Redken Shampoo Review: Is 7x Smoother Hair Possible?

Redken Shampoo Review: Is 7x Smoother Hair Possible?

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Redken is a popular shampoo brand with a flagship store in New York City that claims to make hair “7x smoother, instantly.” The brand describes their product line as "nourishing, strengthening and repairing shampoos for damaged hair."

But is Redken really better than drugstore shampoo? Does it have research-backed ingredients for improving hair quality? Does it have any questionable additive ingredients? And how does Redken compare to other luxury shampoo brands?

In this article we’ll answer all of these questions and more, as we analyze the ingredients in two of Redken’s most popular products (All Soft Shampoo and Purple Shampoo) based on clinical studies to give our take on whether or not these products are likely to improve hair quality.

We’ll feature unsponsored customer reviews of the brand, share a video that compares Redken to other luxury shampoo brands, and provide a cost comparison to show which retailer sells Redken for the best price.

All Soft Shampoo Ingredient Analysis

Redken All Soft Shampoo ingredients

The ingredients in Redken All Soft Shampoo are shown above.

Hydrolyzed soy protein is included in many shampoo products, but we cannot identify any medical research suggesting it improves hair quality, nor does Redken cite any on their product page at the time of updating this article.

Arginine is an amino acid that has a hair-protecting effect.

A clinical trial published in the Journal of Cosmetic Science found that topical arginine reduces hair damage after coloring or bleaching.

Sepicap is a patented blend of two ingredients: sodium cocoyl amino acids and potassium dimethicone PEG-7 panthenyl phosphate.

The manufacturer of Sepicap lists on its website that this blend has “benefits on hair fiber” but fails to provide any evidence.

Redken All Soft Shampoo contains a number of inactive ingredients that we consider to be questionable from a health perspective.

Orange 4 and Red 33 are artificial dyes, and we know from medical research that “hair coloring products have been proven to be potent carcinogens in animal models.”

A carcinogen is a cancer-causing substance. Neither of the two dyes in Redken’s shampoo were specifically described in the above-linked study, but we recommend avoiding use of all artificial dyes in cosmetic products as a precaution.

Benzoic acid, benzyl alcohol, potassium sorbate and phenoxyethanol are preservatives, and phenoxyethanol was shown to be toxic to human cells in a 2020 clinical trial.

Coumarin is a fragrance ingredient that was shown in clinical research to be toxic to lung tissue, as we documented in our review of Touchland hand sanitizer (another brand containing this ingredient).

Many individuals take hot showers and inhale steam, so the health risks of a lung irritant are greater for shampoo products than for hand sanitizer in our opinion.

Fragrance is a broad ingredient descriptor, and a 2016 medical review concluded that “everyday fragranced products can pose serious risks to human health.”

Overall, this is one of the worst shampoo formulations we’ve reviewed on Illuminate Health from a health and safety perspective.

While Redken All Soft Shampoo may be effective for protecting hair from damage due to the arginine, it contains eight additive ingredients we recommend avoiding.

One of the most popular reviews of Redken All Soft Shampoo comes from a YouTube creator named "Egle Bee." Her review focuses more on the aesthetic effects of the shampoo than the health benefits, and appears unsponsored:

Redken vs. Other Luxury Shampoos

A beauty influencer named Abbey Yung compared Redken’s Acidic Bonding Concentrate Shampoo to three other popular shampoo brands.

She breaks down the ingredients in each product and explains which one is her favorite:

Purple Shampoo Ingredient Analysis

Redken Purple Shampoo ingredients

The ingredients in Redken Purple Shampoo (another best-seller) are shown above.

We are unable to identify any ingredients in this shampoo shown in clinical studies to improve hair quality.

Fragrance, sodium benzoate, coumarin and phenoxyethanol are all included in this shampoo, and we outlined in the previous Ingredient Analysis section why we recommend avoiding these ingredients.

This shampoo contains other questionable additives.

Acid violet 43 is the artificial colorant that gives this product its purple color, and according to a medical review is prohibited for use in eye products and any cosmetic that comes into contact with mucous membranes.

BHT has a metabolite that was shown to be a “tumor promoter” in clinical research, as we documented in our Plantur 39 reviews article on another shampoo that contains this ingredient.

Overall, we do not recommend Redken Purple Shampoo, and we are unable to identify any ingredients in this formulation that we consider likely to improve hair quality based on clinical studies.

One of the most popular reviews of Redken Purple Shampoo comes from a YouTube creator named Jamie Wilkenson. She uses the product for three weeks, and provides before-and-after images:

Where to Get the Best Price

Redken Shampoo is sold at a variety of online retailers. Here's a price breakdown for a one-time purchase of the two products reviewed in this article, at the time of updating this article:

All Soft Shampoo (300 mL)

Brand website: $25 (plus shipping, link)

Ulta: $25 (plus shipping, link)

Amazon: $25 (free shipping, link to official Amazon listing)

Purple Shampoo (300 mL)

Brand website: $25 (plus shipping, link)

Ulta: $15 (plus shipping, link)

Amazon: $15 (free shipping, link to official Amazon listing)

Redken Shampoo is currently around 15-40% cheaper on Amazon than the brand's website for a one-time purchase, when factoring in shipping fees.

Real Customers Review Redken

Amazon is a better resource for unbiased customer reviews than a brand's website in our opinion.

Redken All Soft Shampoo has been reviewed over 17,000 times on Amazon, with an average review rating of 4.7 out of 5 stars at the time of updating this article.

The top positive review from a verified purchaser comes from a user named "Linda J Hoover Smith" who gives the product a 5/5 star rating, and likes the overall product experience:

"I have a dry scalp and I couldn't find a shampoo that cleaned my hair and moisterized my scalp so it would not itch. This stuff does both. I am very impressed with this product."

The top negative review from a verified purchaser is written by a user named "Katie" who gives the product a 1/5 star rating, and claims it caused greasy hair and hair fallout:

"I use to be able to go 3-4 days between washes without my hair getting too oily but with the shampoo and conditioner if I wash my hair in the morning it's greasey by night. This is probably because of my hair type but I also struggled with my hair knotting easier and hair fallout."

Our Clean Hair Care Picks

Ingreendients Daily Shampoo is our top shampoo pick.

It's formulated 100% from plants and contains research-backed active ingredients like acetic acid, derived from apple cider vinegar (ACV), which researchers suggest "can condition hair making it softer, silkier, shinier."

Happy Head Topical is our top premium hair growth solution.

This formulation uses FDA-approved hair loss ingredients like minoxidil which is clinically shown to increase hair count by 11%.

Momentous Zinc is our top value hair growth solution.

A 2022 medical review on the use of zinc in dermatology concluded that "This review has found evidence to support the use of hair loss disorders."

All of the products recommended in this section are entirely free of ingredients we consider to be unhealthy.

Pros and Cons of Redken

Here are the pros and cons of Redken Shampoo in our opinion:


  • All Soft Shampoo may have hair-protective effects
  • Highly positive Amazon reviews


  • Contains fragrance ingredients
  • Contains synthetic preservatives
  • Contains synthetic dye in some cases
  • Brand website charges for shipping
  • Products we reviewed don't appear clinically tested
Stay up-to-date on our research reviews


Overall, we're disappointed in the two Redken Shampoo formulations that we analyzed in this article.

This brand is priced like a luxury shampoo, but the formulations are not luxury-standard in regard to efficacy and safety in our opinion. We do not consider Redken Shampoo to be superior to an average drugstore shampoo.

Redken All Soft shampoo contains an amino acid that's clinically shown to protect hair from damage, while we're unable to identify any active ingredients in Redken Purple Shampoo that we consider likely to improve hair quality or apperance.

Both Redken shampoos that we reviewed contained a number of questionable inactive ingredients like synthetic dye and fragrance, that may be harmful to human health.

Redken has one of the better average Amazon ratings that we've come across for a shampoo brand to date.

At the time of updating this article, Amazon has the best prices on a one-time purchase of Redken Shampoo by a significant margin.