Thailand's Restricted and Prohibited Supplement Ingredients: What Your Formula Can and Cannot Contain

Thailand regulates food supplements as a category within the Food Act B.E. 2522, which means every formula has to fit inside a defined set of boundaries before Thai FDA will ever look at a registration application. Some of those boundaries are dose ceilings on otherwise permitted vitamins and minerals. Others are absolute: a handful of ingredient categories cannot appear in a food supplement at any dose, because their presence moves the product out of the food regime entirely and into drug or narcotics regulation instead. Knowing which boundary applies to a given ingredient, before a formula is finalized and a dossier is submitted, is the difference between a smooth registration and a rejected application months into the process.

The Permitted List and Where the Maximum Levels Come From

MOPH Notification No. 448 B.E. 2566 (2023), effective July 2, 2024, sets the current maximum permitted levels for vitamins and minerals in food supplements sold in Thailand. It replaced ceilings that had gone largely unchanged for years, raising the permitted maximum on several key nutrients while tightening or removing others. A supplement formula above the applicable ceiling for any nutrient it delivers cannot be registered as-is, full stop. The complete nutrient-by-nutrient table, verified directly against Thai FDA's primary notification text, lives on DeeMED's own supplement ingredient approval and novel food guide, which is the reference to check before finalizing a dose for any individual nutrient.

No. 448 also sets a floor, not just a ceiling. Where a supplement makes a nutrient delivery claim, that nutrient generally has to be present at not less than 15 percent of the relevant Thai reference daily intake per serving. A product that delivers a nutrient below that threshold cannot support a nutrient function claim under MOPH No. 447, which means the dosing decision and the labeling claim have to be worked out together, not sequentially. Products already approved under the prior, lower ceilings were given a transition window to reformulate rather than an immediate cutoff, but any new application filed after the July 2024 effective date is assessed directly against the current No. 448 levels, with no grandfathering into the old numbers.

The reasoning behind raising some ceilings while tightening or eliminating others is worth understanding, because it shapes how Thai FDA is likely to treat future revisions to this same list. Nutrients with well-established international safety margins and genuine consumer deficiency concerns generally saw their permitted maximums increased, bringing Thailand closer to comparable ceilings in other ASEAN and international markets. Nutrients where Thailand's own public health data pointed toward a specific population-level concern, sodium intake being the clearest example, were tightened or removed from the framework instead, regardless of what other markets permit. A formulator working from a ceiling set in another jurisdiction should never assume Thailand's number will match; the two frameworks are driven by different underlying health data and do not move in lockstep.

Ingredients That Cannot Be in a Supplement at Any Dose

The maximum-level framework only governs ingredients that are permitted to begin with. A separate, harder line exists for substances that cannot appear in a food supplement regardless of quantity. An active pharmaceutical ingredient is the clearest example: if a substance is classified as a drug ingredient under the Drug Act B.E. 2510 (1967), its presence in any amount reclassifies the entire product as a drug, not a food supplement, and no dose adjustment brings it back inside the food regime.

Hormonal substances sit in the same category. Melatonin, DHEA, and comparable compounds are regulated as drugs in Thailand, which means a product containing any of them is a drug product from the outset and was never eligible for the supplement pathway in the first place. The same logic applies to ingredients scheduled under Thailand's narcotics or psychotropic substances framework: a substance being sold freely as a supplement ingredient in another market does not change its status once it is scheduled here.

A fourth category is procedural rather than substance-based, and it catches more formulas than the others combined. Any ingredient used as human food for less than 15 years in Thailand requires a novel food safety assessment under MOPH No. 376 B.E. 2559 (2016) before it can go into a registered product. Using an ingredient of this kind without a completed assessment blocks registration outright, not because the ingredient is unsafe, but because Thailand has not yet formally evaluated it under this specific pathway. This is frequently where a formula built around a trending international ingredient runs into trouble first, well before the vitamin and mineral dosing is even reviewed.

The four categories above are not equally common as rejection causes in practice. Drug substances and scheduled narcotics rarely appear in a serious commercial formula by accident, since most manufacturers already screen for them out of basic legal caution. Hormonal ingredients occasionally slip in through blended "proprietary complex" labeling that obscures a specific compound's presence, which is itself worth flagging to a formulator during screening. By far the most common real-world rejection point is the fourth category: an ingredient trending in the US, EU, or another Asian market that has simply never been used as food in Thailand long enough to clear the 15-year threshold, regardless of how well-established or safe it may be elsewhere. Companies chasing an international ingredient trend into the Thai market should assume a novel food review is required until proven otherwise, not the reverse.

Herbal Ingredients Sit Under a Separate List Entirely

Herbal ingredients in supplements answer to their own classification layer, separate from both the vitamin and mineral ceilings and the novel food threshold. The Thai FDA's Notification Re: Recommendations for the Use of Important Ingredients in Dietary Supplement Products, effective July 8, 2024 (B.E. 2567), with its attached positive list of roughly 444 permitted plant ingredients, sets out the herbal ingredients Thailand permits for use in food, supplements included. An herb that does not appear on this list, or that is instead classified as a herbal medicinal substance under the Traditional Medicine Act, cannot go into a food supplement no matter how established its traditional use is elsewhere.

This distinction catches manufacturers more often than it should, because it is not always intuitive. Some herbs central to traditional medicine practice in a manufacturer's home country are classified in Thailand as medicinal herbs rather than food herbs, which means a formula built around traditional use patterns imported wholesale from another market can include ingredients that simply do not qualify for Thailand's food regime. The only reliable way to catch this is to check every herbal ingredient against Thai FDA's positive plant-ingredient list at the formula screening stage, before a submission is prepared, not after a registration application comes back rejected.

Screening a Formula Before It Ever Reaches a Dossier

The practical lesson across all of these categories is the same: ingredient screening belongs at the start of product development, not at the end of it. Every ingredient in a formula bound for the Thai market should be checked against three things before a dossier is drafted: the No. 448 maximum and minimum levels if it is a vitamin or mineral, Thai FDA's positive plant-ingredient list if it is a botanical, and the 15-year novel food threshold under No. 376 if it is anything newer or less established. A formula that fails one of these checks is not necessarily dead on arrival, but the available path forward, whether that means reformulating below a ceiling, substituting a listed herb for one that is not, or initiating a novel food assessment, needs to be identified while there is still time to act on it, not discovered from a rejection letter.

DeeMED Consulting screens supplement formulas against Thailand's full ingredient framework before a submission is ever prepared, including novel food eligibility review and ingredient-level gap assessment for products headed into Thai FDA registration.