Will Methylene Blue Show Up on a Drug Test? (Australia 2026)

Last updated: November 1, 2026 · Originally published: April 30, 2026 · By Eternal Elixir Editorial

If you take low-dose methylene blue and have a workplace drug test, a roadside swab or a sports test coming up, this guide covers what each test looks for, why methylene blue isn’t on those lists, and the two things it can genuinely affect: the colour of your urine and some medical measurements. It ends with a short checklist for test day.

What Australian Drug Tests Look For

Drug tests in Australia screen for named drug classes, not for everything in your body. Each type of test has its own list.

Employers can pay for extra drugs to be added to a urine panel, so an unusual workplace test could include more classes. Extra drugs are added on request, and methylene blue is not a drug of abuse. Other states run their own roadside programs with their own lists, so check your state’s list if you drive for work.

Could it cause a false positive?

Screening tests use antibodies that react with particular drug shapes. Some medicines can cross-react and trigger a false screen result. We searched PubMed and found no published report of methylene blue causing a false positive on a workplace or roadside drug screen. If a screen ever does come back non-negative, the sample goes for a laboratory confirmation test, which identifies the actual drug rather than a class of shapes.

Blue or Green Urine: What a Collector Might Notice

Methylene blue is a dye, and some of each dose leaves the body through the kidneys. In a study by Peter and colleagues, seven volunteers took 100mg of methylene blue by mouth, and 18% of the dose came out in urine as methylene blue and its colourless form (28% after an injection). That is why urine can look blue or green after you take it.

A coloured sample doesn’t make a drug screen positive. It can, though, prompt questions at a supervised collection. The simple fix is to tell the collector you take methylene blue, and write it on the form where you list medicines and supplements.

How long does methylene blue stay in your system?

Studies give a range. After an injection of 100mg, Peter’s team estimated a terminal half-life of 5.25 hours. After a single 200mg oral dose in healthy volunteers, Repici and colleagues measured half-lives of 14 to 27 hours. On those figures, most of a dose clears over a few days. Both studies used doses many times larger than our 10mg capsule, and no study has measured how long the urine colour lasts at 10mg.

Medical Tests Methylene Blue Can Affect

Where methylene blue does cause real confusion is in some medical measurements, because it absorbs light at the wavelengths certain devices use.

• Pulse oximeters: case reports going back to the 1980s describe falsely low oxygen readings after methylene blue was injected during procedures (Kessler and colleagues, 1986; Scott and Cooper, 1991).
• Colour-based tests: a dyed urine sample can make any test that is read by colour harder to interpret.

These reports involve injected doses in hospital, not a 10mg capsule. Still, if you have surgery, a procedure or pathology tests booked, tell your doctor you take methylene blue. That matters for another reason too, covered below.

Sport: What Tested Athletes Should Know

Methylene blue is not named on WADA’s 2026 Prohibited List, which came into effect on 1 January 2026. The list changes every year, so check the current version before each season and ask your sport’s anti-doping organisation if you are unsure. Athletes are responsible for everything in their sample, so the bigger practical risk with any supplement is contamination from another ingredient, not the named active. Our guide to whether turkesterone fails a drug test covers how the Prohibited List and workplace testing work in more detail.

The Risk That Matters More Than Any Drug Test

The real safety issue with methylene blue is not a drug screen. It is serotonergic medicines. Methylene blue is a potent inhibitor of the enzyme MAO-A, which breaks down serotonin, as Ramsay and colleagues showed in 2007. A 2010 review by Ng and Cameron found 26 patients who developed acute confusion after a methylene blue infusion. Of those, 24 were taking a serotonin reuptake inhibitor, and serotonin syndrome was a possible diagnosis in all 25 on a serotonergic medicine.

People with G6PD deficiency should also avoid it. A 2010 evidence review by Youngster and colleagues listed methylene blue among only seven medicines with solid evidence to avoid in G6PD deficiency. Our methylene blue safety guide on serotonin syndrome and MAO inhibition goes through who should not take it.

Test-Day Checklist

• Workplace urine or saliva test: list methylene blue on the medicines and supplements form, and tell the collector your urine may look blue or green.
• Roadside test: in NSW the roadside screen targets four illegal drugs, so there is nothing extra to do. Other states set their own lists.
• Sports test: check the current Prohibited List, declare everything you take on the doping control form, and keep your supplement labels.
• Medical tests or a procedure: tell your doctor you take methylene blue, and mention any antidepressant or other prescription medicine at the same time.
• Every day: keep to the label serve. For our capsules that is one 10mg capsule a day, and for our drops it is 0.5 to 1ml (5mg to 10mg) a day diluted in water. Don’t take more.

Capsules or Drops: Choosing Our Methylene Blue

Eternal Elixir makes two methylene blue products, and for most people who want a simple daily routine, the capsules are our pick.

• Methylene Blue Capsules 10mg: 10mg of methylene blue per capsule with rice flour, a cellulose capsule and citric acid. There are 60 capsules in a bottle and the label serve is one a day, so a bottle lasts two months at $59.99, or $1.00 a day. You swallow the capsule, so there is no blue mouth or tongue.
• Methylene Blue Liquid 1%: 10mg per ml of methylene blue in purified water, 50ml a bottle for $49.99. The label serve is 0.5 to 1ml a day diluted in water, which suits people who want to start at 5mg. Drops can stain your mouth and tongue.

Add Methylene Blue Capsules to cart · $59.99

Both come with bundle pricing: two, three or five bottles save 10%, 15% or 20%, and orders over $100 ship free from Sydney. For a side-by-side of the two formats, read methylene blue liquid vs capsules. For measuring drops, see how to take methylene blue drops, and for how our products compare with other Australian sellers, see our methylene blue supplements comparison.

People take low-dose methylene blue for focus and daily energy, and the human research at supplement doses is still small. Our methylene blue capsules guide and methylene blue overview cover what has been studied. Our guide to micro-dosing methylene blue explains why the doses used in research differ from a daily supplement serve.

The Bottom Line

Methylene blue will not show up on a standard Australian workplace drug test, the NSW roadside test or WADA sports testing, because none of those tests look for it. It can colour your urine, so tell the collector, and it can affect some medical readings, so tell your doctor. The bigger issue is safety: don’t take it with serotonergic medicines, with G6PD deficiency, in pregnancy or breastfeeding, or under 18. If it suits you, our pick is Eternal Elixir Methylene Blue Capsules at one 10mg capsule a day.

Frequently Asked Questions

Would methylene blue show up on a drug test?

Not on standard Australian drug tests. Workplace urine and saliva screens, the NSW roadside test and the WADA 2026 Prohibited List don’t include methylene blue. It can turn your urine blue or green, so tell the collector you take it.

Add Methylene Blue Capsules to cart · $59.99

Can you buy methylene blue in Australia?

Yes. Eternal Elixir sells Methylene Blue Capsules 10mg (60 capsules, $59.99) and Methylene Blue Liquid 1% (50ml, $49.99), shipped from Sydney. Read the safety points first: it is not for people on serotonergic medicines, with G6PD deficiency, in pregnancy or breastfeeding, or under 18.

Will blue urine look like I tampered with my sample?

It can raise a question at a supervised collection, because an unusual colour stands out. Declaring methylene blue on the medicines and supplements form before you give the sample explains the colour.

Is methylene blue banned in sport?

It is not named on WADA’s 2026 Prohibited List. The list is updated every year, so tested athletes should check the current version and declare every supplement they take.

How long does methylene blue stay in your system?

Studies of single doses found half-lives from about 5 hours after an injection to 14 to 27 hours after a 200mg oral dose, so most of a dose clears over a few days. Those doses were far larger than a 10mg capsule.

Can methylene blue affect blood tests or a pulse oximeter?

Injected methylene blue has caused falsely low pulse oximeter readings in case reports, and dyed urine can make colour-based tests harder to read. If you have a procedure or pathology tests booked, tell your doctor you take it.

Sources

1. Sonic Commercial Pathology. Urine drug testing: drug classes screened under AS/NZS 4308:2023. soniccommercialpath.com.au
2. Alcolizer Technology. AS/NZS 4760:2019 oral fluid screening cut-off levels by drug class. alcolizer.com
3. Transport for NSW. Drugs and driving: mobile drug testing. transport.nsw.gov.au
4. World Anti-Doping Agency. Prohibited List 2026 (in effect 1 January 2026). wada-ama.org
5. Peter C, Hongwan D, Küpfer A, Lauterburg BH. Pharmacokinetics and organ distribution of intravenous and oral methylene blue. European Journal of Clinical Pharmacology. 2000;56(3):247-250. PubMed 10952480
6. Repici A, Di Stefano AF, Radicioni MM, et al. Methylene blue MMX tablets for chromoendoscopy. Safety tolerability and bioavailability in healthy volunteers. Contemporary Clinical Trials. 2012;33(2):260-267. PubMed 22101227
7. Kessler MR, Eide T, Humayun B, Poppers PJ. Spurious pulse oximeter desaturation with methylene blue injection. Anesthesiology. 1986;65(4):435-436. PubMed 3767045
8. Scott DM, Cooper MG. Spurious pulse oximetry with intrauterine methylene blue injection. Anaesthesia and Intensive Care. 1991. PubMed 1829874
9. Ramsay RR, Dunford C, Gillman PK. Methylene blue and serotonin toxicity: inhibition of monoamine oxidase A (MAO A) confirms a theoretical prediction. British Journal of Pharmacology. 2007;152(6):946-951. PubMed 17721552
10. Ng BK, Cameron AJ. The role of methylene blue in serotonin syndrome: a systematic review. Psychosomatics. 2010;51(3):194-200. PubMed 20484716
11. Youngster I, Arcavi L, Schechmaster R, et al. Medications and glucose-6-phosphate dehydrogenase deficiency: an evidence-based review. Drug Safety. 2010;33(9):713-726. PubMed 20701405
12. Eternal Elixir product pages (ingredients, label serve, pricing): Methylene Blue Capsules 10mg, Methylene Blue Liquid 1%.