hand holding 2C-B pills and bag of MDMA in powder form

Nexus Flipping: What Happens When You Combine MDMA and 2C-B

Harm reduction experts weigh in on what you need to know before you flip.

DoubleBlind Mag

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Updated February 20, 2024

Many psychedelic enthusiasts have engaged in “flipping” of some sort — that is, taking MDMA alongside another substance. The most common form of this is candy flipping, or combining MDMA with LSD, leading to euphoric and insight-producing trips. Hippie flipping, where molly is taken alongside mushrooms, provides a similar effect. Some have also heard of kitty flipping, or mixing MDMA and ketamine. For a less well-known combination, some are mixing molly with a synthetic psychedelic called 2C-B, a combination known as nexus flipping.

Nexus Flipping—What Is It?

Chemist Alexander Shulgin, who first synthesized 2C-B and introduced MDMA into popularity, wrote about combining them in his 1991 book PiHKAL: A Chemical Love Story. The practice has faded in and out since then, but over the past few years, nexus flipping has “gained popularity in electronic music scenes and festivals where drug use is more prevalent,” says Mohammad Karamouzian, Assistant Professor at the University of Toronto Dalla Lana School of Public Health.


READ: MDMA: What is Molly?

MDMA in pressed pill and crystal form
MDMA in pressed pill form (left) and crystal form (right) | via Flickr

What’s MDMA?

MDMA — also known as ecstasy or molly — floods your brain with the neurotransmitters serotonin, dopamine, and norepinephrine. “This leads to feelings of euphoria, increased empathy, and emotional openness,” says Karamouzian. “It also heightens perception and distorts our perception of time.” At higher doses, MDMA can cause wakefulness, increased body temperature, dehydration, thirst, and involuntary eye-rolling, which is why taking it is sometimes called “rolling,” says James Giordano, professor of neurology and biochemistry at Georgetown University Medical Center.

While some use MDMA as a club drug or social drug, it also has a history of being taken to facilitate psychotherapy. This usage has historically occurred underground, but clinical trials have recently been conducted in the U.S. to utilize MDMA for therapy, and it is currently pending FDA approval.

What’s 2C-B?

2C-B, or 4-bromo-2,5-dimethoxyphenethylamine, was first developed in the 1970s for medical research, according to Karamouzian. 2C-B is structurally similar to mescaline, though people describe its effects as somewhere between MDMA and LSD: “mildly hallucinogenic, visually stimulating, empathogenic, euphoric, and even sobering,” says Rachel Nguyen, project manager for the harm reduction organization Bunk Police. Before 2C-B was scheduled in 1995, it was sold in head shops as an aphrodisiac, she adds. 2C-B is sometimes called “nexus” — hence the term “nexus flipping.”

“While the population size of people who use 2C-B is unclear, it seems to have regained popularity as a replacement for MDMA in club environments,” says Karamouzian. “When consumed, 2C-B affects the levels of dopamine, serotonin, and norepinephrine in the brain. Animal studies have shown that even small doses of 2C-B can increase dopamine release and slow down its breakdown rate.” These brain changes enhance users’ mood and sociability, and because 2C-B is derived from a chemical called phenylethylamine, it’s also a stimulant, says Anton Gomez-Escolar, a psychopharmacologist and psychedelics expert at Drogopedia

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However, the effects of 2C-B are dose-dependent. At doses below 10 mg or so, one might simply experience “a relaxed and passive mood with erotic overtones,” while doses of 10-20 mg produce “intoxication and sporadic visual hallucinations,” says Giordano. Those who take more than 20 mg may experience vivid hallucinations along with negative side effects, including anxiety, rapid heartbeat, shaking, sweating, and high blood pressure, which can last up to 48 hours, Karamouzian says. Hallucinations on 2C-B may be visual (including colors, shapes, and patterns), auditory (such as music), or even tactile (like exaggerated textures), says Gomez-Escolar.

The Effects of Mixing MDMA and 2C-B

The combined effects of MDMA and 2C-B include “intense euphoria, deep emotional introspection, enhanced sensory perception, and a strong sense of connection to others,” says Gomez-Escolar. Because MDMA and 2C-B both increase the amount of serotonin, dopamine, and norepinephrine in the brain, combining them will amplify the effects of each substance. The activation of the serotonin system through multiple avenues may lead to a strong empathogenic experience — that is, it will increase feelings of empathy and goodwill toward others, says Karamouzian. 

READ: Set and Setting: Here’s How to Prepare Your Mind & Space Before Using Psychedelics

pink NASA 2C-B pill
Pink NASA 2C-B pill | via SaferParty

Similar to candy flipping and other types of “flipping,” nexus flipping typically creates hallucinogenic effects (from the 2C-B) along with euphoric effects (from the MDMA). “Users may experience cartoon-like hallucinations,” says Karamouzian. “People are drawn to this combination for various reasons; some seek the enhanced euphoria and heightened senses provided by MDMA while others are intrigued by the profound self-reflection and spiritual experiences associated with 2C-B.” Compared to candy flipping, however, nexus flipping tends to have fewer visual effects and more of a mood-enhancing effect, says Giordano.

Is There Another Nexus Flip? Mixing MDMA and 2C-I

The term “nexus flipping” also sometimes describes the combination of MDMA and 2C-I, or 4-bromodimethoxyphenethtlamine — a drug that’s very similar to but distinct from 2C-B. “2C-I can produce more intense visual hallucinations, as well as a more pronounced cognitive element,” says Nguyen. “Users often describe it as more psychedelic or introspective compared to 2C-B.” 2C-I may also last longer, and when combined with MDMA, it has a more hallucinogenic effect, which makes it less suited to social settings. Other than that, most of this article applies to both 2C-B and 2C-I.

How to Nexus Flip: Reports from Harm Reduction Experts 

MDMA and 2C-B do not always amplify each other. Some people report that taking them together blunts the effects of one or both substances, says Nguyen. This may be because MDMA blocks the reuptake, or reabsorption, of serotonin in your brain, while 2C-B facilitates it. “It is most commonly recommended to space out the consumption in some way to avoid this possible clash in mechanisms,” says Nguyen. “Most people take the MDMA first, wait some period of time (such as when the peak is on its tail end, to encourage the synergistic effects, rather than a collision of ‘peaking’), and then consume the 2C-B.” Sometimes, this will lead the trip to have an “intense second peak,” she adds.

Some people “reverse nexus flip,” meaning they take the 2C-B first. They’ll usually then wait until after the peak to consume the MDMA, as the 2C-B come-up can be overwhelming and anxiety-inducing in of itself, says Nguyen. “Others might try to time them a bit more closely so that the intensity of effects of both substances is increased.”

Risks and Contraindications of Nexus Flipping

While working at music festivals, Gomez-Escolar has encountered people who had negative reactions to nexus flipping, as well as 2C-B by itself. “Some users had experiences of intense anxiety, panic attacks, confusion, and frightening hallucinations, which can be particularly challenging to manage in environments that lack a sense of safety and support,” he says.

There are also physical risks to nexus flipping, including “an increased chance of overdose and complications related to the heart,” says Karamouzian. “Individuals with conditions like cardiovascular disease, hypertension, or a history of mental health disorders should avoid nexus flipping due to the higher risk of negative effects.” If someone has experienced psychosis or suicidality, nexus flipping could exacerbate these conditions, says Giordano. It’s also important for those on SSRI antidepressants to avoid nexus flipping, as this can lead to serotonin syndrome, a potentially fatal condition involving confusion, restlessness, headaches, fever, shaking, and other dangerous symptoms.

People who have had bad experiences combining MDMA with LSD or other psychedelics are more likely to have negative outcomes with nexus flipping, says Nguyen. In addition, anyone who is on Lithium should avoid 2C-B, as the combination could induce seizures or psychosis, she adds. If you have recently taken cannabis, ayahuasca, monoamine oxidase inhibitors (MAOIs), or cocaine, you should also avoid this combination. 

In addition, any drug you buy on the underground market can be laced with other substances, says Giordano. Both MDMA and 2C-B can contain LSD or psilocybin, which may cause frightening hallucinations, or fentanyl, which can lead to respiratory depression and be deadly.

Harm Reduction for Nexus Flipping

People who want to nexus-flip should start with a lower dose of both drugs than they would take if they were taking just one of them, since each substance will compound the other. “Even if someone is familiar with taking MDMA or 2C-B individually, it is impossible to predict how their particular body will react to these substances when taken together,” says Nguyen. A lower-range dose of MDMA is around 75-90 mg for most people, while a low dose of 2C-B is around 5-10 mg, according to Gomez-Escolar.

Timing each substance so that you are not peaking on both at once also helps prevent strong negative reactions. “The post-high ‘crash’ of either drug tends to be greater when the two are taken together, and this crash can include profound nausea, anxiety, depression, and paranoia,” says Giordano. When considering timing, keep in mind that 2C-B usually peaks around 2-3 hours after oral ingestion, and MDMA peaks after 1-2 hours, according to Giordano.

It’s also important to stay hydrated, but not over-hydrated. Nguyen recommends having one to two glasses of water per hour. One should also avoid very hot environments and refrain from taking any additional substances, especially psychedelics and stimulants, says Gomez-Escolar.

In order to increase your chances of having a positive experience, Nguyen recommends taking time to prepare. “Setting intentions, journaling, or meditating before choosing to nexus-flip could help prepare the person’s mind for challenging or overwhelming moments,” she says. “Some people choose to write an affirmation on their hand that they can come back to if they are feeling out of control, which can help ground them in the moment.”

What to Do If Nexus Flipping Goes Wrong

Some people may feel lightheaded after combining MDMA with 2C-B. If this happens, Nguyen recommends going to a quiet place, sitting down, and drinking water. “If more adverse physical reactions occur, seeking medical help may be the best option,” she says. “This is why it is important to trip with others, so the person has a friend to turn to if they do need help. A simple conversation can help ground someone, and a friend who knows what someone has taken can be useful if they do need to seek medical attention.” 

If you are physically OK but are having a bad trip, there are several strategies you can use to “ground” yourself back to reality, says Gomez-Escolar. These include taking slow, deep breaths, listening to music, touching something with a pleasant texture, or smelling a familiar scent. “Reminding the person of the time, date, and location can help counter feelings of depersonalization or derealization,” he adds. “Eating something, like fruits or chocolate, can help to reduce the intensity of the experience, but be careful not to choke.” It also helps to simply remind yourself that the trip will be over soon, and you will feel like yourself again.

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Was this article on nexus flipping helpful? Deepen your learning here.

One impact of drug prohibition is a lack of access to unadulterated substances. Adulteration—secretly mixing one substance with another—is one of the biggest risks of underground MDMA. Testing your MDMA before you take it can save lives.

Sometimes, MDMA and other substances may be treated with coloring for marketing or branding purposes. Color is not an indicator of quality. In some cases, it may make it easier to hide adulterants.

Having a trusted, sober trip sitter around is always wise when experimenting with substances. This person can help you if something goes awry—or just gets intense. Author Michelle Janikian dives into what makes a good trip sitter.


In the event of an emergency, please dial local emergency services. For mental health services related to substance abuse in the U.S., please dial the Substance Abuse and Mental Health Services Administration National Helpline at +1 (800) 662-4357.

This article is intended for harm reduction purposes and should not be used in place of medical advice. DoubleBlind does not advocate participating in illicit activities. Always consult your local drug laws before engaging with any illicit substance.


This article originally reported that Alexander “Sasha” Shulgin first synthesized MDMA and 2C-B. But, Shulgin was not the first person to synthesize MDMA, only 2C-B.

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DoubleBlind Magazine does not encourage or condone any illegal activities, including but not limited to the use of illegal substances. We do not provide mental health, clinical, or medical services. We are not a substitute for medical, psychological, or psychiatric diagnosis, treatment, or advice. If you are in a crisis or if you or any other person may be in danger or experiencing a mental health emergency, immediately call 911 or your local emergency resources. If you are considering suicide, please call 988 to connect with the National Suicide Prevention Lifeline.

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