Olaplex is a hair products brand that makes some interesting health claims. The company claims that their patented ingredient bis-aminopropyl diglycol dimaleate fixes damaged hair on a molecular level and “provides immediate results for all hair types.”

But is this ingredient actually proven to fix damaged hair or is this just a marketing claim? Does Olaplex have any other research-backed ingredients to justify its high price? Does the brand use any questionable additive ingredients? And how do real Olaplex users rate and describe the effects on their hair?

In this article we'll answer all of these questions and more as we analyze Olaplex's patented ingredient to give our take on whether or not it's likely to repair and rejuvenate hair.

We'll also review the ingredients in two of the brand's most popular products (No. 3 and No. 4) based on clinical studies to give our take on whether or not they're likely to improve hair quality.

Finally, we'll feature unsponsored customer reviews and explain whether or not Olaplex is banned in the EU.

Olaplex's Patented Ingredient

Bis-aminopropyl diglycol dimaleate is the patented ingredient that Olaplex claims repairs damaged hair.

This compound works in theory by repairing the disulfide bridges of keratin, which is the protein that composes most of the structure of our hair.

We’re only able to locate one clinical trial on this patented ingredient.

The above-linked trial examined the chemical composition and potential effects of bis-aminopropyl diglycol dimaleate on hair, but did not test it or prove efficacy in a trial with human participants.

We can’t find any clinical trials showing this ingredient to improve hair quality in humans, so at present we're unconvinced about its potential efficacy.

We hope that in the future, Olaplex funds clinical trials with human participants testing the effects of this ingredient on hair structure and quality.

Olaplex No.3 Ingredient Analysis

The ingredients in Olaplex No.3, also known as Hair Protector, are shown above.

This is a liquid treatment meant to be applied to hair prior to shampoo, and left for 10 minutes or more.

Simmondsia chinensis (jojoba) seed oil may improve hair thread and breakage resistance according to a clinical trial published in the Polymers journal, but only when combined with a class of cosmetic ingredients that does not appear to exist in this product.

We're unable to identify any other active ingredients in this formulation that we can find existing clinical studies to support.

There are several inactive ingredients in this formulation that we consider to be questionable from a health perspective.

Fragrance was analyzed in a 2021 medical review and the researchers concluded that “[the] risks clearly outweigh [the] benefits.”

Sodium benzoate, benzyl benzoate, cetrimonium chloride and phenoxyethanol are synthetic preservatives.

The last of these preservatives was shown in a clinical trial to be toxic to human cells, as we documented in our review of Routine Shampoo (another hair product containing this ingredient).

Overall, we do not consider Olaplex No.3 likely to repair hair or to improve hair quality because we're unable to identify any active ingredients that we consider to be effective in isolation.

We don't currently recommend this product due to the inactive ingredients described above.

A YouTube creator named Gena Marie has an Olaplex No.3 review that includes before-and-after images:

Influencer Reviews All Olaplex Products

A YouTube creator named Audrey Victoria has over 2 million views, and reviews all of the most popular Olaplex products with before-and-after images:

Olaplex No. 4 Ingredient Analysis

The ingredients in Olalpex No.4 Bond Maintenance Shampoo are shown above.

Punica granatum extract, otherwise known as pomegranate extract, is an effective ingredient for a hair restoration shampoo. 

A 2021 meta-study found this ingredient to have anti-lice, antidandruff and hair growth promoting effects.

Argania spinosa kernel oil helps to protect hair against oxidative damage according to a 2022 clinical trial.

Panthenol may have scalp-moisturizing effects based on trials documented in a medical review published in the Journal of Cosmetic Science.

Rosemary leaf extract is clinically shown to support hair growth.

While this formulation contains some research-backed active ingredients, it also contains some inactive ingredients that may be questionable from a health perspective.

Fragrance and phenoxyethanol are ingredients we recommend avoiding, for reasons explained in the previous Ingredient Analysis section.

Chlorphenesin has also been shown in one test tube trial to be toxic to human cells, as we documented in our Maelys review article.

Overall, we consider Olaplex No.4 likely to promote hair growth, support hair quality and repair hair. This is a much more impressive formulation than Olaplex No.3 in our opinion.

We do not currently recommend this product due to the inactive ingredients discussed above.

A YouTube creator named Heidi has an Olaplex No.4 review after six months of use that has over 250,000 views:

Is Olaplex Banned in the EU?

There have been a lot of questions online (especially on TikTok) about whether or not Olaplex products are banned in the EU.

While one of the ingredients in Olaplex's old formulations (lilial) was banned in the EU due to infertility concerns, Olaplex's FAQs page states that this ingredient is not currently in any of their existing formulations, which means that no Olaplex products should be banned in the EU.

We commend the company for being proactive about removal of this ingredient.

Popular beauty blogger Abbey Yung explains the ingredient in question and discusses whether or not consumers should avoid it for health reasons in the below video:

Our Clean Hair Care Picks

Acure Vivacious Volume Shampoo is our top shampoo pick.

It contains argan oil which is clinically shown to help protect hair from damage.

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%.

Ritual HyaCera is our top hair growth supplement.

This supplement contains wheat oil extract, and a 2024 clinical trial reported that a wheat lipid complex had "a reducing effect on hair shedding and a stimulating effect on hair reappearance and growth."

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

Pros and Cons of Olaplex

Here are the pros and cons of Olaplex in our opinion:

Pros:

• Patented ingredient may repair hair
• Olaplex No.4 should strengthen hair
• Olaplex No.4 should repair damaged hair
• Olaplex No.4 should improve hair appearance
• Brand phased out use of potentially harmful ingredient

Cons:

• Both formulations we reviewed contained fragrance
• Both formulations we reviewed contained phenoxyethanol
• Olaplex No.3 formulation is unimpressive from an efficacy perspective
• Olaplex No.4 contains chlorphenesin

Conclusion

Much of Olaplex's marketing centers on their patented ingredient bis-aminopropyl diglycol dimaleate, and while this ingredient may be promising based on early research, we cannot identify a single clinical trial with human subjects showing that it improves hair quality or reduces hair damage.

Olaplex No.3 contains various inactive ingredients we consider to be unhealthy such as fragrance and the synthetic preservative phenoxyethanol.

Olaplex No.4 contains a large number of research-backed active ingredients, and we consider this shampoo likely to improve hair quality, and to have the potential to even cause hair growth.

Of the two products, Olaplex No.4 is the vastly superior formulation in our opinion.

We don't currently recommend either product due to the inclusion of fragrance and other inactive ingredients.

There's a significant amount of confusion online about whether or not Olaplex is banned in the EU. This confusion stems from the fact that Olaplex used to use an ingredient that is banned in the EU.

However, Olaplex phased out use of this ingredient and none of the brand's products appear to be banned in the EU at the time of updating this article.