DALLAS Biotin Thickening Shampoo Retail Liter
DALLAS

Biotin Thickening Shampoo Retail Liter

This thickening shampoo 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 to roots and work through ends.
Step 2
Rinse.
Step 3
Follow with DALLAS Conditioner.

GET THE EXPERT LOOK

IN THE WILD

WHAT PEOPLE ARE SAYING

4.8
Rated 4.8 out of 5 stars
Based on 434 reviews
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434 reviews
  • Kristiina H.
    Verified Buyer
    Hair Type Straight
    Hair Density Fine
    What is your main hair goal? Volume + Texture
    November 10, 2026
    Hair Type Straight
    Hair Density Fine
    What is your main hair goal? Volume + Texture
    Reviewing
    DALLAS Biotin Thickening Shampoo
    Rated 5 out of 5 stars
    Best shampoo for adding volume

    Having tried volume shampoos in the past, I didn’t really expect much, but I was pleasantly surprised to find that it really does add volume to my very fine hair!

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  • Nancy R.
    Verified Buyer
    Hair Type Wavy
    Hair Density Fine
    What is your main hair goal? Volume + Texture
    November 5, 2026
    Hair Type Wavy
    Hair Density Fine
    What is your main hair goal? Volume + Texture
    Reviewing
    DALLAS Biotin Thickening Shampoo
    Rated 5 out of 5 stars
    Great Shampoo

    I love the shampoo and it is so concentrated. I had to get used to using less.

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  • Adrianna C.
    Verified Buyer
    Hair Type Straight
    Hair Density Fine
    What is your main hair goal? Volume + Texture
    October 26, 2026
    Hair Type Straight
    Hair Density Fine
    What is your main hair goal? Volume + Texture
    Reviewing
    DALLAS Biotin Thickening Shampoo Mini
    Rated 5 out of 5 stars
    Love!

    Love so much that I am buying it in full size!

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  • Mary L.
    Verified Buyer
    Hair Type Straight
    Hair Density Fine
    What is your main hair goal? Volume + Texture
    October 20, 2026
    Hair Type Straight
    Hair Density Fine
    What is your main hair goal? Volume + Texture
    Reviewing
    DALLAS Biotin Thickening Shampoo
    Rated 5 out of 5 stars
    Excellent!! daily use thickening shampoo

    Love this shampoo for daily thickening and volume without any drying effects.

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  • Jamie T.
    Verified Buyer
    Hair Type Wavy
    Hair Density Fine
    What is your main hair goal? Hydration + Repair
    October 18, 2026
    Hair Type Wavy
    Hair Density Fine
    What is your main hair goal? Hydration + Repair
    Reviewing
    DALLAS Biotin Thickening Shampoo
    Rated 4 out of 5 stars
    Give my hair volume

    The Dallas shampoo does give my hair volume, but since I struggle with dry, fine, thin hair it tends to make my hair a bit frizzy. I still like the shampoo, but use a good dose of conditioner

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    R+Co
    October 19, 2026

    Thank you so much for your honest 4-star review, Jamie! ✨ We're really glad to hear that DALLAS is giving your hair the volume you're looking for — that's awesome!

    We totally hear you about the frizz though, especially with fine, thin hair that tends to be on the drier side. It sounds like you've found a great solution by pairing the shampoo with a good dose of conditioner to keep your hair feeling the way you want it to. That's such valuable insight into how the formula works with your specific hair type and needs!

    We really appreciate you sharing your experience with DALLAS and for sticking with the shampoo even as you've figured out what works best for your routine. Feedback like yours helps us understand how our thickening formulas perform across different hair types, and we're grateful you took the time to let our community know what to expect! 💫

    With gratitude,
    The R+Co Team