Limonene: A cosmetic fragrance to avoid if you have sensitive skin

What is Limonene?

Limonene is a strong-smelling component found in citrus peels, such as oranges, grapefruits, and lemons, as well as pine and mint. It is thought to be a substance that is naturally produced by plants and fruits to protect themselves from external attacks such as pests.

It is used as a fragrance in cosmetics, and its strong scent is also used in natural insect repellents and insect sprays.

It also has a strong ability to dissolve oils, fats, and resins. Therefore, it also acts as a solvent (a component that dissolves other components). Incidentally, it has the ability to dissolve polystyrene foam, and is also used in the recycling of polystyrene materials.

Why is limonene used in cosmetics?

Limonene has a light, fresh, sweet citrus scent. It is very popular among many people who find the scent soothing. For this reason, fruit peel oils (essential oils) from oranges and lemons that contain limonene are used in a great many cosmetics.
In addition to the scent, it also has the following effects:

Promotes penetration

Limonene has been shown in studies to increase the penetration of skin care products, helping to transport other ingredients that cannot pass through the skin layers.

On the other hand, if its permeability is too high, it may cause unexpected skin problems. It is best to avoid using limonene in combination with products that contain skin sensitizers such as denatured alcohol.

Reduces inflammation

There is also research that proves that limonene has anti-inflammatory properties, which may help soothe rough skin .

Antioxidant

Limonene is said to have strong antioxidant properties. Antioxidants help minimize the disruption of free radicals.

Produced by metabolic activity in the human body and cells Free radicals are essential for the body, but if the balance of free radicals is disrupted due to an unbalanced diet, unhealthy lifestyle, stress, etc., cells can be damaged.

This can lead to accelerated aging, which can lead to skin inflammation, dark spots, and wrinkles , so antioxidants are important for prevention.

However, limonene is a highly volatile component (easily changes from liquid to gas). When it comes into contact with air, it oxidizes and its antioxidant power decreases. For this reason, some research suggests that limonene has only a slight antioxidant effect.

Limonene is a fragrance allergen

Limonene has a nice scent and seems to have beneficial effects on the skin. However, it's not all good. In fact, it poses the risk of allergies and skin sensitization.

In the EU, cosmetics regulations define 26 types of fragrance ingredients that may cause skin sensitization as fragrance allergens, and limonene is one of those fragrance allergens.

When fragrance allergens are included in cosmetics, the following is required by EU law:

Report in advance

When registering a product prior to its release, you must declare any fragrance allergens contained in it.

Listed in all ingredients

Normally, fragrances are OK to list as "fragrance" in the ingredient list, regardless of how many different substances are used. However, when limonene is mixed in at a certain concentration or higher, it is not OK to list it as "fragrance." It must be listed as a separate ingredient, "limonene."

The constant concentrations in this case are as follows:

• 0.001% or more in leave-on cosmetics such as skin care and makeup products
• 0.01% or more in rinse-off products such as shampoo and body wash

The same applies to fragrance allergens other than limonene.

In addition to limonene, other ingredients that require prior declaration and individual labeling include the following:

• Linalool
• Geraniol
• Eugenol

By imposing regulations on these fragrance allergens, the government is practicing allergy prevention on a national scale.

Countries that require fragrance allergen labeling

The EU is not the only country that has rules on fragrance allergens like those mentioned above. The following countries and cosmetic laws also require the declaration of fragrance allergens and the labeling of all ingredients .

• new zealand
• China
• Argentina
• Brazil
• ASEAN Cosmetics Law (Malaysia, Singapore, Thailand, Philippines, Brunei, Vietnam, Laos, Myanmar, Cambodia)

However, in Japan, there is no such obligation, so many cosmetics only list limonene as a "fragrance" or the name of the essential oil, regardless of the concentration of limonene in the product (although it may be listed on products sold in countries other than Japan).

3,000 types of fragrances

There are currently about 3,000 types of fragrances used in cosmetics, and some say that the number of only 26 of these that are considered allergens is too low.

In fact, according to IFRA (International Fragrance Association), fragrance allergy sufferers have been steadily increasing over the past 20 years, and it's estimated that a staggering 80% of all fragrance chemical use is in cosmetics.

Due to the high potential risk, allergy investigations are being conducted on other fragrances in the EU. Currently, 26 types of fragrance allergens are recognized, but this number is expected to increase in the future.

People who should avoid limonene

As mentioned above, limonene poses an allergic risk, and it has also been reported to be a skin irritant, so people with sensitive skin or skin conditions such as eczema, psoriasis, or rosacea may want to avoid products containing limonene.