Nioxin Review: Can Shampoo Really Thicken Hair?

Nioxin Review: Can Shampoo Really Thicken Hair?

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Nioxin is a hair care brand that sells products for thinning or balding hair. The brand claims that their products are “developed specifically for thinning and fine hair.” The brand's most popular products are hair "systems" that contain shampoo, conditioner and treatment.

But do Nioxin's hair products contain research-backed ingredients for promoting hair thickening or are these just marketing claims? Do their products contain any questionable additive ingredients? And how do real users rate and describe the effects of Nioxin?

In this article we’ll answer all of these questions and more as we review the ingredients in Nioxin Shampoo, Nioxin Hair Regrowth Treatment and Nioxin Scalp Treatment based on medical research to give our take on whether or not the products are likely to be effective.

We'll also share a review from a board-certified dermatologist, share real customer reviews including before-and-after images, and explain why we disagree with some of the brand's marketing practices.

Nioxin Shampoo Ingredient Analysis

Nioxin shampoo ingredients

The above ingredients list is for Nioxin “Cleanser Shampoo System 2” which is one of the shampoos sold by the brand for thinning hair. We had to find the ingredients on Ulta, a third-party retailer, because Nioxin fails to publish ingredient lists on their website.

This formulation does contain some effective ingredients for hair growth and hair quality improvement.

Peppermint oil was shown in a clinical trial published in the Toxicological Research journal to cause hair growth when applied topically.

After 4 weeks, the animals receiving the topical peppermint oil treatment had 740% more hair follicles than the control group, and the treatment was found to be equally effective to minoxidil, which is the drug ingredient in hair growth products like Rogaine.

Camellia sinensis leaf extract is another botanical ingredient we could consider effective for a hair thinning shampoo.

A 2019 medical review on this plant's uses in cosmetics stated the following: “Cosmetic preparations containing tea extracts are recommended for patients with androgenetic alopecia and hair loss, regardless of gender.” It appears that topical applications of tea extract decreases dihydrotestosterone (DHT) formation, and this hormone can cause balding by shifting hair growth cycles unfavorably.

Serenoa serrulata fruit extract has demonstrated efficacy for hair growth. A clinical trial examined whether topical application of this botanical ingredient could increase hair count in men with male pattern baldness. The researchers found that average hair count increased significantly by week 12. 

Clearly there are a number of effective ingredients in Nioxin Shampoo 2 for hair thinning. In regard to efficacy alone, this is one of the more impressive formulations we’ve reviewed. 

However, there are unfortunately some questionable additive ingredients as well.

Yellow 5, Blue 1 and Red are artificial dyes. As we documented in our review of skincare brand Maelys Cosmetics, artificial dyes are in some cases contaminated with carcinogens, and there is mixed research on their overall toxicity.

Methylparaben is a type of paraben, which is a class of compounds described in medical research as hormone-disrupting chemicals, and according to the linked research study they are easily absorbed by the human body. 

Sodium benzoate and phenoxyethanol are synthetic preservatives, the latter of which was shown in a 2020 clinical trial to be toxic to human cells.

Overall, we consider Nioxin Shampoo likely to be effective for improving hair growth and thickness due to several clinically-backed ingredients. However, we do not recommend the product due to the inclusion of artificial food dyes, synthetic preservatives and a paraben.

YouTuber Tests Nioxin

A YouTube creator named Robin James tried Nioxin for four weeks and shared his thoughts on whether the treatment improved his hair thickness. He included a product demonstration as well as before-and-after images to analyze hair thickness:

Nioxin Hair Regrowth Treatment Ingredient Analysis

Nioxin Hair Regrowth Treatment ingredients

One of Nioxin’s most popular products is called Hair Regrowth Treatment. The brand sells a different version of this product to men and women, but the active ingredient is the same in both: minoxidil

Nioxin Hair Regrowth Treatment for men contains a concentration of 5% minoxidil, while Nioxin Hair Regrowth Treatment for women contains a concentration of 2% minoxidil. 

Minoxidil is one of the most well-studied chemical compounds for delaying balding and aiding hair regrowth in both men and women when applied topically to the scalp. It’s the active ingredient in the hair loss products sold by many popular brands, such as Rogaine and Keeps.

An extensive medical review of minoxidil for hair regrowth concluded that the compound provides “remarkable benefits.” It can improve both hair growth and hair density when applied daily over a long enough duration.

We don’t understand why Nioxin’s hair regrowth treatment for women has a lower concentration of minoxidil. As we detailed in our review of Rogaine for Women, medical research has shown a 5% concentration of minoxidil to be more effective than the 2% concentration, and just as safe.

While we do consider Nioxin’s hair regrowth treatments likely to be effective, we wouldn’t recommend them for cost reasons.

At the time of writing this article, a one-month supply of Nioxin Hair Regrowth Treatment for men (5% minoxidil concentration) costs $34.19.

A two-month supply of Kirkland Signature Minoxidil at a 5% concentration costs only $18.99 on Amazon.

This means that the price-per-day of Nioxin’s product is $1.14, while the price-per-day of the equivalent Kirkland Signature product is $0.32.

Dermatologist Reviews Nioxin

One of the most popular YouTube reviews of Nioxin is published by a dermatologist named Dr Dray. The video has over 130,000 views and she shares her take on whether or not Nioxin products are worth the money:

Nioxin Scalp Treatment Ingredient Analysis

Nioxin Scalp Relief Cleanser ingredients

The ingredient list above is from Nioxin's Scalp Relief Cleanser. It has several effective ingredients.

Aloe barbadensis leaf juice, more commonly referred to as aloe vera, does have relieving properties. A medical review published in the Italian Journal of Dermatology and Venereology found that aloe vera was effective for treating a number of skin conditions, including inflammation.

Glycerin is another good choice for a scalp relief product, as this compound is proven to have a number of positive effects on skin, such as optimized skin hydration and skin barrier function. The linked research paper details how glycerin also has an antimicrobial effect, which is relevant given that many scalp conditions like dandruff are bacterial or fungal in nature.

Boswellia serrata gum is derived from a plant native to Africa, and a clinical trial found that boswellic acids, which are chemical compounds in boswellia serrata, confer anti-inflammatory properties to skin, and may reduce visible signs of skin aging.

While this product contains a number of effective ingredients, it also contains some additives that we recommend avoiding. This formulation contains three separate preservatives: phenoxyethanol, sodium benzoate, and ethylhexylglycerin.

Fragrance is included, and a medical review on fragranced consumer products found that they are a risk to consumer health, and found that there is a lack of safety testing data on some of the compounds used to make fragrance.

Overall, we consider this product likely to be effective for scalp relief, but we don't recommend it due to the inclusion of synthetic preservatives and fragrance.

Questionable Clinical Efficacy Claims

Nioxin clinical efficacy claims

Nioxin, like many skin and hair care brands, claims that their products are “clinically proven” to work. 

On their System 2 Shampoo Amazon product page, for example, the brand claims that “The kit is clinically proven to reduce by up to 91% hair fall, due to breakage**” and the asterisk notes that this information is “based on a survey among 230 US panelists concerned about thinning hair conducted by SIRS, 2016”.

We do not know how the brand gets such a specific percentage of 91% reduction of hair fall from a user survey. Are the users tracking how many hair follicles they lose throughout the day?

We disagree with describing user surveys as clinical research. When we cite clinical research on Illuminate Health, we're citing studies published in peer-reviewed medical or scientific journals that have a high bar for data quality and methodology. This is an entirely different category of research than user surveys.

We recommend that consumers be wary of claims made by brands that their products are "clinically proven" to work, if those claims are based on user surveys.

Real Customer Reviews of Nioxin

Amazon is a more objective resource than a brand's website for real customer reviews in our opinion.

Nioxin’s most-reviewed product on Amazon is currently their “System 2 Cleanser Shampoo” which has over 8,000 reviews. It has an impressive average rating of 4.7 out of 5 stars.

The top positive review from a verified purchaser comes from a user named “Nimari” who claims that the product solved their balding issues:

“This is the best ever for us a little up in age who find they start shedding like a persian cat...My hair now actually stays on my head instead of on my clothes, my hairbrush is no longer full of hair every time I brush and I love the fresh smell and light tingle in the scalp when this is used with the conditioner.”

The top negative review from a verified purchaser is written by a user named “G. Brown” who claims that the product is poorly-formulated:

“This is so thin and runny that I can't even put it in my hand. It just runs off and I end up wasting a good amount of it. It's like water.” 

Our Clean Hair Growth Picks

Happy Head Topical is our top 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."

MBG Omega-3 Potency+ is our top hair thickness pick.

Supplementation with omega-3 fats and antioxidants is clinically shown to improve hair density, and MBG's supplement contains both.

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

Nioxin Pros and Cons

Here’s our take on the pros and cons of this brand overall:


  • Effective ingredients
  • Good user reviews


  • Contains synthetic preservatives
  • Some products contain fragrance
  • Failure to publish ingredient lists on website
  • Questionable claims of clinical efficacy
Stay up-to-date on our research reviews


We don't currently recommend any Nioxin products. While the brand does have some impressive formulations in regard to efficacy, many of their most popular products contain additive ingredients like fragrance and artificial dye that health-conscious consumers may wish to avoid.

Nioxin's Hair Regrowth Treatments for men and women are free of questionable additives, but the same active ingredient (minoxidil) can be obtained much cheaper from other brands. 

Nioxin claims that their products are "clinically proven" to work based on user surveys, and we disagree with the positioning of user surveys as clinical research.

This brand does appear to have favorable user reviews online.