The U.S. Food and Drug Administration sent warning letters to 11 companies for making unproven claims about products sold to people with opioid addictions.

Federal regulators have taken aim at companies for what they say is illegal marketing of products as tools to treat or cure opioid addiction and withdrawal.

One of the government’s concerns is that people relying on the promise by these unapproved products won’t seek treatments for opioid addiction that have actually been shown to work.

Last month, the U.S. Food and Drug Administration (FDA) and the Federal Trade Commission (FTC) sent letters to 11 companies selling products that target people with opioid addiction.

The agencies cited some of the claims made about these 12 products, such as “number one selling opiate withdrawal brand,” “safe and effective natural supplements that work to ease many physical symptoms of opiate withdrawal,” and “break the pain killer habit.”

Millions of Americans have opioid use disorder. This represents a huge market for companies willing to sell hope in the form of treatments that haven’t been shown to work.

“Many unproven medications or treatment programs for addiction take advantage of the fact that there are people who are vulnerable and in need of help — and who don’t always have the best ways to evaluate whether something is helpful,” said Dr. Carla Marienfeld, an addiction psychiatrist and an associate professor of psychiatry at the University of California, San Diego.

Because the claims made by the 11 companies are unproven, the products fall under the FDA’s authority as a “new drug.” The FTC is responsible for reviewing whether the advertising made by these companies is deceptive.

The companies have 15 days to respond to the letters. If they fail to correct these violations, the companies may face “legal action without further notice, including, without limitation, seizure and/or injunction,” the agencies wrote in the warning letters.

When it comes to dietary, herbal, and other supplements, the FDA largely ignores them unless it’s shown that people could be harmed by taking them — such as if the product is laced with a harmful compound or if it might interact with medications.

Some people may argue that if a dietary supplement doesn’t work but doesn’t make you sick, then you’re only out the money you spent on it.

But for people with addiction — who are also often dealing with other co-occurring conditions — there are other ways for an unproven treatment to harm them.

“These products may not be doing direct harm,” said Marienfeld. “But it can also be very detrimental for companies to promise hope, when a person could instead be using an intervention that actually has a lot of evidence showing it is helpful.”

The biggest problem with the claims made by these companies is that none of the products have been tested in a randomized, clinical trial — the kind of study used to make sure that medications made by pharmaceutical companies work and aren’t harmful.

Last year, the nonprofit Center for Science in the Public Interest contacted eight companies to ask about the lack of evidence backing up their claims. In a letter to the FDA and FTC, the nonprofit said that the responses were “often flip, cursory, riddled with pseudoscientific jargon or frighteningly ill-informed.”

Here’s a look at five of the unapproved products, along with some of the problems with their claims.

Several of the companies have recently updated their websites to remove the claims cited by the FDA, or to add a disclaimer.

This product is a mix of supplements that are supposed to support a person “before, during or after detox.”

The product is no longer listed on the company’s website, so the ingredients are unknown.

In its warning letter, the FDA cites the company’s use of testimonials on its website and Facebook page as evidence of the product’s usefulness.

Dr. Harriet Hall, author of the SkepDoc column in Skeptic magazine, described in a post how customer feedback — aka anecdotal evidence — doesn’t replace clinical trials.

“Scientists know that the plural of anecdote is not data. No matter how many testimonials you accumulate, they can’t ever prove that the treatment works,” wrote Hall.

She gives the example of bloodletting to cure illness, which for a long time probably had many customer testimonials to back it up.

This product contains a mix of vitamins and herbal supplements, previously marketed to “ease the symptoms of opiate withdrawal,” according to the FDA letter.

The company lists the ingredients, along with scientific studies that looked at the potential benefits of these compounds.

But none of these studies — as far as can be seen — were done on people with addiction. And at least one of the studies was done on animals.

Even if this type of preclinical study shows that a compound works in animals, you still need clinical trials to know if it works the same way in people and is safe.

This product contains a mix of Chinese and Western herbs.

The FDA letter cites the company as previously marketing it as helping to “lower tolerance to opioids, including oxycontin, morphine, oxycodone, opium, Vicodin, demerol, hydrocodone, methadone, suboxone, heroin, and tramadol.”

The company doesn’t list any studies on its website showing that these compounds can lower a person’s tolerance.

But if they did work that way, this could be more harmful than helpful.

People who go through detox for opioids are already at a higher risk of opioid overdose because of a reduced tolerance. Detoxing without medical supervision also carries other risks.

“When you do opioid detox alone,” said Marienfeld, “the relapse rates are incredibly high — around 80 to 100 percent.”

This product is a blend of vitamins, amino acids, and herbal supplements.

The FDA warned the company about claiming that its product could “help reduce withdrawal symptoms related to listed drugs, alcohol and tobacco.”

On its website, the company cites a study that found that some people with opioid addiction have deficiencies of calcium and magnesium, which may worsen certain symptoms.

But this study doesn’t show whether taking supplements of those minerals can relieve symptoms.

Again, a clinical trial would be needed to know if supplements helped and what dose is needed.

This product is a homeopathic remedy that claims to “diminish cravings and desires,” according to the FDA letter.

According to homeopathy, the benefits of compounds increase when they’re diluted — which goes against the laws of medicine and science.

The FTC recently ruled that homeopathic products need to carry a label that homeopathy is “not accepted by most modern medical experts” and that “there is no scientific evidence the product works.”

The company’s website now has a note that states this product is no longer available.

Several scientifically proven treatments are available for people with addiction.

Marienfeld said medication-assisted treatments using methadone and buprenorphine have “many years of very good data showing that they help decrease cravings, they help retain people in treatment, and they help dramatically decrease use of illicit opioids.”

Psychosocial interventions — such as individual or group counseling — can also be helpful.

These may teach you how to manage cravings, avoid relapse triggers, and manage anxiety or depression that often occurs alongside addiction.

There are also opioid and non-opioid medications to help people get through detox and withdrawal.

But these are just the first steps to getting over an addiction.

“Detox alone isn’t really treatment,” said Marienfeld. “Detox is just getting the person to be in a stable enough place to participate in treatment.”

And although many of the products flagged by the FDA make it seem like recovering from addiction is a quick process, that’s not the case at all.

“For most people with addiction, it’s a long-term problem that requires a lot of different things,” said Marienfeld, “including medication, support from the community, and changes in your behaviors and lifestyle.”