Curcumin and bioavailability: why the form can be just as important as the ingredient

Curcumin is a natural polyphenol from the plant Curcuma longa and is one of the most researched compounds in turmeric. In laboratory and clinical research, it is studied for its interaction with processes related to oxidative stress, inflammatory signaling pathways, metabolism, and other biological functions.

However, there is one important problem with curcumin: what we ingest is not necessarily what our body can effectively utilize.

Classic curcumin is poorly soluble in water, has limited absorption from the digestive system, and is relatively quickly metabolized and eliminated after absorption. Because of this, the concentration of free curcumin that can be found in the blood after oral intake often remains very low. [1,2] PubMed Central (PMC)

This is precisely why, in recent years, a large portion of research has focused not only on the question of how much curcumin we take, but also on in what form we take it.

What does bioavailability actually mean?

Bioavailability describes how much of an ingested substance becomes available to the organism after administration, that is, how much of it we can detect in systemic circulation and over what period.

For two capsules that contain the same amount of curcumin on the label, the actual exposure of the body to curcumin does not have to be the same.

The reason lies in the physical and chemical properties of the compound itself.

Curcumin is highly lipophilic, meaning it binds better with fats than with water. Since the digestive system is a predominantly aqueous environment, this hinders its dispersion and absorption. After passing through the intestinal wall, a large portion of curcumin additionally undergoes conjugation processes, such as glucuronidation and sulfation. [1,3] PubMed Central (PMC)

That is why increasing bioavailability has become one of the key areas of research for modern curcumin formulations.

What are liposomes?

Liposomes can be thought of as extremely small structures made of phospholipids.

Phospholipids are interesting because one part of their molecule has an affinity for water, while the other has an affinity for fats. When in an appropriate environment, they can organize into structures with a lipid bilayer similar to those found in biological membranes.

This makes them interesting carriers for various active compounds.

With lipophilic molecules like curcumin, the goal is to increase their dispersibility in the digestive system, protect them during their passage through the gastrointestinal environment, and create conditions that can increase their absorption. [1,2] PubMed Central (PMC)

In other words, the idea is not necessarily to use more curcumin, but to deliver the ingested curcumin more effectively.

And what is proliposomal, i.e., dry liposomal powder?

In dietary supplements, the development of so-called proliposomal systems is particularly interesting.

Unlike classic liquid liposomal dispersion, a proliposomal system can be produced as a dry powder designed to reorganize into lipid structures upon contact with water or gastrointestinal fluids.

Such an approach can be technologically interesting because it enables the application of a lipid system within capsules and potentially greater stability during storage compared to some liquid dispersions.

However, there is an important scientific nuance here: the word "liposomal" in itself is not proof of increased bioavailability.

The result depends on many factors, including phospholipid composition, particle size, production method, formulation stability, degree of encapsulation, and the behavior of the formulation after passing through the digestive system. PubMed Central (PMC)

How much can liposomal technology actually increase absorption?

This is where science becomes particularly interesting.

The results do not show a single universal value like "5 times" or "10 times".

For example, in a randomized crossover study of the phospholipid complex of curcumin Meriva®, the total absorption of curcuminoids was approximately 29 times higher than after a comparable unformulated mixture of curcuminoids. It is important to emphasize that Meriva is not a classic liposome, but a complex of curcuminoids and phosphatidylcholine, and that researchers mainly detected curcuminoid metabolites in the blood. [4] PubMed

On the other hand, a randomized crossover study from 2021 compared several different curcumin delivery technologies, including liposomes, micellar systems, phytosomes, and cyclodextrin complexes. In that study, the largest increase in systemic exposure was recorded for a micellar formulation and a complex with γ-cyclodextrin, while the tested liposomal formulation itself did not show a statistically significant increase compared to native curcumin. [5] Wiley Online Library

A newer randomized clinical trial published in 2026 examined a specific double-layered nano-liposomal formulation in healthy men. After adjusting for the dose ingested, the area under the plasma concentration-time curve, or AUC, was approximately 23 times higher, and the maximum plasma concentration was more than 50 times higher than that of conventional curcumin. However, this is a small study of 18 subjects, and the result refers specifically to that formulation, and not automatically to every product labeled as liposomal curcumin. [6] PubMed

So, is liposomal curcumin 5–10 times better absorbed?

There is no single scientifically justified figure that can be applied to all liposomal formulations.

Depending on the technology, very different values have been recorded in studies, from a lack of significant improvement to multi-fold higher systemic exposure.

That is why, regarding bioavailability claims, it is more important to ask:

Which specific formulation was tested?

rather than just:

Is the product liposomal?

That is the essential difference between a marketing claim and a pharmacokinetic proof. PubMed Central (PMC)

Why is higher bioavailability important at all?

If a particular formulation manages to increase absorption, the same oral dose can potentially result in higher systemic exposure to curcumin or its metabolites.

This is particularly relevant because a large part of curcumin's biological activity has been identified in experimental models, while its poor oral bioavailability is one of the main reasons why it is not simple to translate laboratory research results to humans. PubMed Central (PMC)

But higher absorption does not automatically mean a proportionally greater health effect.

Pharmacokinetics tells us how much of a substance is available to the organism. Clinical efficacy answers a different question: does that substance meaningfully change a specific health outcome.

This requires separate clinical research.

Curcumin and inflammatory processes

One of the most researched areas of curcumin is its connection to inflammatory signaling pathways.

Large analyses of randomized clinical trials show that curcumin supplementation in certain populations can influence some biomarkers related to inflammation and oxidative stress. A meta-analysis of over 100 randomized studies, for example, found statistically significant changes for some parameters, including C-reactive protein. [7] PubMed

This, however, is not the same as the claim that curcumin "cures inflammation" or a specific inflammatory disease.

For osteoarthritis, there are promising results related to pain and joint function, but the US National Center for Complementary and Integrative Health still states that higher-quality research is needed before drawing final conclusions. [8] PubMed

And what about the brain and cognitive functions?

Curcumin is also being intensively researched in the field of neurobiology.

Preclinical research shows several potentially interesting mechanisms, including interaction with oxidative and inflammatory processes. However, results in humans are not consistent enough to claim that curcumin generally "protects the brain" or improves cognitive abilities.

Some meta-analyses note improvements in individual domains such as working memory, while others find no significant change in overall cognitive function. [9] PubMed

Therefore, the claim that "liposomes help curcumin cross the blood-brain barrier" should not be used as a general clinical claim without evidence for a specific formulation.

More is not always better

Increased bioavailability generally sounds like an advantage, but there is another side to the story.

If technology significantly increases systemic exposure to an active substance, then safety, dosage, and potential side effects must also be considered.

The NCCIH states that conventional turmeric and curcumin preparations can cause digestive side effects such as nausea, reflux, diarrhea, or constipation. Rare cases of liver damage associated with some high-bioavailability preparations have also been reported, which is why "higher absorption" should not be viewed as a synonym for "the more, the better." NCCIH

Science before the number on the label

Curcumin is a good example of how far modern nutritional science has gone beyond the simple question of how many milligrams of a certain ingredient a product contains.

For compounds with naturally poor solubility and limited oral bioavailability, the delivery method can be as important as the amount of the active ingredient.

Liposomes, proliposomal powders, phospholipid complexes, micellar systems, and other technologies are attempting to solve the same problem with different approaches.

Research clearly shows that the bioavailability of curcumin can be significantly increased. What science does not support is the assumption that every liposomal formulation will achieve the same result.

That is why perhaps the most precise question we can ask is:

Not just "how much curcumin does it contain?", but also "how is that curcumin formulated?"

Literature and sources

[1] Tabanelli R. et al. Improving Curcumin Bioavailability: Current Strategies and Future Perspectives. Pharmaceutics. 2021;13(10):1715. DOI: 10.3390/pharmaceutics13101715. PubMed Central (PMC)

[2] Stohs SJ. et al. Highly Bioavailable Forms of Curcumin and Promising Avenues for Curcumin-Based Research and Application: A Review. Molecules. 2020;25(6):1397. PubMed Central (PMC)

[3] Biomedical Applications and Bioavailability of Curcumin—An Updated Overview. Review of data on absorption, metabolism, and curcumin delivery technologies. PubMed Central (PMC)

[4] Cuomo J. et al. Comparative Absorption of a Standardized Curcuminoid Mixture and Its Lecithin Formulation. Journal of Natural Products. 2011;74(4):664–669. DOI: 10.1021/np1007262. PubMed

[5] Flory S. et al. Increasing Post-Digestive Solubility of Curcumin Is the Most Successful Strategy to Improve its Oral Bioavailability: A Randomized Cross-Over Trial in Healthy Adults and In Vitro Bioaccessibility Experiments. Molecular Nutrition & Food Research. 2021;65(24):2100613. DOI: 10.1002/mnfr.202100613. Wiley Online Library

[6] Enhanced bioavailability of a novel double-layered nano-liposomal curcumin (BNT-C060): a randomized, double-blind, clinical trial. Scientific Reports. 2026. DOI: 10.1038/s41598-026-53709-8. Nature

[7] Curcumin on Human Health: A Comprehensive Systematic Review and Meta-Analysis of 103 Randomized Controlled Trials. Phytotherapy Research. Analysis of 103 RCTs and 7,216 subjects. PubMed

[8] National Center for Complementary and Integrative Health (NCCIH). Turmeric: Usefulness and Safety. Current review of clinical evidence and safety of turmeric and curcumin. NCCIH

[9] Targeting cognitive aging with curcumin supplementation: A systematic review and meta-analysis. Systematic review of preclinical and human research on cognitive outcomes. 2025.