Can I use henna with homeopathic medicines?

Henna: Harmful or Safe?

Even the ancient Egyptians knew henna as a vegetable dye and used it to dye their hair, nails and fingers. Even today, henna is used in cosmetics - primarily for dyeing hair. In other countries and cultures, such as India, people often use henna on special occasions, for example at a wedding: They then decorate their hands with ornate, often symbolically or ritually significant ornaments (mehndi painting).

With us you can now have henna tattoos or paint them yourself on your skin using stencils. Holidaymakers get a taste for it every now and then at the resort and let themselves be seduced into a cheap henna tattoo.

Advantages of so-called temporary tattoos, also known as body painting: Unlike normal tattoos, no colors are stabbed into the skin, which means there is no risk of infection or pain. And the tattoo fades as soon as the top layer of skin has completely renewed.

What is henna

Henna is a red-yellow dye made from the leaves of the henna bush (Lawsonia inermis) is won. The Lawson pigment, which is responsible for the characteristic color, is an essential component of henna. The dye is obtained by drying the leaves of the plant and grinding them into a powder.

Man-made henna: Prohibited in cosmetics

In the meantime, henna can also be produced artificially. "Chemically reproduced henna dye is forbidden in cosmetic products," says Dr. Annegret Blume, who heads the Commission for Cosmetic Products at the Federal Institute for Risk Assessment (BfR). "It cannot be ruled out that it has genotoxic properties." That means: The dye can possibly change the genetic material.

But Lawson's natural pigment was also suspected, not least because of skin problems caused by henna tattoos. "In its traditional, plant-based preparation method, the henna dye is harmless. This was confirmed by the EU Commission's scientific expert committee for consumer safety in 2013," says Blume. The experts expressly refer to pure, natural henna powder as it is used as a hair dye. Further tests are necessary to confirm that henna is generally safe.

Henna as a hair dye

Hair dyes made from henna permanently color the hair. That means: the color cannot be washed out, it has to grow out. For coloring, the powder is mixed with boiling water, mixed into a paste and worked into the hair while it is still warm. The mass has a strong odor. There are also ready-made mixes. In order to achieve a lasting effect, the henna mixture must act for up to two hours or more. The longer the exposure time, the more intense the result. "During this time, henna reacts with the proteins in the hair, the keratins," explains expert Blume. The result: different shades of red depending on the hair type, its own color and pre-treatment.

Sometimes so-called henna hair dyes do not only consist of the natural product. In order to accelerate the dyeing process or to create a more intense shade, some manufacturers sometimes add chemicals, such as the artificially produced dye para-phenylenediamine (PPD).

Caution, allergy risk!

Under certain conditions, PPD or some reaction products of the substance have a strong allergenic and genotoxic potential. The substances have a sensitizing effect, especially after prolonged skin contact and depending on which other components the henna hair color has. Henna itself is not considered to be allergenic. In hair dyes, PPD is permissible up to a certain concentration, if other substances ("couplers") are contained in sufficient quantities that bind PPD. This creates a normally harmless dye in the hair.

In contrast, some henna hair dyes have been found to contain PPD without couplers: a significant health risk.

Para-phenylenediamine is also often found in the mixtures from which henna tattoos can be made. The Federal Institute for Risk Assessment therefore warns against henna tattoos as a holiday souvenir. PPD fulfills the following purpose in body painting: adding PPD creates the impression of a classic tattoo, as the substance makes the originally orange-brown body painting appear darker - so-called black henna. In addition, the tattoo is finished faster.

The fact that the use of PPD as an additive in skin dyes is prohibited across Europe does not bother many body artists on distant beaches. Sometimes even henna hair dye containing PPD is simply used. And: black henna is not pure henna.

Henna tattoos are particularly problematic

Henna tattoos in particular have a high allergenic risk due to the potential component PPD. Because when making a tattoo - and as long as the tattoo lasts - the substance can act on the skin there, i.e. for a long time. As a result, itching, painful redness and swelling can occur. So-called contact eczema develops.

The skin reactions usually develop within two to ten days. "Sometimes even inflammations and open wounds develop, which heal very slowly," explains Blume. It is not uncommon for ugly scars, color disorders and increased light sensitivity of the skin to remain. Expert Blume warns of another series of henna tattoos: "Those affected are sensitized to PPD for the rest of their lives."

The problem with this is that the artificial color is found in numerous products. Anyone who is allergic to PPD or its breakdown products may have to do without many hair dyes and avoid contact with dark textiles or various plastics. It is even worse if the allergy spreads to other chemical substances with a similar structure. Those affected are then limited in their quality of life in the long term. In addition, remaining skin damage can be psychologically and socially stressful.

Conclusion: Henna itself is not considered to be allergenic. Pure henna natural hair color can be an alternative to chemically produced hair dyes. Consumers should, however, carefully study the name and composition of the product and pay attention to statements such as "PPD" or "Phenylenediamine". Preferably choose a domestic branded product. Those who also want to avoid other chemical residues can fall back on products from ecologically controlled cultivation.

As a precaution, the Federal Institute for Risk Assessment advises against henna tattoos in holiday destinations for the reasons mentioned above. But you should also be careful with temporary tattoos or Internet goods offered in Germany and carefully examine the product (product description, color, smell, effective time).