Although there have been conflicting reports about the duration of methylenedioxy- amphetamine's effects, the canonical sources generally agree on a duration of 8- 12 hours. This would place MDA's duration at around double that of MDMA, which is generally documented at 4-6 hours.

After receiving a number of credible reports that the duration of MDA is perhaps shorter than generally reported, more in the range of 3-6 hours, we were spurred to look into the matter further. After some digging, it appears there is good reason for confusion. While the question of duration will not be resolved here, we can lay out the data as it stands today.

Perhaps the first to publish about the duration of MDA was Gordon Alles, a UCLA researcher who tested the activity of the substance on himself in the mid-1950s. He wrote that "The remarkable subjective changes continued with varying emphasis for three to four hours."¹ He also noted that marked pupil dilation lasted 1-2 hours with some dilation for as long as 12 hours at high doses.²

Published MDA Duration References
1959 - Alles	"subjective changes continued [...] for 3-4 hours"
1967 - Naranjo/Shulgin	"effects [...] lasted for approximately 8 hours"
1970 - Jackson	"effects [...] last between 6 and 10 hours"
1972 - Richards	8 hrs (citing Naranjo/Shulgin)
1974 - Turek	"Most subjects [...] could still feel some effects after 12 hours
	Blood pressure returned to normal at 5 hrs
1976 -Weil	"effects [...] persist for about 12 hrs"
1976 - Yensen	6-14 hrs, with a mean of 8 hrs
1978 - High Times	"trip lasts about 8 hrs"
1978 - Stafford	12 hrs (citing Weil)
1996 - Shulgin	"8-12 hrs"

When MDA hit the streets in the mid-1960s, there was still only minimal information publicly available about its effects or duration. MDA gained in popularity through the ‘60s and was made illegal in 1970 with the passage of the Comprehensive Drug Abuse Prevention and Control Act. After a decade of popular use, there were several articles published during the mid- 1970s which included information about duration.

These new published durations included "6-10 hours",³ "8 hours",⁴ and Turek et al. who reported that "Most subjects [...] could still feel some effects after 12 hours" though blood pressure increases detected during the first few hours had subsided to baseline levels by hour five.⁵ An interesting note is that lab research with MDMA has found that blood pressure largely returns to normal within 4- 5 hours but pupil diameter takes longer to return to normal, approximately 8-12 hours.⁶ Although MDA's metabolism and physiological effects are largely similar to MDMA, equivalent research has not been done with MDA.

In 1976, Andrew Weil published a report about MDA in the Journal of Psychedelic Drugs where he stated that at a dose of 90- 150 mg, "effects persist for about twelve hours"⁷; this quote was subsequently included in the widely read Psychedelics Encyclopedia by Peter Stafford (1978). Around the same time, the High Times Encyclopedia of Recreational Drugs (now out of print) reported that at an effective dose of 120-150 mg MDA lasts about eight hours. And finally, in PiHKAL (1991), Alexander Shulgin lists the duration of MDA as "8-12 hours" [After personal discussion between Erowid and Alexander Shulgin in 2001, Sasha checked his records and agreed that MDA's duration was shorter than he had original published in PiHKAL.]

Interviews with more than a dozen MDA users in the summer of 2001 found there were consistent reports of a shorter duration. At doses ranging from 90-150 mg, most of the individuals interviewed placed the duration of primary effects at less than 5 hours with some reporting primary effects as short as 3 hours.

Most of those interviewed said they found the curve of MDA very similar to that of MDMA; this included peak duration as well as an abrupt drop-off of effects from the plateau to near baseline. A couple of individuals reported being able to intentionally hold the warm, positive space for 6 hours or more, but these individuals also reported the ability to do the same with MDMA.

Among those to whom we talked were several respected, knowledgeable, and experienced members of the community who report having seen or had experiences which support the 8-12 hour duration. Several reports even mentioned experiences of 12-24 hours after a single moderate-tohigh level dose of known material.

One chemist who produced MDA in the 1980s, both for himself and friends, reported that while he experienced a duration of 6-8 hours, others had experienced idiosyncratically long experiences of more than 12 hours.

Obviously, an important issue to address is whether the material being used was MDA and not some other MD-- compound. For the published cited in the table, we feel reasonably confident that the materials used were in fact MDA. For the dozens of people interviewed this summer, all reported using material from known experienced chemists who asserted that the material was MDA. Some of the material was tested using Marquis, Mecke, and Simons reagents and results were consistent with MDA.⁸

MDA is often sold in pressed tablets as "ecstasy" and there is a huge amount of confusion among users about what is contained in these tablets. Some reports we have received about "MDA" ingestion are more properly described as "suspected- MDA" reports. None of those reports have been included in this review.

Excerpts from Shulgin's Notes
1. 60 mg ++	peak: 2-2.5 hrs. 3.5 hr, largely cleared
2. 80 mg ++	peak: 1.5-2 hrs. By 3 hr largely out but there was an unworldliness and lingering effect that went on to about the tenth hour.
3. 100 mg ++	2.5 hr. dropping off and pretty much out something after 3 hrs. At the 10th hr, there was still tooth gritty, some leg pains and absolutely no appetite.
4. 120 mg ++	2.5-3 hr. max. 3:40 dropping 4.5 hrs gone except for peripheral grindy that lasted into the evening.
5. 140 mg (#1) 100 mg (#2) 80 mg (#3)	2 hrs, everyone at ++, 2:40 dropping. 4:20 heavy teeth clench which lasted on to 8 hrs.

One point that could account for some, though not all, of the discrepancy in reports, is differing definitions of duration. Does the duration of a substance include all time during which one can detect any effects? Does it end when one can go to sleep? Or does it end when physiological changes such as increased blood pressure or dilated pupils return to normal?

Many of those who report a 3-6 hour duration also described lingering after-effects ranging from mild to strong in intensity, and lasting an additional 1-6 hours after "primary effects" ended. Some found the after-effects sedating, while others report lingering stimulation and jaw tension.

It is quite possible that some of those who report an 8-12 hour duration could be including these "after-effects" in their duration. Without a shared, unambiguous terminology, it is difficult to compare reports reliably.

For most psychoactives, increasing dosage increases duration. One veteran psychedelic chemist, who preferred not to be named, said s/he believed MDA's duration was more dose sensitive than that of MDMA.

"Whereas the duration of MDMA seems not to be prolonged very much by increasing the dose a bit (e.g. going from 100 to 200 mg), if you double the dose of MDA from 100 to 200 mg you will definitely [be affected] for a whole lot longer."

Although MDA's pharmacokinetics (the how & when of metabolism) have not been studied, MDMA's pharmacokinetics have been shown to have a non-linearity at doses between 75 and 200 mg: in some people an increase of 25 mg from 125 to 150 mg of MDMA can double the blood concentrations of MDMA.8 While the research provides no information about whether the increase in blood levels affected experiential duration, it is possible that a non-linearity in metabolism could play a part in this confusion. The role of dosage in user reports is also complicated by the fact that dosage is often unknown or unreliable.

Over the years we have received a handful of reports which describe unusually long experiences from MDMA alone. While the average peak MDMA experience lasts perhaps 3-4 hours, there are a small number of credible reports from people who report strong effects lasting 8-16 hours after a single dose of known pure material.

Some of the recent pharmacokinetic data on MDMA from Marta Mas et al.8 has shown that there is a wide variability in physiological metabolism of MDMA. Of eight individuals who were tested, there was a range of over three fold between the fastest metabolizer and the slowest: between 3.8 hours and over 11 hours to reach half of the peak blood concentrations of MDMA.

Knowing this, it's difficult to rule out the possibility that there is a percentage of the population who metabolize MD-- compounds significantly more slowly than the average person or have some other factor which causes the duration to be radically longer. Unfortunately, it is difficult to make any reliable assertions about how common these reactions are.

As we began digging into this quandary, we sought out some respected individuals who had experience with MDA.

First we talked to Nick Sand, a well known chemist who produced MDA in the late 1960s. He said he initially synthesized MDA in the search for a less-controlled LSD replacement. His working group was looking for a long-acting compound (approximately the same duration as LSD) and found MDA completely unsuitable because they came down abruptly at around 4 hours. Some in the group ended up taking three successive doses in order to maintain effects for 10-12 hours. Nick reported that redosing in this way led to "the worst hangovers [they] ever had" which lasted several days. Because of this, the group quickly abandoned MDA.⁹

Next we asked Alexander Shulgin for his thoughts on the matter. After going back to his original notes, he agreed that the duration listed in PiHKAL is too long. Dr. Shulgin wrote:

"Describing the difference between MDMA and MDA to the unexperienced is like trying to explain the difference between shiraz and cabernet to someone who only thinks in terms of 'red wine / white wine'." - - Lamont Granquist

"My notes pretty much support the shorter duration that you mentioned (around 4 hrs) and that is what I should have put into PiHKAL. The consistent awareness of some past impact on the body that always stretched out 8 hrs or more is what probably prompted the longer time range. An added nuance was from a number of reports by Claudio Naranjo, all of which stretched out for hours, but I now suspect that he was calling the session finished when his subjects (or he) got completely to baseline.

Also, I have just glanced at his chapter on MDA in The Healing Journey where he explored MDA in some 30 patients. In some, there was a supplement given, and in most he apparently continued the therapeutic interactions through what may well have been that body memory period. I suspect that he may have equated the end of the therapy session with the full end of the drug's effect.

If I were to write PiHKAL today, [MDA] would have a duration of about 4-5 hours and a strong emphasis on the fact that you weren't completely out of it, bodywise, for quite a few more hours."⁹

Rick Doblin, president of MAPS (the Multidisciplinary Association for Psychedelic Studies), commented:

"My experience with MDA has been very positive and pleasurable. I'd also say the duration is 4-6 hours, though I'm not surprised that it lasts much longer in some people since psychological processes can impact duration."⁹

MDA Timeline
1910	MDA first synthesized by chemists G. mannish and W. Jacobson.
1939	First animal tests done with MDA.
1941	First human trials with MDA during search for parkinsonism therapy.
1949-1957	MDA studied as a potential antidepressant and anorexic agent by Smith, Klein and French.
1953	Harold Blauer dies of an overdose of MDA (code name EA-1298) during an army-sponsored drug experiment.
1957	Gordon Alles describes the MDA experience at a conference in Princeton, New Jersey.
1958-1961	MDA is patented by several companies for a variety of purposes.
1963-1964	MDA begins showing up in the counterculture.
1970	MDA begins showing up in the counterculture.
1970-2001	Recreational and underground therapeutic use continues despite its illegal status.

"The total experience is 8 hours, but the "trip" is 4-5 hours like X. The after-effects are like being way-laid: definitely washing around in the afterswell of a full experience of an amphetaminehallucinogen. We call MDA ‘industrial electronic mushrooms' and compare the post-peak to riding the diesel-electric locomotive all the way home. Your feet & teeth vibrate for some time after you step off a huge machine like that: tingling and numb. There's no finer intoxicant, but you need careful and considerable support or the body load can turn you into a vegetable for the latter half of the experience and the day after."⁹

Although most sources list the duration of MDA as between 6 and 12 hours, usually stressing that it is significantly longer in duration than MDMA, many users of MDA have found the two to be of similar duration and effects. A number of very credible reports exist of MDA-only experiences lasting 12-24 hours, but these appear to be far less common than experiences under 6 hours.

Based on our analysis of the available data, we have recently changed our documentation of MDA duration from "8- 12 hours" to "3-5 hours" and added notes about the confusion and lingering effects.

There are several open questions: whether MDA's duration may be more dosesensitive than MDMA; what percentage of users experience what duration; how to describe the effects-time curve so that we have a shared terminology for describing when effects "end"; and whether some of the duration confusion is due to including boosts in duration calculations.

If you have information about MDA duration that is not mentioned in this article (including experience reports with known-pure material), please let us know.