What are the risks associated with the internal use of essential oils?

Nowadays, essential oils are hugely popular, and their use has expanded from traditional aromatherapy into the realm of internal use. Despite the fact that recommendations for the internal use of essential oils are often found on the internet and social media, the professional community is reserved about this approach. In this article, we will explain why the internal use of essential oils in home aromatherapy is discouraged and present the scientifically based arguments in this area.

What is the Tisserand Institute and why is it important

The Tisserand Institute is an internationally recognized organization founded by Robert Tisserand, one of the foremost experts on the safety of essential oils. Robert Tisserand is the author of the first English-language book on aromatherapy, written in 1977, and co-author of the second edition of "Essential Oil Safety," which has become the gold standard for setting safety guidelines in the industry.

The Tisserand Institute specializes in translating the latest scientific research into evidence-based education focused on the safety and benefits of essential oils. The organization provides objective, evidence-based information to help establish safe standards for the use of essential oils throughout the industry. Its recommendations are considered the professional standard in the international aromatherapy community and are often referenced by regulators and cosmetic manufacturers.

Concentration and potency

One of the key arguments against the internal use of essential oils is their extreme concentration. An essential oil in a bottle is 50-100 times more concentrated than in the original plant. This fact has major implications for the safety of use.

To illustrate: one drop of peppermint essential oil is equivalent to approximately 26-28 cups of peppermint tea. Such a concentration can cause irritation of the mucous membranes of the digestive tract, while long-term use can cause liver or kidney damage.

Approximately 200-250 kg of fresh leaves are neededto produce 1 litre of peppermint essential oil. In the case of lemon balm (Melissa officinalis), even 3-5 tonnes of plant matter. This explains both the high price of peppermint oil and the extreme concentration of active substances.

The bioavailability of the essential oils is up to 95 % when taken internally, around 50 % when inhaled and only around 5 % when applied to the skin. This means that when ingested, almost the entire dose enters the bloodstream - a major burden on the liver and a risk of toxicity.

Risk of toxicity

Many essential oils contain substances that are potentially toxic when taken internally. Among the riskiest are:

Oregano (Origanum vulgare):

• Contains high concentrations of carvacrol (60-80%)
• May cause mucosal irritation and hepatotoxicity
• Interacts with drugs metabolized in the liver

Thyme (Thymus vulgaris):

• Contains up to 54% thymol
• High doses may cause gastrointestinal irritation
• Potential hepatotoxic effects

Cinnamon bark (Cinnamomum verum):

• Contains 50-90% cinnamaldehyde
• May cause allergic reactions and mucous membrane damage
• High risk of hepatotoxicity

Eucalyptus (Eucalyptus globulus):

• Contains 60-85% 1,8-cineole
• May cause respiratory problems and neurological symptoms
• Particularly dangerous for children

Wintergreen (Gaultheria procumbens):

• Contains up to 98% methyl salicylate
• Even small amounts can cause serious poisoning

Tea Tree (Melaleuca alternifolia):

• Toxic when taken internally
• Reported cases of poisoning in children with as little as a few ml

Lack of regulation and standardisation

Unlike pharmaceutical preparations, essential oils intended for internal use are not subject to strict regulation. There are no standardised dosage levels, leading to situations where consumers have insufficient information on safe levels.

In the food industry, some essential oil components are used as flavourings(GRAS - Generally Recognized As Safe), but these are highly purified substances and in micro quantities. This is fundamentally different from the use of conventional EOs marketed for cosmetics or aromatherapy. The marketing of cosmetic EOs as 'fit for consumption' may contravene legislation.

Specific risks of internal use

Damage to the digestive system

• Burning and irritation in the oral cavity
• Sudden vomiting and nausea
• Gastroesophageal reflux
• Damage to tooth enamel on direct contact

Hepatotoxicity

• The liver is the main organ responsible for detoxification of essential oils
• Long-term or high doses may cause hepatocyte damage, elevated enzyme levels or acute hepatitis

Drug interactions

• Essential oils may significantly affect drug metabolism via cytochrome P450
• May increase or decrease drug efficacy and toxic levels

Neurological effects

• Dizziness and disorientation
• Convulsions at high doses
• Central nervous system depression

Safe ways to use EO

Inhalation

• Aromatherapy diffusers (electric or candle diffusers)
• Inhalation from a bowl of warm water

Topical application

• Massage mixtures (1-3% concentration)
• Cosmetic preparations (0.5-1% concentration)
• Always observe IFRA limits and categories of use

Aromatic baths

• EO added to the bath always via a solubilizer or emulsifier, or in the form of bath salts
• Proper dilution minimizes risk of skin irritation

Conclusion

Internal use of essential oils poses disproportionately high risks compared to the potential benefits. The extreme concentration of active ingredients, the lack of regulation and the possibility of serious side effects make this practice unsafe for the general public.

The internal use of essential oils should only take place under the supervision of qualified healthcare professionals with appropriate knowledge of aromatherapy and essential oil interactions. In the European Union, essential oils are classified as food supplements only if they meet strict quality and safety criteria. However, most essential oils available on the market are not intended for internal use and their sale for this purpose may be in breach of legislation.

Although many of the essential oils in our range are classified as food supplements, we do not recommend their internal use and sell them exclusively for aromatherapy and cosmetic purposes.