Vitamins and Supplements on a Plane: Security and Customs Rules

Can you fly with vitamins and supplements?

Vitamins and supplements pass airport security easily: TSA allows vitamins in both carry-on and checked bags^[1], and only liquids and powders face container rules. The risk sits at customs, where the same bottle can change legal category. Melatonin is prescription-only in the UK, a medicine-only ingredient in Japan; CBD has been a dangerous drug in Hong Kong since February 2023.

This guide is general information, not medical advice. Rules change; check with the destination's embassy or health ministry and your prescriber before you travel.

Security and customs check different things

Airport security screens for threats to the aircraft, not for banned ingredients. TSA officers do not search for illegal drugs^[5], although they refer anything illegal they find to law enforcement.

Customs and health regulators ask a different question: may this product legally enter the country? That is where gummies bought at a US pharmacy can become an unlicensed medicine or a controlled drug.

What airport security allows

Pills, capsules and tablets

Solid vitamins and supplements have no quantity limit at security. TSA lists vitamins as allowed in carry-on and checked bags^[1], with the usual caveat that the officer has the final say.

Pack anything you take daily in your cabin bag. Checked luggage goes missing, and a replacement abroad may come in a different strength or not be sold at all.

Gummies and chewables

Gummies screen as solid food, not as liquid, so the 100 ml rule does not apply. TSA allows candy in carry-on and checked bags^[42], and vitamin or melatonin gummies are treated the same way.

Gummies cause more trouble at customs than at security. CBD gummies look identical to vitamin gummies, and one product in a JAMA study of 25 US melatonin gummy brands contained no melatonin, only CBD^[40].

Liquid supplements, tinctures and oils

Liquid vitamins, fish oil, tinctures and drops count as liquids. TSA allows containers of 3.4 ounces (100 ml) or less in one quart-sized bag^[4], and most airports elsewhere use the same 100 ml limit.

Some UK airports with new scanners allow containers up to 2 litres^[6], so check your departure and return airports. The UK's larger-container exemption covers essential medical purposes^[6], which a daily fish oil is unlikely to meet.

The simplest fix is to switch to capsules for the trip or pack the bottle in your hold bag. For medicines that only come as liquids, our guide to liquid medication on a plane covers the exemptions in detail.

Protein powder, collagen and electrolytes

In the US, carry-on powders over 12 oz (350 ml) must go in a separate bin for X-ray screening^[2]. They may need extra checks. On flights into the US from abroad, powders over 350 ml that cannot be cleared are not allowed in the cabin and are disposed of^[3].

Australia splits powders by what they are made from. Organic powders such as protein powder have no limit^[7]. Inorganic powders like salt are capped at 350 ml or 350 g per person on international flights.

Salt-heavy electrolyte mixes sit closest to that inorganic line. Pack bulk tubs in your hold bag and carry single-serve sachets in the cabin.

Original packaging or a pill organiser?

Security does not care whether pills sit in a bottle or a weekly organiser, but customs often does. Australia's regulator asks travellers to keep products in original packaging with dispensing labels^[9]. Singapore expects each medication in its original container or packaging^[21].

A handful of unlabelled capsules is impossible for an officer to identify. Keep anything regulated in its labelled pack, and use an organiser only for plain vitamins and minerals.

If you must decant, carry the original box or a photo of the label with the ingredient list. A blister pack is the most border-friendly format because every tablet stays labelled.

Customs: when a supplement becomes a medicine or a drug

Supplement law is national, and the line between food and medicine moves at every border. Japan's health ministry warns that a product sold abroad as a supplement can count as a medicine in Japan^[15] if it contains a drug ingredient.

The same logic makes melatonin a prescription drug in some countries and hemp extracts a narcotic in others. The table covers the rules we could verify with regulators and customs authorities; the sections below give the detail and sources.

What rarely causes problems

Plain vitamins and minerals in retail packs, such as vitamin C, vitamin D, magnesium and fish oil, rarely interest customs in personal amounts. Trouble starts with hormones, cannabinoids, stimulants and psychoactive plants.

Australia is the main exception for everyday products, because travellers must declare vitamins and mineral preparations along with other medicines^[8]. Declaring a multivitamin costs a few minutes; not declaring it risks a fine.

Country guides for the places above:

• Asia-Pacific: Japan, Australia, New Zealand, Singapore, Hong Kong, Indonesia and South Korea.
• Middle East: United Arab Emirates, plus our overview of UAE and Gulf medication import rules.
• Europe and North America: United Kingdom, Switzerland, Denmark, Germany, Canada and the United States.

The supplements most likely to cause trouble

Melatonin

It is a shelf supplement in the US, but in the UK melatonin is available on prescription only^[13]. In 2023 Japan kept melatonin on its list of exclusively pharmaceutical ingredients^[16]. The reason given: it is a hormone used there as a prescription drug.

Australia allows two pharmacist-only uses. These are 2 mg modified-release tablets for insomnia in over-55s, and 5 mg or less for adult jet lag^[10]. All other melatonin products are prescription-only^[10].

Germany moved the other way in 2026. Melatonin 3 mg in packs up to 30 mg can now be sold without prescription for adult jet lag^[27]. Every other melatonin medicine stays prescription-only.

South Korea licenses and manages melatonin as a prescription drug^[32]. Its regulator asked customs to halt clearance of overseas sleep products^[31] found to contain banned ingredients. Switzerland sells melatonin only as a medicine and lets individuals import small personal quantities, roughly one month's need^[25].

New Zealand opened up in October 2025, making approved melatonin products available from pharmacies without a consultation for adults 18 and over^[28]. For the full picture, see countries where melatonin is prescription-only.

Our country melatonin guides cover Europe: UK, Germany, France, Italy, Spain and Portugal. In Asia: Japan, South Korea, China, Thailand, Vietnam, Indonesia and the Philippines. Elsewhere: Australia, the UAE, Mexico and the US.

CBD and hemp products

TSA notes that some CBD oil remains federally illegal unless it has no more than 0.3% THC or is FDA-approved^[5]. That federal line tightens on 12 November 2026, when products with more than 0.4 mg total THC per container fall outside the definition of hemp^[37].

Abroad, the line is often zero. Singapore treats hemp and CBD products as Class A controlled drugs^[20], and importing them even in trace amounts is an offence.

Hong Kong made CBD a dangerous drug from 1 February 2023^[19], with possession carrying up to seven years and a HK$1 million fine (about US$128,000). Indonesia bans CBD, THC, hemp-based products and cannabis oils^[23], whether in a bottle, a vape or any other form.

Japan permits CBD only under strict THC limits: 10 ppm for oils and powders, 1 ppm for other products and 0.1 ppm for drinks^[17]. Above those limits, the product counts as a narcotic.

The UAE warns that some CBD products are illegal, including some skincare and e-cigarette refills^[22]. Even residual amounts of drugs can lead to arrest. Canada says bringing CBD across the border without a permit is illegal, even if it is hemp-derived^[24].

For prescribed cannabis and the countries in between, read prescription cannabis abroad and its legal grey zones.

Kratom

Australia classifies Mitragyna speciosa as a Schedule 9 prohibited substance^[12]. Importing prohibited goods can bring fines of up to 2,500 penalty units or 10 years in prison^[12]. In the US, kratom sits on an FDA import alert^[35].

In the UK, prosecutors state that importing a psychoactive substance in small amounts consistent with personal use is an offence^[34] under the 2016 Act. Kratom is generally treated as falling under that Act, so do not pack it.

DHEA and hormone supplements

DHEA is sold as a food supplement in the US. Switzerland treats imported DHEA as a doping agent, or as a prescription medicine with a medical certificate^[26]. Swissmedic adds that imports face zero tolerance and are seized^[25].

Australia lists DHEA as a controlled substance that needs an import permit^[11]. Health Canada states that DHEA is a controlled substance under the Controlled Drugs and Substances Act^[41].

Pre-workouts, fat burners and stimulant blends

The FDA says DMAA products marketed as dietary supplements are illegal^[36], and it banned supplements containing ephedrine alkaloids in 2004^[35]. The same FDA list flags SARMs and other ingredients that turn up in muscle-building products.

Stimulant blends overlap with cold medicine. Japan classes pseudoephedrine as a stimulants' raw material^[18] that needs advance permission. See countries where pseudoephedrine is illegal for the full regulatory context.

Ashwagandha

Denmark's food authority lists ashwagandha among plant ingredients that are both illegal and harmful to health^[30] in supplements. It cites possible effects on the immune system and thyroid. Do not plan on buying it in Denmark, and check before posting it there.

Red yeast rice

The EU requires a daily portion to provide less than 3 mg of monacolins from red yeast rice^[33], with warning labels. A product bought outside the EU may be stronger than anything legally sold there.

Red yeast rice contains the same compound as a statin, so treat it like one. Our guide to statins abroad covers the overlap with supplements and corresponding import requirements.

How much you can bring

Customs officers judge intent partly by quantity. A month's supply in a labelled bottle looks personal; three 1 kg tubs of the same product look like stock for resale.

Japan allows one month of prescription drugs and two months of other medicines^[14] without an import confirmation. It also bars selling or giving imported medicines to others, or importing other people's supplies together^[15].

Australia caps travellers at a 3-month supply^[9]. New Zealand limits prescription medicines to three months^[29] (six for oral contraceptives), and Singapore allows up to three months^[21] where no approval is needed. Our pillar guide on flying with prescription medication also explains supply limits across popular countries.

Declaring at the border

Australia requires travellers to declare all medicine, including vitamins, herbal medicines and performance-enhancing drugs^[8]. In many cases officers return declared goods after inspection^[8], while undeclared controlled goods can bring fines or prosecution.

Plant and animal ingredients add a biosecurity layer. Australia warns that traditional medicines using animal parts must be declared^[8], and herbal products from endangered plants need a permit^[9].

New Zealand's regulator says anything that might be a prescription medicine there must be declared^[29], with the advice: if in doubt, declare it. For staying longer, plan to buy locally; our medication import rules glossary explains the terms.

Buying supplements abroad

Labels are less reliable than they look. In a JAMA analysis, 22 of 25 US melatonin gummy brands were inaccurately labelled^[40], with actual melatonin between 74% and 347% of the stated dose.

TGA laboratory testing found overseas melatonin products with significantly higher doses than labelled^[10], while others contained less or none. Korea's regulator found banned ingredients in 19 of 30 sleep and mood products^[32] bought from overseas websites.

Same name, different product

Strengths and formats differ by country. A melatonin pack in a German pharmacy is now a licensed 3 mg jet-lag medicine. The US gummies in the JAMA study held 1.3 mg to 13.1 mg per serving^[40].

Herbal products vary even more, because species, plant part and extract strength rarely match across brands. Buy from a pharmacy rather than a market stall or marketplace seller, and compare the amount per dose, not the brand.

Our glossary entry on counterfeit medication explains what to check on an unfamiliar pack.

Bringing them home

Your home country's rules apply when you return. Melatonin bought over the counter in New York is a prescription medicine again in the UK. Keep it in its original bottle and in personal-use quantity.

Interactions worth knowing when you travel

Supplements are not tested against other medicines the way prescription drugs are. The NHS notes there is not enough information to say other herbal remedies and supplements are safe to take with melatonin^[13].

St John's wort and the pill. The MHRA advises that women using hormonal contraception should not take St John's wort^[38], because it reduces contraceptive effectiveness. That matters more on long trips when you may switch pill brands; see the pill abroad for more information.

St John's wort and antidepressants. SSRIs taken with St John's wort can increase the risk of serotonin syndrome^[39]. Read our guides to SSRI rules by country, SNRIs abroad and countries that control antidepressants.

Ginkgo, garlic and blood thinners. Ginkgo biloba, garlic and glucosamine can increase the effects of warfarin, DOACs and antiplatelets^[39], raising the risk of bleeding and bruising. Our anticoagulants travel guide covers INR shifts abroad.

Stacking sleep aids for jet lag. Melatonin, sedating antihistamines and sleeping tablets can add up, and the NHS warns some medicines can make you feel much more drowsy with melatonin^[13]. Compare options listed in our dedicated guides for zolpidem bans and jet-lag alternatives and motion sickness medication abroad.

Heading to altitude. Ask a pharmacist before adding stimulant pre-workouts or new herbal remedies to an altitude plan. Our altitude sickness medications guide lists what is usually prescribed.

None of this replaces a pharmacist reviewing your full list of medicines and supplements.

How to pack supplements for an international trip

1. ·
   Check the rules for your destination and every transit country, not just where you land last.
2. ·
   Cut the list to what you need for the trip, and leave bulk tubs at home.
3. ·
   Keep melatonin, herbals and anything hormone-based in original labelled packs.
4. ·
   Put liquids in containers of 100 ml or less, or in the hold; carry powders as sachets.
5. ·
   Carry a prescription or doctor's letter for anything that is prescription-only at your destination.
6. ·
   Remove every CBD and hemp product before flying to or through Asia or the Gulf.
7. ·
   Tick the medicines box on arrival cards when a form asks, and keep products ready to show.

Supplements usually travel alongside prescription medicines, so read flying with prescription medication next. If anything needs refrigeration, see how to travel with insulin, biologics and refrigerated medication.

Frequently asked questions

Sources

1. [1] TSA: What Can I Bring? Vitamins
2. [2] TSA: Protein or Energy Powders
3. [3] TSA FAQ: What is the policy on powders?
4. [4] TSA: Liquids, Aerosols, and Gels Rule
5. [5] TSA: What Can I Bring? Medical (cannabis and CBD oil note)
6. [6] GOV.UK: Hand luggage restrictions at UK airports, liquids
7. [7] Australian Department of Home Affairs TravelSECURE: What you can and can't bring (powders)
8. [8] Smartraveller (Australian Government): Australia's biosecurity and border controls
9. [9] TGA: Travelling with medicines, entering Australia (traveller's exemption)
10. [10] TGA: Regulation of melatonin products in Australia (September 2025)
11. [11] Office of Drug Control (Australia): DHEA and its metabolites
12. [12] Australian Border Force: ABF seizes psychoactive plant in Sydney (kratom, August 2024)
13. [13] NHS: Melatonin
14. [14] MHLW Japan: Information for those who are bringing medicines for personal use into Japan
15. [15] MHLW Japan: 医薬品等の個人輸入について (Personal import of medicines, Japanese)
16. [16] MHLW Japan: Working group on pharmaceutical ingredient classification, June 2023 (melatonin)
17. [17] MHLW / Aichi Prefecture: Products exceeding the Δ9-THC residual limit (April 2026, with limit table)
18. [18] Narcotics Control Department, MHLW Japan: Application guidance
19. [19] Hong Kong Government: CBD to become dangerous drug from 1 February 2023
20. [20] Central Narcotics Bureau Singapore: FAQ (hemp and CBD oil products)
21. [21] Health Sciences Authority Singapore: Travelling with personal medications
22. [22] FCDO: United Arab Emirates travel advice, safety and security
23. [23] FCDO: Indonesia travel advice, safety and security
24. [24] Canada Border Services Agency: CBSA reminds Canadians of cannabis border laws (May 2022)
25. [25] Swissmedic: Warning on private imports of melatonin and DHEA (November 2023)
26. [26] Swissmedic: Import ban on DHEA
27. [27] apotheke adhoc: Änderung der AMVV, Melatonin 3 mg ist rezeptfrei (June 2026)
28. [28] Medsafe New Zealand: Melatonin classification change (October 2025)
29. [29] Medsafe New Zealand: Bringing medicines into New Zealand
30. [30] Fødevarestyrelsen (Danish Veterinary and Food Administration): Warning on supplements that can harm organs and nervous system (January 2025)
31. [31] Ministry of Food and Drug Safety (Korea): Press release on overseas direct-purchase sleep and mood products (2 July 2026)
32. [32] Seoul Economic Daily: Harmful ingredients found in 19 imported sleep, anxiety products (July 2026)
33. [33] Commission Regulation (EU) 2022/860 on monacolins from red yeast rice
34. [34] Crown Prosecution Service: Psychoactive substances, prosecution guidance
35. [35] FDA: Information on select dietary supplement ingredients and other substances
36. [36] FDA: DMAA in products marketed as dietary supplements
37. [37] Congressional Research Service: Change to federal definition of hemp (IN12620)
38. [38] MHRA Drug Safety Update: St John's wort interaction with hormonal contraceptives
39. [39] NHS Specialist Pharmacy Service: Advising on complementary products and conventional medicines
40. [40] Cohen et al. Quantity of melatonin and CBD in melatonin gummies sold in the US. JAMA 2023 (PMC)
41. [41] Health Canada: Unauthorized Natrol DHEA product advisory (July 2025)
42. [42] TSA: What Can I Bring? Candy

Topics

• TopicPrescriptions Abroad
• TopicPharmacy Guide
• TopicDigital Nomad Health

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