What is Resorcinol ?

Have you ever seen this name on the ingredient list of hair dye, acne cream or hair conditioner – Resorcinol (Resorcinol)? It often appears together with ingredients like p-phenylenediamine (PPD) in hair dye formulas, and also plays an important role in dermatological drugs and industrial adhesives. But many people have no idea about this ingredient: What exactly is it? Is it safe to use on the hair? Will it cause irritation to the skin?

If you have any doubts about this, you are not alone. Resorcinol is a chemical component that has been in use for over a hundred years. It is both an essential industrial raw material and a substance that requires careful handling.

-- What exactly is Resorcinol? --

Resorcinol, also known as Resorcinol in English, is also called Rieszoxine or Rieszophenol. Its chemical name is 1,3-dihydroxybenzene. From the chemical structure, its molecular formula is C₆H₆O₂, with a molecular weight of 110.11. It is an organic compound with a benzene ring having two hydroxyl groups connected in the middle position. It is an isomer of catechol and resorcinolphenol – the chemical formulas are the same for all three, but the positions of the hydroxyl groups on the benzene ring are different, resulting in different properties.

At room temperature, Resorcinol appears as white needle-like crystals, has a sweet taste and is flammable. Its melting point is 109-111°C, its boiling point is 280°C, and its relative density is 1.272. It is soluble in water, ethanol and ether, and slightly soluble in chloroform and dithiocarbonane.

Resorcinol is sensitive to light and air – it turns pink when exposed to the air or in contact with iron, so it is usually stored in a dark place. In terms of smell, it has characteristics similar to nuts, phenols and cherries, and is therefore also used as an ingredient in perfumes.

-- What are the main applications of Resorcinol?--

The applications of Resorcinol are very extensive, covering multiple industrial fields such as cosmetics, medicine, rubber, and plastics.

In the cosmetics industry, the most important application of Resorcinol is as a coupling agent for hair dyes. In oxidative hair dye products, it is usually used in combination with main dyeing intermediates such as p-phenylenediamine.

The research found that when para-phenylenediamine is used alone, it will dye the hair to a purple-brown or purple-black color, with a distinct purple tint. However, when Resorcinol is oxidized together with para-phenylenediamine, they will react to form a green tri-nuclear dye molecule. When this green dye is mixed with the purple tint, it can generate a wide band of absorption in the visible light region, ultimately presenting a natural brown color.

This is the core function of Resorcinol in hair dyes – to eliminate purple/red tones and help achieve a natural brown color.

In the field of skin care, Resorcinol is used to treat acne. The prescription drug ADULT ACNOMEL approved by the US FDA contains 2% Resorcinol and 8% sulfur, which is used to treat acne, helping to clear existing pimples and prevent the formation of new ones. At low concentrations, Resorcinol has antibacterial and soothing effects; at slightly higher concentrations, it can remove the skin’s stratum corneum; and at even higher concentrations, it can be used as a skin exfoliant.

In the food industry, Resorcinol has been approved by the US FDA for use as a flavor enhancer and flavoring agent. It has also been evaluated by JECFA as a safe food flavoring component.

In industrial applications, Resorcinol is an important raw material for synthetic resins, adhesives, rubber tire cord impregnants, flame retardants, and dyes. Its derivative Resorcinol diol is used as an unhalogenated flame retardant and is applied in engineering plastics.

--Is Resorcinol safe? --

The safety of Resorcinol is a matter that requires serious consideration – it is classified as a moderately toxic substance.

According to toxicological data, the MLD (median lethal dose) for rats injected subcutaneously is 450 mg/kg. It can irritate the skin and mucous membranes, and can be rapidly absorbed by the human body through the skin. Once inside the body, Resorcinol will form methemoglobin, causing cyanosis, drowsiness, and in severe cases, may lead to kidney damage. People with skin allergies or allergic reactions may be at risk of dangerous poisoning if they inhale its vapor or dust.

In terms of skin irritation, Resorcinol is a “double-edged sword”: at low concentrations, it is an effective skin treatment ingredient, but at high concentrations, it can cause intense burning sensations and redness and swelling of the skin. When used as a skin exfoliant at high concentrations, it may cause a variety of problems including swelling.

In October 2020, the European Union Consumer Safety Science Committee (SCCS) released the latest scientific opinion on Resorcinol (SCCS/1619/20), re-evaluating its safety in cosmetics and proposing concentration limit recommendations. In hair dyes, the usage concentration of Resorcinol is strictly regulated.

-- What is the effect of resorcinol in hair dyeing? Does it affect the melanin in natural hair? --

Manufacturer of Resorcinol

Zhishang Bio is a key partner in the global supply of surfactants, daily-use chemicals and other products. They focus on supplying high-purity and quality Resorcinol.

We provide stable, cost-effective, and efficient one-stop purchasing solutions to global customers. We understand how important a reliable supply is to your business. Therefore, we strive to be the best in all aspects.

We have a close relationship with the leading manufacturers in order to guarantee that our products are of high quality and meet industry standards. We are able, through our large-scale purchasing and efficient supply management, to offer customers highly competitive market prices. We also offer flexible quotes based upon the volume of the purchase to help them optimize their production costs.

Our services are characterized by a highly developed logistics system. We achieve visual tracking through multiple warehouse layouts and digital logistic management systems both at home and abroad. This allows us to support multimodal intermodal transport such as rail, road, and sea.

Our service system is designed around the needs of our customers. Our team of professionals responds quickly 7×24 hours per day. We offer personalized services such as product packaging and customized packaging according to customer needs. We focus on creating stable, long-term strategic partnerships with our clients in order to achieve mutual growth.

The logistics system is one of the core advantages of our services. Through multiple warehousing layouts and digital logistics management systems at home and abroad, we achieve visual tracking of the entire transportation process, supporting multimodal intermodal transportation such as sea, rail, and road, strictly ensuring delivery timeliness, and even safe and compliant professional distribution for dangerous goods transportation.

We are committed to building a customer-centric service system. Our professional team provides 7 × 24-hour rapid response, which not only provides precise technical support and after-sales guarantee, but also offers personalized services such as product packaging and customized packaging according to customer needs. We focus on establishing long-term and stable strategic partnerships with our clients, achieving mutual growth through continuous value creation

By choosing us, you are not only selecting a supplier; you are also choosing a partner that is dedicated to your success. We will be happy to offer you free samples and detailed technical support.

Shandong Zhishang Bio Co., Ltd

Zhishang Bio, a subsidiary of Zhishang Chemical Co., Ltd., was established in 2016 and is a new type of chemical enterprise that integrates research and development, production, and sales. Zhishang Bio always adheres to the concept of “integrity management, strict quality control, customer first”.

Through continuous efforts, significant breakthroughs have been made in industries such as pharmaceutical intermediates, pesticide intermediates, food additives, and cosmetic raw materials. The domestic trade team sells well throughout the country, while the foreign trade team is exported to more than 30 countries and regions including the United States, Russia, Spain, Brazil, and enjoys a global reputation.

Invited to participate in this exhibition, Zhishang Bio will comprehensively showcase the company’s strength and achievements in the research and development, production, and quality control of pharmaceutical and pesticide intermediates! At that time, our company will set up an CPHI exhibition at booth E12D29 at the venue, and we will take you to further understand our company’s advantageous products in detail!