Kratom, phenibut and poppers: easy to buy, banned at these borders

Kratom, phenibut and poppers are easy to buy in some countries, in shops or online. That tells you nothing about what happens when you land somewhere else. For several popular destinations, the answer is simple: don't pack them.

Kratom

Australia: not allowed. Australia's customs rules list kratom (Mitragyna speciosa) as a drug you can't import without a licence and a permit from the health department. The only exception for travellers is a drug a doctor prescribed to you, and Australia's Poisons Standard puts kratom in Schedule 9, its list of prohibited substances.

Japan: not allowed. Kratom, and its main compounds mitragynine and 7-hydroxymitragynine, have been "designated substances" in Japan since 2016. Japan Customs lists designated substances among the goods that can't be imported, and having or using them is generally prohibited too.

Singapore: not allowed, with severe penalties. Mitragynine and 7-hydroxymitragynine are Class A controlled drugs in Singapore. Importing kratom carries at least 5 years in prison and 5 strokes of the cane. Possessing it can mean up to 10 years in prison.

Sweden: not allowed. Sweden classified kratom as a narcotic from 11 March 2025, and the government says Swedish Customs can now stop it at the border. This is a Swedish rule, so it applies even if you're arriving from an EU country where kratom is legal.

New Zealand: only with a doctor's authority. Kratom is a prescription medicine in New Zealand. Medsafe says kratom found at the border is referred to it and released only on the authority of a medical practitioner, who takes responsibility for it. Kratom isn't approved for any medical use there.

Phenibut

Australia: not allowed. Like kratom, phenibut is on Australia's customs list of drugs that need an import licence and permit, and it's in Schedule 9 of the Poisons Standard.

Poppers

Japan: not allowed. The nitrites in poppers, such as isobutyl, isopropyl, isopentyl (isoamyl) and butyl nitrite, have been designated substances in Japan since 2007. That puts them on Japan Customs' list of prohibited imports. Amyl nitrite isn't on the list by that name, and we haven't confirmed how Japan treats it, so check the label.

What we haven't checked yet

We haven't verified the rules for kratom in the UK, Thailand or Malaysia, or for poppers in Australia. If you're travelling there, check with the country's customs or health authority. We'd rather say we don't know than guess.

Check yours

Search the item for your destination in Trip Check, or see kratom, country by country. Every answer links to the government source it comes from.