You might ask, “Doesn’t the peel contain vitamin C?” Good question.
An important fact is that lemon essential oil is not derived from the pulp of the lemon but from the peel of the lemon, which is extracted from the peel by cold pressing.
The main chemical constituents of lemon essential oil are some monoterpenes.
Properties of essential oil molecules: small molecules, volatile, insoluble in water.
Properties of the vitamin C molecule: larger molecule, stable, non-volatile, water-soluble.
We see that the vitamin C molecule is soluble in water and that there is very little water in the peel; in fact, there is much less vitamin C in the peel compared to the flesh of the fruit.
But this is not enough to prove that essential oils do not contain vitamin C. We also have to look at the extraction process of essential oils:
Different extraction processes
The lemon peel is pressed and becomes a mixture of: essential oil, water, and solids, which are then separated out by a centrifugal action and filtration process.
We know that essential oils are insoluble in water and easily layer with water after resting, while vitamins are mainly soluble in water.
Therefore, from the different extraction process and chemical properties of essential oils, it is impossible for essential oils to contain vitamin C. This is indeed verified if you check the list of chemical composition of lemon essential oil.
You may ask, “Most essential oils are not extracted by cold pressing, but by steam distillation, so can certain ingredients get into the oil?
Steam distillation is designed to take advantage of the very properties of essential oil molecules: volatile, small, and insoluble in water.
The chemical substances in the plant, only part of the volatile and smaller molecules are separated from the plant, with the water vapor into the condenser, in the condenser reduced to condensate and essential oil, due to the difference in specific gravity of the two, in the oil-water separator into oil and water layer, the oil layer above the export is the essential oil.
Therefore, not all the chemicals in the plant will be separated out with the water vapor, even if they are separated out, the substances that are easily soluble in water will be dissolved in the condensate, which is the pure dew.
From this, we can see that essential oils are just one of the more specific parts of the many chemicals in the plant.
Then we can assume that the various vitamins cannot be present in the essential oils extracted by steam distillation. Other vitamins can be derived in a similar way.
Lemon essential oil cannot contain vitamin C. By the same token, it can be deduced that essential oils do not contain vitamins.
Further, when we say that a plant contains a certain active ingredient, it does not mean that it is also contained in the essential oil.
Some chemical components in plants are difficult to be present in essential oils due to factors such as large molecules, solubility in water, and lack of volatility.
This reminds us that the intake of nutrients required by the body (such as vitamin C, etc.) cannot simply be replaced by essential oils and if deficient need to be supplemented separately.