An new study reveals major gaps in the regulation and transparency of turmeric supplements, highlighting how weak oversight and unclear labeling may put consumers at risk, despite turmeric’s generally healthy reputation.
Study: A market and risk assessment of 125 turmeric supplements available in Australia, Germany, India, UK, and USA. Image Credit: shinshila / Shutterstock
In a recent research article published in the journal Naunyn-Schmiedeberg's Archives of Pharmacology, researchers systematically assessed 125 turmeric (curcumin) supplements from Australia, Germany, India, the UK, and the USA. The study aimed to evaluate the consistency of these products (and their labels) with public health dosage recommendations by abstracting package labels and advertising websites in April and May 2022.
Labeling Inconsistencies and Public Health Risks
Review findings revealed significant inconsistencies in labeling and dosage recommendations, indicating that 34.4% of products failed to disclose the amount of active curcuminoids, while 28.8% of products with dosage information recommended a maximum daily dose exceeding the JECFA acceptable daily intake of 0–3 mg per kg body weight for curcumin. Because the JECFA ADI excludes preparations using turmeric effect-enhancing substances such as piperine, exceedances may underestimate risk in highly bioavailable formulations.
These findings highlight a poorly regulated global market where consumers are exposed to potential risks of overdose and adverse effects, underscoring an urgent need for harmonized international standards.
Traditional Significance of Turmeric
Turmeric (Curcuma longa) has been a cornerstone of Ayurvedic medicine and a staple spice in South Asian cuisine for thousands of years, prized for its vibrant color and purported health benefits.
Curcuminoid Compounds and Therapeutic Properties
Previous research has identified several reported physiologically beneficial medicinal properties that are attributed to a class of bioactive compounds called curcuminoids (curcumin, demethoxycurcumin, and bis-demethoxycurcumin). These molecules are best known for their anti-inflammatory and antioxidant effects.
Challenge of Low Curcumin Bioavailability
Unfortunately, despite its popularity in supplements, curcumin has a significant drawback: poor bioavailability. Studies have shown that the human digestive tract is inefficient at absorbing curcuminoids, as most of them are quickly metabolized and excreted, thereby limiting their therapeutic potential.
Use of Bioavailability Enhancers and Safety Issues
To address this, manufacturers have developed advanced formulations using turmeric effect-enhancing substances (TEES), such as piperine (from black pepper), or creating complexes with lipids and nanoparticles to boost absorption. While these methods have been shown to increase bioavailability, they also raise safety questions, as the toxicity of these highly bioavailable forms has not been thoroughly studied or validated through human clinical trials. Signals of hepatotoxicity have been reported, particularly with products containing TEES.
Global Study Design and Data Sources
To address this need and inform future public health safety policy, the present study conducted a global market and risk assessment of 125 online turmeric supplements in five countries: Australia, Germany, India, the UK, and the USA. Study data collection involved collating package label information and advertising website information for 25 products from each included country in April and May 2022.
Parameters Evaluated and Comparative Approach
Study analyses focused on several key parameters to gauge product transparency and consumer safety:
- The type of turmeric used (e.g., powder, extract, complex)
- The specified amount of active curcuminoids per unit
- The manufacturer's maximum recommended daily dose (MDD)
Furthermore, the presence of any TEES, product price, advertised health benefits, and critical safety information, such as warnings for overdose, potential drug interactions, and use during pregnancy, was included for product-specific evaluation and model standardization. This approach directly compared how supplements are formulated, labeled, and marketed across different regulatory landscapes.
Findings on Dosing Variation and Product Transparency
Study analyses revealed a startling lack of consistency and transparency, demonstrating that 43 of 125 products (34.4%) did not specify the amount of active curcuminoids, leaving consumers (and health professionals) unable to make informed decisions about dosage or value.
Furthermore, dosage recommendations were observed to vary dramatically across products, even from the same nation, and in many cases conflicted with international guidelines. For context, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) set an acceptable daily intake for curcumin of 0–3 mg/kg body weight, about 210 mg for a 70 kg adult, excluding preparations with TEES. Overall, 28.8% of products with dosage information exceeded this threshold.
Indian supplements had the highest average MDD at 457.4 mg, while UK products had the lowest at 123.4 mg. Germany had the highest proportion of products exceeding the ADI (44%), illustrating a “transparency paradox,” as German products were the most likely to disclose dosing information (88%).
Deficiencies in Product Warnings and Health Claims
Finally, product safety labeling was also found to be inadequate and oftentimes misleading. In Australia, 0 of 25 products were observed to carry an overdose warning. In India, 23 of 25 (92%) were found to lack this warning, despite it being a legal requirement.
Warnings about potential drug interactions (e.g., with anticoagulants) and use during pregnancy were also frequently missing, particularly in the USA and India, where no products carried pregnancy warnings.
Notably, “liver health” claims appeared on five products in Australia, 4 in India, and 1 in the UK, despite emerging reports of turmeric-associated liver injury. Gummies were identified in several markets, but no pediatric safety data were referenced on product labels.
Regulatory Gaps and Recommendations for Oversight Reform
The present article underscores an alarming picture of the global turmeric supplement industry, revealing it to be riddled with regulatory gaps and inconsistent labelling that prioritizes marketing over consumer safety.
The wide variations in curcuminoid content, daily dose recommendations, and safety warnings across (and sometimes even within) countries demonstrate that consumers are often ill-equipped to assess the benefits and risks of these increasingly popular supplements. While the UK market showed comparatively lower recommended doses and better labeling compliance, the Indian market exhibited the poorest adherence to safety standards.
Current regulations, which in four of the five countries assessed classify turmeric supplements under food law (with Australia classifying them as complementary medicines), are insufficient to protect the public from the potential biotoxicity of curcumin, especially for highly bioavailable formulations.
Future regulations should be stricter and harmonized across international borders to ensure that the real-world risks of an unregulated market do not overshadow the potential physiological benefits of turmeric.
The authors note that these findings should also be viewed in the context of therapeutic curcumin use in clinical trials, where effective daily doses typically range between 180 mg and 2000 mg, depending on bioavailability, underscoring that higher supplemental doses are not necessarily more beneficial.