While fully legal pot is still the exception in the United States, chances are good that you live somewhere where you can buy marijuana for health reasons. 

Since California legalized the medical use of marijuana in 1996, another 32 states, along with the District of Columbia and Puerto Rico, have followed suit. In the mid-term elections last fall, Utah and Missouri became the latest two states to do so. In another 16 states, there are efforts underway to permit medical marijuana.

This shifting legal landscape may leave you with a lot of questions: What exactly is legal in your home state? Are the purported health benefits hype or backed by science? What about the dangers of drug dependence?

To cut through the smoke, here’s what you’ll want to know before you head to your local dispensary to try to cure what ails you.

Legal doesn’t mean the same thing everywhere

Medical marijuana laws vary widely state by state, sometimes even from city to city. The variations include what health conditions qualify you for a state-issued medical marijuana card, what forms of marijuana are legal, and the percentage of THC, the psychoactive chemical in the marijuana plant, that’s allowed in various products.

For example, laws are expansive in trail-blazing California. So-called “qualifying medical conditions” include arthritis, cancer, chronic pain, glaucoma, migraines, multiple sclerosis, and the broad catchall “any other chronic or persistent medical condition that limits the ability of the patient to conduct one or more major life activities.” 

Medical marijuana dispensaries can sell cannabis in many forms, including edibles, topicals, concentrates, and buds for vaping and smoking. 

New York, on the other hand, has both stricter medical criteria and fewer legal ways to consume. Smoking is forbidden, as are edibles; only capsules, liquids, oils, and vaporized weed are permitted. 

To find out what’s allowed in your state, check out this state-by-state guide from the National Conference on State Legislatures (scroll down to Table 1).

The medical benefits could be far reaching

The claims are broad, but the scientific support for what really works varies. According to an exhaustive report issued in 2017 by the National Academies of Sciences, Engineering and Medicine, there’s conclusive or substantial evidence that cannabis is effective in treating chronic pain, nausea and vomiting due to chemotherapy, and the spasticity caused by multiple sclerosis.

Chronic pain is by far the most common reason to turn to medical marijuana. A recent study published in Health Affairs found that more than 60% of patients who qualified for a medical marijuana license did so due to chronic pain.

There’s moderate evidence that cannabis can help with sleep disorders and fibromyalgia, and some signs that it might boost appetite for people at risk of unwanted weight loss; improve the symptoms of Tourette syndrome, and relieve anxiety and PTSD. 

For a wide range of other conditions, such as the tremors of Parkinson’s disease or digestive issues like irritable bowel syndrome, medical marijuana is seen as promising

Federal laws hampers research into these health benefits

The Drug Enforcement Agency classifies marijuana as a Schedule 1 substance, a category that includes heroin, LSD, Ecstasy, and peyote. Schedule 1 drugs are defined as having “no currently accepted medical use and a high potential for abuse.”

This means there are strict regulatory barriers to conducting the double-blind randomized studies that are the gold standard in medical research. One big challenge is that scientists can do research only with weed obtained from the federal farm in Mississippi. 

There are regulatory barriers to conducting the double-blind randomized studies that are the gold standard in medical research.

“Everyone at cannabis conference always talks about how substandard this marijuana is,” says Diana Martins-Welch, a physician in the division of geriatric and palliative medicine at Northwell Health in Great Neck, N.Y., who directed a recent survey on older adults using medical marijuana for pain relief.

“Critics say there’s not enough evidence on the health benefits of marijuana. Well, if we’re going to do valid studies marijuana needs to be rescheduled.”

You have to pay for medical marijuana out of pocket

Because marijuana is still illegal under federal law, your health insurance—be it Medicare, your employer coverage, or a private plan—won’t cover the cost. You can’t apply what you spend toward the deductible in your prescription drug plan. And you can’t use a health savings account (HSA) or flexible savings account (FSA) to buy it.

Still, there are some limited ways you may be able to get coverage in some parts of the country, according to the National Law Review. 

For example, thanks to a recent court ruling, insurers in New York must cover a visit to a physician to obtain a medical marijuana card, as long as that wasn’t the sole reason for the appointment. In several states, workers compensation boards have okayed medical marijuana coverage.

Your doctor can be your guide

Since medical marijuana is not an FDA-approved drug, doctors do not “prescribe” it or hand out “prescriptions.” Beyond certifying that you have a qualifying medical condition so you can qualify for a medical marijuana card, all your doctor can do is make recommendations. But that doesn’t mean you should skip getting that professional input.

Get guidance from a knowledgeable physician, not the “bud-tender” at your local dispensary.

Responses to cannabis are very individual. The Purple Haze or Strawberry Fields that relieves your best friend’s aching knees may not work for you (all the more reason to follow the “start low and go slow” approach to dosing). 

What’s more, says Martins-Welch, cannabis may speed up or slow down the metabolism rate of other medications. That’s why she suggests getting guidance from a knowledgeable physician, not the “bud-tender” at your local dispensary. 

Martins-Welch says she often has seniors tell her they shared a joint with a friend and it helped lessen the joint pain of osteoarthritis. Her response: “Great! Now we know that you respond to cannabis. Let’s find the dose that’s right for you.” 

Medical marijuana may help counter the opioid epidemic

The survey by Martins-Welch, which looked at men and women aged 61 to 70 who used marijuana to manage chronic pain, found that two in three significantly reduced their dependence on opioid painkillers. 

Other research supports these findings. A study published in May 2018 by the Journal of the American Medical Association’s JAMA Internal Medicine revealed that in states with medical marijuana laws, the number of opioid prescriptions processed through Medicare and Medicaid decreased by 2.21 million daily doses per year. 

In states where medical marijuana is available, opioid doses, spending, and prescriptions dropped by nearly 30%

Another study, published in 2018 in the Society for the Study of Addiction’s journal Addiction, concluded that in states where medical marijuana is available, opioid doses, spending, and prescriptions dropped by nearly 30%.

Far from fueling drug dependence, legalized marijuana may be saving lives. A 2017 report published in the Elsevier peer-reviewed journal Drug and Alcohol Dependence showed that there was a significant decrease in hospitalizations for opioid dependence or abuse as well as a reduction in opioid overdoses in states that had some form of legalized marijuana. At the same time, there was no increase in hospitalizations related to marijuana. 

Even the National Institute of Drug Abuse concedes that marijuana is not a gateway drug, writing that  “the majority of people who use marijuana do not go on to use other ‘harder’ substances.”