DALLAS Biotin Thickening Liter Wash Kit
DALLAS

Biotin Thickening Shampoo + Conditioner Liter Set

This thickening duo adds vitality to fine, flat hair while nourishing and strengthening from root to tip.

High-performance

Award-winning

Vegan

Cruelty-free

How to use

Step 1
Apply shampoo from roots and work through ends.
Step 2
Rinse before applying conditioner from mid-lengths to ends.
Step 3
Leave on for 1-2 minutes and rinse.

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IN THE WILD

WHAT PEOPLE ARE SAYING

4.9
Rated 4.9 out of 5 stars
Based on 57 reviews
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57 reviews
  • Linda L.
    Verified Buyer
    Hair Type Straight
    Hair Density Medium
    What is your main hair goal? Volume + Texture
    July 14, 2026
    Hair Type Straight
    Hair Density Medium
    What is your main hair goal? Volume + Texture
    Reviewing
    DALLAS Biotin Thickening Liter Wash Kit
    Rated 5 out of 5 stars
    My new favorite

    I am 72 years old with long grey hair. I can honestly say that I can't remember it looking this good. Lays nicely amazing shine and the smell is fantastic!

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  • Chandra K.
    Verified Buyer
    Hair Type Straight
    Hair Density Fine
    What is your main hair goal? Volume + Texture
    June 22, 2026
    Hair Type Straight
    Hair Density Fine
    What is your main hair goal? Volume + Texture
    Reviewing
    DALLAS Biotin Thickening Liter Wash Kit
    Rated 5 out of 5 stars
    Recent purchase

    Have used the Dallas Biotin thickening shampoo and absolutely love it.

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  • Rebecca S.
    Verified Buyer
    Hair Type Straight
    Hair Density Fine
    What is your main hair goal? Volume + Texture
    February 20, 2026
    Hair Type Straight
    Hair Density Fine
    What is your main hair goal? Volume + Texture
    Reviewing
    DALLAS Biotin Thickening Liter Wash Kit
    Rated 5 out of 5 stars
    the best solution for fine hair I've ever found

    I love this shampoo and conditioner, thus the purchase in large quantities. My only complaint was that the pump for the shampoo arrived broken and inoperable- which is very inconvenient since it's a liter bottle. Hoping someone @ R&Co will see my review and send me a replacement

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    R+Co
    February 21, 2026

    Hi Rebecca! Thank you so much for the amazing 5-star review and for being such a loyal customer - we're absolutely thrilled that the DALLAS Biotin Thickening Kit has become your go-to solution for fine hair! Your satisfaction means the world to us.

    I'm so sorry to hear that the pump arrived broken - that's definitely not the experience we want for you, especially with a liter bottle. We completely understand how inconvenient that must be! Please don't worry, our customer service team will absolutely take care of getting you a replacement pump right away. We'll make sure you can enjoy your favorite products without any hassle.

    Thanks again for choosing R+Co and for taking the time to share your experience. Customers like you make what we do so rewarding!

  • Genevieve
    November 25, 2025
    Reviewing
    DALLAS Biotin Thickening Liter Wash Kit
    Rated 5 out of 5 stars
    5 Stars

    This makes my hair feel great and gives wonderful volume!!! I love the waynit smells too:)

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  • Michelle C.
    Verified Buyer
    Hair Type Straight
    Hair Density Fine
    What is your main hair goal? Volume + Texture
    July 4, 2025
    Hair Type Straight
    Hair Density Fine
    What is your main hair goal? Volume + Texture
    Reviewing
    DALLAS Biotin Thickening Liter Wash Kit
    Rated 5 out of 5 stars
    Awesome

    This shampoo and conditioner makes my hair feel thick and full

    Was this helpful?