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Do Hair Thickening Shampoos Work?

    Quick Summary: Hair Thickening Shampoos

    About Hair Thickening Shampoos: These products are designed to temporarily increase hair volume and thickness. They typically contain ingredients like keratin, biotin, or panthenol that coat the hair shaft and add volume by swelling the cuticle with moisture.

    How They Work: Hair absorbs moisture, allowing it to swell up to 15% thicker in diameter. Hair thickening shampoos use this property, giving hair a fuller, more voluminous appearance.

    Key Hair Thickening Ingredients: Proteins and polymers are key ingredients in hair thickening products. Proteins like keratin, collagen, and silk proteins help repair and protect, while polymers add texture and increase hair diameter by coating the hair shaft.

    Hair Porosity and Volume: Hair porosity influences how much moisture hair absorbs and retains. High porosity absorbs moisture well but may become flat, and go frizzy as it dries. Medium porosity hair holds volume well, while low porosity hair may require extra effort to open the cuticle for moisture absorption.

    Choosing your products: Consider the product’s moisturisation capabilities, protein and polymer content, compatibility with your hair type, and any other additional benefits to make sure it aligns with your hair’s texture and porosity.

    Hair Loss, and When To Be Concerned: It’s normal to lose about 50-100 hairs daily due to the natural hair growth cycle. However, significant or sudden hair loss might indicate an underlying issue. Consult a GP or hair specialist such as our clinic to help identify the cause and provide appropriate treatments, such as medicated shampoos, medication, or even hair transplant surgery.

    Key Takeaways: Hair thickening shampoos can offer a temporary boost in hair volume by coating the hair shaft and enhancing moisture retention. However, they don’t address underlying causes of hair thinning or loss. If you have concerns about hair loss, consult a specialist for advice. Ultimately, the best results come from choosing products that suit your hair’s unique needs. The best way to maintain hair health is through proper hair care and lifestyle, and seeking professional guidance when needed.

    Hair thinning and hair loss are common experiences for people of all ages and genders. Hair thickening shampoos and other products claim to help you achieve fuller hair, but do they work as effectively as they claim?

    What Are Hair Thickening Shampoos? 

    Hair thickening shampoos are products designed to temporarily increase hair volume and thickness. They often include ingredients like keratin, biotin, or panthenol, which coat the hair shaft and add volume by swelling the hair cuticle layer with moisture. Although they don’t address the root causes of hair thinning, they can temporarily give the hair a fuller, more textured look. 

    hair shaft diagram

    How Do Hair Thickening (and Volumising) Products Work? 

    Hair can absorb water and physically change its appearance depending on different environments. Hair fibres are hygroscopic, a scientific way of saying that they tend to absorb moisture from the environment, and how much moisture they absorb depends on other factors like hair type and overall hair health. Research indicates that hair can swell by up to 15% in diameter due to moisture absorption.1 This effect is more pronounced in humid conditions, where higher moisture levels correlate with increased hair volume.1  

    Hair thickening shampoos and other treatments use this property of hair shafts to temporarily increase thickness and make the hair look more voluminous. 

    Key Hair Thickening Ingredients 

    Proteins and polymers are key ingredients in hair thickening products. Proteins are well absorbed into the hair shaft. Examples include collagen, casein (derived from milk), fibroin (from silk), and wheat derivatives.1,2 These proteins work by repairing and protecting hair, boosting its elasticity, and giving it a smoother and shinier look. Some proteins also help retain moisture, which in turn reduces hair porosity and creates a volumising effect. By retaining moisture, these proteins prevent the hair from becoming overly dry, which can lead to brittleness, while also avoiding excess hydration that can weigh hair down, causing it to look flat.

    Proteins commonly used in hair thickening products include: 

    Keratin: Naturally found in hair, keratin fills gaps in damaged cuticles, aiding in moisture retention and reducing porosity. This leads to stronger, smoother hair with less frizz. 

    Silk Proteins (Fibroin): Derived from silk, these proteins are known for their moisture-binding properties. They form a protective layer on the hair, enhancing softness and flexibility. 

    Hydrolysed Wheat or Soy Protein: These proteins can increase moisture retention, add volume to hair, and improve elasticity and manageability. 

    Polymers, also known as thickening agents, add texture and increase hair diameter by coating the hair shaft and swelling the cuticle.2,3,4 Some commonly used polymers in hair thickening products that you might see on the back label are: 

    Film-forming Polymers:

    • Polyquaternium-10: Helps condition hair and reduce static electricity, contributing to smoother hair with fewer flyaways. This makes the hair more manageable and helps decrease the likelihood of damage caused by tangling or static-induced breakage.
    • Polyvinylpyrrolidone (PVP): Creates a film that adds texture and body to hair.
    • Acrylate Copolymers/Carbomers: Forms a structure or film that adds body to hair.

    Viscosity Modifiers (for creamier and richer products):

    • Hydroxyethylcellulose: Increases the thickness of the product, contributing to its consistency and creaminess. This can also help create a film on hair strands, contributing to a temporary thickening effect.
    • Polyethylene Glycols (PEGs): Serve a similar purpose in thickening and maintaining consistency.

    Silicone-based Polymers:

    • Dimethicone: A silicone-based polymer that coats hair for a smoother and shinier appearance.
    • Carbopol Polymers: Although commonly used to thicken the product’s consistency, they also stabilise the product’s formulation by ensuring all ingredients remain evenly mixed for consistent application. They are related to acrylate copolymers mentioned above.

    Together, these proteins and polymers work to give hair a fuller appearance, addressing common issues like frizz, dryness, and breakage while improving hair texture and volume. 

    Hair Porosity and Volume 

    Hair porosity refers to the hair’s ability to absorb and retain moisture, influenced by the condition of the cuticle—the outermost part of the hair strand. Porosity is mostly genetic, but it can be affected by hair grooming practices. Understanding hair porosity is key to managing hair volume and thickness. Here’s a breakdown of different porosity levels and how they affect hair volume3,5

    Low Porosity: This type has a tightly sealed cuticle that resists moisture penetration. Low porosity hair may struggle and take longer to gain volume because products and moisture have difficulty being absorbed. However, it can maintain moisture well with proper management, needing heat to open the cuticle for better absorption

    Medium Porosity: With a cuticle layer that balances moisture absorption and retention, this hair type generally has good volume and holds styles well without becoming excessively frizzy. It’s often considered the ideal porosity for healthy hair because of its easy manageability. 

    High Porosity: This hair type has a damaged or raised cuticle, allowing moisture to enter and exit easily. It may look voluminous when wet due to increased water absorption but can become frizzy and lose volume as it dries. High porosity hair can also be prone to damage and breakage because of the open cuticle structure. 

    hair porosity explained

    Hair porosity and hair thickening shampoos

    To recap what we’ve explored so far, hair thickening products work by adding density to individual strands through proteins and polymers. These ingredients coat the strand, increasing its diameter and giving it a fuller, more voluminous appearance. Hair porosity dictates how well your hair absorbs these, and there are suitable options for all hair types. It’s essential to understand your hair type and use products designed for your specific needs to achieve the best results.5

    Now that we have explored the science behind how hair can be thickened, let’s look at how hair thickening shampoos use these principles. They work by:

    1. Using keratin and other protein-based formulas
    2. Adding polymer-based formulas as both stabilising and thickening agents that keep the products thick and smooth.
    3. Incorporating other volumising agents and ingredients known to benefit hair health and enhance temporary thickness like natural oils/ingredients (e.g. rosemary, coconut, caffeine) and beneficial nutrient derivatives like panthenol (provitamin B5), biotin (vitamin B7), and niacinamide (vitamin B3).6,7

    Here are some key factors to consider when choosing your hair thickening products: 

    • Moisturisation: Ensure the product provides adequate hydration for your hair type, as dryness can cause brittleness and breakage, potentially leading to thinner hair. 
    • Proteins, Polymers, and Volumising Agents: As discussed above, look for keratin and other additional ingredients which can help strengthen and thicken the hair shaft.
    • Compatibility with Your Hair Type and Skin: Ensure the product suits your hair’s texture and porosity, whether it’s straight, wavy, curly, or coiled, and is kind on your skin to avoid unwanted side effects and irritation. 
    • Additional Benefits to Scalp Health: Some thickening products contain natural extracts like rosemary oil and caffeine, which can potentially improve blood circulation and encourage hair growth according to certain studies.7 

    The Independent has an article reviewing hair thickening products, which you can go through if you’re interested here. As we mentioned earlier, it’s important to note that thickening shampoos are typically a temporary solution and do not permanently change the hair’s growth pattern. If you’re experiencing hair loss or thinning, at The Treatment Rooms we can help you identify the root cause and determine appropriate treatment options. If you are using thickening shampoos, be aware that some ingredients might cause scalp irritation, so it’s best to listen to your scalp and discontinue use if you notice irritation or shedding. 

    Hair Loss, and When to be Concerned  

    It’s normal to lose about 50-100 hairs a day due to the hair’s natural growth cycle. However, if you experience sudden or excessive hair loss, it may indicate an underlying health issue. If you notice any significant and unexplained changes in hair density, hairline, or shedding, it is best to have a chat with your GP or hair specialists like our clinic. They can assess your hair health, identify potential causes and recommend appropriate treatments, this may include the use of medicated shampoos containing minoxidil, taking oral and/or topical medication (like minoxidil, finasteride) or more permanent solutions such as hair transplant surgery if applicable – if you’re thinking about this option, contact our experts today to discuss your hair concerns and explore treatment options.  


    Navigating the world of hair care products, particularly those promising to thicken hair, requires understanding the science behind how these products work. While hair thickening shampoos and other related products can provide a temporary boost in volume by coating the hair shaft and enhancing moisture retention, they are not a cure for underlying hair thinning or loss. When looking for hair thickening products, it’s essential to consider factors such as hair porosity, the specific needs of your hair type, and the overall health of your scalp. Remember, maintaining a healthy scalp environment and consulting with hair specialists when necessary can lead to more effective and sustainable hair health solutions.


    1. Cruz CF, Ribeiro A, Martins M, Cavaco-Paulo A. Effect of a peptide in cosmetic formulations for hair volume control. Int J Cosmet Sci. 2017;39(6):600-609. doi:10.1111/ics.12415. Available from:
    2. Alves TFR, Morsink M, Batain F, Chaud MV, Almeida T, Fernandes DA, da Silva CF, Souto EB, Severino P. Applications of Natural, Semi-Synthetic, and Synthetic Polymers in Cosmetic Formulations. Cosmetics. 2020; 7(4):75. Available from: 
    3. Gavazzoni Dias MF. Hair cosmetics: an overview. Int J Trichology. 2015;7(1):2-15. doi:10.4103/0974-7753.153450. Available from: 
    4. Mahajan, A. Advancements in polymers used in hair care a review. Int J Cosmet Sci. 2016; 6(1): 6-16. Available from: 
    5. Nall R. High porosity hair: Characteristics, products, and tips for care. Healthline. September 19, 2019. Accessed April 20, 2024.
    6. Davis MG, Thomas JH, van de Velde S, et al. A novel cosmetic approach to treat thinning hair. Br J Dermatol. 2011;165 Suppl 3:24-30. doi:10.1111/j.1365-2133.2011.10633.x. Available from: 
    7. Hosking AM, Juhasz M, Atanaskova Mesinkovska N. Complementary and Alternative Treatments for Alopecia: A Comprehensive Review. Skin Appendage Disord. 2019;5(2):72-89. doi:10.1159/000492035. Available from: 
    8. Hair Porosity Diagram edited in

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