May didn’t notice much with the first dose of LSD. She felt good, and she got a lot accomplished, and that was all.

It was the day after that things really clicked. She felt even better, and she got a lot more accomplished. She repeated this pattern for a month — one 10-microgram dose of LSD every fourth day — as per the regimen recommended by psychologist and microdosing research pioneer James Fadiman’s protocol, made mainstream-famous by Ayelet Waldman’s monthlong LSD self-study chronicled in last year’s A Really Good Day.

“I did a little experiment,” says May, a 64-year-old psychotherapist in Marin County requesting anonymity. “It was this game on my iPad that I was kind of stuck on, and I noticed that whenever I was on day two of the microdosing [regimen], my performance was significantly better.”

This wasn’t May’s first time doing acid. She’d taken LSD (full name: lysergic acid diethylamide) sporadically over the past 40 years. This was, however, her first foray into microdosing. She’d heard promises that microdosing LSD would yield heightened productivity and dissipate mental clutter.

Microdosing provided that sharpness for May, as advertised.

“For me, it’s just clarity. It’s like how you would feel if you had a really good, deep rest, and then woke up and were able to focus very clearly.”

Microdosing is trendy. From Waldman’s 2016 book and media tour, to coverage at Marie Claire and The New Yorker, to fodder for podcasts geared toward self-described psychonauts and psychedelic-naive laypeople alike, to how-to manuals and private “microdosing coaching” sessions at $97 a pop, low-dose psychedelic use has become the drug fad du jour. The subscribers on a Reddit forum devoted to microdosing nearly quintupled in the span of a year and a half, as Wired noted last summer. Then, there were 7,500 members. The forum has doubled in size in the year since then.

So what’s happening physiologically to someone on a low dose of LSD? In the absence of hard science, reports from volunteers like May make up the only existing literature. And if the dose is in fact very, very micro, not much happens at all. Says May, “I did not have any sensory stuff tied to it.” On occasions where she’d taken higher doses of LSD in the past, she’d experienced some hallmarks of an altered state, but not with microdosing. “That’s not what I was going for.”

All reporting on microdosing’s purported benefits has been anecdotal, speculative. The machinery of science moves much more slowly than hype. But the science is starting to catch up. The first glimpses of data on microdosing were presented on April 21, at Psychedelic Science 2017, a six-day summit in Oakland of more than 100 clinical researchers and physicians and 2,500 psychedelic enthusiasts. Fadiman shared results from his ongoing study’s first 418 volunteers. (He’s hesitant to call them “subjects,” because his study doesn’t follow classic research design.) People sign up to receive his self-study protocol and instructions online, which detail the month-long plan that May and Waldman followed. The participants have to find the study drugs on their own. A notice on the study’s site reads, “Please DO NOT ASK US about: how or where to find substances. [sic]”

LSD isn’t the only microdose included in the protocol; psilocybin (the active alkaloid in magic mushrooms) and iboga (a psychoactive shrub) are part of it as well, plus other psychedelics as long as they’re dosed somewhere between 5 and 10 percent of the “normal recreational dose.” For LSD, Fadiman accepts self-reports from individuals ingesting between 8 and 15 micrograms, though he recommends starting with 10. A daily check-in instrument asks contributors to rate their mood, productivity, and energy on a scale.

“And then we ask people to write us a report,” says Fadiman in an interview with The Verge. “Which is where, from my point of view, things get really interesting.”

Fadiman and co-investigator Sophia Korb’s site went up in February; over 1,000 people have filed self-reports to date. On one (really good) day, participants submitting write-ups hailed from nine different countries.

He briefly shares a few stories from the project with me: A man suffering depression credits microdosing with giving him the confidence to bid for a whole project on behalf of his company, rather than for a small piece. An engineer who says he gains the ability to see all the moving parts of the machine he’s working on in synchronicity, rather than fixating on one aspect. Another individual who, Fadiman reports, “said it very nicely: ‘I’m a much better version of myself.’” There are two big takeaways from Fadiman’s results so far: microdosing can be an aid for productivity, and it can provide relief for treatment-resistant depression.

LSD is mostly known as the mascot for 1960s counterculture. Its widespread use became one of the impetuses for 1970’s Controlled Substances Act. But there are no known overdose deaths attributed to LSD. Psychedelic resource Erowid does report on a low number of deaths associated with LSD, and advises caution. In some cases, though, deaths linked to LSD were either not LSD at all (other drugs come on blotters, too), or the result of accidents or suicide on especially high doses.

Says Erowid, “Put simply, LSD does not cause death at recreational or therapeutic doses (less than 500 [micrograms]).” Microdosing is one-fiftieth of that amount.

“LSD is a totally amazing substance,” says Ralph Metzner, a psychopharmacologist considered a forefather of LSD research. “Because it is so potent, and such tiny amounts and tiny differences in tiny amounts make such a huge difference. […] Its sensitivity is off the charts. There’s no other drug that comes close to that kind of sensitivity.”

Microdosing’s tiny dose is its key selling point. “The benefit of it being micro is you go about your normal daily activities,” says Rick Doblin, executive director of psychedelic research nonprofit MAPS. “Your cognitive processing is slightly enhanced in certain ways — more creative, more focused, little bit of a mood elevation — but you’re not in any way tripping. And you can drive. You can do all sorts of things that you wouldn’t do if the dose were higher.”

Lex Pelger, a 34-year-old biochemist and writer in Brooklyn, agrees that the effects are so mild they’re almost imperceptible. Pelger hosts Psymposia, an events group centered on psychedelic science, and says he microdoses every couple days, finding it helpful for interviewing, lecturing, and writing. “You just don’t need as much coffee that day,” he says.

Microdosing also has some history. Albert Hofmann, the Swiss chemist credited as the first person to synthesize and ingest LSD in 1943, told Metzner that he self-experimented with low doses of LSD in his later years, circa the 1990s. “Just to think,” Metzner says. Microdosing is quiet, reflective. Metzner likens it to taking a vitamin.

And though modern clinical investigations of psychedelics regulate dosage, mindset, and the environment around test subjects to ensure streamlined data, they can’t account for two factors that Metzner says determine the quality and intensity of a psychedelic experience: individual variability and learned sensitivity. Every individual will react to a psychedelic, particularly LSD, in a unique way. That microdosing is “micro” renders it a teaching tool.

“It’s like learning to use a microscope,” says Metzner. “How to adjust the lens, and of course you have to know what it is that you’re looking at.”

While we wait for the definitive science on what microdosing does in the body, it’s possible to review what we know about larger doses of LSD.  A new report will soon be out from the Center for Brain and Cognition at Universitat Pompeu Fabra in Barcelona that does just that. The scientists collected data from the rainbow-hued neuroimages of twelve brains on LSD, taken in fMRI sessions  by a team at Imperial College London last year. The goal was to try a new analysis that might lead to more information on how the drug works, says computational neuroscientist Selen Atasoy of her collaboration with Imperial. “We wanted to look at the dynamics, rather than static images […] to analyze how brain activity changes over time.”

Atasoy and her team translated Imperial’s data into what they call “harmonic brain states.” Basically, the fMRI measures blood flow to brain structures; each unique pattern of brain activation gets a “frequency,” which Atasoy likens to a musical note. The notes can then be strung together. By doing this, the researchers can see how many brain states the volunteers went through — or the “complexity of the music,” as Atasoy puts it — and compare that to a placebo.

“It’s really like jazz improvisation, what LSD does to your brain,” says Atasoy. “Your brain seems to use many more of these brain states, similar to [how] in improvisation, people use many more musical notes.” And as with jazz improvisation, the notes are not random, Atasoy says.

The idea of harmonic brain states is relatively new; the first publication was from Atasoy last year. “I would say in general the concept of ‘harmonic brain states’ does not enjoy a huge following,” says Robert Bilder, a neuropsychologist at UCLA. The research is interesting and seems well done, he says.

Imperial College London’s neuroimaging study used 75 micrograms of LSD, a dose seven and a half times larger than a true microdose. Still, the results on higher doses can provide insight on what happens to people like May on low doses. “I expect that the microdose would enable some flexibility while you can still remain focused, while you can still maintain that structure,” says Atasoy. Any theories on microdosing are still speculation for now.

But neuroimaging studies for low-dose LSD are on the way. Amanda Feilding, director of the UK-based Beckley Foundation, announced at Psychedelic Science that a microdosing LSD study will take place at Imperial later this year. The plan is to recruit 20 participants to test a variety of LSD doses. Then they’ll play the strategy game Go inside an fMRI machine — while researchers monitor their brains’ blood flow.

“I rather love brain imaging in the sense that it gives you a pictorial explanation,” Feilding tells The Verge, pulling out a sample of the neuroimages from Beckley and Imperial’s moderate-dose LSD study last year. Feilding designed the microdosing protocol to learn more about how a low dose of LSD affects the brain. “I just want to go in more deeply, trying to track down the physiological basis of the reported feelings of increased well being, or overcoming depression or [improving] cognitive functioning.” The study isn’t yet funded.

“It’s amazing what a craze microdosing has become,” says Viceland’s Hamilton Morris in a recent live podcast recording of The Duncan Trussell Family Hour. “I would’ve never expected that the way to get everybody interested in psychedelics was to make them not psychedelic.”

Microdosing LSD sounds like a trip, but its secret weapon is that it is, all said, a ho-hum experience. Many of the studies in the current wave of clinical psychedelic research add to this perceived tameness; after all, the aim appears to be making LSD legal for prescription or therapeutic use. To do that, the “Orange Sunshine” of the ‘60s must be deemed respectable, which in the United States means pharmaceutical. There’s a future where LSD is not simply decriminalized but also legally accessible, says Ethan Nadelmann, founder and outgoing executive director of Drug Policy Alliance, who Rolling Stone has dubbed “the real drug czar.”

“The information that’s increasingly coming out about microdosing makes it more likely that it will happen sooner than later,” says Nadelmann. “It’s presenting a growing segment of the public with a new perspective on LSD, and it’s something that really shatters the images of LSD that people may have in their minds.”

LSD is synthetic, which makes it easier to accurately measure dosage compared to plant-based psychedelics or cannabis. That means the effects of prescription LSD would be much easier to replicate. (The same holds true for synthetic psilocybin.) More studies will be needed to establish that micodosing works and is safe for that to happen, says Nadelmann.

In fact, findings from the first known scientific study investigating safety and tolerability of low-dose LSD were slated to go public at Psychedelic Science last weekend. But three weeks before the scheduled presentation, lead investigator Neiloufar Family and her UK-based team at Eleusis Benefit Corporation, a pharmaceutical company, withdrew their study from the conference lineup, leaving the timing for LSD’s prescription drug future uncertain.

“Certainly, nobody else is working with LSD in a drug development context,” says Doblin. “So if their study isn’t the first step, there is no first step.”

Family told The Verge that she and her team are hoping to have everything completed this summer, but are unable to comment on the study until that time. When reached for clarification via email, Eleusis’s founder Shlomi Raz wrote that though the clinical trial is complete, its analysis continues, alongside other studies in process.“We hope to be able to release these aggregated findings at the same time so as to provide the scientific, medical, and broader public with a more comprehensive perspective on the research and its implications,” Raz wrote in the email.

Raz declined to comment on whether Eleusis plans to patent and sell low-dose LSD for prescription use. “They’re pretty secretive,” says Doblin, “so I’m not exactly sure what’s going on.”

That leaves Fadiman with the only game in town: an ongoing self-report study. It may serve as a road map for the next round of needed clinical LSD research. “Microdosing is a case study in citizen science,” he says of his 1,000-participant-and-growing study. “There’s no way that conventional science could really replicate what we’re doing.” Approved double-blind studies at research hospitals like Johns Hopkins, New York University, and Harbor-UCLA are the gold standard for research in the field. But these studies are very small, sometimes with 20 participants or fewer. Fadiman’s admittedly messier work does serve its own purpose, then — by gathering experiences from larger groups of people. That may guide future controlled trials by suggesting new questions about these psychedelic drugs.

Here’s an example: Fadiman reads an email from a British art historian in her 20s, long afflicted with painful, irregular menstruation. “‘I only microdosed that one month. My periods are regular. You have changed my life. Thank you.’ I’ve been in psychedelic research a long, long time, and no one’s ever considered or mentioned or thought about the possibility that psychedelics had anything do with menstrual periods, particularly difficult ones. However, now that that bit of search has happened, we started looking for it.” Twelve women, he says, have reported improved menstruation after microdosing.

If you think this is the part of the story where we tell you that May’s life has changed because of her microdosing, it’s not. Because her life hasn’t changed.

“While you’re doing it, it’s very useful,” she says. “When you stop, you stop.” She hasn’t microdosed since.

For May, withdrawal after LSD left her system — a feeling she can best describe as a “vague sense of difficulty getting your traction” — was enough for her to not repeat the month over. Microdosing is not something she’d want to do every day. She sees its value for someone with ADD or ADHD, especially as an alternative to Adderall. But that’s not the case with May.

“To be honest with you, I can get to the same state of consciousness with daily meditation practice, and that’s more sustainable,” says May.

Her fellow microdoser, Pelger also admits it’s possible to experience the heightened concentration through more mundane means. “It’s just a little bit harder to achieve,” he says. ”Just like reaching the mystical mountaintop is a little bit harder to achieve via yoga than via LSD.” He still microdoses occasionally, either with psilocybin or LSD, when he feels he needs it.

If the scientific studies emerge to support it, microdosing LSD could be just like any other prescription drug experience: useful for some, less so for others, and perhaps best prescribed as temporary treatment. And like other drugs, there are some people who probably shouldn’t use it at all.

For instance, Fadiman has learned not to recommend microdosing to people who experience anxiety, since anxiety seems to be exacerbated by even small doses of LSD. And though his research in the 1960s found a correlation between high-dose LSD and scientific breakthrough of “unsolvable problems,” this study hasn’t produced the same results for microdosing.

But if there’s any hope for microdosing’s prescription drug future, it’s that the least trippy and most clinical of scientific studies must pave the way. As Doblin points out, “You can’t get FDA approval for personal growth.”

Stephie Grob Plante is the daughter of Charles Grob, a psychiatrist who studies MDMA, ayahuasca, and psilocybin for use in therapy.