Leave-In Hair Mask for Damaged Hair

ReNu21 Nano Repair Leave-In Mask for Damaged Hair

ReNu21 Nano Repair Leave-In Mask for Damaged Hair

$60.00 $80.00

Size: 3.38 oz / 100 ml

3.38 oz / 100 ml
1.69 oz / 50 ml

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Give dry, damaged hair a fresh start with ReNu21 Nano Repair Leave-In Mask, an intensive 4 minute leave-in hair treatment powered by 21 amino acids and hydrolyzed proteins. Designed for damaged, bleached and color-treated hair, this lightweight amino acid and protein treatment helps restore moisture, softness, smoothness and shine while improving the look and feel of stressed strands without weighing hair down.

No rinsing required just apply to damp hair, wait 4 minutes and style.

Product details

Product Description

ReNu21 Nano Repair Leave-In Mask is an intensive amino acid and protein hair treatment designed to improve the look and feel of dry, damaged, bleached and color-treated hair.

This lightweight leave-in hair mask combines 21 amino acids with hydrolyzed wheat, corn and soy proteins, Panthenol and moisture-supporting ingredients to help condition stressed strands while restoring softness, smoothness, shine and manageability.

Ideal as a damaged hair treatment for strands affected by bleaching, coloring, chemical services and regular heat styling, ReNu21 helps reduce the appearance of dryness and roughness while supporting stronger, healthier-looking hair.

Unlike a traditional rinse-out hair mask or deep conditioning treatment, ReNu21 stays in your hair. After shampooing, skip conditioner and apply to towel-dried hair. Allow the treatment to work for 4 minutes, then style as usual—no rinsing required.

ReNu21 works as an intensive hair mask for dry, damaged hair and a lightweight leave-in treatment for strands stressed by bleaching, coloring and chemical services.

For the initial treatment, use ReNu21 for 4 consecutive washes. After that, use once a week or as needed as part of your regular hair care routine.

Product Details

Product Type: Leave-In Hair Mask & Amino Acid Hair Treatment

Best For: Dry, damaged, bleached and color-treated hair

Hair Types: All hair types and textures

Key Complex: 21 amino acids + hydrolyzed wheat, corn and soy proteins

Use On: Clean, towel-dried damp hair

Treatment Time: 4 minutes before styling

Rinse Required: No

Conditioner: Skip conditioner before application

Routine: Use for the first 4 consecutive washes, then once weekly or as needed

Finish: Softer, smoother, shinier and more manageable hair

Who it's For

All hair types and textures
Dry and damaged hair
Bleached or highlighted hair
Color-treated hair
Hair stressed by chemical services
Hair exposed to regular heat styling
Rough, frizzy or difficult-to-manage hair

Benefits

21 Amino Acid & Protein Complex

A blend of 21 amino acids and hydrolyzed proteins helps condition stressed strands and support softer, smoother and stronger-looking hair.

Treatment for Damaged, Bleached & Color-Treated Hair

Designed for hair affected by bleaching, coloring, chemical services and regular heat styling to help improve the look and feel of dry, stressed strands.

Moisture & Frizz Control

Helps replenish moisture and smooth rough, frizzy hair for a softer, more polished and manageable finish.

Hydrolyzed Protein Blend

Hydrolyzed wheat, corn and soy proteins help condition hair and support improved softness, smoothness and manageability.

Lightweight Leave-In Formula

Provides intensive conditioning without the heavy feel of a traditional hair mask and does not require rinsing.

Restores Softness, Smoothness & Shine

Helps revive dull, stressed-looking hair and leaves strands softer, smoother, shinier and healthier-looking.

Fast 4-Minute Treatment

Skip conditioner, apply after shampooing, wait just 4 minutes and continue with your styling routine—no rinsing required.

Ingredients

21-Amino Acid Blend

A blend of amino acids helps condition hair, support moisture balance and improve the look and feel of dry, stressed strands.

Hydrolyzed Wheat, Corn & Soy Proteins

A plant-derived protein blend that helps condition hair and support improved softness, smoothness and manageability.

Panthenol – Pro-Vitamin B5

Helps support moisture retention, softness and flexibility for smoother, more manageable hair.

Sodium PCA

A humectant that helps attract and retain moisture, supporting hydration and softness.

Linseed & Chia Seed Extracts

Plant-derived extracts that complement the conditioning formula and help support softer, smoother and healthier-looking hair.

Vitamin E

Tocopheryl Acetate helps condition the formula and supports a smoother, healthier-looking finish.

Full Ingredient List

Aqua, Cetearyl Alcohol, Propylene Glycol, Behentrimonium Chloride, Isopropyl Palmitate, Myristyl Lactate, Phenoxyethanol, Parfum, Arginine, Itaconic Acid, Alcohol, Linum Usitatissimum (Linseed) Seed Extract, Panthenol, Hydrolyzed Wheat Protein, DMDM Hydantoin, Tocopheryl Acetate, Polyglyceryl-10 Laurate, Salvia Hispanica Seed Extract, Lactic Acid, Hydrolyzed Corn Protein, Hydrolyzed Soy Protein, Alanine, Lysine, Caprylic Acid, Xylitol, Aspartic Acid, Sodium PCA, Leucine, Serine, Proline, Hydroxyproline, Phenylalanine, Threonine, Glycine, Glutamic Acid, Histidine, Isoleucine, Methionine, Tyrosine, Tryptophan.

How to Use

Step 1: Shampoo

Shampoo hair thoroughly. Do not apply conditioner.

Step 2: Towel Dry

Towel dry hair to remove excess water, leaving hair damp.

Step 3: Apply ReNu21

Apply up to 5 pumps of ReNu21 and distribute thoroughly through damp hair, focusing on mid-lengths and ends.

Step 4: Wait 4 Minutes

Allow the leave-in treatment to sit for 4 minutes. Do not rinse.

Step 5: Style

After 4 minutes, continue with your regular styling products and styling routine.

How Often

For the initial treatment, use ReNu21 for 4 consecutive washes. After that, use once a week or as needed.

Every time you use ReNu21, shampoo first and skip conditioner before applying the treatment.

Overall rating: 4.8414893 / 5 from 940 reviews.

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Reviews

Great product!!

"This my second time perching the hair straightener and now I’m going to have to get one for my self, it’s by far the best one that I’ve ever own!!"

— Rosalinda C. (5/5)

Amazing!

"Leaves my hair sooo soft! My hair is longs thick and frizzy, this product made my hair look so shiny and healthy!"

— Sofia D. (5/5)

Incredible Repair Mask!

"This product worked wonders on my damaged hair after just one application. The formula is vegan, cruelty-free, and delivers lasting results. Fast shipping and secure packaging were perfect."

— Leah W. (5/5)

Smooth, Frizz-Free Hair

"ReNu21 helped smooth my frizzy hair, and it feels so much healthier now. The amino acids really make a difference, leaving my hair soft, shiny, and full of life. Love this product!"

— Lisa F. (5/5)

Brittle Hair Savior!

"The ReNu21 Nano Repair Leave-In Mask is the best thing I’ve used for my fragile hair. Aspartic Acid supports keratin production. Fast delivery and secure packaging were also appreciated!"

— Lillian L. (5/5)

Instantly Repairs Split Ends!

"ReNu21’s formula is a lifesaver for damaged hair. I saw immediate improvement, and the results have lasted! Fast shipping and secure packaging were a huge plus too!"

— Molly W. (5/5)

Goodbye Dry Scalp!

"Thanks to serine, my scalp feels healthier and moisturized. Natural hair feels soft and shiny with the RENU21 Nano Repair Leave-In Mask. Fast shipping and secure packaging were a great touch!"

— Wanda J. (5/5)

Instant and Long-Lasting Repair!

"ReNu21 repaired my hair instantly! I love that it’s vegan and cruelty-free. My package was delivered quickly, and it was securely packed. My hair has never looked better!"

— Jennifer J. (5/5)

Grays Gone, Youth Restored

"Tyrosine in ReNu21 brought my color back! I feel like myself again. The fast delivery and secure packaging were exactly what I needed in my busy life."

— Kylie A. (5/5)

Subtle Scent, Stunning Strands!

"The scent of the ReNu21 Nano Repair Leave-In Mask is super mild, yet so refreshing! My hair feels strong and silky without being weighed down. Shipping was quick, and the packaging was secure."

— Tanya O. (5/5)

Q&A

ReNu21 Nano Repair Leave-In Mask Buying Guide

What Is the Best Hair Mask for Damaged, Bleached or Color-Treated Hair?

The best hair mask for damaged hair should address the concerns commonly associated with bleaching, coloring, chemical processing and repeated styling, including dryness, roughness, weakness and loss of softness.

ReNu21 Nano Repair Leave-In Mask is a 100% vegan leave-in hair mask formulated specifically for damaged, bleached and color-treated hair. Its repair-focused formula contains 21 amino acids and conditioning ingredients designed to support weakened hair while improving softness, smoothness and manageability.

Unlike a traditional rinse-out mask, ReNu21 stays in the hair as part of the styling routine. This makes it particularly useful for people looking for a leave-in hair mask or leave-in treatment for damaged hair rather than another step that needs to be rinsed away.

For shoppers searching for the best hair mask for damaged hair, bleached hair or over-processed hair, look for a formula that addresses the actual condition of the hair rather than simply providing temporary surface conditioning.

What Does a Leave-In Hair Mask Do for Damaged Hair?

A leave-in hair mask provides concentrated conditioning and repair support without being rinsed away immediately. This allows the treatment to remain on damaged areas of the hair while you continue with your normal styling routine.

ReNu21 is a lightweight leave-in hair repair mask created for hair affected by bleaching, coloring, chemical processing and other sources of damage. It helps improve the feel and appearance of weakened lengths and ends while supporting smoother, softer and healthier-looking hair.

Because it remains in the hair, ReNu21 has a different role from a traditional deep-conditioning mask. It combines the convenience of a leave-in treatment with a more targeted approach to damaged and over-processed hair.

For anyone looking for a leave-in hair mask for damaged hair, the goal is not simply added moisture but better manageability, softness and repair-focused care for hair stressed by chemical or styling processes.

How Do Amino Acids and Bonding Hair Treatments Help Damaged or Over-Processed Hair?

Bleaching, coloring, chemical processing and repeated heat styling can weaken the hair fiber and leave it feeling rough, brittle or more prone to breakage. Amino acid and bond repair treatments are designed to support compromised areas of the hair and improve how damaged hair looks and feels.

ReNu21 contains a blend of 21 amino acids along with hydrolyzed proteins and conditioning ingredients. Its bonding formula is designed to help reconnect broken bonds and support weakened hair, making it particularly relevant for bleached, color-treated and over-processed hair.

This gives ReNu21 a different role from a basic moisturizing mask. It combines conditioning with bond repair and amino acid-based care for hair that has experienced chemical processing, bleaching or repeated styling.

No cosmetic treatment can return heavily processed hair to its untouched biological state, but a targeted bond repair hair mask can help damaged hair look and feel stronger, smoother and healthier.

How Often Should You Use a Leave-In Hair Mask for Damaged Hair?

The right frequency for a hair repair mask depends on the formula and the condition of your hair. ReNu21 uses a staged routine, with more frequent application at the beginning followed by maintenance use.

After shampooing, skip conditioner and towel-dry your hair. Apply ReNu21 to damp hair, distribute it through the lengths and allow it to sit for approximately four minutes before continuing with styling.

For the initial repair phase, use ReNu21 for four to six consecutive washes. After that, use it approximately every four washes as a maintenance treatment.

If you’re wondering how often to use a hair mask for damaged hair, following the routine designed for the specific product is more useful than assuming every repair mask should be used once a week.

For the initial repair phase, use ReNu21 for four to six consecutive washes. After that, use it approximately every four washes as a maintenance treatment.

If you’re wondering how often to use a hair mask for damaged hair, following the routine designed for the specific product is more useful than assuming every repair mask should be used once a week.

FAQs

Please read our FAQs page to find out more.

What is this product?

It’s a leave-in mask formulated with 21 amino acids designed to strengthen and repair damaged hair by reconnecting broken bonds.

How do I use it?

After shampooing, skip conditioner, towel-dry hair, apply up to 5 pumps of the mask to damp hair, massage through, allow to sit about 4 minutes, then style as usual.

How often should I use it?

For best results, use it consecutively for the first 4-6 washes, then switch to every 4 washes for maintenance.

Can I use ReNu21 with other styling products?

Yes. Apply ReNu21 first to clean, towel-dried hair, wait 4 minutes, then continue with your regular styling products and styling routine.

Why should I skip conditioner before using ReNu21?

For best results, use ReNu21 directly after shampooing as instructed. Skip conditioner, towel-dry your hair, apply ReNu21 and wait 4 minutes before styling.

Is ReNu21 suitable for bleached and color-treated hair?

Yes. ReNu21 is designed for bleached, color-treated and chemically treated hair and helps improve the softness, smoothness and manageability of stressed strands.

Do I rinse ReNu21 out after 4 minutes?

No. ReNu21 is a leave-in hair mask. Leave it in your hair for 4 minutes, then continue with your regular styling routine without rinsing.