Properly diluting essential oils is one of the most important steps in safe and effective aromatherapy and topical use. Because essential oils are highly concentrated plant extracts, using them undiluted can cause skin irritation, sensitization, or allergic reactions — concerns many users search for before applying oils to the skin. This guide explains why dilution matters, how to calculate dilution ratios, and practical tips for blending essential oils with carrier oils for safe daily use.
Why essential oils must be diluted before skin application
Although derived from plants and completely natural, essential oils are highly concentrated mixtures of biologically active chemical compounds—such as limonene, linalool, eugenol, citral, and menthol, etc., extracted from leaves, flowers, peels, or roots. While these compounds contribute to the oils’ pleasant aromas and therapeutic benefits, their high concentration means that, depending on individual sensitivity and method of use, even a small amount may cause skin irritation or allergic reactions.
Diluting essential oils helps reduce the concentration of these active compounds, thereby minimizing the risk of adverse skin reactions. Dilution is not only a key safety practice, but also an effective way to enjoy the full benefits of essential oils without placing unnecessary stress on the skin.
In addition, essential oils are more easily absorbed through skin when diluted with a carrier oil. Essential oils are volatile aromatic compounds, whereas carrier oils are non-volatile. By blending the two, the essential oil remains on the skin longer, absorbs more effectively, and provides a more comfortable and balanced experience during use.
What is carrier oil and how it helps dilution
Carrier oils, such as jojoba, almond, or coconut oil, are vegetable oils derived from seeds, fruits, or kernels. Their mild scent and non-volatile nature make them ideal for safely facilitating essential oil absorption into the skin.
Here are some carrier oils to use with essential oils:
- Jojoba oil: Suitable for most skin types, even sensitive skin, thanks to its light and non-greasy texture. Jojoba oil is miscible with face sebum, giving it high balancing and moisturizing properties.
- Coconut oil (cold-pressed): Suitable for dry skin and body massage thanks to its high moisturizing properties. However, coconut oil may not be the best oil for facial use, especially oily and acne-prone skin, as it has been shown to clog your skin pores and cause acne breakouts.
- Almond oil: Suitable for normal to dry skin. It’s rich in vitamin E, A, and fatty acids, ideal for softening, moisturizing and enhancing skin elasticity.
- Grapeseed oil: Suitable for oily and acne-prone skin thanks to its light, fast-absorbing texture that won't clog pores. This oil contains antioxidants that protect skin.
- Olive oil: Suitable for dry or aging skin thanks to its high antioxidant content (such as vitamin E and polyphenols). However, for oily or acne-prone skin, it is advisable to do a patch test first as olive oil can clog pores in some people.
- Argan oil: Suitable for sensitive and aging skin. Rich in vitamin E, fatty acids and antioxidants, helps soften skin, increase elasticity and minimize signs of aging.
How to calculate dilution ratio
An essential oil dilution ratio refers to the percentage of pure essential oil in relation to the total mixture (essential oil + diluent) used. This is a fundamental principle for ensuring both safety and effectiveness when using essential oils, especially for direct application on the skin.
How to calculate the dilution ratio:
Concentration (%) = Essential oil (ml) ÷ Total mixture volume (ml) × 100
*** Note: For convenience, 1 drop of essential oil is estimated equal to 0.05ml
Conversion examples:
- 1% dilution: 1 drop of essential oil + 5ml carrier oil (or 2 drops + 10ml carrier oil).
- 2% dilution: 2 drops of essential oil + 5ml carrier oil (or 4 drops + 10ml carrier oil).
- 3% dilution: 3 drops of essential oil + 5ml carrier oil (or 6 drops + 10ml carrier oil)
In aromatherapy, essential oil dilution ratios generally vary depending on the type of essential oil, the intended use, the person using it, and the area of the body where it is applied. For adult skin, a dilution of approximately 1–2% is commonly recommended. However, when used by pregnant women, children, or individuals with sensitive skin, lower dilution ratios should be considered to ensure safety.
The Essential Oil Association of Japan (AEAJ) recommends the following dilution ratios for topical (skin and body) application of essential oils:
- Body use: under 1% of dilution ratio
- Facial and sensitive skin use: from 0.1% to a maximum of 0.5%
Essential safety tips before diluting essential oils
- Always mix essential oils with a carrier oil before topical use.
- Do a patch test on a small area to check for irritation.
- Use lower dilution for children, elderly, or sensitive skin.
- Some oils may cause phototoxic reactions (e.g., citrus oils like lemon or bergamot) — avoid sun exposure on treated skin.
Properly diluting essential oils is a basic yet essential step that allows you to use them more effectively while minimizing potential risks when applied to the skin. When diluted appropriately, essential oils retain their natural properties and benefits, while becoming safer and easier to incorporate into daily body care routines.
If you are looking for high-quality, pure natural essential oils with distinctive, authentic aromas that are suitable for therapeutic use, we invite you to explore areme’s essential oils, developed for a variety of practical applications. We hope the information shared in this article will help you in using essential oils safely and effectively in everyday life.