Naltrexone is a medication that helps to manage alcohol and opioid addiction by preventing the “high” caused by these substances. But doctors also use low-dose naltrexone (LDN) to treat a variety of conditions, including multiple sclerosis (MS).

The use of LDN for MS is what’s known as an off-label use. This refers to using a medication for something other than what it was approved to treat. It also means that the medication hasn’t gone through the same amount of rigorous testing to confirm its effectiveness and safety for treating these other conditions.

LDN is taken in doses that are about a tenth of the size of a traditional dose, usually less than 5 milligrams (mg) per day. It releases hormones called endorphins over an extended period of time. Endorphins help to reduce inflammation, the root cause of many MS symptoms.

Read on to learn more about using LDN for multiple sclerosis, including how soon it starts to work and the side effects it can cause.

There’s limited research surrounding the use of LDN for MS. However, there’s anecdotal evidence from people living with MS. Many say that taking LDN helped to reduce their number of flare-ups. Others noted that it seemed to slow down the progression of the condition with fewer side effects that traditional MS medications.

The studies that do exist show mixed results. For example, a 2014 case study involved a woman who reported an improvement in her MS-related fatigue after she started taking 3 mg of LDN daily. But she also developed thrombocytopenia, a condition caused by a low platelet count. The authors of the study believe this was related to LDN.

In a 2010 study involving 80 people with MS, LDN was associated with significant mental health improvements that affected the participants’ quality of life. But it didn’t seem to do much for the physical symptoms of MS.

A more recent study published in 2017 looked at prescription data from 2009 to 2015 to see whether people with MS needed fewer medications after taking LDN. The authors didn’t find any major differences in the number of medications between those who did and didn’t take LDN. This echoes the results of a 2016 study that looked over laboratory and clinical data about people with MS at a specific medical center over the course of 10 years.

Very few studies about the benefits of LDN for people with MS involve real participants. Instead, most rely on individual cases or data from medical facilities. While they all suggest that LDN doesn’t make MS symptoms worse, more long-term studies involving a range of participants are needed to fully understand its benefits.

It’s not clear how long LDN takes to work for MS symptoms. This is partly due to the lack of research and testing about this off-label use. Based on existing studies, it should start working within three months.

LDN also appears to be safe for long-term use. In a 2016 study, subjects took it for an average of three to four years.

There’s no standard dosage for using LDN for MS. But people generally take 3 to 5 mg a day. You can take this dose at any time of day, but it’s best to drink a full glass of water with it.

Full-dose naltrexone may cause the following side effects:

  • nausea and vomiting
  • abdominal pain
  • constipation
  • decreased appetite
  • headache
  • fatigue
  • insomnia
  • dizziness
  • depression
  • anxiety

It also carries a black box warning for liver toxicity, which can lead to permanent liver damage. A black box warning is a serious warning provided by the Food and Drug Administration to inform people about dangerous side effects. This risk may be lower when taking a lower dose for treating MS.

LDN may also increase your risk of thrombocytopenia, so call your doctor right away if you notice increased bruising or uncontrollable bleeding.

You shouldn’t take LDN if you:

  • take opioid medications
  • are in an opioid maintenance program
  • are in acute opiate withdrawal
  • have liver problems

Never try to split naltrexone tablets on your own to create LDN. Your doctor can help you find a compounding pharmacy that prepares LDN.

Remember, LDN for MS is considered an off-label use. It’s very important to talk to your doctor before trying it. They can make sure it won’t interact with any other medications you might be taking for MS.

LDN is a promising potential treatment for MS symptoms with relatively few side effects compared to other treatments. However, experts are still trying to figure out exactly how it affects MS symptoms. If you’re interested in trying it, talk to your doctor to make sure it’s a safe option. They can also help you find a compounding pharmacy that prepares it.