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When Cheryl Walser was 19, she gave birth to her first child, Ethan. The newborn phase is hard for all young mothers, but for her it was a nightmare. Ethan cried almost constantly and rarely smiled. At 18 months, when most babies giggle, play, and begin to chat with their parents, Ethan was silent and withdrawn—he would barely make eye contact. She knew something was wrong. A few months later, a doctor confirmed her suspicions: Ethan was diagnosed with autism. “I felt incredibly alone, and so ashamed,” Walser, now 33, recalls. “I believed that I had done something to cause it, and I had no idea how to fix it.”

The next several years were a blur of doctors’ appointments, special diets, and therapy. Some of the treatments helped, but “it felt like two steps forward, three steps back,” Walser recalls. When Ethan was five, a friend invited her to an evening class she taught about so-called essential oils made by a Utah-based company called DoTerra. The friend thought the oils could help Ethan.

“‘Think of your boy and hold this oil, and if your heart says get this oil, you should get it.'”

Walser attended and was intrigued by the little vials with romantic herbal names: vetiver, Roman chamomile, frankincense. Extracted and distilled from aromatic plants, each oil had a unique aroma that could help with specific physical and psychological problems, her friend explained. Some people applied them directly onto their bodies, like perfumes. Others used electronic diffusers to scent entire rooms. At the end of the class, Walser asked her friend which oil she should try. “She told me, ‘Think of your boy and hold this oil, and if your heart says get this oil, you should get it.’”

Walser finally settled on a $150 starter kit, plus two sample-size vials of Balance, a proprietary blend that, according to the promotional material, “promotes tranquility while bringing harmony to the mind and body, and balance to the emotions.” That night, Walser crept into Ethan’s room and rubbed the oil on her sleeping son’s feet. He woke up, and Walser explained what she was doing and gave him the bottle to smell. “Mommy, I need this,” he said. Over the next few weeks, Walser noticed improvements in her son’s behavior, so she began to experiment with other oils. As she delved deeper into DoTerra, she developed feelings of expertise. “I definitely felt that sense of empowerment, that I knew exactly what to do with it,” she recalls. Soon, she signed up with DoTerra and began selling the oils to others.

This transition from consumer to salesperson is common in the world of DoTerra, a multilevel marketing (MLM) company that works like the Tupperware parties of old: Salespeople invite friends to their homes for sales events disguised as parties or classes. They give a spiel about the product, maybe hand out a few free samples, and then offer their guests the opportunity to buy. Selling is good, but recruiting new salespeople is better: If you convince a friend to sell DoTerra products, you take a commission on every sale she makes. If she recruits her friends, you then get a cut of their sales, too. This model has done well for the company, which has gross annual revenues in excess of $1.5 billion.

Over the past five years or so, with a big assist from DoTerra and its main competitor, an MLM company called Young Living, essential oils have taken off in the autism community. Some parents I talked to told me they spend more than $200 a month on DoTerra products. On Facebook, there are dozens of essential oil groups for parents of kids on the spectrum—the group Autism, ADHD, and Essential Oils, for example, has more than 19,000 members.

Dawna Toews, an Ontario-based DoTerra saleswoman, told me she holds sales events all over the United States and Canada, where she teaches the families of children with autism how to use oils as a complementary therapy to help with some of the symptoms. “When you get an autism diagnosis for your child, you feel incredibly helpless, and you just want to be able to do something,” Toews told me. While she emphasizes that she never implies that her products can cure or treat autism, “Essential oils make parents feel empowered,” she says. It’s also a smart way to recruit salespeople: Moms who stay home to care for kids with autism are often eager to earn a little money on the side.

One-third of DoTerra salespeople, or “wellness advocates,” earn nothing from their sales efforts.

Just one problem: There’s little published scientific evidence on the effects of DoTerra’s oils—or any essential oils—on people with autism. These products, indeed, are not regulated. And the company requires its salespeople to spend at least $100 a month on DoTerra products in order to qualify for sales commissions. According to DoTerra’s 2016 member earnings disclosure and spokeswoman Missy Larsen, one-third of the salespeople—which the company calls “wellness advocates”—earn nothing from their sales efforts.

DoTerra isn’t required by law to disclose how many of its salespeople actually lose money, but the Federal Trade Commission has cited a 2011 investigation involving about 350 multilevel marketing companies (including DoTerra) and found that the vast majority of the salespeople for such operations end up in the red—usually because they can’t manage to sell the products they’re required to buy.

Nor are the companies obligated to tell prospective salespeople that they may come out behind. The rules probably won’t change anytime soon. The FTC cracked down on multilevel marketing firms under President Barack Obama, but President Donald Trump, who made millions of dollars as a spokesman for an MLM company, is considered more likely to ease business restrictions than tighten them.

Whether they sell or not, parents of kids with autism are often financially vulnerable thanks to health-related expenses, says Catherine Lord, director of Cornell University’s Center for Autism and the Developing Brain. Her fear is that families are blowing money on essential oils at the expense of proven treatments. “What are you not doing because you’re doing this?” she asks.

In 2014, the Food and Drug Administration put DoTerra on notice that its salespeople were violating federal law by claiming the company’s essential oils could cure or treat a wide variety of health problems—“viral infections (including ebola), bacterial infections, cancer, brain injury, autism, endometriosis, Grave’s Disease, Alzheimer’s Disease, tumor reduction, ADD/ADHD, and other conditions that are not amenable to self-diagnosis and treatment by individuals who are not medical practitioners.”

After receiving the FDA’s letter, DoTerra warned its army of more than 3 million wellness advocates to refrain from making such claims, but not all of them listened—as of last week, at least one representative was touting the company’s essential oils on Facebook for flu prevention. When asked about salespeople still making health claims, DoTerra’s Larsen responded in an email that the company is “committed to absolute compliance with the FDA and similar regulatory bodies around the world.”

There’s no “biological plausibility,” one specialist told me, for how an essential oil would improve autism symptoms.

In any case, DoTerra salespeople have found a clever workaround. Instead of explicitly touting the oils’ ability to treat autism, salespeople need only share their personal experiences, telling potential customers about, say, the time vetiver helped their child sit through math class, or how a special blend prompted little Billy to hug Grandma for the first time. This sort of anecdotal marketing worries Jeremy Veenstra-VanderWeele, an autism specialist and professor of psychiatry at Columbia University’s medical school. “People sharing their own stories—that does not really tell us much about whether a treatment works,” he says. In fact, there’s no “biological plausibility” for how an essential oil would improve autism symptoms.

Why, then, are so many parents of children on the spectrum convinced that essential oils help? One reason is that they seem like they should, Cornell’s Lord told me. Many children with autism react strongly to loud noises, unusual textures, and strong tastes and smells, she points out, so it’s understandable parents would seek out treatments involving the senses. Lord says she knows several families who have tried essential oils, as well as an occupational therapist who uses them in her practice.

A confounding factor is that parents often attribute any progress they see in their child to specific treatments they’re using at the time. So if, for example, your nonverbal kid starts talking a few days after a treatment with an essential oil, it’s tempting to connect those events. But Veenstra-VanderWeele points out that autism is incredibly complex; rarely does any single treatment yield major improvements. “Kids continue to develop whether or not they have a developmental disorder, and their progress also can be uneven,” he says. “That can make it difficult to assess treatments.”

The existing research on sensory-based treatments for autism—massage, music therapy, “environmental enrichment,” and so on—is extremely limited, says Amy Sue Weitlauf, a childhood autism specialist at Vanderbilt University. In a 2017 review of such therapies, she and her colleagues found that while a few methods yielded “modest short-term” results, such as improved motor skills or cognition, long-term data was inconsistent or lacking. Weitlauf, who has scoured the science literature, told me she isn’t aware of any robust peer-reviewed research on essential oils and autism. DoTerra’s Larsen claims in her email that there are “somewhere in the neighborhood of ten thousand peer-reviewed studies speaking to [essential oils’] benefits in supporting and promoting various markers of health”—but she wasn’t allowed to point me toward any evidence specifically related to essential oils and autism.

DoTerra maintains that it educates its sales force on the rules around health claims. “If a non-compliant claim is found we ask that it be removed, if the claims continue DoTerra terminates the non-compliant account,” Larsen wrote. She implied, however, that DoTerra can’t possibly police all the members of its independent sales force.

And yet the company courts the autism community independently. For example, it recently funded a new autism center at Utah Valley University, including a “sensory garden” that features the plants used in its oils. “Aromatic plants will be a beautiful addition to the space and will provide an uplifting, powerful experience for children and families, while also representing what DoTerra does,” reads a press release.

Some high-profile wellness gurus beloved in the autism community have connections with DoTerra. Take “Dr.” Josh Axe, a naturopath who used to sell DoTerra and now peddles his own line of oils. In the “autism natural treatments” section of his website, Axe claims that “Vetiver essential oil has proven to balance brain waves, lavender oil can calm the body and frankincense oil supports neurological development.”

After the FDA cautioned DoTerra against making unfounded health claims, the company quietly began to market its products using more scientific language. On a spiffy new website called Source to You, customers can read about DoTerra’s complicated distillation process and its medical advisory board. In August, the company announced plans for a major build-out, including a 39,500-square-foot medical clinic at its Utah headquarters “where we can validate the medical benefits of oils with modern medicine.” (By next year, the company projects it will have nearly 3,000 regular employees.)

“We still can’t make health claims, but it’s changing,” says a DoTerra sales rep. “The Trump administration is much more lax about this.”

The FDA’s admonition certainly hasn’t discouraged DoTerra reps from marketing heavily to the autism community. Toews, the Ontario saleswoman who regularly hosts DoTerra events, including ones specifically focused on autism, at one point achieved DoTerra’s ultra-elite Blue Diamond level, which according to company disclosures means she had hundreds of salespeople working under her and pulled in about $450,000 a year.

Some Republican legislators are trying to relax the rules multilevel marketing companies must adhere to. In the past, the FTC has found that companies that get the majority of their income by recruiting new sales reps—as opposed to from sales of the end product to consumers—are illegal pyramid schemes. (There is no indication the FTC has investigated DoTerra.) But Rep. John Moolenaar (R-Mich.) has proposed changes that would shield MLMs from investigation by the FTC so long as the companies don’t require salespeople to buy excessive inventory, and so long as they offer to buy back a portion of the product a sales rep cannot sell.

One DoTerra saleswoman in Utah told me she had heard the company may soon be allowed to tout its products as medical treatments again. “We still can’t make health claims, but it’s changing,” she said. “The Trump administration is much more lax about this.”

That’s speculation, of course. But in a way, it doesn’t matter whether the rules change, because the feds can’t touch DoTerra’s most powerful sales tool: the personal testimonial. Last year, Walser told me, she attended a session at DoTerra’s annual convention where a speaker talked about a nonverbal child who called his mother “mommy” for the first time after receiving daily applications of frankincense.

Walser loves sharing these kinds of stories. She has even produced a series of YouTube videos aimed at her fellow parents in the autism community. “I just go back to how I felt—it was this really helpless feeling,” she says. “I want other parents to have hope.”