Bioavailability Enhancers in Ayurveda: The Science Behind Anupana and Sahapana

A useful modern example of co-administration is the 1998 Planta Medica study in which 20 mg of isolated piperine was given with 2 g of curcumin. The investigators reported markedly greater short-term serum exposure than with curcumin alone. Piperine is a major pungent alkaloid of Piper nigrum (Maricha, black pepper), but this experiment does not prove that every classical pepper-containing prescription was designed around what is now called “bioavailability enhancement.” It tested one defined combination and dose.

Anupana has a broader and more precise classical meaning than “absorption enhancer.” In Charaka Samhita, Sutra Sthana 27, the discussion is primarily about a suitable drink taken with or after food, selected in relation to the meal and so that it is not harmful to dosha or dhatu. Later pharmacy also applies anupana to a substance given with or after medicine. Sahapana, emphasized in later Rasa-shastra literature, refers to a medium administered together with medicine; it is not a synonym for every kind of herbal synergy. Traditional prescribing and modern pharmacokinetics may overlap, but they are not interchangeable.

Why Anupana Matters: Form, Context and Bioavailability

Bioavailability is the proportion of an administered substance that reaches systemic circulation in a measurable form. It is not the only measure of activity: a preparation may act locally in the gut, be converted into metabolites, or contain constituents with different absorption profiles. A single percentage therefore cannot describe an entire herb.

• Curcumin: Human studies find low and variable systemic exposure because of limited aqueous solubility, metabolism and elimination. Exposure depends on dose, analytical method and formulation; “1% bioavailability” is not universal.
• Berberine and quercetin: Oral exposure varies with chemical form, food matrix, metabolism and product. Broad ranges such as “5–20%” or “0–50%” are too imprecise to guide clinical use.
• Ashwagandha: Human withanolide studies examine particular standardized extracts; they do not justify a universal 20–40% figure for all ashwagandha products.

Charaka does not describe CYP enzymes, P-glycoprotein, chylomicrons or modern tissue targeting. Sutra Sthana 27, verses 319–326, says an appropriate post-prandial drink is chosen according to the food and person, and describes nourishment, satisfaction, softening and liquefaction of food, digestion, assimilation and diffusion. These classical observations may inspire hypotheses, but should not be rewritten as direct statements of contemporary pharmacokinetics.

Major Anupana Categories: What Is Traditional and What Is Proven

The same substance can be food, vehicle, adjuvant or medicine depending on context. The table separates classical use, reasonable formulation principles and claims that still require direct testing.

Piperine: The Best-Studied Example, with Important Limits

Shoba and colleagues gave healthy volunteers 2 g of curcumin alone or with 20 mg of piperine. Levels were very low or undetectable after curcumin alone, whereas co-administration produced higher concentrations during the first hour; the area-under-the-curve calculation yielded a reported 2000% increase. This small, single-dose experiment used isolated piperine. It did not show that household black pepper reproduces the result or establish long-term efficacy.

The 1998 paper referred to inhibition of glucuronidation, but did not demonstrate CYP3A4 or P-glycoprotein inhibition in those volunteers. Earlier laboratory work showed reduced glucuronidation, and a later human-cell and microsomal study found P-glycoprotein and CYP3A4 inhibition. These are plausible mechanisms, but in-vitro results do not predict the size of an interaction in an individual patient.

Trikatu is Shunthi (dry ginger), Maricha (black pepper) and Pippali (long pepper). It occurs in many formulations, but no authoritative source supports the claim that every classical Haridra formula contains it. Combinations may address taste, digestion, dosage form and therapeutic intent; one modern piperine-curcumin experiment cannot prove the purpose of every traditional prescription.

Ghrita: A Lipid Dosage Form, Not Automatically a Nano-Carrier

Medicated ghrita is a genuine Ayurvedic pharmaceutical dosage form in which a lipid medium is processed with herbal materials according to a defined method. Modern oral-delivery science confirms the general principle that lipids can improve the apparent solubility and intestinal presentation of some poorly water-soluble molecules. Lipid digestion can also support intestinal lymphatic transport for compounds whose physicochemical properties favor that route.

That principle does not mean that any herb swallowed with ghee enters chylomicrons, avoids first-pass metabolism or becomes two to ten times more bioavailable. Lymphatic transport depends on the molecule, lipid composition, digestion, dose and formulation. Each ghrita needs direct comparative study.

Brahmi Ghrita should therefore be described as a classical multi-ingredient lipid preparation, not as a clinically proven “optimized bacoside nano-carrier.” The behavior of a finished ghrita cannot be inferred from data on one isolated constituent; preparation, identity, quality and intended indication must be assessed as a whole.

Honey as Anupana: Classical Guidance without Modern Overreach

Charaka Samhita, Sutra Sthana 27, verses 245–249, describes honey as sweet and astringent, dry, heavy and cooling, and calls it an excellent yogavahi or vehicle because it is composed of many substances. The same passage warns against heated or warm honey. This is an authentic classical instruction and should be presented as such rather than converted into an unsupported claim that honey enzymatically transforms every herb into a more absorbable drug.

Modern chemistry shows that 5-hydroxymethylfurfural (HMF), a sugar-degradation product, rises with heat and storage. Current toxicological reviews do not establish that ordinary warmed honey becomes a human poison because of HMF. The classical prohibition and the HMF observation are not equivalent proof, and one should not be presented as scientific validation of the other.

Honey’s viscosity and sweetness can make powdered medicines easier to administer, but evidence for systemic “permeability enhancement,” targeted delivery to skin or nerves, or prolonged contact with the lower respiratory tract is lacking. Swallowed honey does not coat the bronchi. The dose, medicine, patient and classical restriction on heating remain relevant.

Sahapana and Combination Formulation

Later Ayurvedic pharmaceutical writing uses sahapana for a substance mixed with and administered together with a medicine. A review of the term reports that it is not found in earlier Ayurvedic texts before Rasa Tarangini. It is therefore historically misleading to make Sahapana a major doctrine of Charaka or to define it broadly as any pair of herbs that “mutually potentiates” each other.

Combination formulation remains important. Co-administered ingredients can change taste, dispersion, dissolution, gastric emptying, metabolism, transport and toxicity. Effects are not always beneficial; an ingredient may reduce exposure, intensify an adverse effect or interact with a drug. “Synergy” should be demonstrated for a specified formula and outcome.

Claims that Triphala functions as a controlled-release tannin matrix for unrelated medicines, or that Vidanga is a general intestinal permeation enhancer, lack direct formulation-specific clinical support. Likewise, laboratory findings on Piper longum or its constituents cannot be used to promise predictable CYP inhibition or improved absorption in patients.

Emerging Research: Formulation Parallels, Not Equivalence

Traditional dosage forms can be studied with modern tools, but resemblance is not equivalence. Lipid formulations may form emulsified or colloidal structures during processing and digestion, fermented preparations contain complex products, and milk proteins can be engineered into carriers. None of this makes every ghrita, asava, arishta or milk anupana a standardized nanomedicine.

Some bhasma studies report micro- or nanoscale particles and altered chemical forms compared with starting material. Size varies with material and manufacturing, and nanoscale particles alone prove neither bioavailability nor safety. Characterization, reproducible manufacture, quality control and toxicology remain essential; “Swarna Bhasma is always 56–78 nm” is not defensible across products.

Bhasma and other mineral-containing products should not be recommended for casual self-treatment on a nanoparticle analogy. Identity, processing, contamination testing, dose and clinical supervision are essential. A “nano” label does not rescue a poorly characterized product, and historical use does not replace safety assessment.

Practical Anupana Guide: Use the Prescribed Context

The practical lesson is not to treat anupana as a universal absorption hack. The medicine, dosage form, food, digestive state, dosha assessment, disease, age and strength of the patient may alter the choice. Changing the vehicle can change the prescription.

• Classical powders, decoctions, ghrita and avaleha: Follow the exact formula’s instructions or a qualified practitioner. Do not add milk, ghee, honey or pepper merely because they are used elsewhere.
• Turmeric used as food: It may be eaten in a normal meal, including one containing fat. This is not equivalent to 2 g purified curcumin with 20 mg isolated piperine, so no “2000%” promise applies to kitchen turmeric.
• Curcumin supplements: Formulations differ substantially. Follow the product directions and seek professional advice rather than adding concentrated piperine to a product that may already contain an enhancer.
• Milk or ghee vehicles: These are not suitable for everyone, including people with milk allergy, lactose intolerance or individualized dietary-fat restrictions.
• Honey vehicles: When following classical use, do not cook or heat the honey with the medicine. People for whom sugar intake requires restriction should obtain individualized advice.
• Piperine supplements: Review all medicines with a pharmacist or physician. Laboratory and human pharmacokinetic studies show that concentrated piperine can alter the handling of some medicines.

For related evidence reviews, see our post on Kutki (Picrorhiza kurroa) research and our systematic review of Ayurvedic hepatoprotective herbs. Evidence for a botanical or finished formulation must be judged on its own methods and outcomes; anupana theory cannot substitute for direct clinical data.

The most responsible change is methodological: do not convert every classical vehicle into a bioavailability claim. Preserve the textual context, identify the product and dose, distinguish culinary pepper from isolated piperine, and ask whether the mechanism was demonstrated in humans for that formulation.

Disclaimer: This article is educational and is not a prescription. Concentrated piperine and some herbal or mineral preparations may alter drug exposure or cause adverse effects. Consult a qualified Ayurvedic practitioner and a physician or pharmacist before changing a prescribed anupana, combining supplements with medicines, or using bhasma or other mineral-containing products.

References

1. Charaka Samhita — Annapanavidhi Adhyaya
2. Jaims (jaims.in)
3. Piperine, a major constituent of black pepper, inhibits human P-glycoprotein and CYP3A4 (2002), PubMed
4. Influence of piperine on the pharmacokinetics of curcumin in animals and human volunteers (1998), PubMed
5. Piperine-mediated inhibition of glucuronidation activity in isolated epithelial cells of the guinea-pig small intestine: evidence that piperine lowers the endogeneous UDP-glucuronic acid content (1986), PubMed
6. Study on influence of piperine treatment on the pharmacokinetics of diclofenac in healthy volunteers (2017), PubMed
7. An Ayurvedic formulation ‘Trikatu’ and its constituents (1992), PubMed
8. Bioavailability of curcumin: problems and promises (2007), PubMed
9. Pharmacokinetics and bioequivalence of Withania somnifera (Ashwagandha) extracts – A double blind, crossover study in healthy adults (2023), PubMed
10. Lipids and lipid-based formulations: optimizing the oral delivery of lipophilic drugs (2007), PubMed
11. Ayurvedic lipid based rasayans – A perspective on the preparation and pharmacological significance of lipids on the bioavailability of phytoconstituents (2022), PubMed Central
12. Lipid-based formulations for oral administration of poorly water-soluble drugs (2013), PubMed
13. Beta-casein-based nanovehicles for oral delivery of chemotherapeutic drugs: drug-protein interactions and mitoxantrone loading capacity (2010), PubMed
14. The role of 5-hydroxymethylfurfural in food and recent advances in analytical methods (2022), PubMed
15. Dietary glycation compounds – implications for human health (2024), PubMed
16. Bhasma : The ancient Indian nanomedicine (2014), PubMed Central
17. Preparation and Characterization of Suvarna Bhasma Parada Marit (2017), PubMed
18. Blood compatibility studies of Swarna bhasma (gold bhasma), an Ayurvedic drug (2011), PubMed
19. NCCIH