Redken is a popular shampoo brand with a flagship store in New York City that claims to make hair “7x smoother, instantly.” The brand sells products on their website, in many salons, and on Amazon and other third-party retailers.
But is Redken really better than drugstore shampoo? Does it have research-backed ingredients? Is it worth the incredibly high price? And how do real users rate it?
In this article we’ll answer all of these questions and more as we review the ingredients in Redken’s two most popular products: Redken All Soft Shampoo and Redken Purple Shampoo. We’ll share real, unsponsored user reviews of each product and give our take on whether they’re likely to improve hair quality or if they’re a waste of money.
Redken All Soft Shampoo Ingredient Review
Redken claims that their All Soft shampoo makes hair softer because it provides “3 proteins attracted to where the hair needs it most.” Those three proteins are listed as soy protein, arginine and a trademarked ingredient called “Sepicap.”
Hydrolyzed soy protein is included in many shampoo products, but we cannot identify any medical research suggesting it improves hair quality, nor does Redken appear to cite any.
Arginine is not a protein, it’s an amino acid (a building block of protein). A clinical trial published in the Journal of Cosmetic Science found that topical arginine may reduce hair damage after coloring or bleaching, but we cannot locate any studies suggesting that this ingredient improves the quality of non-treated hair.
Sepicap does not appear to be a protein either, but rather a blend of two ingredients: sodium cocoyl amino acids and potassium dimethicone PEG-7 panthenyl phosphate. The manufacturer of Sepicap lists on its website that the trademarked blend has “benefits on hair fiber” without providing any proof or data.
Overall we’re unimpressed by these three highlighted ingredients given that we are only able to identify one as potentially effective.
Redken All Soft Shampoo also contains a number of additive ingredients that we recommend avoiding.
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 cited in the above-linked study, but we recommend avoiding use of all artificial dyes in cosmetic products as a precaution.
This shampoo contains four separate preservatives: benzoic acid, benzyl alcohol, potassium sorbate and phenoxyethanol. The last of these compounds 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 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, especially considering the cost. While Redken All Soft Shampoo may be effective for improving hair quality due to the arginine, it contains eight additive ingredients we recommend avoiding.
One of the most popular YouTube reviews of Redken All Soft Shampoo is published by a creator named Egle Bee. Her review focuses more on the aesthetic effects of the shampoo than the health benefits, and the video appears unsponsored:
Beauty Influencer Compares Redken to Other Shampoo Brands
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:
Redken Purple Shampoo Ingredient Review
Redken’s second-most popular shampoo is their Purple Shampoo.
We are unable to identify any ingredients in this shampoo proven in clinical research to improve hair quality.
Redken Purple Shampoo contains several ingredients we highlighted in the previous ingredient review and recommend avoiding: fragrance, sodium benzoate, coumarin and phenoxyethanol.
This shampoo contains other ingredients we recommend avoiding.
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 review of skincare brand Crepe Erase.
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 medical research.
One of the most popular YouTube reviews of Redken Purple Shampoo is published by a creator named Jamie Wilkenson. She uses the product over the course of three weeks, and provides before-and-after images:
Redken Real Customer Reviews
Redken is sold on Amazon, which is a more objective resource for customer reviews than a brand's website in our opinion. The brand's most popular product on Amazon is called "One United All-In-One Leave In Conditioner" and has over 19,000 reviews currently.
The product's average review rating is an impressive 4.7 out of 5 stars, and Fakespot gives the conditioner a "B" grade which suggests that most of the reviews are legitimate. Fakespot is a software tool that detects potentially fake Amazon reviews.
The top positive review from a verified purchaser comes from a user named "Sarah" who claims the product improved their hair quality:
"My hair never ever came out this good!!! I did research on line looking for a good heat protector, detangle for my hair and what could be better then this having all of that in one bottle! So now I don’t need to put more products in my hair. This product was voted one of the best! Now I have Soft, silky manageable hair!!! Before my hair was dry and brittle looking!"
The top negative review from a verified purchaser is written by a user named "karenrn94" who claims the product had no effect:
"I should have returned this product. It was expensive to start with. The advertising on the Amazon site and reviews had me. But when I used it. No results that were any different from my other spray in conditioners. I would not buy again. I have frizzy hair and it’s not that bad but honestly no difference."
Our Non-Toxic Shampoo Recommendation
The shampoo we recommend is Acure Vivacious Volume Shampoo.
This shampoo is formulated with effective and non-toxic plant-based compounds like aloe vera juice and argan oil. It also contains rosemary leaf oil which was shown in a clinical trial published in the Phytotherapy Research journal to promote hair growth.
Most importantly, this shampoo contains no questionable additive ingredients like fragrance or synthetic preservatives. It’s less than half of the price of Redken shampoo, costing only $8.49 at the time of updating this article.
Interested consumers can check out Acure Vivacious Volume Shampoo at this Amazon link.
