Increasing the viscosity of gels and shampoos is one of the main challenges in cosmetic product development. This property not only affects product stability and appearance, but also its sensory profile and ease of application—key factors for consumer experience.
In this blog post, we explain how to increase viscosity in both traditional (sulfate-based) and sulfate-free formulas, which are increasingly in demand in natural cosmetics and wellness-focused personal care.
Viscosity directly influences the perception of a product. A shampoo that is too runny may be perceived as low quality, whereas one with the right consistency conveys higher efficacy and value. Additionally, it improves dosage control and enhances application experience.
Some of the main factors that determine the viscosity of a gel or shampoo include:
Sulfate-free formulas pose an added challenge. Here are some effective solutions:
For products that require transparency or the avoidance of ethoxylated ingredients, systems based on Laureth-2 and PEG-90 Glyceryl Isostearate can be used. However, they should be avoided in 100% natural or PEG-free formulations.
Choosing the right method to increase viscosity in shampoos and gels depends on the type of surfactants used and the objectives of the formulation—whether sensory quality, natural positioning, transparency, or performance. In today’s market, where sulfate-free and natural formulas are growing in popularity, it’s essential to understand the most effective and stable alternatives to ensure product quality and user experience.
Need Help with Your Cosmetic Formulations?
Contact us and discover Lemmel’s portfolio of specialized raw materials designed to enhance viscosity and performance in your personal care products.
In this blog post, we explain how to increase viscosity in both traditional (sulfate-based) and sulfate-free formulas, which are increasingly in demand in natural cosmetics and wellness-focused personal care.
Why Is Viscosity Important in Gels and Shampoos?
Viscosity directly influences the perception of a product. A shampoo that is too runny may be perceived as low quality, whereas one with the right consistency conveys higher efficacy and value. Additionally, it improves dosage control and enhances application experience.
Key Factors Influencing Viscosity
Some of the main factors that determine the viscosity of a gel or shampoo include:
- Type and concentration of surfactants
- pH adjustment
- Presence of salts or thickeners
- Formulation temperature
- Interaction with fragrances and other ingredients
Techniques to Increase Viscosity in Shampoos and Gels
1. Use of Salts: The Most Common Approach
In formulas containing surfactants such as Sodium Laureth Sulfate, the addition of sodium chloride (common salt) is a cost-effective and efficient solution to increase viscosity. However, it must be used carefully to avoid viscosity inversion (when excess salt reduces viscosity).2. Incorporating Surfactants with Thickening Effects
Surfactants like Cocamide DEA or Cocamide MEA act as co-thickeners and foam stabilizers. They are ideal in traditional formulas, though their use is increasingly regulated. Glucamides—non-ionic surfactants such as Lauroyl/Myristoyl Methyl Glucamide—are excellent foam boosters and help improve viscosity while offering thickening properties.3. pH Adjustment in Amino Acid–Based Surfactants
Surfactants like Sodium Lauroyl Sarcosinate allow viscosity modulation by adjusting the pH to between 5.0 and 5.5 using organic acids such as lactic acid. It's crucial to experimentally determine the optimal point, as viscosity may drop sharply outside this range.4. Use of Natural Esters as Thickeners
Ingredients like Myristyl Lactate or Lauryl Lactate work in both sulfate and sulfate-free systems. In addition to thickening, they offer sensory benefits such as conditioning effects—especially valuable in shampoos.5. Natural Gums: A “Clean Beauty” Option
Xanthan gum is a natural alternative that, while sometimes challenging to work with, aligns well with current trends in natural and vegan cosmetics.Effective Combinations in Sulfate-Based Formulas
- Sodium Laureth Sulfate + Cocamidopropyl Betaine: a classic combination easily thickened with Cocamide DEA or NaCl.
- Ammonium Lauryl Sulfate + Coco-Betaine: less common but effective when a small amount of Myristyl Lactate or Ammonium Chloride is added.
How to Increase Viscosity in Sulfate-Free Formulas
Sulfate-free formulas pose an added challenge. Here are some effective solutions:
- Amino acid–derived surfactants (sarcosinates, glutamates, glycinates) combined with amphoteric agents like betaines or amine oxides.
- Use of Sodium Lauroyl Sarcosinate + Cocamidopropyl Betaine with pH adjustment to modulate viscosity.
- Incorporation of sulfosuccinates and glucamides, which are excellent co-surfactants and foam boosters. Glucamides such as Lauroyl/Myristoyl Methyl Glucamide enhance both viscosity and foam.
- Sodium Cocoyl Glycinate: excellent for longer-lasting foam, though with lower volume than sulfates.
- Thickeners such as Lauryl Lactate also improve sensory performance and combability.
Transparent and Gentle Solutions
For products that require transparency or the avoidance of ethoxylated ingredients, systems based on Laureth-2 and PEG-90 Glyceryl Isostearate can be used. However, they should be avoided in 100% natural or PEG-free formulations.
Conclusion
Choosing the right method to increase viscosity in shampoos and gels depends on the type of surfactants used and the objectives of the formulation—whether sensory quality, natural positioning, transparency, or performance. In today’s market, where sulfate-free and natural formulas are growing in popularity, it’s essential to understand the most effective and stable alternatives to ensure product quality and user experience.
Need Help with Your Cosmetic Formulations?
Contact us and discover Lemmel’s portfolio of specialized raw materials designed to enhance viscosity and performance in your personal care products.