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National Geographic
21 hours ago
- Health
- National Geographic
What exactly is in gas station weed?
Edibles containing the psychoactive compound delta-8-THC, derived from federally legal hemp, are available even in some U.S. states where cannabis remains banned—although they are not FDA-approved. Photographs by Rebecca Hale This article is part of The New Cannabis, a National Geographic exploration into the most critical questions raised by today's stronger, stranger, ever more accessible weed. Learn more. Though the term is widely used in today's cannabis culture, synthetic marijuana is a bit of a misnomer. The truth is, 'there's no such thing as synthetic marijuana or synthetic cannabis,' says Deepak Cyril D'Souza, professor of psychiatry at the Yale School of Medicine and director of the Yale Center for the Science of Cannabis and Cannabinoids. Usually people use synthetic marijuana to refer to a cannabis product that was derived from hemp and contains the psychoactive substance delta-8, or one that was produced from a series of compounds that were synthetically made in a lab (aka synthetic cannabinoids). While both types of products mimic the effects of THC, the primary psychoactive compound in marijuana, 'synthetic cannabinoids are between 10 and 200 times more potent' than the usual THC in cannabis, D'Souza says. Yet many people don't realize this, and synthetic cannabinoids are very easy to purchase. They are often sold at gas stations, bodegas, convenience stores, and smoke shops around the United States. And because of a loophole in federal law, which makes delta-8-THC legal (unlike delta-9-THC, the primary psychoactive compound in cannabis), teenagers can buy gummies, flavored vaping cartridges, and other delta-8-containing products right off the shelf. (Delta-8 tends to be less potent than delta-9 but still carries risks on its own.) A study last year found that 11 percent of high school seniors reported using delta-8. This selection of cannabis edibles contains both delta-8-THC and delta-9-THC. Synthesized delta-8 also comes in other forms, including vapes, tinctures, and smokable hemp flower. How delta-8 products differ from regular marijuana Delta-9 creates the high that people typically experience from consuming cannabis. Delta-8 has psychoactive effects that are similar to those produced by delta-9, though delta-8 is naturally less potent. While delta-9 continues to be illegal at the federal level, delta-8 is legal because of a loophole in the U.S. Agriculture Improvement Act of 2018, which legalized the cultivation and sale of hemp. Though hemp and marijuana both come from the Cannabis sativa plant, they differ in their chemical composition, especially their concentration of delta-9. By definition, hemp may not contain a delta-9 concentration of more than 0.3 percent on a dry weight basis, whereas marijuana can contain significantly more. Hemp also contains small amounts of delta-8. To get enough delta-8 for commercial products, manufacturers extract and convert CBD (cannabidiol, another compound naturally present in cannabis that is legal and nonintoxicating) from hemp to delta-8 in a lab, using chemicals such as sulfuric acid, hydrochloric acid, toluene, or heptane. Despite delta-8 being legal on a federal level, some states have banned or severely restricted it in recent years, which puts its legal status in a gray area. Even so, delta-8 remains legal in more states than not, as well as in Washington, D.C. Unlike products that contain delta-9, delta-8 products are not regulated by the U.S. Food and Drug Administration, which means that potency and purity can vary. There's also a risk they may contain undetected impurities from the environment or the conversion process, research has found. In fact, common contaminants in delta-8 products include residual solvents, pesticides, microbes, and heavy metals like lead, arsenic, and mercury, all of which may pose their own health risks, according to studies. Meanwhile, there was a significant uptick in concerned calls from consumers to America's Poison Centers about experiences with delta-8, with an 82 percent increase from 2021 to 2022 (to 3,358 calls). Even without the presence of impurities, delta-8 can have problematic effects, especially because many people are consuming it in high amounts since they view it as 'weed lite' or 'marijuana lite,' experts say. 'A lot of young people think delta-8 is not as potent as delta-9,' notes Akhil Anand, an addiction psychiatrist and clinical assistant professor at the Cleveland Clinic. 'But because of the lack of regulations, the way it's consumed, and the risk of contaminants and adulterants … people can become dependent or addicted.' Edibles, like this chocolate bar containing delta-8 and delta-9, make up the third largest segment of the legal U.S. cannabis market, behind flower and vaping products. K2, spice, and skunk: 'off-the-charts intoxicating' Unlike delta-8, synthetic cannabinoids are a class of substances that are made in a lab and designed to mimic THC from cannabis. 'It's not really cannabis at all,' Anand says, because synthetic cannabinoids are entirely manufactured from chemicals. Some of these synthetic products—with names like K2, spice, Scooby snacks, or skunk—are marketed in colorful packaging as herbal incense or potpourri, and they're often made by spraying synthetic compounds (such as naphthoylindoles, naphthylmethylindoles, phenylacetylindoles, and others with equally tongue-twisting names) onto dried plant material so it looks like cannabis, Anand says. These products are not legal—when it comes to their manufacturing, sale, or consumption—at the federal level or the state level. In fact, many of these compounds have been banned by the federal government and classified as Schedule I controlled substances by the Drug Enforcement Administration. In recent years there have been several arrests and indictments of people involved in synthetic cannabinoid drug trafficking rings, including arrests this year related to a website-driven scheme to provide K2 and spice to people in prisons. Because standard drug tests are designed to detect traditional THC, they won't detect synthetic cannabinoids. Not surprisingly, these products often appeal to people who are concerned about being tested for drugs such as those in the military, the federal government, or the prison system, D'Souza says. A complicating factor: 'We can't test for these in the emergency department,' Anand explains, 'so it becomes challenging to treat these patients because we don't know what they have taken.' And the patients can't or won't tell emergency department doctors what they have taken because 'they're often not in the right state of mind,' Anand says. Consuming synthetic cannabinoids can be dangerous. One review of studies found these products were responsible for a 'higher toxicity than THC and longer-lasting effects,' including increased risk of psychiatric disorders. And deaths have been linked to synthetic cannabinoids laced with chemicals found in rat poison. In a study in the July 2025 issue of the journal Drug and Alcohol Dependence, researchers analyzed adverse effects associated with the use of synthetic cannabinoids, as reported in 49 published studies. The predominant ones involved the neurological and cardiovascular systems, with symptoms such as seizures, altered consciousness, tachycardia (rapid heart rate), and hypertension. Another 2025 study found that people with a dependence on synthetic cannabinoids exhibited more impulsivity and self-harming behaviors than their healthy peers. These products are especially risky for teens because their brains are still developing, D'Souza adds. 'These can be off-the-charts intoxicating because manufacturers are putting high concentrations in these products,' says Robert Welch, a pharmacist and director of the National Center for Cannabis Research and Education at the University of Mississippi. 'My advice is just to avoid this stuff because there's no way to know what you're taking.' Besides being dangerous in their own right, these synthetic products take attention 'away from the health benefits that properly grown and sourced cannabis products can have,' Welch says. 'People don't understand the differences.' A version of this story appears in the September 2025 issue of National Geographic magazine.
National Geographic
5 days ago
- Health
- National Geographic
How cutting out certain foods can trigger new allergies
Bagels, which often include gluten, are one of many foods often excluded in elimination diets. But for allergy-prone individuals, cutting out foods for too long may disrupt immune tolerance and trigger dangerous reactions. Photograph by Rebecca Hale, National Geographic Elimination diets are everywhere—from parents managing eczema to influencers cutting out gluten and dairy in pursuit of 'clean eating.' But research shows that removing foods from your diet can subtly change how your immune system reacts when you eat them again. In some people, especially those with conditions like eczema or past food allergies, that loss of tolerance can spark dangerous reactions—even life-threatening anaphylaxis—when the food returns. This risk is often overlooked in the growing popularity of elimination diets. According to the CDC's National Center for Health Statistics, Americans are cutting more from their plates than ever. Some do it to manage celiac disease or irritable bowel syndrome, others to reduce bloating, fatigue, or joint pain. Social media trends like #cleaneating have only amplified the appeal. By 2024, more than half of Americans reported following a specific diet or eating pattern, compared to just 38 percent in 2019. Yet for the immune system, regular exposure to food proteins helps maintain a state of tolerance—one that can be disrupted when those foods disappear from the menu for too long. Understanding how and why that shift happens is key to knowing when elimination diets help, and when they might put you at risk. The science of oral tolerance and food allergies 'The intestine has an unenviable task,' says Brian Vickery, chief of allergy and immunology and director of the food allergy program at Emory's Children's Healthcare of Atlanta. 'It has to identify and respond to a constant barrage of environmental stimuli that can be both dangerous and beneficial.' (Is gluten really that bad for you? Here's what happens when you stop eating it.) The gastrointestinal tract, which has more immune lymphocytes than any other body part, encounters trillions of microbes and more than 30 kilograms of food proteins each year. Yet, it manages to defend against harmful invaders while ignoring harmless foods and friendly bacteria. This balancing act relies on oral tolerance, a process in which immune responses to ingested food proteins are actively suppressed, which in turn prevents harmful reactions like food allergies. While the underlying immune mechanisms are not entirely understood, the latest studies indicate it begins with specialized antigen-presenting cells that capture food antigens in the gut and instruct nearby T cells to stand down. This signal gives rise to antigen-specific regulatory T cells, which calm the immune response to food proteins. (As food allergies rise, new treatments are on the horizon.) 'The gut is important in the initial establishment of tolerance,' says Michael Pistiner, director of Food Allergy Advocacy, Education and Prevention, Food Allergy Center at the MassGeneral Hospital for Children. 'If you're not already allergic, early introduction to foods can help promote tolerance and protect infants from developing a food allergy.' That protection doesn't end in childhood. Regular, ongoing exposure to foods helps maintain oral tolerance throughout life. Recent research in food allergy patients treated with oral immunotherapy, where gradually increasing doses of the culprit food are given orally, highlights how continued ingestion is often needed to maintain a desensitized state. Conversely, there's evidence that elimination diets for some can disrupt oral tolerance and encourage the immune system to develop allergies. When elimination diets increase allergy risk For parents of children with eczema, it's common to suspect certain foods are worsening flare-ups. Many turn to elimination diets in hopes of finding the culprit. But research has uncovered a hidden risk. Anne Marie Singh, professor and chief of Division of Allergy, Immunology, and Rheumatology at the University of Wisconsin-Madison, and her colleagues evaluated almost 300 children with eczema on elimination diets. (How a tick bite can cause food allergies in humans.) 'We found that if you removed the food from their diet, upon reintroduction there was a significant increase in the risk of allergic reactions, including potentially severe immediate allergic reactions,' says Singh. The results were striking: almost one in five children (19 percent) developed new immediate allergic reactions when the eliminated foods were reintroduced, even though they had no previous history of such responses. Most were mild, but alarmingly, 30 percent of reactions were severe, classified as anaphylaxis. The danger isn't limited to children. In a separate study of 30 adults who developed allergies to foods they had previously tolerated, 70 percent had been on elimination diets beforehand. Half experienced anaphylaxis, and the vast majority (80 percent) had pre-existing allergic conditions such as environmental allergies, asthma, or eczema. For people without a history of allergies, the risk appears much lower. If you're thinking about trying an elimination diet, experts say the safest approach depends on your risk level. If you're at higher risk (children or anyone with pre-existing allergy conditions), consult with a healthcare professional before starting an elimination diet. 'The more allergic you are, an elimination diet could potentially be a problem,' says Singh. Pistiner adds that 'in infants with eczema, elimination diets can be detrimental, especially at this very important time of early introduction.' Experts also recommend that children following elimination diets have close medical supervision to ensure nutritional adequacy and healthy growth. (What scientists are learning about how to prevent allergies in kids.) Duration matters, too. A shorter elimination phase gives less time for oral tolerance to break down. Singh notes that 'two to four weeks of elimination should be enough time to know if it makes a difference and also short enough to not risk an allergic reaction when you try it again.' In some cases, completely cutting out a food isn't necessary. If symptoms are mild, keeping small, tolerable amounts in the diet may help maintain oral tolerance while still easing discomfort, adds Singh.
National Geographic
24-07-2025
- Health
- National Geographic
Is it possible to take too much melatonin? We asked the experts.
Melatonin is a widely used supplement, touted for its sleep inducing effects. However, experts say the benefits only apply in certain situations—and as a result, it has been banned from being sold over the counter in various other countries including the United Kingdom, where it is only available as a prescription medication. Photograph by Rebecca Hale, National Geographic If you've ever taken a melatonin supplement as a last-ditch attempt to save your sleep, you're in good company: Research suggests people in the U.S. have steadily reached for more melatonin over the past couple of decades, and an American Academy of Sleep Medicine (AASM) survey estimates that roughly two-thirds of U.S. adults have used some form of melatonin to help them drift off. The appeal is undeniable: Your brain naturally makes this hormone to regulate your sleep-wake cycle. The synthetic form of melatonin usually found in supplements is a relatively low-risk substance for adults, plus it's available over the counter. Package this into a trendy bottle brimming with colorful gummies (with plenty of endorsements from 'wellness' influencers), and you're giving the chronically exhausted a glimmer of hope for better rest. 'People can become quite desperate,' says Jade Wu, a behavioral sleep medicine psychologist and the author of Hello Sleep. 'I don't blame them for trying whatever they can. And they're trying really hard to not abuse prescription medication.' (What's in melatonin—and is it giving you nightmares?) When a low dose of those melatonin gummies doesn't actually stop them from tossing and turning, many of these sleep-deprived people are mainlining higher and higher doses. But Wu, among other sleep experts, says melatonin is a widely misunderstood hormone. Taking it as a supplement night after night doesn't necessarily translate to better sleep—and for most people, neither does taking larger amounts of it. Which begs the question: Are we taking melatonin too often, and at too high of doses? Here's what the science says so far. How melatonin influences sleep Your body relies on two systems to help you sleep, says Joshua Tal, a clinical psychologist specializing in sleep therapy in New York City. The first is your homeostatic sleep drive, or sleep pressure, a physiological process that kicks in after you wake up. As the day progresses, it drives your need for sleep, a bit like hunger drives your need for food, Tal explains. Melatonin influences the second system: the circadian rhythm, or your body's internal clock. The average adult needs about eight hours of sleep each day; your circadian rhythm organizes when you achieve this rest. (Are you a 'lark' or an 'owl'? Your body clock holds the answer.) 'While the homeostatic drive promotes how much sleep we need, the circadian rhythm optimizes our ability to achieve that sleep at nighttime,' says sleep medicine specialist David Nelson Neubauer, an associate professor of psychiatry and behavioral sciences at Johns Hopkins Bayview Medical Center. As you get closer to your typical bedtime, a small part of your brain—the suprachiasmatic nucleus, or 'the master timekeeper,' per Neubauer—regulates the release of melatonin into your bloodstream via your pineal gland. This suppresses your alertness, which indirectly helps you doze off because your body is being told it's time to be less active. Your melatonin levels stay high throughout the night, and then start to subside in the early morning hours. What we often misunderstand about melatonin Prescription sleep medications, including benzodiazepines like Valium and 'Z' drugs like Ambien, are sedatives; they have a deeply tranquilizing effect. They're easy to misuse and notoriously habit-forming when taken long-term. (Your brain 'washes' itself at night. Sleep aids may get in the way.) By contrast, a melatonin supplement may facilitate the processes that help you fall asleep, but it won't make you stay asleep. 'A lot of people think of melatonin as a kind of sleeping pill, but it is not sedating,' Neubauer says. 'It is more of a signal to your circadian rhythm.' Taking melatonin can work 'phenomenally well' if you have to get to bed at odd hours—say, if you're a night shift worker trying to sleep during the day or a traveler suffering from jet lag, says James K. Wyatt, director of the Section of Sleep Disorders and Sleep-Wake Research at Rush University Medical Center in Chicago. It can also be effective for people with a circadian rhythm disorder or delayed sleep phase who have trouble falling asleep early enough to wake up during typical morning hours. Otherwise, for the average person, Wyatt says a melatonin supplement probably won't do much to improve sleep. While studies have yielded mixed results, Tal notes their findings suggest melatonin likely works no better than a placebo for insomnia (when you have trouble falling asleep, staying asleep, or both). Both the AASM and the American College of Physicians also maintain there's not enough evidence to recommend melatonin supplements as a safe or initial treatment for insomnia. Can you take 'too much' melatonin? Much of the data scientists have on melatonin is based on a low dose of around 0.3 to 1 milligram, which is close to what our bodies naturally produce. The average supplement claims to offer between 3 to 5 milligrams, which may seem high at first. 'Nearly every drug has a 'dose response curve.' The bigger the dose, the bigger the effect,' Wyatt explains. But melatonin's curve is pretty flat because it doesn't work like a typical sleep medication in the body. Taking 3 milligrams versus 0.3 milligrams of melatonin, for instance, is 'mostly irrelevant from a clinical point of view,' Neubauer notes. So taking a higher dose likely won't make a difference in helping you fall asleep. (Some exceptions: Studies suggest higher doses may be beneficial for children with autism and folks with Parkinson's disease.) (More parents are using sleep aids for their kids. Experts say they shouldn't.) Yet supplements can pack a lot more—or less—melatonin than their bottles claim. One 2023 analysis found that, of 25 melatonin gummies on the market, a majority were stuffed with much more melatonin than what was listed on the label. One brand claimed to offer 3 mg per serving, but actually contained 10 mg; another melatonin/CBD hybrid contained no melatonin at all but exceeded its proposed level of CBD. A slightly larger dose of melatonin (think: a serving size difference in the single digits) likely won't be harmful for most adults, but people also tend to have a more-is-more mentality with supplements, Wu notes. All the sleep experts interviewed for this article say they've had patients who came to them after taking high doses of melatonin, sometimes upwards of 30 mg a night, which can up the risk of unpleasant side effects like headaches, grogginess, nausea, dizziness, and vivid dreams or nightmares—not exactly soothing. As for whether it's possible to 'overdose' on melatonin? There's no scientific consensus on what that exact amount would be for adults. Taking a high dose like 30 mg and up probably won't make you feel great, but it's very rarely life-threatening. (The story is different for children, who can end up in the hospital due to more serious toxicity risks.) Given a lack of longitudinal data, we also don't know whether there are negative long-term effects of taking melatonin, Wyatt says. Ideally, scientists would regularly give the same group of study participants melatonin or a placebo, follow them over decades, and document the effects. But funding this research is expensive and tough to pull off even for strictly regulated prescription medications, let alone a supplement, he notes. What to keep in mind if you're melatonin-curious It's never a bad idea to support your body's natural production of melatonin, Neubauer says. To do that without supplements, opt for dim and warm lighting at nighttime, avoid screens before bed if they're overstimulating to you, and do your best to get a dose of natural sunlight shortly after you wake up, as well as throughout the day. (Light pollution is harming our health.) If taking a supplement makes sense for your situation because you travel a lot or work the night shift, know that the U.S. Food and Drug Administration doesn't regulate melatonin in the same way it rigorously regulates drugs, which opens the door for flashy marketing claims that aren't scientifically up to snuff, according to Pieter Cohen, an associate professor of medicine who researches the safety of supplements at Harvard Medical School. That's why he recommends looking for a product that's been independently tested by a third-party lab, like USP or NSF. The good news is, melatonin supplements don't pose the same risk for physical dependency like sleep medications do, Tal says. So you could try melatonin without experiencing physical withdrawal symptoms or rebound insomnia when you stop taking it. But there's a flipside to be aware of: Experts agree that you can become psychologically dependent on having a gummy each night (or doing any pre-sleep ritual, for that matter). Many sleep problems are rooted in anxiety about falling and staying asleep, Tal explains. So when you take something that promises to ease that process—whether it be melatonin or another 'natural' sleep aid—you give yourself the mental greenlight to relax and doze off, creating a positive association between that behavior and snoozing away. This powerful placebo effect is not necessarily harmful unless it's potentially masking a bigger problem. If you have undiagnosed sleep apnea, for example, you could be delaying a more effective treatment plan if you head for the supplement aisle before your doctor's office, Neubauer says. The same goes for insomnia: The gold-standard treatment is cognitive behavioral therapy for insomnia, not medication or supplements, Wyatt notes. 'Melatonin is not a panacea for all sleep problems, and it could even backfire depending on what your actual sleep problem is,' Wu says. 'So let's slow down from the quick fixes and figure out what the issue is in the first place. That's where a sleep professional can be really helpful.'
