Does dyeing your hair often cause cancer? How often is it better to dye it? It’s never too late to understand

Dyeing hair hurts the liver?

Recently, according to media reports, Ms. Li, a 50-year-old from Hebei, usually likes to dress up, and dyes her hair about twice a month. Unexpectedly, Ms. Li suddenly turned yellow and couldn’t eat without knowing what was going on. In desperation, she had to go to the hospital for examination. The doctor said that she had developed drug-induced hepatitis because of too frequent hair dyeing.drug-induced hepatitis.

It is said that everyone loves beauty. Have you ever dyed your hair? “2020 China Good Consumption Trend Report” shows that in 2019, the average Chinese people dye their hair 2.9 times a year. Dyeing your hair can improve your self-image, but it also has hidden health risks behind it.

1. Frequently dyeing hair, what harm will it do to the body?

Under normal circumstances, hair dyeing will not cause adverse reactions. But there are also the following health problems caused by hair dyeing:

1. Liver damage

The composition of hair dyes is complex, among which Including p-phenylenediamine, hydroquinone, resorcinol and other harmful substances. Take p-phenylenediamine as an example, it is a colorant that must be used in hair dyes. Animal experiments have confirmed that p-phenylenediamine can affect the liver function of mice.

2. Hair loss

The principle of hair dye is to open the hair scales on the surface of the hair. This allows the dye to penetrate the hair strands and colour within the strands. This means that frequent hair dyeing will easily cause more damage to the hair and scalp, and the hair follicles cannot be metabolized normally, which will accelerate hair loss.

3. Allergies

The ingredients in hair dyes are complex, and the phenolic substances such as hydroquinone and resorcinol, once absorbed through the skin, can cause dermatitis, and in severe cases can also cause symptoms such as redness, swelling, and peeling. Clinical practice has also proved that occupational exposure to phenolic substances can also cause liver damage.

4. Stimulation

Dyeing hair may also stimulate hair scales and cause dry hair , Short hair is serious. Some asthma or rhinitis patients may experience cough, sore throat and other symptoms when exposed to irritating agents such as inhaled hair dyes, and in severe cases can lead to edema of the throat.

Second, frequent hair dyeing and potential carcinogenic potential

The safety of hair dyes has always been a concern, and its potential carcinogenic risk, It has been discussed repeatedly. Currently, hair dyes are classified as Group 3 carcinogens, i.e. carcinogenicity is uncertain.

In 2020, the international journal BMJ published a study on hair coloring The study, which evaluated 117,000 U.S. nurses and followed them for 36 years, found no overall increased risk of cancer among those who used permanent hair dye, but in some cancers, such as< strong>Breast cancer, ovarian cancer, basal cell carcinoma, etc., the risk is increased.

Tao Sifeng, Deputy Chief Physician of Breast Surgery, Second Hospital of Zhejiang University< /strong> said that ingredients with the words “amine” and “phenol” are common in hair dyes, and these ingredients basically belong to the “third class carcinogens” with suspected carcinogenicity to humans, while < strong>The longer hair dyes retain their color, the higher the concentration of chemicals added to them.

Of course, the medical community often uses dose as a measure of toxicity. It is impossible to assert that breast cancer and other cancers are related to the use of hair dyes, but reducing the use of hair dyes and reducing exposure to chemicals in hair dyes to reduce the risk of cancer is a complete effort.

Three, if these symptoms appear after dyeing hair, seek medical attention in time

Drug-induced hepatitis is very easy to be ignored by the public, it is mainly derived from chemical drugs, natural drugs , health products, dietary supplements, etc. induced liver damage. In the case, Ms. Li suffered liver damage due to excessive absorption of hair dye by her skin, resulting in yellowing of her skin and inability to eat. Therefore, when these symptoms appear after dyeing your hair, you should be alert:

1. Yellowing of the skin

< span>There is a problem in the liver area, and the cholestasis is obvious, which will cause the skin color, the patient’s body will become more and more yellow, and the stool will become lighter, and the skin will be itchy.

2. Digestive deterioration

Some patients with drug-induced liver injury due to digestive function obstruction , can cause general fatigue, poor appetite, and epigastric discomfort and other symptoms.

3. Allergies

A small number of patients will have allergic manifestations, specifically fever, skin There are rashes, joint pains, etc.

Fourth, dye your hair with peace of mind, keep these points in mind

It is a “ceremonial sense” for modern people to change their hairstyle and hair color during Chinese New Year and festivals. Although the carcinogenicity of hair dyeing is uncertain, from a safety point of view, you must pay attention to these points before dyeing your hair:

1. Use with caution under the age of 16 span>

People under the age of 16 do not have the ability to carefully read, understand and follow the instructions of hair dyes, so these people are not suitable for hair dyeing.

2. The interval between two hair dyeings should not be too close

The European Cosmetics Association recommends, usually There should be an interval of 4-6 weeks between two hair dyes. The frequency of hair dyeing is too dense, which can increase the dose exposure and increase the safety risk.

Control the number of times you dye your hair in a year, and the hair care experts in Life Times recommend the best number of times a yearNo more than 4 times.

3. Pre-warning test before dyeing

Before you start dyeing, you should do it once Early warning test. Even if there has been no allergic reaction in the past, it is difficult to guarantee that the ingredients in hair dye cosmetics are the same every time. In order to ensure safety, it is recommended to carry out an allergy warning test.

4. Avoid direct contact with skin

When dyeing hair, be sure to take protective measures to avoid direct contact with the skin. Sensitive people can apply a layer of lotion on the forehead and behind the ears along the hairline for protection before dyeing their hair.

I didn’t expect that dyeing hair may also cause liver damage? We have the right to pursue beauty, but it must also be based on the premise of health. When any adverse reaction occurs after hair dyeing, we must stop using it, and it is best to go to the hospital for diagnosis as soon as possible.


[1] “Those Things That Hair Dye Injures the Liver”. The First Affiliated Hospital of Hepatology Fu Medical University. 2018-12 -07

[2] “How does hair dye “scrape” open hair and deliver “carcinogens” to us? The doctor tells you the truth…”. The Second Hospital of Zhejiang University. 2019-12-19

[3] “[Science Lecture Hall] Scientific Hair Dyeing is Safe and Beautiful”. Zhejiang Medicine News. 2021-11-10

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