There is no standard lavender "dosage," since the product is used in various ways. It can be taken by mouth, applied to the skin, or inhaled as aromatherapy. Since very little information is available to guide you in choosing an appropriate lavender dose, it is reasonable to follow the directions on the label of your particular lavender product.
It is important to note that unlike medications (for which the standard doses have been well established), there is less information for determining the best dose for products like lavender. In fact, it is a little strange to discuss a lavender "dosage," since most people use it as an aromatherapy oil or in foods or beverages (such as tea). However, because lavender is sometimes used medicinally, a brief discussion of lavender dosing may be useful.
Medicinally, lavender is claimed to be useful for treating various conditions, such as depression, migraines, and insomnia (see Benefits of Lavender), and is used in a variety of ways. It is taken by mouth, applied to the skin, or inhaled as aromatherapy. However, a safe and effective lavender dose for medicinal use has not been determined. Because there is little or no scientific evidence to guide you in choosing an appropriate lavender dosage, it is reasonable to follow the directions on the label of your particular lavender product, keeping in mind that there is no guarantee that such dosages are either safe or effective.