volume to justify the cost compared to larger-bottle competitors. A handful of users mention the oceanic scent is stronger than expected, which lands firmly in personal-preference territory. Lather expectations also catch some people off guard — worth knowing before switching from a conventional sulfate-based shampoo.

#Shampoos
#Shampoo & Conditioner
#Hair Care
#Beauty & Personal Care

Pros

  • Sulfate-free and sodium-free formula cleans effectively without stripping natural oils from the scalp or strands.
  • Color-treated hair retains vibrancy noticeably longer compared to conventional shampoos with harsh surfactants.
  • Soothes dry, flaky scalps without medicated ingredients or leaving behind heavy residue.
  • Fully vegan, cruelty-free, and free of parabens, gluten, and shark squalene — clean credentials that hold up to scrutiny.
  • The hydrating shampoo works across all hair types, including fine, coarse, curly, and chemically treated hair.
  • Multiple size options make it easy to try before committing to a larger, more cost-effective bottle.
  • L'Eau De Mare scent is distinctive and long-lasting without being overpowering for most users.
  • Hair feels noticeably softer and more manageable after consistent use over several weeks.
  • Gentle enough for sensitive scalps that react poorly to fragrance-heavy or chemical-laden alternatives.

Cons

  • Premium price per ounce is hard to justify for daily washers or those with very long, thick hair.
  • Lather is noticeably thinner than sulfate-based shampoos, which can feel unfamiliar and unconvincing at first use.
  • The 8.5oz bottle runs out faster than expected for anyone who applies generously each wash.
  • The oceanic scent, while pleasant to many, is strong enough to clash with certain perfumes or conditioners.
  • Results on softness and shine may take several consistent uses to become clearly noticeable.
  • Not ideal for oily scalp types, as the moisture-rich formula can feel heavy on finer, greasier hair.
  • No pump dispenser included, which makes portion control trickier and can lead to product waste.
  • Limited availability outside of Amazon and specialty beauty retailers makes it harder to find in a pinch.
  • The compact 1.5oz travel size is priced proportionally high for what amounts to just a few washes.

Ratings

Our AI-powered scoring system analyzed thousands of verified global purchases of the Number 4 Hydrating Shampoo 8.5 oz, actively filtering out incentivized, duplicate, and bot-generated feedback to surface what real buyers consistently experience. The scores below reflect both the genuine strengths and the honest frustrations that surface across different hair types, routines, and price expectations. Nothing has been softened — if a category has real friction, the score and commentary reflect it.

Moisture & Hydration
91%
This is the formula's clearest strength, and buyers with dry or brittle hair notice it within the first few washes. Hair feels genuinely softer after towel drying — not coated or product-heavy, but actually more pliable and less prone to snapping during combing. People dealing with seasonal dryness or heat-damage fallout report consistent improvement over several weeks.
A small number of users with naturally oily hair find the hydration level tips into heaviness by mid-day, leaving roots looking flat or slightly greasy. The moisture payoff is most pronounced on medium-to-coarse hair types; very fine hair may need a lighter application to avoid the same effect.
Color Protection
88%
Color-treated buyers are the most vocal advocates for this sulfate-free shampoo, with many reporting their dye or highlights look visibly fresher for longer between salon visits. Balayage and toned hair in particular seem to hold better, likely because the formula skips the harsh surfactants most responsible for stripping pigment from the hair shaft.
A few users note that on very porous or heavily bleached hair, color fade still progresses at a similar rate regardless of shampoo choice — at that level of damage, the shampoo alone cannot compensate. Results also depend on water hardness; users in areas with hard tap water report less dramatic color preservation.
Scalp Comfort
86%
Buyers who have struggled with dry, itchy, or flaky scalps mention this hydrating shampoo as one of the few that reduces irritation without making them feel like they are using a medicated product. The absence of sodium and sulfates removes two common triggers of scalp dryness, and several users with sensitive skin describe washing as noticeably more comfortable than with previous shampoos.
For scalp conditions with a fungal or bacterial component — like seborrheic dermatitis — the formula's moisturizing focus does not address the root cause, and some users report flaking returning quickly. Those expecting an active therapeutic effect comparable to a medicated shampoo are likely to be disappointed.
Lather & Cleansing Feel
63%
37%
Buyers who are already familiar with sulfate-free shampoos have no complaints here — they understand the thinner foam is by design and report that hair feels clean and residue-free after rinsing. The formula does remove buildup and daily oils without leaving a waxy or heavy film, which is the actual measure of cleansing performance.
First-time sulfate-free users are routinely caught off guard by the minimal lather, and a meaningful portion of negative reviews trace back to this single expectation mismatch. Some users compensate by using significantly more product than needed, which accelerates how quickly the bottle runs out and adds to the cost-per-wash frustration.
Value for Money
58%
42%
Buyers who commit to the larger 25 oz or 64 oz sizes find the cost-per-wash more defensible, especially when they factor in the clean formulation, color longevity savings, and the reduced need for heavy conditioning treatments. For salon-goers, the argument is that protecting a color service between appointments offsets part of the product cost.
At the 8.5 oz size, this is one of the more expensive shampoos per ounce in its category, and that friction shows up consistently in reviews. Buyers who wash their hair daily or have long, thick hair that requires generous application find the bottle depletes much faster than expected, pushing the effective cost higher than anticipated.
Ingredient Quality
93%
The ingredient omissions here are genuinely substantive — no sulfates, no sodium, no parabens, no gluten, no shark squalene — and buyers who scrutinize labels before purchasing respond strongly to the clean credential list. The vegan and cruelty-free certifications carry weight with ethically conscious consumers who have seen other brands make similar claims without backing them up.
The full ingredient list is not prominently published on all retail listings, which frustrates buyers with specific allergies or sensitivities who want to verify before purchasing. A handful of fragrance-sensitive users note that despite the otherwise clean formula, the L'Eau De Mare scent still contains undisclosed fragrance compounds.
Scent Experience
76%
24%
Most buyers find the oceanic L'Eau De Mare scent to be a pleasant departure from the sweet or heavily floral fragrances that dominate the shampoo market. It reads as fresh and clean during washing, and the light residual scent on dry hair is subtle enough not to compete with perfume or other styling products.
Scent is inherently subjective, and a consistent minority of reviewers find the oceanic profile too strong during application or describe it as reminiscent of sunscreen rather than a luxurious hair product. Fragrance-sensitive users note there is no unscented version available in this collection, which effectively excludes them from the line.
Hair Shine & Appearance
82%
18%
Buyers report a visible improvement in shine after several weeks of consistent use, particularly those coming from sulfate-heavy shampoos that had been dulling the hair's surface over time. Color-treated hair in particular looks more reflective and vibrant, which users attribute to the gentler cleansing preserving the hair cuticle's smooth alignment.
Results on shine are not immediate — most users do not notice a significant difference until the second or third week of regular use, which can feel underwhelming at the premium price point. Hair that is severely damaged from bleaching or heat may show limited shine improvement from shampoo alone without complementary treatments.
Manageability & Detangling
79%
21%
Users with medium to coarse or curly hair note that combing through wet hair after washing is noticeably easier, with less breakage at the ends. The hydration seems to smooth the hair fiber enough to reduce friction during detangling, which is particularly meaningful for anyone who has been dealing with post-color brittleness.
Fine-haired buyers occasionally report that the added moisture makes their hair feel slightly limp or harder to style with volume after drying. The formula works better as a standalone on coarser textures; fine hair often benefits from pairing it with a lightweight, non-moisturizing conditioner to balance the effect.
Packaging & Dispensing
67%
33%
The bottle is clean and understated in design, fitting well on a shelf or in a shower caddy without looking cluttered. The size range — from 1.5 oz up to 64 oz — gives buyers genuinely useful flexibility depending on whether they are traveling or stocking a home bathroom for long-term use.
The 8.5 oz bottle does not include a pump dispenser, which makes it easy to accidentally pour out more product than needed — a notable issue given the cost per ounce. Some users also note the cap design is not as secure as expected for a premium-tier product, with a few reports of leakage during travel.
Suitability for All Hair Types
74%
26%
The formula is genuinely functional across a wide range of textures, from straight fine hair to coiled and coarse strands, which makes it a practical household option when multiple people with different hair types share a bathroom. Chemically treated hair — permed, relaxed, or colored — responds particularly well to the gentler cleansing approach.
The broad all-hair-types claim somewhat undersells the fact that this hydrating shampoo is most effective for dry and damaged hair. Users with naturally oily scalps or fine, limp hair are the most likely to find the formula too heavy for regular use, and several leave reviews noting it is not quite the universal option the branding suggests.
Residue & Buildup
83%
Despite the moisture-rich formulation, the Number 4 formula rinses clean without leaving the waxy or heavy coating that some hydrating shampoos deposit on the hair shaft. Users who had previously struggled with buildup from silicone-heavy products report feeling a noticeable difference in scalp freshness after switching.
With daily use over extended periods, a small number of users report a subtle accumulation on the scalp, particularly if they use leave-in treatments or dry shampoos between washes. Occasional use of a clarifying shampoo every few weeks is advisable for heavy product users, even though this sulfate-free formula itself is not the primary culprit.
Ethical & Clean Credentials
94%
The combination of vegan, cruelty-free, gluten-free, paraben-free, and shark squalene-free certifications puts this formula in a genuinely small category of shampoos that take clean formulation seriously across multiple dimensions simultaneously. Ethically motivated buyers consistently cite these credentials as a major factor in their purchasing decision and brand loyalty.
Some sustainability-focused buyers note the absence of any recyclability or eco-packaging information on the listing, which feels inconsistent with the otherwise clean ethos of the brand. There is also limited transparency around specific sustainability practices in the supply chain, which more environmentally driven consumers tend to expect at this price tier.

Suitable for:

The Number 4 Hydrating Shampoo 8.5 oz is a strong fit for anyone whose hair takes regular hits from coloring, highlights, balayage, or chemical treatments — basically anyone who wants their salon investment to last longer between appointments. If your scalp tends to run dry, flaky, or irritated, the sulfate-free and sodium-free formula addresses that without leaning on medicated ingredients or heavy silicones. People who care about what goes on their body will appreciate that the clean-label credentials here are genuine: vegan, cruelty-free, gluten-free, and free of shark squalene. It also suits anyone who has previously experienced dryness, brittleness, or dullness after switching from conventional shampoos, since the moisture-forward formula is built to restore rather than strip. The range of available sizes makes it practical whether you are testing it out with the travel-friendly 1.5oz or committing fully with a larger bottle.

Not suitable for:

Buyers who prioritize a rich, foamy lather may find this sulfate-free shampoo underwhelming right out of the gate — that adjustment can feel like the product is not working, even when it is. The Number 4 Hydrating Shampoo 8.5 oz sits at a premium price point, and if you wash your hair daily or have very long, thick hair that requires generous product use, the cost-per-wash math can get uncomfortable fast. Anyone with naturally oily hair or an oily scalp may find that the moisture-heavy formulation feels too rich, leaving hair looking weighed down rather than fresh. The L'Eau De Mare scent is distinctive enough that fragrance-sensitive users or those who prefer unscented products should be cautious. If you are mainly looking for a budget-friendly, high-volume shampoo for everyday casual use, there are more economical options that will serve you better.

Specifications

  • Brand: Manufactured by Number 4 High Performance Hair Care, a professional-grade hair care brand.
  • Collection: Part of the Hydrate Collection, which is formulated specifically around deep moisture restoration.
  • Size: The standard retail size contains 8.5 oz (approximately 251 ml) of liquid shampoo.
  • Available Sizes: Also sold in 1.5 oz, 25 oz, and 64 oz formats to suit travel, home, or salon use.
  • Product Form: Liquid shampoo in a sealed bottle, intended for topical scalp and hair application.
  • Scent: Fragranced with L'Eau De Mare, an oceanic-inspired scent profile distinct from typical floral or citrus shampoos.
  • Hair Type: Formulated to be suitable for all hair types, including fine, coarse, curly, and chemically treated hair.
  • Sulfate-Free: Contains no sulfate surfactants, reducing the risk of stripping natural oils during cleansing.
  • Sodium-Free: Free of sodium-based compounds, which can dehydrate hair fiber and irritate sensitive scalps.
  • Paraben-Free: Formulated without parabens, addressing concerns around common synthetic preservatives.
  • Gluten-Free: Does not contain gluten-derived ingredients, making it suitable for individuals with gluten sensitivities.
  • Vegan Status: The formula contains no animal-derived ingredients and carries vegan certification.
  • Cruelty-Free: Not tested on animals, as indicated by the brand's cruelty-free certification.
  • Squalene Source: Explicitly free of shark squalene, using only ethically sourced or plant-derived alternatives if applicable.
  • Color Safety: Designed to be color-safe, helping preserve the vibrancy and longevity of dyed or chemically treated hair.
  • Scalp Use: Suitable for use on dry or flaky scalps, with a formula intended to hydrate without causing buildup or irritation.
  • Age Range: Intended for adult use only.
  • Amazon Rating: Holds a 4.4 out of 5 star rating on Amazon, placing it among the top-ranked shampoos in its category.

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FAQ

The Number 4 Hydrating Shampoo 8.5 oz is genuinely formulated to be color-safe, meaning it avoids the harsh surfactants — specifically sulfates — that are most responsible for accelerating color fade. That said, no shampoo can completely stop color from fading over time; it just slows the process down. Users with dyed or highlighted hair consistently report their color looking fresher for longer between salon visits when using this formula.

Nothing is wrong — this is completely expected with any sulfate-free formula. Sulfates are the ingredient responsible for the thick, foamy lather most people associate with shampoo, and this formula deliberately leaves them out. Less foam does not mean less cleansing; the formula still removes dirt, oil, and buildup effectively. It just takes a wash or two to mentally adjust if you are coming from a conventional shampoo.

This hydrating shampoo is actually a reasonable option for sensitive scalps precisely because it skips the ingredients — sulfates, sodium compounds, parabens — that most commonly trigger irritation or dryness. The moisturizing focus means it is designed to hydrate the scalp rather than strip it. That said, everyone's scalp chemistry is different, so if you have a diagnosed condition like seborrheic dermatitis or psoriasis, it is worth checking with a dermatologist before switching.

For most people, two to three times per week is enough to see the hydrating benefits without over-washing. If you have very dry or color-treated hair, washing less frequently actually helps preserve both moisture and color. Daily use is fine if your lifestyle requires it, but you may find results are more noticeable with a slightly spaced-out routine.

The L'Eau De Mare scent is noticeable while washing and tends to leave a light residual fragrance on the hair after rinsing — not heavy or perfume-like, but present. Most users find it pleasant and subtle once dry. If you are particularly scent-sensitive or prefer fragrance-free hair care, this is worth factoring into your decision.

Sulfate-free formulas are generally recommended by stylists for anyone who has had a keratin treatment, Brazilian blowout, or similar service, because sulfates break down the treatment faster. The Number 4 formula fits that requirement well. If you have had a very specific chemical service, it is always a good idea to confirm with your stylist, but the sulfate-free composition makes this a compatible choice in most cases.

This is where the formula's moisture-rich focus requires a little caution. Fine hair types can sometimes find hydrating shampoos a bit weighty, especially if applied generously or left on too long before rinsing. Using a small amount and rinsing thoroughly helps. Some fine-haired users report no issue at all, while others prefer to use it every other wash rather than every time.

The 8.5 oz size is a sensible starting point if you have not used this sulfate-free shampoo before, since it gives you enough product to genuinely assess how your hair responds — usually at least four to six weeks of regular use. Once you know it works for you, the 25 oz or 64 oz sizes offer better value per ounce. Jumping to the largest bottle before testing it is a real financial risk.

L'Eau De Mare translates roughly to sea water, and the scent reflects that — it is clean, slightly marine, and cool rather than sweet or fruity. Think of it as understated and fresh rather than bold or cologne-like. It sits somewhere between a light aquatic fragrance and a clean linen scent, making it fairly neutral and unisex in character.

This hydrating shampoo functions well on its own and does not require you to use a matching conditioner to see results. That said, pairing it with a compatible conditioner from the Hydrate Collection will amplify the moisture benefits, especially for very dry or damaged hair. If you already have a conditioner you love, there is no reason to replace it immediately — you can always add the conditioner later if you feel you need more.