2C-B vs Tusi: Pink Cocaine Is Not 2C-B

Tusi and 2C-B are not the same drug. “Tusi” (also spelled tucibi, tuci, or toosie) is how “2CB” sounds said in Spanish, but almost nothing sold under that name in the US or Europe contains 2C-B. Lab after lab finds the same thing instead: ketamine, usually with MDMA, dyed pink. That matters because a ketamine-heavy powder and a psychedelic phenethylamine fail in completely different ways, and the things you would do to stay safe on one do not carry over to the other.

How a name outlived its drug

2C-B (4-bromo-2,5-dimethoxyphenethylamine) is a synthetic psychedelic that Alexander Shulgin first made in the 1970s. It went around Colombia as “tusi,” and in that early form it sometimes really was 2C-B, pink food coloring added as a branding mark.

Then demand outran supply. Real 2C-B is hard to source in quantity, so traffickers swapped in what was cheap and available. By the time pink cocaine reached US and European clubs in volume, roughly 2017 to 2020, the ketamine-and-MDMA blend had almost entirely replaced the original. The name stuck. The contents did not.

Actual 2C-B is worth knowing on its own terms, because it is the thing people think they are buying. It is a partial agonist at 5-HT2A and 5-HT2C receptors and an alpha-1 adrenergic agonist, active orally at roughly 10 to 25 mg, lasting 4 to 6 hours. Papaseit and colleagues ran the first controlled human pharmacology study in 2018, giving 10 to 20 mg to 16 experienced volunteers and documenting moderate rises in heart rate and blood pressure alongside euphoria and altered perception. A 2023 trial by Mallaroni compared it head to head with psilocybin and found it sits apart: more entactogenic, less classically psychedelic. What it has none of is stimulant activity, dopamine release, or dissociation. Our 2C-B harm reduction guide has the dosing and interaction detail.

What the labs keep finding

The forensic record is not ambiguous. Palamar and colleagues reviewed 19 pink-powder submissions to DrugsData.org sold as tusi or 2C-B between 2019 and 2022, published in 2023: most contained ketamine, frequently with MDMA, and 2C-B was rarely detected at all.

A 2025 case series from the Miami-Dade County Medical Examiner, Moore and colleagues, covered eight fatal cases involving colored powders sold as tusi between 2020 and 2024. None of the powders contained 2C-B. Every decedent had multiple drugs in postmortem blood, ketamine and MDMA turning up across the cases alongside cocaine and others.

Spanish drug checking data says the same at larger scale. Across 470 samples, 36 distinct substances were identified, with ketamine in 93.2% and MDMA in 92.1%. 2C-B barely appeared.

So if you have something sold as tusi, pink cocaine, tucibi, or 2C-B, the base rate says you have ketamine and MDMA plus something unlisted. Not knowing which is the actual problem.

Ketamine plus MDMA is its own specific danger

MDMA floods the synapse with serotonin, dopamine and norepinephrine. It raises core temperature, breaks thermoregulation, and causes water retention, which is where hyponatremia risk comes from. Full profile in the MDMA guide.

Ketamine is a dissociative NMDA antagonist that takes out coordination, judgment, and your ability to notice that anything is wrong. In tusi samples it can be most of the powder by mass, so the dissociation can be deep. Full profile in the ketamine guide.

Put together:

• Overheating gets much more dangerous. MDMA stops your body from shedding heat and ketamine stops you from noticing. You do not feel the discomfort that would normally make you sit down, find water, or leave the floor. In a hot room this is the failure mode that kills people.
• You are pushing the accelerator and the brake. Ketamine’s sedation against MDMA’s cardiovascular load gives erratic heart rate and blood pressure rather than a predictable curve.
• Consent gets compromised. Heavy dissociation plus MDMA’s disinhibition means reduced capacity to make decisions or communicate them, in both directions. Watch out for each other.
• There is a preclinical neurotoxicity signal. Binge ketamine pretreatment worsened MDMA-induced dopaminergic toxicity in mice (PMID 18666708). The doses were far above anything recreational, 50 mg/kg ketamine seven times over and 20 mg/kg MDMA three times, so this does not transfer to a human night out. It is a mechanistic reason for concern about heavy repeated use, nothing stronger.
• Then the adulterants. Batch to batch you may also be taking synthetic cathinones, methamphetamine, cocaine, opioids or benzodiazepines, each adding its own interactions on top. The interaction checker covers the common ones.

Testing a mixture is harder, and still worth it

No reagent kit resolves every component of a blend. It can still tell you a lot, and one reagent alone will mislead you here, which is the argument for owning a set rather than a single bottle.

• Marquis goes purple to black with MDMA, gives no reaction or a faint yellow with 2C-B, and nothing with ketamine. Strong purple-black means MDMA is in there.
• Mecke turns blue-green with MDMA and blue-black with 2C-B, which is the pair that separates them.
• Simon’s turns blue for secondary amines like MDMA. 2C-B is a primary amine and will not react.
• A fentanyl test strip, every time. Fentanyl has been found in pink cocaine in the US. Read it carefully: one line means fentanyl is present, two lines means it is not, which is the reverse of what most people assume. Fentanyl strips are cheap insurance on any powder.

The complete DanceSafe reagent set covers all of these together, and our test kit videos show the reactions in real time. A test that shows MDMA and no 2C-B reaction will not tell you everything in the bag, but it does confirm you were sold something other than what was named.

If someone goes wrong on tusi, do not wait it out. Call emergency services. Overheating, deep dissociation, chest pain and seizures can arrive together and escalate faster than you can talk someone down, and staying with them while help comes matters more than anything else you can do. Get them somewhere cool, keep them on their side if they are not fully conscious, and tell the responders it may have been ketamine and MDMA rather than 2C-B. The name on the bag has misled clinicians too.

Sources

PMID 37162319 | PMID 40082214 | PMID 29593537 | PMID 18666708 | Mallaroni et al. 2023, DOI 10.1002/cpt.2958