Vegetable dyes: what you need to know about the risk of allergy to henna and natural pigments
Hair coloring remains a widespread beauty ritual in France and Europe. However, the French National Health and Safety Agency (Anses) warns of the allergy risks associated with coloring hair coloring. Are plant-based formulas really a safer alternative for your scalp?
Hair coloring: a common but risky practice
According to the European Commission, over 60% of women and 10% of men dye their hair. These products are part of the daily lives of millions of people. Yet their use is not harmless to health.
As the Anses specifies, the risk of undesirable effects exists whatever the type of hair color. These products contain fairly allergenic substances. They can cause scalp irritation, and edema of the face or eyelids.
Sometimes, respiratory symptoms also appear. Faced with these risks, many people turn to so-called natural alternatives. But is it enough to protect oneself?
“You can be allergic to the natural pigments frequently used, such as henna, indigo, amla…”
How plant dyes work
Botanical hair color works differently from conventional products. It doesn’t use chemicals to open the hair scales. Nor does it destroy the natural pigments before applying the desired shade.
Instead, these formulas use plants containing natural pigments. These pigments bind to the hair fiber without altering its basic color. That’s why a radical change of color is impossible with this type of product.
Vegetable dyes and allergies: beware of preconceived ideas
Many people believe that plant-based formulas eliminate all allergic risks. Professor Laurence Coiffard, cosmetologist at the University of Nantes, qualifies this belief. In her opinion, the absence of ammonia or the use of natural ingredients does not eliminate the danger.
PPD, a highly allergenic chemical agent used to darken or blacken hair, is not authorized for use in natural colorants. However, it has been found in adulterated black henna. This underlines the importance of choosing the right products.
- Henna can cause allergic reactions in some people.
- Indigo and amla are also potentially allergenic pigments.
- The absence of ammonia does not guarantee a risk-free formula
- Adulterated black henna may contain prohibited PPD
- No color, plant-based or otherwise, is totally hypoallergenic.
Why natural doesn’t mean safe
Plants contain active molecules capable of triggering immune reactions. The body’s defense system doesn’t know the difference between a synthetic substance and a plant extract. So a sensitive person may react to henna as to any other allergen.
What’s more, the quality of products varies greatly from brand to brand and from distribution channel to distribution channel. Rigorous control of product composition is therefore essential before making any purchase. This applies to both classic formulas and plant-based alternatives.
How to limit the risks when coloring
There are several precautions you can take to minimize potential side effects. First of all, hair dyeing sessions should be spaced as far apart as possible. The less you expose your scalp to these substances, the better it is for your body.
Scrupulously following the instructions in the manual is essential. In particular, you must respect the application time indicated by the manufacturer. Exceeding it can increase the risk of skin irritation.
We never color hair before the age of 16. The later you start, the better for the health of your hair and scalp. This recommendation applies to all product types.
In the past, it was advisable to make a test touch on the crease of the elbow or behind the ear 48 hours before the session. This practice is no longer recommended. It increases the number of exposures to the product and may sensitize rather than protect the body.
