Olive leaf – properties and how to use it?

Leaves have been used in herbal medicine for centuries, which is why the question of what this raw material helps with and whether its uses are confirmed by research is asked relatively often. Scientists are still investigating the potential benefits of olive leaves, analysing their composition and the results of human studies, as well as comparing observations with historical evidence. Many studies point out that ancient sources and modern research are largely consistent in terms of the best form in which to use olive leaves.

1. Harvesting olive leaves
2. Active compounds in olive leaves
3. Use of olive leaves

Harvesting olive leaves

The olive tree (Olea europaea) is a slow-growing, short tree with a twisted trunk and dense crown, tolerant of drought and poor soils. Its leaves are leathery and arranged oppositely. They are narrow and elongated, grey-green on top and silvery underneath. Olive leaves are mainly obtained from olive trees grown in orchards.

Most of the raw material available on the market comes from two moments in the season: from maintenance pruning (crown pruning) and from fruit cleaning in mills and presses. The leaves are collected from the trees and dried after harvesting. Traditionally, drying is carried out in the shade to limit undesirable changes in quality. The olive tree blooms with small, white to light yellow flowers, gathered in clusters. A single flower is small, but there can be from a dozen to several dozen in one cluster.

The fruit is a drupe, i.e. a typical olive fruit with a fleshy edible part and a hard stone inside. When ripe, it usually darkens, and it is from the ripe fraction that oil is obtained by pressing. Its native range includes Africa and the Mediterranean region and extends as far as south-central China. It is not exclusively a European plant. At the same time, olive cultivation, which has been practised for thousands of years in the Mediterranean basin, has spread widely beyond this region, wherever climatic conditions are similar to those of the Mediterranean. Olive groves can be found in both Americas and Australia.

General characteristics of olive leaves

Active compounds in olive leaves

Olive tree leaves are naturally rich in polyphenols, which are plant compounds that plants produce in response to environmental stress, among other things. In the case of olive leaves, the most commonly mentioned compounds are oleuropein and related compounds, as well as hydroxytyrosol and tyrosol. In addition, there are various flavonoids and simple phenolic acids. It is these substances that are largely responsible for the dry, bitter taste of the leaf infusion.

The labels of olive leaf products may contain information about standardisation, for example, the oleuropein content or the total polyphenol content. The differences between selected products are also influenced by the tree variety, growing conditions, harvest date, and the method of drying and storing the leaves. A typical infusion made from olive leaves contains virtually no calories (~0.3 kcal/100 g) or macronutrients, as only trace amounts of soluble compounds are transferred to the water, with carbohydrates at fractions of a gram.

Use of olive leaves

Olive leaves are most often used in the form of an infusion, i.e. tea made from dried leaves, which is drunk like a classic herbal drink, usually 1-2 times a day. At home, the dried leaves are poured over with hot water and brewed for a few minutes, giving them a distinctive bitter taste. Olive leaves are less commonly used as a spice in cooking because of their intense bitterness. They are sometimes added in small quantities to flavour marinades or broths.

"The main difference between green and black olives is their degree of ripeness at the time of harvest. Green olives are harvested before they are fully ripe, while black olives remain on the tree longer until they reach full ripeness, resulting in a darker colour and milder flavour." Łukasz Domeracki - Dietician

Another popular way to use olive leaves is in supplements, most often capsules or tablets containing the extract. In such preparations, it is important that the extract is concentrated and has a specific content of bioactive substances.

Olive leaves are also used as an ingredient in cosmetics, mainly creams, lotions, serums and products for sensitive skin. In home care, they also appear as an ingredient in simple scalp rinses or bath additives.

Sources:

• de Bock, M., Derraik, J. G., Brennan, C. M., Biggs, J. B., Morgan, P. E., Hodgkinson, S. C., Hofman, P. L., & Cutfield, W. S. (2013). Olive (Olea europaea L.) leaf polyphenols improve insulin sensitivity in middle-aged overweight men: a randomized, placebo-controlled, crossover trial. PloS one, 8(3), e57622. https://doi.org/10.1371/journal.pone.0057622
• Leach, M. J., & Breakspear, I. (2025). Efficacy and safety of olive leaf extract (Olea europaea L.) for glycaemic control in adults with type 2 diabetes mellitus (ESOLED): A pilot randomised controlled trial. Complementary therapies in clinical practice, 59, 101949. https://doi.org/10.1016/j.ctcp.2025.101949