Using henna safely: What is Lawsone/Naftoquinone, Prohibition in case of Favism and Allergy Risk

Is the use of henna potentially dangerous?

This is the question that occasionally pops up following the various rumors and scaremongering recently triggered on the web which only create even more confusion and sow doubts and fears.

Here on the site, but also on social networks and on the Youtube channel, I have always encouraged and promoted awareness in all the daily choices, beauty and otherwise, that we make. In addition, I have dedicated a lot of time to facilitate the knowledge of dyeing herbs and their conscious and safe use.

So I chose to dwell and deepen the topic to clarify things.

Returning to our original question:

Is lawsonia inermis - red henna - a potentially dangerous plant?

Henna for hair , specifically lawsonia inermis - which is the focus of this article - can be potentially dangerous. It is like any other plant present in nature that is not used with due care:

Beans should not be eaten raw because they contain the toxin phytohaemagglutinin (PHA) in sufficient quantities to cause acute symptoms, even if ingested in small doses.

Tomato leaves and stems contain atropine and other tropane alkaloids which are toxic if ingested, causing digestive and nervous arousal disturbances.

Apples and Cherries : The seeds of these fruits are highly poisonous. Leaves and seeds contain highly toxic cyanogenic glucosides for our body.

In large doses, nutmeg causes hallucinations, nausea, vomiting, visual distortions.

Yet we consume this fruit and vegetable every day with due care.

The same goes for hair henna .

Its use is safe if we use tested, certified powders, with the bacterial load reduced and with a standard label and if we respect the safety parameters and instructions for use.

It is obvious that if we buy herbal dye powders in bulk or in ethnic shops that have imported them under the counter, putting them on sale with packaging without a standard label, usually not even in Italian, then it is much easier for their use to be potentially harmful to our health precisely because we are uncertain about the controls carried out on these products.

Using henna safely: What is Lawsone/Naftoquinone, Prohibition in case of Favism and Allergy Risk

Henna - can it be harmful to health?

The fact that henna powder is a natural product derived exclusively from the dried and micronized lawsonia inermis plant does not mean that it is a harmless product for our health and that it does not present risks of use.

It should be used with due precautions: dilution of the batter, method of use, processing times, frequency of applications, etc.

Expedients extensively discussed here on the blog to avoid improper use of herbal dyes.

Anyone who already uses Beautilicious Delights products and has consulted the blog or video tutorials published in the last 6 years will not sound new. Because I said it over and over again: if a product is NATURAL it doesn't mean it's HARMLESS.

But what makes the use of lawsonia inermis potentially dangerous?

Let's start from the premise that, like all other plants in nature, the lawsonia inermis plant is also rich in allergens. This means that:

  • it should only be used after a skin allergy test as already widely explained here on the site

  • It should NOT be used by subjects suffering from FAVISMO (herbs belonging to the Fabaceae family can cause haemolytic crises, i.e. the destruction of red blood cells)

  • cancer and hematological patients can only use henna following the approval of their doctor. Chemotherapy makes the epithelial barrier more permeable and therefore the irritation of the scalp could be further accentuated. In addition, the hair structure undergoes mutations and tends to grow back more fragile. The ideal would be to wait at least 6 months from the end of the therapy ( source: AIRC )

As I anticipated earlier, the lawsonia inermis powder is obtained from the leaves of the plant which are dried and micronized more or less finely.

Leaves that have a complex chemical composition, which contains essential oils, resins (2-3%), tannins (5-10%), gallic acid, flavonoids, terpenoids, lipids and the list goes on..

In addition, it contains a coloring molecule - lawsone, 2-hydroxy-1,4-naphthoquinone , a molecule linked to other molecules present in the leaves of lawsonia and which together create the phytocomplex of the plant, essential for coloring our hair .

The lawsone is released into the dye batter only upon contact with water thanks to the slightly acidic environment that is created naturally.

And it is thanks to lawsone that lawsonia manages to permanently cover white hair. It is among other things the only dyeing plant capable of doing so because the pigment penetrates the cuticle and at the level of the cortex through a chemical reaction " Michael's addition " binds stably to the keratin.

The lawsone content of henna leaves varies from region to region and according to environmental factors, soil and cultivation method .

It is present in a concentration that can vary from 0.5 to 2% up to 5% in the dried leaves of the plant.

With this in-depth analysis we are going to see if lawsone is really potentially dangerous due to the use made of henna powder in hair dye packs.

Lawsonia Inermis - the vegetable hair dye

Lawsonia inermis is not currently on the official dye list.

In order to get a new cosmetic ingredient approved, the single active ingredient is chemically extracted and then tested for toxicity.

In the specific case of lawsonia, naphthoquinone was chemically extracted and isolated. If approved following various studies, the molecule could be used as a cosmetic ingredient in chemical hair dyes.

So the studies I will tell you about later were carried out by isolating the active principle of lawsone while the chemical composition of the dye mixture that results when we use the powder contains many other active ingredients present in the phytocomplex of the leaves of the plant .

As also emerges from the study carried out in 2014 by some professors of the La Sapienza University of Rome "other components present in the lawsonia leaves are necessary in the coloring process, such as chlorophyll, flavonoids, tanins, coumarins, volatile and non-volatile terpenes, steroids, resins, mucilages and other phyto-chemicals ".

Why is the active ingredient isolated from the lawsonia powder phytocomplex analyzed?

The active ingredient, lawsone , is isolated because when it is approved as a dye , the entire phytocomplex of the plant with all its active ingredients will not be used , but only the lawsone will be chemically extracted and expressly used.

Naphthoquinone /lawsone has some inherent toxicity.

But like all potentially dangerous substances it can be used safely if the critical points are discovered and the safety parameters are respected.

So the purpose of the study dedicated to Lawsone was also to understand these critical issues and the limits of use. 

Lawsone: the studies

Following the last study carried out in 2013 , Lawsone was approved as SAFE for coloring hair when used within specific parameters which we elaborate on below.

Point 1 of the article clearly mentions toxicity following repeated administration of oral doses from 7 to 29MG/KG/DIE. But it is not applicable in case the henna powder is not ingested but used with topical applications.

The CSSC, i.e. the Scientific Committee for Consumer Safety, concluded that the information provided by the study was sufficient to evaluate the safe use of henna as a hair dye .

Tests were carried out on 3 different lots of lawsonia powder which all had a lawsone concentration of less than 2% and the 2 lots below below 1.4%.

The conclusion reached by the scientific committee is:

"The CSSC believes that the information provided is sufficient to evaluate the safe use of henna as a hair dye. The evaluation of the henna is based on batches 1271 and 830.72 and refers to a maximum Lawsone content of 1.4 % It is considered safe for the consumer, when formulated and applied as indicated in the directions for use, for example 100 g of henna powder mixed with 300 ml of boiling henna water.

Other types of henna extracts which may have different compositions are not covered by this rating."

Then date:

  • both the percentage of lawsone in a henna dye mix and
  • and the absorption capacity of the lawsone in the skin

the CSSC has declared it safe as a hair dye .

Is there evidence of pathologies developed following the use of henna? 

Also in the same study published by the CSSC we talk about allergic reactions following the skin tests carried out and not about pathologies developed following the use of dye packs. 

Allergies that can be avoided by carrying out the skin sensitivity test that should be done with any cosmetic that we apply on our skin for the first time.

What if the lawsone concentration is higher than 1.4?

If the concentration of lawsone in the henna powder is higher than 1.4% there is no certainty of what the risks are and if there are any , given that both batches tested were below this threshold and further studies would be needed research to be able to prove its safe use. 

But studies of this type require huge budgets and let's remember that we are always talking about tests carried out using the isolated molecule and not the phytocomplex of the plant, which could still make a difference.

How can you make an informed purchase and use henna for hair safely? 

First of all by purchasing products that are certified, tested, regulated and in accordance with the law. Respecting the directions for use and buying from trusted suppliers. 

If, on the other hand, you prefer to save money by buying uncertified, uncontrolled products and you think you can spread powders of unknown origin, you can do it knowingly, at your own risk.

Read also: Are Beautilicious Delights herbal dyes certified?

Beautilicious Delights tests Lawsone percentage?

Yes, we test it for every single imported lot and this percentage always varies from harvest to harvest and from now on you will always find it specified in the product sheet here on the site .

Just to give you an idea of ​​what a certificate attesting the percentage of naphthoquinone looks like, you can view the certificate of analysis of the 2019 Lawsonia Batch and 2020 Harvest. For privacy reasons and as sensitive data, I have removed the data of the laboratory and of the manager who released it.

So do all companies control the percentage of Lawsone in the Lawsonia they market?

It must be said that as of today, 09.01.2020, there is no law regulating the trade of dyeing herbs or imposing a check on the percentage of lawsone/naphthoquinone present in the lawsonia powder or which requires that this percentage be explicitly indicated on the label.

It is up to the individual manufacturer to check that the percentage of lawsone falls within the safety parameters.

Until last year these parameters were totally ignored and indeed, boasting a percentage of lawsone equal to 1.9-2.5% was an incentive to purchase because it was assumed that the higher the percentage of naphthoquinone, the greater the dyeing power some dust.

To conclude, consciously buy certified and controlled dyeing herbs (sanitized and tested for heavy metals and pesticides) and use consciously following the instructions for use scrupulously without making improbable mixtures or too long and unnecessary exposure times which, on the contrary, can only irritate and sensitize the skin.

© Beautiful Delights

In the online shop you will find everything you need (including herbal dyes) to take care of your skin and hair in a conscious way. Click HERE to visit it!

************************************************** ************************************

Keep in touch with us:

Follow us on SOCIAL by clicking on the icons below to stay up to date on the latest news:


Rozalia & the Beautilicious Delights Team.

************************************************** ************************************


Back to blog

Leave a comment