How Long Does It Take Low Dose Naltrexone (LDN) to Work?


Naltrexone, a medication primarily known for its use in treating opioid and alcohol addiction, has gained attention in lower doses for a range of conditions. How does this medication function, and how long does it take low dose naltrexone to work? Dive in to understand the nuances of Low Dose Naltrexone.


What is Naltrexone, and How Does it Work?

Naltrexone is an opioid antagonist. It works by binding to opioid receptors in the brain, blocking the effects of opioids and alcohol. By doing this, it helps reduce cravings and the rewarding effects of these substances, making it a vital tool for recovery.

What is the Regular Naltrexone Dose?

The typical dosage for naltrexone when treating alcohol or opioid addiction ranges from 50mg to 100mg daily. It’s prescribed as part of a comprehensive treatment plan that includes counseling and support.

What is Low Dose Naltrexone (LDN)?

Low Dose Naltrexone (LDN) refers to a reduced dosage of the opioid antagonist, typically ranging between 1mg to 4.5mg. Unlike its standard dosage, LDN is believed to modulate the immune system and exhibit anti-inflammatory properties, making it a potential therapeutic option for various conditions beyond addiction.

What are the Side Effects of Low Dose Naltrexone?

While LDN is generally well-tolerated, some users report side effects, including:
Vivid dreams: Some users experience more vivid or unusual dreams.
Possible headaches: Initial days might see an increase in headaches.
Loss of Appetite: A reduced desire to eat might be noted.
Nausea: Some individuals might feel queasy, especially when starting.
Insomnia: Sleep disturbances can occasionally occur.
Hallucinations: Rare, but some report altered perceptions.
Unwanted Weight-Loss: Due to appetite changes, weight loss might occur.
Vomiting: In rare cases, severe nausea might lead to vomiting.

How Long Does it Take Low Dose Naltrexone to Work?

Low Dose Naltrexone (LDN) varies in its onset of action among individuals. While some might observe benefits within a few days, for others, it may take several weeks. Regular monitoring and potential dose adjustments are crucial to optimizing its therapeutic effect.

Understanding the duration of the Low Dose of Naltrexone (LDN) to work is crucial for optimal therapeutic outcomes. This knowledge helps patients set realistic expectations and enhances treatment adherence.

Furthermore, healthcare providers can monitor and adjust dosages more effectively, ensuring safety and efficacy.

What is Low Dose Naltrexone Used For?

LDN’s immune-modulating properties have expanded its potential applications. Let’s explore some of these conditions.

  • Fibromyalgia and Chronic Fatigue Syndrome: LDN may reduce pain and fatigue associated with these conditions.
  • Naltrexone for Inflammation: LDN can be highly useful in combatting inflammation.
  • Pain: LDN can be an adjunct to chronic pain management, offering an alternative to opioids.
  • Cholestatic Pruritus: Preliminary research suggests LDN might reduce itching in liver conditions.
  • Obesity: Some studies indicate LDN might help with weight management.
  • Autoimmune Disorders: LDN may downregulate auto-immune responses, benefiting conditions like Multiple Sclerosis.
  • Depression: There’s emerging evidence that LDN could assist in managing depressive symptoms.
  • Post-Traumatic Stress Disorder (PTSD): LDN is being explored as a potential adjunct therapy.
  • Autism: Some parents report improvements in behaviors, though research is ongoing.
  • Cancer: Some lab studies suggest that LDN might be a potential cancer treatment. However, there have yet to be extensive human trials to validate this claim.
What are the Side Effects of Low Dose Naltrexone?

How Long Does LDN Stay in Your System?

So how long does low dose naltrexone stay in your system? The half-life of a drug indicates the time for its blood concentration to decrease by half. For Naltrexone in pill form, its half-life is 4-6 hours, leading to full elimination in about 20-30 hours.

In its extended-release version, the half-life extends to 5-10 days, meaning it could stay in the body for 25-50 days.

However, factors like liver health, genetics, and muscle mass can influence these durations. Always consult with a medical expert before taking any medication.

How is Low-Dose Naltrexone Dosed for Fibromyalgia?

The question of how long does it take for LDN to work has become common among people. The answer is administering LDN begins at a modest amount, often around 1mg. This dosage is then gradually increased based on individual response and tolerance.

The objective is to identify the most effective dosage while minimizing potential side effects. Regular consultations with a healthcare specialist are essential throughout this process.

Naltrexone vs Low-Dose Naltrexone?

While both forms bind to opioid receptors, their purposes differ. Regular naltrexone aims to prevent opioid and alcohol effects, while LDN focuses on immune regulation and anti-inflammatory actions.

How to Prevent LDN Side Effects?

Starting at a low dose and gradually increasing, taking it with food, and monitoring regularly with a physician can help mitigate potential side effects.

What to Avoid When Taking Low Dose Naltrexone?

It’s essential to avoid opioid medications while on LDN, as it can block their effects. Alcohol consumption should be limited or monitored, and any new medication should be discussed with a healthcare provider.

Who Should Use and Who Should Avoid Low Dose Naltrexone?

LDN can benefit various conditions, but it’s not for everyone. Those with liver diseases, opioid dependency, or pregnant women should avoid it. Always consult a healthcare professional before starting.


Naltrexone for depression or anxiety may work for some individuals, but its effectiveness can vary. Consult a healthcare professional for guidance on its use.

While they are the same medication, the dosages and purposes differ. Regular naltrexone is used in higher doses, primarily for addiction treatment. LDN, as the name suggests, employs a much lower dose and serves different therapeutic purposes, such as immune system modulation.

While LDN can be taken with many medications, it’s essential to consult with your healthcare provider. LDN can interact with certain drugs, especially opioids, potentially diminishing their efficacy or causing adverse reactions.

Yes, LDN is a prescription medication. It’s crucial to obtain it through legitimate channels under the guidance of a healthcare professional to ensure the proper dosage and monitoring.

If you’re considering discontinuing LDN or any medication, it’s always best to consult your healthcare provider. They can guide whether a gradual tapering is necessary and monitor any potential withdrawal symptoms or side effects.

Yes, low dose naltrexone weight loss works in a way that it controls appetite. However, it’s best to consult your healthcare provider before taking any doses. 


Low Dose Naltrexone (LDN) has emerged as a transformative medication, lauded for its immune-regulating capabilities. Its effects, however, take time and effort; they can manifest anywhere from a few days to weeks.

Due to this variable response and its myriad applications, engaging with a healthcare specialist is crucial. This ensures individuals receive personalized guidance, optimizing the potential benefits of LDN.

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