Some supplement ingredients that are easy to buy overseas are blocked or limited when you try to bring them into Japan. This page describes only the import and legal status of those ingredients. It does not describe what any ingredient does, and nothing here should be read as a claim about health, effect, or benefit. The point is simple: can it clear customs, and in what quantity.
Japan treats certain ingredients as drug (medicine) components rather than as ordinary food or supplement components. When an ingredient is classified that way, importing it for personal use can require a document from the Ministry of Health, Labour and Welfare (MHLW) confirming the import. In practice this is what "needs MHLW confirmation" means below: the ingredient is handled as a drug ingredient, and without that confirmation it will not be allowed through. Many retailers, including iHerb, will simply not ship such items to Japan rather than ask customers to file paperwork.
Status table
| Ingredient | Import status for Japan | What this means in practice |
|---|---|---|
| Melatonin | Quantity-limited (about a 2-month supply) | Allowed in small personal amounts. iHerb enforces a roughly 2-month cap at checkout. |
| 5-HTP | Quantity-limited (about a 2-month supply) | Same rough 2-month personal-use limit enforced by iHerb. |
| Yohimbe | Quantity-limited (about a 2-month supply) | Same rough 2-month personal-use limit enforced by iHerb. |
| DHEA | Needs MHLW confirmation; iHerb will not ship | Treated as a drug ingredient. Not sent to Japan by iHerb. |
| Pregnenolone | Needs MHLW confirmation; iHerb will not ship | Treated as a drug ingredient. Not sent to Japan by iHerb. |
| Racetams (piracetam and similar) | Needs MHLW confirmation; iHerb will not ship | Treated as a drug ingredient. Not sent to Japan by iHerb. |
| Adrafinil | Needs MHLW confirmation; iHerb will not ship | Treated as a drug ingredient. Not sent to Japan by iHerb. |
| Vinpocetine | Needs MHLW confirmation; iHerb will not ship | Treated as a drug ingredient. Not sent to Japan by iHerb. |
| Hemp and CBD products | Refused | Blocked under Japan's THC rules, which were tightened in December 2024. |
The 2-month group
Melatonin, 5-HTP, and yohimbe are not banned outright, but they are limited to roughly a two-month personal-use quantity. If you order more than that, the excess can be held or returned at customs. iHerb applies this limit for you: it caps how much of these items a Japan-bound order can contain, so an over-limit cart is adjusted or blocked before it ships. That built-in enforcement is one reason it helps to see what a retailer will actually let you buy before you plan an order.
Import rules and quantity limits still apply. We make no health claims; this is only where to buy.
The "needs MHLW confirmation" group
DHEA, pregnenolone, racetams such as piracetam, adrafinil, and vinpocetine fall into a stricter category. Because Japan classifies them as drug ingredients, a personal import normally requires the MHLW confirmation document described above. Rather than route customers through that process, iHerb does not ship these ingredients to Japan at all. If you see one of them listed, expect it to be unavailable at a Japanese address regardless of quantity.
Hemp and CBD
Hemp and CBD products are refused entry under Japan's rules on THC, the controlled component. Those rules were tightened in December 2024, and the practical result for importers is that CBD oils, gummies, and similar hemp-derived items are turned away. This applies even to products marketed abroad as low-THC or THC-free, because the compliance burden sits on the importer.
Before you order
Rules and enforced quantities change, and retailers update their own shipping restrictions on their own schedule, so always confirm the current status before buying. For the wider picture, see our overview of whether you can import a given item, the detail on supplement and medicine quantity limits, and the practical iHerb Japan guide. When in doubt, treat the retailer's checkout behavior and the MHLW guidance as the deciding factors, not a product's overseas availability.
Source: MHLW (mhlw.go.jp), verified 2026-09-07. Import rules, classifications, and enforced quantities can change without notice; verify the current status before ordering.