K18 vs Olaplex Purple Shampoo: 4,449 Sephora Reviews Read

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Review-analysis guide: 4,449 customer reviews read on Sephora (November 10, 2026), sorted and counted by us; product details from the Sephora listings checked November 10, 2026.

By The Beauty Read · Checked November 10, 2026 · AI-assisted research and editing · Contains Amazon affiliate links

K18 vs Olaplex purple shampoo (paid link), by Sephora buyers: 38% of 469 usable Olaplex No.4P reviewers said brass toned down, though 14% said it left a purple or gray tint. K18's TripleBright foam is too new to judge well; 215 of its 257 reviews came in a sampled first month, and half of the 40 buyers since called it drying.

K18 vs Olaplex purple shampoo: what 4,449 Sephora reviews show

Purple shampoo has one job, cancelling yellow and orange brass, and two ways to fail: doing nothing, or doing too much. To settle the k18 vs olaplex purple shampoo question, we read every review the Sephora pages served for K18's new TripleBright foam, Olaplex's No.4P and Moroccanoil (paid link)'s Blonde Perfecting shampoo, 4,449 cards in all, and counted toning, dryness, tint and stains. [4] [5] [6]

All three use the same violet dye. The differences sit around it. K18 delivers it as a pump foam with chelating agents the brand says pull hard-water metals out of hair. Olaplex pairs it with its bond-building ingredient and asks for two minutes on the hair. Moroccanoil adds argan oil and asks for three to five minutes. [1] [2] [3]

Most of what we read could not count. 3,693 cards sat in sampling months, when a page fills with free-product reviews, and we set those months aside whole. What remained was 40 usable reviews for K18, 469 for Olaplex and 182 for Moroccanoil, so K18's numbers rest on a small group. [4] [5] [6]

K18 purple shampoo review: a sampled first month and 40 buyer reviews

K18's first Sephora reviews date from March 2026, and they came in a burst. 215 of its 257 cards were posted that month and 202 of them carried the Incentivized or Staff badge, so we set the month aside. This k18 purple shampoo review rests on the 40 buyers who wrote from April to early November. [4]

They were split. 35% said brass or yellow toned down and 15% saw it work in one wash, but 50%, 20 people, called it drying or straw-like, and 28% said it did nothing for their tone. 35% gave one or two stars, the highest share of the three. [4]

Few raised the problem the brand says it avoids. 1 buyer mentioned staining and 3 a purple or gray tint, and 2 said it was mess-free or left no tint. 10% liked the foam itself, and 2 judged it together with a matching mask or conditioner. [4] [1]

Is Olaplex purple shampoo worth it? Steady toning with a catch

Olaplex No.4P has the longest usable record, 469 reviews after its September and October 2023 sampling wave (240 cards) was set aside. 38% said brass or yellow toned down, 20% described brighter or fresher color and 24% said hair felt soft afterwards. [5]

Some said it overshot. 14% said it left a purple, lilac or gray tint, 12% said it stained hands, nails or the tub, and 8% said it lathered poorly or ran out fast. Only 8% said it did nothing, the lowest share of the three. [5]

So is olaplex purple shampoo worth it? For toning, 38% said brass toned down and 55% named toning or brighter color, against 8% who said it did nothing. The ratings have cooled, though. One- and two-star reviews made up 16% of the 243 from 2021, its first year of reviews on the page, 32% of the 169 from 2022 and 2023 and 42% of the 57 written since 2024. [5]

Moroccanoil purple shampoo review: thousands read, 182 usable

Moroccanoil's page looks like the safest bet, with about 3,500 reviews. Almost all of them came in waves. 3,238 of the 3,462 cards fell in sampling months, from a first wave in mid-2020 through winter 2021 to 2022, summer and autumn 2022 and spring 2024. This moroccanoil purple shampoo review rests on the 182 that remain. [6]

Those 182 were the most positive of the three on toning. 46% said brass or yellow toned down, 26% said hair felt soft and 21% praised the scent. Drying came up for 21% and a purple or gray tint for 8%. [6]

Its complaints ran differently from Olaplex's. Fewer reported a tint or stains, but 11% said it did nothing, against 8% for Olaplex, 7% said it lathered poorly or ran out fast, and 22% gave one or two stars. 12 usable reviewers said they kept it on longer than directed or five minutes and more, and 11 of them reported brass toned down. [6]

Moroccanoil purple shampoo vs Olaplex purple shampoo on bleached and gray hair

Reviewers who said their hair was bleached, highlighted or lightened are the core buyers of purple shampoo for bleached hair, and both brands drew plenty of them. 57 of 106 such Olaplex reviewers said brass toned down, against 29 of 45 for Moroccanoil. Over-toning came up for 12 and 4 of them. [5] [6]

Gray and silver hair is a smaller group. 23 Olaplex reviewers described gray or silver hair and 7 said brass toned down, while 4 saw a tint. Moroccanoil had 8 such reviewers, 5 of them happy with the tone. K18 had 9 bleached and 2 gray-haired buyers, too few to split. [5] [6] [4]

In the moroccanoil purple shampoo vs olaplex purple shampoo choice, the trade is tint risk against softness. Olaplex drew more talk of a tint and stains, Moroccanoil more talk of soft hair and scent, and drying sat near a fifth for both (22% and 21%). [5] [6]

How often can you use purple shampoo, and how hair felt afterwards

The labels answer part of how often can you use purple shampoo. K18 says to leave its foam on for one to three minutes and to use it weekly. Olaplex says two minutes and suggests its No.5P conditioner after. Moroccanoil says three to five minutes and a Moroccanoil conditioner after. [1] [2] [3]

Reviewers who went past the label told mixed stories. 38 Olaplex reviewers said they left it on longer than directed or five minutes and more, and 23 of them said brass toned down while 6 reported a purple or gray tint and 7 stains. [5]

Dryness came up too. 160 of 691 usable reviewers called their pick drying, and 48 judged it together with a matching conditioner or mask. Only K18's label gives a frequency, once a week. [4] [5] [6] [1] [2] [3]

Hair feel split the three apart. Soft or smooth hair came up for 26% of Moroccanoil reviewers, 24% for Olaplex and 5% for K18, while scent praise went mostly to Moroccanoil (39 reviewers, against 32 for Olaplex and 0 for K18). Results showing after one wash were named by 15% of K18 buyers, 9% for Moroccanoil and 8% for Olaplex. [4] [5] [6]

How we read each Sephora page for this K18 vs Olaplex purple shampoo check

Of the 4,449 Sephora cards we read, 3,529 sat in months with 20 or more reviews on a page and more than half of them marked Incentivized or Staff or saying the product was free, and we set those months aside whole, organic reviews included: 215 on the K18 page in its first month of reviews, March 2026, 240 on the Olaplex page in September and October 2023, and 3,074 on the Moroccanoil page across 15 months. We also set aside 164 Moroccanoil cards from September and October 2022, explained below. Another 57 outside those months carried the Incentivized or Staff badge or said the product was free, 40 of them on the Moroccanoil page, and 8 were in another language, about shipping or not yet used. That left 691. [4] [5] [6]

Two of the Moroccanoil months, September and October 2022, did not cross that line on their own, but 164 cards landed there against 11 to 17 in the nearby unsampled months of 2022, nine in ten gave four or five stars, and dozens said the bottle was a free sample without carrying a badge. We set those two months aside too, as an editor's call. [6]

Our Amazon links open listings we found through search results on November 10, 2026; Amazon's own pages would not load for us, so we could not read who sells them, and each card says so. Sephora labels the K18 foam as sold only at Sephora, so check the seller line on Amazon before you order it. Every product detail here comes from the Sephora pages, not from Amazon.

Keep reading

• Deep conditioner: Mielle, SheaMoisture and amika across 5,482 reviews
• Clarifying shampoo: Redken, Paul Mitchell and Olaplex
• Leave-in conditioner: amika, Briogeo and Kristin Ess

Frequently asked questions

Is K18 purple shampoo worth it?

Too early to say with confidence. 215 of its 257 Sephora reviews came in a sampled first month, and of the 40 buyers since, 35% said brass toned down while 50% called it drying and 28% saw no toning. If you try it, follow the weekly, one-to-three-minute directions, and since half called it drying, consider a conditioner or mask after.

Is Olaplex purple shampoo drying?

For some. 22% of 469 usable Sephora reviewers called No.4P drying or said it left hair rough, against 24% who said hair felt soft. Olaplex asks for two minutes on the hair and suggests its No.5P conditioner after, and 37 reviewers judged it together with a conditioner or mask.

K18 vs Olaplex purple shampoo: which tones more?

Olaplex, on the larger record. 38% of 469 usable Olaplex reviewers said brass toned down against 35% of 40 K18 buyers, and far fewer said it did nothing (8% against 28%). Moroccanoil came in at 46% of 182. The trade-off is tint, reported by 14% of Olaplex reviewers against 8% for Moroccanoil.

Will purple shampoo turn bleached hair purple?

It can. 12 of 106 Olaplex reviewers with bleached or highlighted hair reported a purple or gray tint, and 4 of 45 for Moroccanoil. Olaplex's label says two minutes and Moroccanoil's three to five, and those printed times are the place to start before going longer on very pale strands.

Do you need conditioner after purple shampoo?

Two of the three brands say so. Olaplex suggests No.5P and Moroccanoil one of its conditioners, while K18 gives no conditioner step but asks for weekly use. Drying came up for 50% of K18 buyers, 22% of Olaplex reviewers and 21% of Moroccanoil reviewers.