China classifies hair dye cosmetics as special-purpose cosmetics, using hair dyes as their active ingredients. Manufacturers produce different types of hair dyes to achieve varying coloring effects. We categorize hair dyes into three types based on these effects: temporary, semi-permanent, and permanent hair dyes. Temporary hair dyes retain color for the shortest time, lasting only 7-10 days and washing out easily, thus serving only as a temporary decoration. Semi-permanent hair dyes maintain color for 3-4 weeks. Permanent hair dyes offer the longest-lasting effect, maintaining color for 1-3 months. This long-lasting quality makes permanent hair dyes the most commonly used and important type in the market.

Temporary hair dyes

These are generally composed of large molecule dyes or pigments. Due to their large molecular weight, they cannot penetrate the hair shaft and mostly adhere to the hair surface, making them easy to wash off with shampoo and water. However, these dyes rarely damage the hair and are less likely to penetrate the skin, making them highly safe.

Semi-permanent hair dyes

These are mainly dyes with relatively low molecular weight that can penetrate the hair shaft and have some affinity with the hair’s cuticle layer. However, these small molecules seep out during washing and generally withstand about 12 washes.

Permanent hair dyes

These are mainly oxidative hair dyes. Their formula primarily includes dye intermediates, couplers, and oxidizing agents. The principle behind these dyes is not to use direct dyes but colorless dye intermediates. These intermediate molecules are small enough to penetrate the hair shaft and react with oxidizing agents and couplers that have also penetrated the hair, undergoing oxidative polymerization to form large molecule dyes that color the hair. The large molecule dyes formed inside the hair shaft are difficult to seep out, making them hard to wash off and resulting in longer-lasting color.

These hair dye products are usually made into two separate tubes, A and B. Tube A mainly contains dye intermediates, while tube B contains oxidizing agents. The two are mixed just before use. Commercially available two-component hair dye cosmetics come in powder, liquid, or cream forms, with cream being the most common.

Allergic reactions are common when using hair dye products. The main substances causing these reactions are dye intermediates and oxidizing agents, which can trigger acute allergic reactions in sensitive individuals, such as dermatitis, urticaria, asthma, and even severe reactions like fever, chills, and difficulty breathing. Therefore, consumers must purchase legitimate products, carefully read the instructions before use, and perform a patch test as required to ensure safety before application.

Permanent hair dyes manufacturer ZeLin Biotech

ZeLin Biotech specializes in developing and manufacturing high-quality permanent hair dyes. The company leverages cutting-edge biotechnology to create innovative, long-lasting coloring solutions. ZeLin’s products feature advanced gentle formulas, incorporating carefully selected dye intermediates and couplers to achieve vibrant, natural-looking results.

With a focus on safety and performance, ZeLin Biotech invests heavily in research and development. Their team of expert chemists continually refines formulations to minimize allergic reactions while maximizing color retention. The company prides itself on producing eco-friendly options and ammonia-free alternatives to traditional permanent dyes.

ZeLin Biotech serves both professional salons and the retail market, offering a wide range of shades to suit diverse customer needs. Their commitment to quality control and regulatory compliance has established them as a trusted name in the global hair care industry.