A new way to use old medication

Naltrexone has been around for decades, but its uses have changed over time. Developed in the 1980s, it was originally used to treat alcohol and addiction. Today, it’s experiencing a resurgence—not for addiction treatment, but as a promising new therapy to treat a variety of conditions at a fraction of the dose.

Low-dose naltrexone (LDN) is used today to support immune function, reduce inflammation, and improve overall quality of life, and its popularity is only growing. Let’s break down the science, benefits, and everything else you need to know about LDN.

What is low-dose naltrexone (LDN)?

LDN is a medication used in very small doses to help regulate the immune system and reduce inflammation. Standard-dose naltrexone is 50 mg and up per day; low-dose naltrexone is just 1/10th of that (or less), typically 0.5 mg to 4.5 mg per day.

While the higher dose is designed to block opioid receptors entirely, low-dose naltrexone serves an entirely different purpose. The low dose works to subtly nudge the immune system toward balance. It does this by modulating the body’s immune response and reducing persistent inflammation. Clinicians often aim for 3 to 5 mg daily, with 4.5 mg a common target in reports.

While LDN is not FDA-approved for these off label uses, forward-thinking clinicians have prescribed them to help treat autoimmune disorders, chronic pain, and even mood disorders. If you are exploring options, Shed offers access to low-dose naltrexone through licensed providers and related longevity treatments.

How does LDN work in the body?

LDN works by briefly blocking opioid receptors in the brain. This stimulates a rebound effect, causing the body to ramp up production of endorphins (the body’s natural “feel good” and anti-inflammatory chemicals) and opioid growth factor (a lesser-known molecule believed to play a role in immune regulation and cellular health). Researchers also suggest that low doses may calm overactive immune and glial pathways, including effects on microglia and Toll-like receptor 4. Preclinical pharmacology shows that naltrexone and its isomers can antagonize Toll-like receptor 4 (TLR4) on microglia, providing a plausible biochemical route for reducing neuroinflammation and central sensitization (pharmacological characterization of naltrexone isomers).

This temporary blockade helps reset immune signaling and reduce chronic inflammation over time. This type of treatment is especially promising for people with autoimmune conditions, chronic pain, and mood disorders.

How LDN differs from standard-dose naltrexone

• Standard-dose naltrexone, usually 50 to 100 mg daily, fully blocks opioid receptors and is used for opioid and alcohol dependence.
• Low-dose naltrexone, about 1 to 5 mg daily, is used for immune modulation, pain, and inflammation. The treatment goals and mechanisms differ, even though the base medication is the same.
• If you are researching weight or behavioral therapies, there is also a fixed-dose option that pairs naltrexone with bupropion. Learn more about naltrexone plus bupropion as a separate prescription.

What LDN is used for

While more research is needed, LDN is currently being explored in clinical trials and used off-label for a wide range of conditions. These include:

• Autoimmune diseases: MS, Hashimoto’s, lupus
• Chronic pain: fibromyalgia, complex regional pain syndrome (CRPS)
• Mood and mental health disorders: depression, anxiety, PTSD
• Long COVID and other post-viral symptoms
• Gut inflammation: IBS, Crohn’s disease, ulcers
• Hormone-related conditions: endometriosis, PCOS

Early studies and case series suggest possible improvements in pain, fatigue, sleep, and mood, but results vary. Larger randomized trials are still needed to confirm who benefits most and how best to dose over time. A comprehensive review concluded that mechanistic, safety, and small clinical-study data support LDN’s anti-inflammatory and analgesic potential across MS, Crohn’s disease, fibromyalgia, and related conditions, while emphasizing the need for larger randomized trials (systematic review of LDN efficacy and safety). Small randomized trials in fibromyalgia have also reported clinically meaningful reductions in daily pain and improved mood and life satisfaction with 4.5 mg/day LDN compared with placebo (Young et al., randomized crossover trial).

What to expect when taking LDN

LDN is usually prescribed as a compounded medication, in tablet form, prescribed through a licensed healthcare professional. It is taken once a day, often at night, with doses ranging from 0.5 mg to 4.5 mg. While dosing is determined by your healthcare provider, most people start with a small dose and gradually increase it until they have reached the prescribed amount. This ramp-up process typically takes about a month.

Most people tolerate LDN well, although mild side effects may occur. These include sleep disturbances, vivid dreams, nausea, and headaches, but side effects tend to fade quickly as your body adjusts to the medication. If you want a deeper overview of adverse effects, visit Shed’s guide to common side effects. LDN does not cause euphoria or dependence and is not habit-forming.

Practical dosing and titration tips

Your exact plan should be individualized by your clinician. A common approach:

• Start low: for example 0.5 to 1 mg nightly for 1 week
• Increase gradually: add 0.5 to 1 mg each week as tolerated
• Typical target: 3 to 4.5 mg daily, adjusted based on response
• If side effects occur: consider holding the dose or stepping back to a lower dose. Some patients do better around 3 mg if vivid dreams or headaches arise

Benefits can take several weeks. Give the plan time before deciding on long-term effectiveness.

Who should take LDN?

LDN is one of the lowest-risk prescription therapies available for inflammation and immune-related symptoms. However, it is not for everyone, and it is not a quick fix. Keep the following in mind before considering LDN:

• LDN is not for people actively taking opioid pain medications, as it blocks the effects of pain meds and may lead to withdrawal symptoms.
• LDN therapy is designed to build up over weeks or months. Some people notice improvements in a few weeks, but it may take 1 to 3 months to see significant benefits. Patience and consistency are very important for LDN treatment.

Talk to a provider who understands LDN before making any decisions. They can evaluate your needs and symptoms and see if LDN is a good fit for your health goals. To explore options with Shed, visit the LDN product page or browse related longevity offerings.

Safety, screening, and interactions

Before starting LDN, your clinician may review:

• Recent opioid use: Cctive opioid therapy is a contraindication, and recent use can precipitate withdrawal. Opioids generally need to be stopped or tapered about a week before starting naltrexone.
• Medical history: Prior liver problems, current mental health concerns, or hypersensitivity to naltrexone.
• Medications: Tramadol and other centrally acting analgesics require caution.
• Testing concerns: If workplace drug testing is a concern, discuss specifics with your clinician.

The official prescribing information for naltrexone lists active opioid therapy and opioid dependence as contraindications and recommends opioid-challenge testing or confirmed opioid-negative screens before initiating therapy to avoid precipitating withdrawal (naltrexone prescribing information). If serious side effects occur while taking naltrexone, contact your clinician promptly. For a broad overview, see Shed’s resource on common side effects.