INCI names Alginic acid, sodium salt
CAS number 9005-38-3
Algin (sodium alginate) is a natural thickener and hydrator used in cosmetics for texture, viscosity, and soothing benefits. Hydrolyzed algin enhances solubility and skin absorption. Found in masks, moisturizers, and lotions, it pairs well with glycerin and aloe vera. Chemical formula: (C6H7NaO6)n.
Purpose
Sodium alginate acts as a binder, helping ingredients adhere and form stable formulations. It has moisturizing properties, retaining water to keep the skin hydrated. Its soothing effects calm and protect the skin, making it ideal for sensitive formulations. Additionally, it serves as a viscosity controller, adjusting the thickness and texture of products for smooth application.
Origin
Algin is derived from brown seaweed using acid precipitation. The seaweed is harvested, cleaned, and finely ground. An acid solution is then applied to extract algin by separating it from other compounds. Finally, the algin is isolated, dried, and processed into a powder for use in cosmetics and various applications.
| Feature | Description |
|---|---|
| Name | Sodium alginate |
| Type | Natural polysaccharide, hydrocolloid |
| Source | Extracted from the cell walls of brown seaweed (Phaeophyceae), such as Laminaria, Macrocystis, and Ascophyllum species |
| Solubility | Soluble in cold and warm water; insoluble in organic solvents |
| Concentration | 0.5% to 5% |
| PH | 2.8-4.5 |
| Color | White to yellowish-brown |
| Odor | Odorless or slightly marine-like |
| Physical state | Powder or granules |
| Boiling Point | 495.2°C |
Natural Origin
Algin is a naturally occurring polysaccharide extracted from brown seaweed. It is a renewable, biodegradable, and eco-friendly ingredient, making it an excellent choice for sustainable cosmetic formulations.
Hydrocolloid Properties
As a hydrocolloid, algin has the ability to thicken and form gels without requiring heat. This property makes it highly versatile for use in both water-based and oil-based formulations.
Moisture Retention
Algin has excellent water-binding properties, helping to lock in moisture and keep the skin hydrated. This makes it ideal for skincare products like moisturizers, masks, and serums.
Soothing & Skin-Protective
With its natural ability to calm and protect the skin, algin is particularly beneficial for sensitive or irritated skin. It helps to reduce redness and discomfort while forming a protective barrier.
Film-Forming Ability
Algin creates a thin, breathable film on the skin, enhancing product application and providing a smooth, soft finish. This feature is particularly useful in face masks, serums, and setting sprays.
Ionic Gelation
Algin can form stable gels when exposed to calcium ions, making it useful in advanced formulations like encapsulated skincare ingredients, wound dressings, and pharmaceutical applications.
Enhanced Texture & Viscosity Control
It improves the consistency and texture of cosmetic formulations, ensuring a smooth, non-greasy feel. It helps maintain product stability and enhances the overall sensory experience.
Biodegradable & Non-Toxic
Algin is completely biodegradable and non-toxic, making it safe for use in cosmetics, pharmaceuticals, and food products. It is free from harmful chemicals and suitable for all skin types.
Applications of Algin (Sodium Alginate) in Skincare
Moisturizers & Creams
Algin helps retain moisture, keeping the skin hydrated and soft. It also enhances the texture of creams, making them smooth and easy to apply.
Face Masks
Commonly used in peel-off and hydrating masks, algin forms a flexible film that locks in active ingredients and provides a soothing effect on the skin.
Serums & Essences
Due to its water-binding and film-forming properties, algin improves the delivery of active ingredients, enhancing skin absorption and hydration.
Cleansers & Face Washes
Algin adds a gentle thickening effect to facial cleansers, providing a smooth and luxurious texture while maintaining skin moisture.
Exfoliators & Scrubs
It helps create a smooth base in exfoliating products, allowing for even application while preventing excessive dryness or irritation.
Sunscreens
Used as a stabilizer in sunscreen formulations, algin ensures even distribution of UV filters while providing a lightweight, non-greasy feel.
Body Lotions & Gels
Algin improves the spreadability and consistency of body lotions and gels, enhancing hydration and providing a silky finish.
Eye & Lip Care
Its soothing and hydrating properties make it a beneficial ingredient in eye gels, under-eye masks, and lip balms, helping to retain moisture and prevent dryness.
Anti-Aging Products
Algin supports skin elasticity and hydration, making it a valuable addition to anti-aging creams and serums that aim to reduce fine lines and wrinkles.