Is it harmful to dye your hair once a year?

Modern young people are very fond of beauty. Many people have the habit of taking care of their hair. Some people like to dye their hair and dye their hair into their favorite colors. Some people dye their hair very frequently, but some people do not dye their hair very frequently. Everyone knows that the harm of hair dyeing is very great. Generally speaking, the harm of dyeing hair once a year is relatively small. You must wash your hair frequently after dyeing and drink more water.

Hair dye can cause cancer and other diseases

Hair dye can cause cancer and other diseases

Studies have shown that hair dyeing increases women's risk of leukemia and lymphoma. Many middle-aged and elderly leukemia patients have a history of hair dyeing. At the same time, hair dyes can reduce the weight of the uterus and cause damage to reproductive organs, especially black hair dyes, which are more harmful!

Commonly used dyes, such as azo and nitro, contain many heavy metal elements that are harmful to the human body. They are carcinogenic to varying degrees and can also cause various diseases such as blood diseases. Because when dyeing hair, the dye is applied to the hair for a long time, it will enter the skin through the scalp and penetrate into the blood. Over time, it will induce cancer and other diseases.

In addition, even though most hair dyes say "people with skin allergies" should use with caution, there is almost no packaging that lists in detail the range of "people who should not dye their hair", and hairdressers in hair salons rarely remind customers.

But even though there are so many harms to hair dyeing, it can’t stop the elderly from dyeing their hair!

Because, my hair has turned grey, how can I not dye it?

In addition, even though most hair dyes say "people with skin allergies" should use with caution, there is almost no packaging that lists in detail the range of "people who should not dye their hair", and hairdressers in hair salons rarely remind customers.

But even though there are so many harms to hair dyeing, it can’t stop the elderly from dyeing their hair!

Old people rarely dye their hair

Many elderly people dye their hair to turn their gray hair black, but hair grows very fast, so they have to dye their hair frequently. Moreover, older men have to dye their hair from the roots, so the hair dye will be in close contact with the scalp, which is more likely to cause harm to the body, so it is better for older men to dye their hair less.

Many elderly people want to turn their gray hair black.

These people should not dye their hair

People who are allergic to drugs, paints, food, pollen, etc., as well as those who suffer from asthma, urticaria, heart disease, high blood pressure or other diseases or those who are recovering from illness and are in a weak state should not dye their hair.

Seven secrets of hair dyes: pure plant-based ones are also very harmful

Plant-based hair dyes are difficult to last

When it comes to plant-based hair dyes, the main character is mostly henna (English name is henna, Chinese name is Impatiens balsamina, commonly known as henna). This plant-based dye has been approved by the FDA as a safe hair dye for colors ranging from dark coffee to reddish brown, but it does not work well for black hair.

"If it is purely plant-based hair dye, the principle is different from that of chemical hair dye. Plant-based hair dye is direct dyeing, which attaches the dye molecules directly to the surface of the hair; while common chemical hair dyeing allows small aniline molecules to penetrate into the cortex of the hair, causing a high-molecular chemical reaction, turning small aniline molecules into colored macromolecular dyes, which will change color." said the expert. If the dye only adheres to the surface of the hair, it will be difficult to last long.

"Those claims that pure natural plant-based hair dyes will naturally darken hair over time and will have an impact on hair follicles, and that they can fundamentally solve the problem of gray hair, are not credible. The original color of the new hair that grows out of the hair follicles after dyeing will not change."

There are currently no approved pure plant-based hair dyes

The safety of henna, a plant-based dye, is beyond doubt. However, in order to pursue a darker pattern tone or hair dyeing effect, other dyes such as PPD (paraphenylenediamine) are usually added to the so-called henna tattoo dye to shorten the reaction time, make the color appear ebony, and prolong the coloring time.

The safety of henna, a plant-based dye, is beyond doubt

The concentration of PPD added to tattoos is often as high as 26%, while the PPD content in general hair dyes is only 6%. Individuals sensitized by henna tattoos with this high concentration of PPD may experience severe allergic symptoms after using oxidative hair dye products.

It can be inferred that even safe plant-based dyes may cause allergic reactions or other risk factors when mixed with other chemical ingredients. "As far as I know, the Ministry of Health has not yet successfully approved any 'pure plant-based hair dye' that is completely extracted from plants. Generally speaking, so-called plant-based hair dyes are chemical preparations with plant extracts added. For example, PPD paraphenylenediamine and its derivatives, which are widely used in hair dyes, may cause skin contact allergies." Experts say that hair dyes with added plant extracts are not pure plant-based hair dyes.

Pure plant-based ones may be more powerful

"Many plant juices and extracts have certain hair dyeing effects, such as Schisandra chinensis. However, such plant hair dyeing ingredients are difficult to promote in the market due to color, stability, durability and other reasons, so there are very few pure plant hair dyes. Most hair dyes are traditional hair dyes that claim to contain plant ingredients but whose core ingredients have not changed much." A cosmetics developer said, "If there is a plant hair dye that does not contain the core ingredients of conventional hair dyes such as diphenylamines, phenols, aminophenols and peroxides such as hydrogen peroxide, its safety is better than traditional hair dyes."

In addition, not all plants are safe, Yan Shixiang said, some Chinese medicines, plants, etc. are banned in cosmetics. For example, the plant Angelica dahurica is a strong photosensitizer. Whether eaten or applied topically, it can easily cause photosensitivity and cause damage to the liver and kidneys. Natural products that are banned in skin care products, such as coumarin, are harmful. "Pure plants are also made up of chemical ingredients. It doesn't mean that pure plants are necessarily safe. They may be more ferocious."

Common hair dyes contain potential carcinogens

The main ingredients of commonly used oxidative hair dyes are p-phenylenediamine and its aniline derivatives, both of which may cause skin contact allergies.

Experts say that paraphenylenediamine is PPD, which is one of the simple aromatic diamines and a widely used dye intermediate. It is a potential carcinogen. According to the 2007 edition of my country's new "Cosmetic Hygiene Standards", the content of p-phenylenediamine in hair dyes shall not exceed 6%. That is, although it is allowed to be used in the production of hair dyes, there are clear restrictions on its usage.

"It would be fine if the content of p-phenylenediamine in the hair dyes sold did not exceed the standard, but some non-standard manufacturers do not label the harmful substances, and instead label some good ingredients that they do not contain at all, such as plant extracts such as ginseng."

It is understood that p-phenylenediamine and o-phenylenediamine belong to Class 3 carcinogens in the list of carcinogens of the International Cancer Agency, which means that "limited evidence shows that they may be carcinogenic, that is, the evidence is insufficient."

The EU's CLP (EU Regulation on Classification, Labelling and Packaging of Substances and Mixtures) has not yet listed p-phenylenediamine as a carcinogen, and no company has provided effective evidence that p-phenylenediamine is carcinogenic. However, it is also possible that further toxicological test data will indicate that p-phenylenediamine should be classified as a Category 1 or 2 carcinogen. Therefore, at present, we can only say that p-phenylenediamine is suspected to be carcinogenic.

"Paraphenylenediamine plays a role in long-lasting dyeing in the production of hair dyes. According to our observations, so-called pure plant hair dyes all contain a certain amount of paraphenylenediamine. Therefore, people who are allergic should use them with caution."

Doctors say that although the carcinogenicity of p-phenylenediamine is controversial and there is no scientific research worldwide to prove that hair dyeing can cause cancer, the allergenicity of p-phenylenediamine is well-documented and there is no injustice. As early as before the 20th century, people knew that hair dyes containing PPD could cause contact allergic reactions. In 2006, the American Contact Dermatitis Society listed PPD as the contact allergen of the year, and the incidence of contact allergy to PPD is increasing.