Piperine

Piperine is the substance that gives black pepper its pungent taste. It occurs in black pepper (Piper nigrum) and long pepper (Piper longum) fruits [2]. Black pepper is used as a spice and preservative in food, and as a fragrance raw material in perfumery [1]. The extract has a strong pungent taste. Supplement manufacturers use piperine to increase the absorption of co-administered substances [13]. Feed manufacturers use it in botanical additive blends [14]. In light, piperine converts into other forms (isomers) with the same formula. This conversion determines the analytical result and storage conditions [3]. How much piperine is in pepper? What is the difference between 25% and 95%? What to look for on a certificate? What do light and storage do?

How much is in pepper?

A study conducted in Korea reports an average of 4418 mg/100 g piperine in black pepper. This corresponds to approximately 4.4% by mass [2]. The same study measured 28 mg/100 g in curry powder, 3.4 mg/100 g in instant curry, and 4.2 to 4.3 mg/100 g in instant and cup noodles [2].

Long pepper also contains piperine and other specific substances. Piperlongumine is the foremost among them [4], [5]. Extracts of the two species are not interchangeable. The certificate must state which species was used.

The composition of black pepper varies by harvest season and drying method. One study reports that essential oil and mineral composition change with season. Mechanical drying at high temperatures degrades the essential oil. Direct-fired dryers introduce iron and chromium to the pepper. In the same study, some samples exceeded reference limits for arsenic (0.46 mg/kg) and lead (0.56 mg/kg) [6]. The quality of a black pepper extract is determined by testing that specific lot, not by the plant name.

Piperine, chavicine, piperlongumine: what is the difference?

Values are taken from PubChem. XLogP shows whether the substance is lipophilic or hydrophilic. Higher values indicate higher lipophilicity.

Piperine has four isomers. Piperine, isopiperine, chavicine, and isochavicine share the same chemical formula. They differ in the orientation of two double bonds within the molecule. Piperine provides the primary pungent taste [1]. A study established an HPLC (liquid chromatography) method to separate all four isomers. The same study reports that piperine converts to the other isomers under fluorescent light, sunlight, and UV light [3]. HPLC separates the components in a mixture and quantifies each individually. In an extract exposed to light, the piperine proportion decreases and its isomers increase.

Insoluble in water. Piperine is practically insoluble in water. Solubility is very low in pure water. In Transcutol, a pharmaceutical and cosmetic solvent, solubility was measured thousands of times higher than in water [12]. The carrier in a formulation is selected accordingly.

What is it used for?

Food. Black pepper is one of the most common spices, and its pungent taste comes from piperine [1]. In Korea, daily dietary intake of piperine was calculated as 123.66 µg/kg body weight. The no-observed-adverse-effect level in animals is 162 times this intake. The authors do not consider this intake level a public health risk [2].

Supplements: absorption enhancer. Piperine inhibits enzymes that metabolize drugs in the liver and intestine [1]. Therefore, blood levels of co-administered substances increase. In rats, 20 mg/kg piperine increased the bioavailability of curcumin by 154% [13]. In healthy human volunteers, 20 mg piperine combined with 2 g curcumin increased this bioavailability approximately 20-fold, with no adverse effects observed [13]. The same mechanism applies to drugs [1]. Therefore, drug interactions must be evaluated in products containing piperine.

Feed. Piperine is used in feed not alone, but as a component of botanical additive blends. The rationale is digestion. A review reports that piperine stimulates pancreatic digestive enzymes and shortens intestinal transit time [1]. In a 35-day trial with 640 broiler chickens, micellar (water-dispersible) piperine was added to feed at 0.02% to 0.08%. After day 21, weight gain increased, final weight rose dose-dependently, and meat quality was unchanged [15]. The European Food Safety Authority (EFSA) found a feed additive blend containing benzoic acid, thymol, eugenol, piperine, and three flavoring components safe for chickens for fattening at 300 mg/kg [14]. In the same opinion, performance parameters improved in three out of ten studies. The panel concluded the additive has the potential to be efficacious to some extent [14]. This opinion applies to the blend, not to piperine alone.

Cosmetics and dermatology. Black pepper is used as a fragrance raw material in perfumery [1]. Black pepper extract is also included as a fragrance ingredient in cosmetics. The cosmetic ingredient name (INCI) is Piper Nigrum Fruit Extract, and for long pepper it is Piper Longum Fruit Extract. Primary literature on applying piperine to skin belongs to dermatology and falls under pharmaceuticals. In a double-blind study of 63 patients with facial vitiligo, topical piperine was added to phototherapy. It provided higher repigmentation at months 1, 2, and 3 compared to placebo (an inactive control product). Transient burning occurred in 10 patients, and transient erythema occurred in 6 patients [16]. This is a clinical treatment study. It cannot be converted into a cosmetic product claim.

25% or 95%: which form?

Piperine is commercially available in three forms.

Supercritical CO₂ (carbon dioxide acting like a liquid under pressure) extraction of black pepper has been studied since the 1990s [7]. Enzymatic pretreatment of pepper increased piperine yield [8]. The composition of essential oil accompanying the oleoresin varies by pepper cultivar [9].

Selection depends on four questions.

• How much piperine is needed? One gram of a 25% extract contains 250 mg piperine. To achieve 1 g piperine in a 1 kg blend, 4 g of 25% extract or 1.05 g of 95% purified piperine is required. Both deliver the same amount of piperine. The difference is the accompanying essential oil, aroma, and bulk volume. Numbers are examples.
• Is aroma desired? Black pepper aroma is desired in sauces and seasoning blends. Oleoresin or standardized extract delivers this. In capsules, aroma and bulk volume are unwanted. High-assay extracts or purified piperine are used there. Selection depends on the finished product.
• Light history. Inquire about extract packaging and the date of the certificate (see "Piperine, chavicine, piperlongumine: what is the difference?").
• Price. Compare the price per kilogram of piperine, not the price per kilogram of raw material.

How to read the analysis report?

Method. Piperine is quantified by HPLC. A validated HPLC method separates piperine from degradation products [10]. Ultraviolet (UV) spectrophotometry counts all light-absorbing isomers and similar compounds as piperine. A 1963 study compared UV with an older colorimetric method. It reports that colorimetry gave consistently high results and that piperettine (another pepper compound) interfered [11]. The certificate must state the method name. If the method is UV, the "piperine" value may include isomers.

Piperine or total isomers? HPLC separates piperine from its isomers [3], [10]. If a document states "piperine", the other three isomers must not be included in the figure. In a sample exposed to light, total isomers are high and piperine is low. A sample exposed to light prior to analysis shows lower piperine for the same reason [3].

Specification and measured value are different. A specification is the manufacturer's commitment. The measured value is the result for that specific lot. A technical data sheet (TDS) is a general document. A certificate of analysis (CoA) belongs to the lot.

What indicates quality?

Isomer profile. The ratio of piperine to its isomers indicates the light history of the extract [3]. A high proportion of isomers points to poor storage.

Heavy metals. Arsenic and lead exceeded limits in some black pepper samples. Direct-fired dryers also introduce iron and chromium [6]. The certificate must include a heavy metal line for the raw material.

Solvent residue. Residue depends on the extraction solvent. For oleoresin extracted with organic solvents, residual solvent limits must be checked. The same applies if a co-solvent was used in CO₂ extraction.

Required items on the certificate. The certificate must include the piperine assay and test method, isomer differentiation status, essential oil content, loss on drying, heavy metals, and microbiology. For botanical raw materials, it must also include pesticides, aflatoxins, and benzo(a)pyrene.

How does it behave in formulations?

Solubility and taste. Piperine is insoluble in water [12]. It has a sharp, pungent taste. Pungency limits the usable quantity in non-capsule applications.

Light and storage. Store the extract in light-proof, cool, and tightly closed containers [3]. Transparent packaging and open shelves degrade the piperine assay below the certified value.

Interactions. Piperine increases the absorption of co-administered substances [1], [13]. This effect is used in supplements. In products intended for consumers taking medication, it is evaluated as an interaction risk.

Safety documentation and labeling. Follow the product safety data sheet (SDS) when handling powder. The identifier on the label depends on product category and regulatory requirements.