There are many articles online that discuss the shelf life of natural henna cones (mehndi). Primarily, such articles are written by small businesses or individuals who produce their own henna cones. Therefore, they have a vested interest and as such may be biased in what they write.
It benefits them to push the narrative that no natural henna cones can last more than 3 days without being refrigerated. Some even state that it can only last a few hours. They assert, therefore, that any cones that have a long shelf life are not 100% natural and contain chemicals, potentially even harmful ones. This not exactly true.
Unfortunately, every person or company producing and selling henna cones claims to be an expert in this area. The truth of the matter is that anyone can produce henna cones. It is not a difficult process at all. In fact, it is rather simple and has very few steps. It does not, however, make a person an expert in henna and its properties.
WHAT IS THE SHELF LIFE OF NATURAL HENNA CONES?
Natural henna cones can be produced using just henna powder and water, without adding anything else at all. If henna is produced in this manner, the shelf life will not be that long, as there are no preservatives to extend the shelf life.
In order to extend the shelf life, some form of preservative must be added. Some of the ingredients that can be added to the mixture may be unnatural and harmful, such as PPD and Ammonia. However, many other ingredients are completely safe and natural which help increase the shelf life of the henna, such as essential oils. Adding these additional ingredients does not make the henna cone unnatural. It is still natural as all the ingredients are natural.
For a henna cone to be considered 100% natural, it does not mean that it only contains henna and nothing else. It means that it contains all-natural ingredients. Essential oils are considered natural.
Many famous branded henna cones contain essential oils to preserve the shelf life of the cones. This can make them last 6-12 months when stored in a cool, dry place.
To then state that they are not natural and contain harmful chemicals is unfair and untrue. Of course, there may be products out there that claim to be natural when in fact they are not natural at all – however, to say that every cone that is branded as 100% natural cannot have an extended shelf life is definitely incorrect. Let us turn to scientific research.
ESSENTIAL OILS AND SHELF LIFE
Essential oils with active ingredients can be used as an alternative management method to control microorganisms. Many essential oils have shown antibacterial, antifungal, and antioxidant properties against some important food-borne and plant pathogens.
Essential oils are generally considered safe for treating food products, and are even beneficial in extending their shelf life. There is plenty of research on essential oils and shelf life, which you can find online. For example, there is this article which explains the details of essentials oils extending the shelf life of small fruits.
WHICH ESSENTIAL OILS ARE IN HENNA CONES?
Most brands that produce natural henna cones, such as Kajal, Kaveri and Naaz may include the following natural essential oils in their henna cones to help preserve them and increase their shelf life:
- Clove Oil – Clove oil contains a natural chemical called eugenol, which acts as an anaesthetic and antibacterial agent (reference). Clove oils are also used in the production of antibiotics for its antimicrobial properties. They have been screened for their potential uses as alternative remedies for the treatment of many infectious diseases (reference). Researchers find that both clove oil and eugenol express significantly inhibitory effects on numerous kinds of food source microorganisms (reference). It is a natural preservative used in many items to preserve and extend shelf life. For example, it has been shown to preserve and extend the shelf life of seafood products due to the high antimicrobial effect obtained from clove against a wide range of food pathogen and spoilage bacteria (reference).
- Terpineol Oil – Terpineols are naturally occurring unsaturated monocyclic mono-terpenoid alcohols and can be found in flowers such as narcissus and freesia, in herbs, such as marjoram, oregano, rosemary and in lemon peel oil. In one study it has been shown that terpineol completely inhibited the growth of all tested bacteria and totally reduced their initial inoculum (reference). In another study, it was shown that the essential oils of terpineols caused complete inhibition of mould growth for 7 days at room temperature (reference). You can see this article which outlines the various tests conducted with a variety of terpimeol oils and how they preserved and extended shelf life.
As outlined in detail above, henna cones can be 100% natural while also having a long shelf life of 6-12 months. Natural essential oils are used in the mixture to preserve and increase the shelf life of the henna cones due to their anti-bacterial and antimicrobial properties. This does not mean the cones are unnatural or unsafe, or that they contain harmful chemicals. Essential oils are 100% natural and mostly safe when used correctly. Information on the internet which states that henna cones cannot have a long shelf life if they are 100% natural is simply untrue and does not consider the effectiveness of natural essential oils in increasing shelf life. It is clear from scientific research that a lot of essential oils can be used as bio-preservatives to increase the shelf life of many products, which is what many henna cone manufacturers use in their mixtures.
Always read the label on the box, which lists the ingredients. The ingredients list should only contain henna, water and any other type of essential oil. If there are other ingredients that are not essential oils, then the cones are not 100% natural. Likewise, be careful with fast colour and instant henna cones, which are in fact colour dyes and not natural henna – although they produce similar results to natural henna (and hence why they are referred to as henna despite not containing henna), but contain unnatural chemicals; some may be harmful some may be completely safe. Always conduct a skin sensitivity test and only use realiable manufacturers, such as Golecha. Read our article on this topic.