Propolis is roughly 50% plant resins, 30% beeswax, 10% essential and aromatic oils, 5% pollen, and 5% other organic compounds. But that broad breakdown only tells part of the story. The resins alone contain hundreds of biologically active chemicals, and the exact recipe changes depending on where the bees live and which plants grow nearby.
The Raw Ingredients Bees Collect
Honeybees gather the sticky resins that form the backbone of propolis from tree wounds, leaf buds, flowers, and fruits. In Europe and North America, the primary source is bud exudate from poplar trees, especially black poplar. In Brazil, bees harvest resin from a shrub called Baccharis dracunculifolia, which produces a distinctive green propolis. Tropical bees in Southeast Asia tap dipterocarp trees and other rainforest species. The plant source is the single biggest factor determining what ends up in the final product.
Back at the hive, bees chew the collected resin and mix it with salivary enzymes. This partial digestion appears to chemically modify some of the plant compounds. The partially processed resin is then blended with beeswax. Bees use the finished propolis to seal cracks, reinforce the hive structure, and coat the interior walls, where it acts as a kind of antimicrobial barrier.
Flavonoids and Phenolic Acids
The most studied components of propolis are its polyphenols: flavonoids and phenolic acids. These are the compounds responsible for most of propolis’s antioxidant and antimicrobial properties. The major phenolic acids include caffeic acid, ferulic acid, p-coumaric acid, chlorogenic acid, and trans-cinnamic acid. Among flavonoids, the most commonly identified are pinocembrin, pinobanksin, kaempferol, apigenin, chrysin, and galangin.
Concentrations vary widely from sample to sample. In one analysis of 24 propolis samples from Turkey, pinobanksin ranged from about 2 to 39 mg per gram of crude propolis, while caffeic acid ranged from less than 1 to over 7 mg per gram. Ferulic acid showed even more variation, from 0.4 to over 17 mg per gram. This kind of spread is normal for a natural product and reflects differences in the local plant environment.
Quality benchmarks proposed by researchers suggest that good propolis should contain at least 20% total phenolics by weight, with flavonoids making up a meaningful share of that. No universal international standard exists yet, though Argentina and Russia have developed national standards.
CAPE: A Signature Compound
One compound gets special attention in propolis research: caffeic acid phenethyl ester, commonly called CAPE. It’s found abundantly in poplar-type propolis and is one of the most potent antioxidants in the mix. Ethanol extracts of propolis typically yield around 10 to 16 mg of CAPE per gram. French poplar propolis, for example, contains roughly 10 to 12 mg/g of CAPE depending on the extraction method. CAPE has shown anti-inflammatory effects in lab studies and has been investigated for its ability to interfere with fat cell formation in early stages of development.
How Geography Changes the Formula
Propolis from temperate climates (most of Europe, North America, and nontropical Asia) is dominated by poplar-derived compounds. Its chemical fingerprint features high levels of cinnamic acid derivatives and flavonoids like pinocembrin, which can reach 35 to 50 mg per gram in French samples. This “poplar type” is the most thoroughly studied variety.
Brazilian green propolis has a completely different profile. Its signature compound is artepillin C, derived from the Baccharis shrub. Artepillin C has been studied for anti-inflammatory and anticancer properties and is largely absent from European propolis. The color, smell, and biological activity of Brazilian green propolis are noticeably distinct from the darker, poplar-based varieties common in Europe.
Tropical propolis from regions like Southeast Asia, Africa, and the Pacific Islands draws from yet another set of plant species, producing still different chemical profiles. This is why two propolis supplements from different parts of the world can look, taste, and behave very differently.
Minerals and Vitamins
Beyond its polyphenol content, propolis contains a range of minerals and vitamins in small amounts. The mineral profile includes calcium, magnesium, potassium, zinc, copper, manganese, iron, sodium, and iodine. On the vitamin side, propolis provides B1, B2, B6, vitamin C, and vitamin E. These aren’t present in therapeutic doses the way they’d be in a multivitamin, but they contribute to propolis’s overall nutritional complexity.
Physical Properties
Raw propolis is a sticky, resinous substance that softens and becomes pliable at warm temperatures. It melts between 54 and 62°C (roughly 129 to 144°F). One practical detail that matters for supplements: propolis doesn’t dissolve well in water. Its active compounds are much more soluble in alcohol, which is why most commercial propolis extracts use ethanol (often 70% to 96% concentration) as the solvent. If you see a propolis tincture, it’s almost certainly alcohol-based for this reason. Water-based extracts exist but capture fewer of the bioactive polyphenols.
The wax content of raw propolis also matters for quality. Researchers have proposed capping wax at 40% of the total weight, since anything above that level makes it difficult to distinguish genuine propolis from adulterated or low-quality material. When shopping for propolis products, extracts that list total polyphenol or flavonoid content give you a better sense of potency than raw weight alone.