top of page
Drug Science

Effects of Mixing and Dosing MDMA, LSD, and 2C-B with Dr Friederike Meckel Fischer



Dosing in psychoactive drugs

Dosing represents one of the three critical elements that determine the quality of a drug experience, alongside set and setting. Determining appropriate dosages can be difficult due to ambiguity in drug purity, drug experience of the individual, tolerance, and the aforementioned set and setting.


While these represent general guidelines, experience, variability of individuals, and drug quality will play a major role in determining an appropriate dose. As a guiding principle, Myron Stolaroff defines a ‘useful dose’ as being “as much as necessary, as little as possible.”

How much is a dose of MDMA?

A typical dose of MDMA is between 100-150 mg, while a high dose of MDMA is above 150 mg.


3,4-methylenedioxymethamphetamine (MDMA) is characterised as both a stimulant and psychedelic, and acts by triggering the release of monoamine neurotransmitters (mainly serotonin, but also dopamine and noradrenaline) and preventing their reuptake.


MDMA induces entactogenic effects, or an ‘open mind state’ characterised by empathy and self-awareness. Other effects include increased energy, increased body temperature, heart rate and blood pressure, lowered anxiety, and euphoria.

How much is a dose of LSD?

Generally speaking, a typical dose of LSD can be considered between 30-200 micrograms. Within this range, the intensity of the experience will vary significantly dependant on the dose. A high dose of LSD is considered to be 250 micrograms or higher.


Some experienced psychedelic users (sometimes referred to as psychonauts) refer to 150-400 micrograms as a normal dose, but this may be too high for inexperienced users.


D-lysergic acid diethylamide (LSD) is a semi-synthetic psychedelic drug derived from the ergot fungus. The effects of LSD typically begin about one hour after ingestion of the drug and can peak for about 4 hours before ‘coming down’. The effects of LSD include various visual hallucinations, euphoria, and a distorted perception of time.


Taking LSD with psychiatric medications is generally advised against due to the potential risk of interaction effects.

What are the effects of mixing MDMA and LSD?

Consuming LSD with MDMA is sometimes known as a candyflip and typically leads to generally extended effects, though this will depend both on the dosages and on the timing of consumption.


When taken together, an individual will experience a higher and longer-lasting peak. When LSD is taken towards the end of the MDMA peak, the LSD tends to have a quicker onset, extending the peak effects. Alternatively, when LSD is consumed after the MDMA peak, a second ascent can be seen.


When LSD is consumed first, it predominates the psychotropic effects, creating an LSD experience with more emotional range, and a more sober version of MDMA. Again, the timing of MDMA consumption is significant in the subsequent experience. When taken together, the peak is heightened, and the duration is overall longer compared to one drug only. When MDMA is taken immediately after the LSD peak, the LSD experience becomes a bit more emotionally-involved, although the MDMA involvement is otherwise less apparent. Taking MDMA just before the descent of a LSD experience can bring about a brief interval of almost complete sobriety before a particularly bold MDMA period. MDMA consumed after the LSD descent has begun will induce a separate ascension effectively representing a completely new experience.

How much is a dose of 2C-B?

For 2C-B, a normal dose is considered around 10-25 mg, while 30 mg is categorised as toxic.


2,5-dimethoxy-4-bromophenethylamine (2-CB) is a synthetically-derived psychedelic drug with hallucogenic and stimulant properties similar to both MDMA and LSD. It is suggested that the mechanism of action for 2C-B involves 5-HT2 and alpha-adrenergic receptors, including the 5-HT2a receptor implicated in LSD. The effects usually take place approximately 45-75 minutes after consumption and include euphoria, laughter, hallucinations, and enhanced energy and sexual arousal. Nausea, vomiting, and diarrhoea may also occur.

What are the effects of mixing MDMA and 2C-B?

MDMA and 2C-B have antagonistic mechanisms, meaning that consuming both together would not be an effective strategy. However, consuming 2C-B after the full duration of MDMA effects can prepare the body and mind for a more comfortable 2C-B experience. Conversely, ingesting MDMA after 2C-B can ease the descent from a 2C-B peak, and has been used in therapeutic settings when addressing unpleasant topics.

Effects of Mixing 2C-B with other drugs

Combining 2C-B with tramadol increases the risk of seizure, while 2C-B should also not be consumed alongside ayahuasca or ‘changa’, as these both contain MAOIs (monoamine oxidase inhibitors). Additionally, combining 2C-B with cannabis, cocaine, amphetamines, or other stimulants should be avoided.

Effects of drinking alcohol when taking MDMA

Taking MDMA with alcohol should be avoided due to the added risk of dehydration, and poor judgment induced by alcohol.

Taking MDMA while on antidepressants

MDMA combined with some antidepressants can cause excessive levels of serotonin that can be fatal, even when consumed several days apart. Similarly, MDMA mixed with other stimulants can cause serotonin syndrome.

This webinar was recorded during a Drug Science Live Event which included a live Q&A session from the audience. If you want to ensure that you don’t miss any of our events, so that you can ask your questions live, all you need to do is join the Drug Science Mailing List.


Drug Science is the leading independent scientific body on drugs in the UK. We rely on donations to provide clear, evidence-based information without political or commercial interference. Drug Science webinars are free, and always will be, so if you’d like to support us then please consider joining the Drug Science Community

Keep up with developments in drug science

Reading, engaging with, and sharing our publications, papers and commentary gives evidence-based science and policy the audience it needs and deserves.

bottom of page