By Trevor Hughes, Published: March 11, 2015 at 7:29 PM

DENVER — Federal drug regulators have ordered several cannabis companies to stop claiming their hemp oil products can cure everything from cancer to Ebola after testing showed some of them contained none of the advertised ingredient.

In a series of strongly worded letters, federal safety regulators warned the companies to stop marketing cannabis and hemp oil as treatments for skin conditions, panic attacks, arthritis, cancer and Ebola. The warning letters came after federal officials tested the products and evaluated their marketing claims. The testing didn’t examine whether the active component actually did anything for the users — just whether it was in the product.

The Food and Drug Administration oversees the nation’s legal drugs, requiring safety and efficacy testing. It also oversees food and dietary supplements, which is how hemp oil products are often marketed. Marijuana products aren’t subject to the same kinds of regulation as prescription drugs, in part because there’s an ongoing debate over whether it’s is a food or a drug.

In this case, the letters went to six companies selling what are known as “CBD” products, which claim to be legal in every state because they contain no actual marijuana, and are often derived from hemp, a strain of the cannabis plant.

While most people are familiar with THC, which is the component of marijuana that gives users a high, marijuana plants also contain dozens of other compounds, including cannabidiol, or CBD.

“Your product is not generally recognized as safe and effective for the above referenced uses and, therefore, the product is a ‘new drug’…” the FDA wrote to CBD Life Holdings of Arizona on Feb. 26. “Additionally, your product is offered for conditions that are not amenable to self-diagnosis and treatment by individuals who are not medical practitioners; therefore, adequate directions for use cannot be written so that a layperson can use this drug safely for its intended purposes.”

CBD Life Holding’s product, Ultra CBD, sells for $45 for a 1-ounce bottle. The company’s current website says the extract can help with pain relief, sleep, anxiety and overall wellness, and includes a mandatory FDA disclaimer that it is not intended to treat, diagnose or cure any disease. The FDA tests found no CBD in one of the company’s hemp oil supplements and very little in another.

CBD Life Holdings spokesman Mo Asnani said the his company is stepping up its third-party testing to ensure its products contain what they say they do.

“We have third-party test results that are different than theirs,” he said, declining to discuss specifics. “The FDA letter really helped shine a light on our practices and we hope to be better at what we do as a result of that.”

David Mouser of Twin Falls Biotech, which makes CDB lozenges under the name ArisiTol, admits his company violated the FDA regulations. He said regulators were upset his company posted testimonials to its website in which customers said the product offered specific benefits. Regulators said ArisiTol contained 0.2% CBD, which Mouser said was right in line with what the company claims. He said he welcomes testing requirements.

“CDB is the Wild West. What you’ve got going on is a bunch of people who don’t know what they’re doing. There’s a lot of people with a lot of good intentions … I want the cheats on notice that they’ve got to test,” he said.

Two companies that sell hemp oil dog treats also received similar FDA letters.

And late last year, New Jersey-based company Natural Solutions Foundation was warned to stop selling a package of silver particles combined with hemp oil, a substance the company claimed would fight Ebola and the accompanying pain.

In a statement announcing the warning letters, the FDA said it had tested some of the products being marketed, “and, in some of them, did not detect any CBD,” the agency said. “It is important to note that these products are not approved by FDA for the diagnosis, cure, mitigation, treatment, or prevention of any disease, and often they do not even contain the ingredients found on the label. Consumers should beware purchasing and using any such products.”

In Colorado, many parents swear by a marijuana product known as Charlotte’s Web, which is a low-THC and high-CBD oil given to children suffering from seizures.

Charlotte’s Web and its believers have received national attention for what they say are its miraculous benefits, and some parents have even brought it with them into hospital emergency rooms to dose their kids when conventional medicine fails. The drug’s promise has prompted dozens of families to move to Colorado to seek treatment, and there’s a lengthy waiting list to acquire it. But there are also no state or federal quality controls on Charlotte’s Web.

Marijuana remains the most widely used illegal drug in the country, and advocates say a drug that’s been used safely for so long, and by so many people, needs little or no federal oversight. Other industry experts, however, welcome the kind of scrutiny and research pharmaceutical companies conduct.

“There are some snake-oil salesmen out there, but in some respects that’s going to happen in any industry,” said Alex Thiersch, managing principal of Chicago-based Salveo Capital, which invests in the medical marijuana industry. “We need to figure out what marijuana does. You talk to cancer patients, for instance, and from a medical standpoint, it appears to work. But why does it work? You talk to pharmaceutical companies and they’ve been doing research on their drugs for years. And we need that kind of work on marijuana.”

The FDA’s action heartened marijuana critics like Kevin Sabet of Safe Alternatives to Marijuana, an advocacy group that opposes widespread legalization.

“Let’s hope this is a sign of more intervention to come,” Sabet wrote in a Wednesday e-mail to supporters.

Twenty-three states allow some form of medical marijuana use, although doctors in those states can only recommend a patient use pot, since prescribing it would violate federal law.

Claims of medical benefits have long been made by marijuana advocates. In Colorado, stores are marked with green crosses and often named in a way that evokes medical benefits: High Level Health, Advanced Medical Alternatives, Kind Meds.

As of January, Colorado alone had more than 113,000 people listed on its medical marijuana registry. Of those, 65% are men, and the average age is 42. The claim of “severe pain,” is listed as the primary ailment for 93% of all Colorado medical marijuana patients.

The FDA has the legal authority to seize unapproved drugs and unsafe food additives, and traces its founding in part to national outrage in the early 1900s of snake-oil salesmen selling unregulated patent medicines that did more harm than good.

Former FDA regulator Dan Fabricant said much of the confusion exists because it’s unclear whether marijuana will be treated as a food or a drug. He said the natural products and marijuana industries are closely watching what the FDA does next.

“When you blur the lines between food and medicines, that’s where everyone gets confused,” said Fabricant, who now runs the Natural Products Association. “If you’re claiming effectiveness, you have to go through the drug-approval process.”

In a statement, the FDA said it will continue monitoring the marijuana marketplace, and will step in where warranted.

“FDA is concerned that these products have not been evaluated for safety and effectiveness,” the agency said. “Consumers who are misled by false claims may delay seeking important medical care, such as proper diagnosis and supportive care. It is extremely important that patients talk to their doctors about the best way to treat a disease or condition.”

The agency added that it “reserves the right to take action when appropriate to preserve and protect the public health and is committed to working with the states and other federal partners to ensure that regulatory programs at the state level do not permit those products to falsely claim that they diagnosis, cure, mitigate, treat, or prevent diseases.”

Independent strength testing conducted by USA TODAY and other media organizations has shown wide variation in the potency of marijuana products being sold across the country. Many products contain far less THC than they claim, but state regulators generally don’t care about weak products, don’t evaluate if they work, and generally get involved only if marijuana products are too strong.