Low-Dose Naltrexone Dosage: A Complete Reference to LDN Dosing and Titration

The Short Answer

Low-dose naltrexone (LDN) is most commonly dosed at 1.5 mg to 4.5 mg taken once daily, started at the low end and titrated up over 3–4 weeks.

The standard titration schedule, used in most clinical trials and recommended by the American Academy of Family Physicians, is:

Week: Daily Dose

• Week 1: 1.5mg daily
• Week 2: 3.0mg daily
• Week 3: 4.5mg daily
• Week 4 and beyond: 4.5mg (target dose)

This is the most widely used schedule, but it is not the only one—and emerging clinical evidence suggests that the most effective dose is highly individual. Some patients respond best at 1.5 mg, others at 4.5 mg, and a meaningful subset at doses outside this range entirely (0.5–6 mg/day).

The rest of this article walks through dosing by condition, formulation differences (capsule, liquid, troche), timing considerations (morning vs nightly), what to do when standard dosing isn't working, and how dosing is adjusted in special populations.

Why LDN Has a Different Dosing Logic Than Most Medications

Most medications follow a simple principle: a higher dose produces a stronger effect, up to a maximum tolerated dose. LDN does not work this way.

At its FDA-approved 50 mg/day dose, naltrexone produces sustained opioid receptor blockade—the basis of its use in treating opioid and alcohol use disorder. At 1.5–4.5 mg/day, naltrexone produces only brief, partial opioid receptor blockade that triggers a compensatory upregulation of endogenous opioid signaling. It also acts on microglial cells through a separate non-opioid mechanism, reducing neuroinflammation.

These two low-dose mechanisms together produce LDN's clinical effects. Increasing the dose beyond 4.5 mg/day does not strengthen these effects—and in many patients, higher doses actually reduce benefit by approaching the sustained-blockade range where naltrexone behaves more like its addiction-treatment dose.

This is why LDN dosing is not "as high as you can tolerate." It is "the dose that engages the low-dose mechanisms most effectively for this individual."

For a fuller treatment of LDN's mechanisms, see our evidence-based guide to LDN benefits.

Standard LDN Titration Schedule

The standard schedule used in most clinical practice and reflected in published trials and clinical guidance:

Week 1: 1.5 mg daily

Most patients start at 1.5 mg nightly. This starting dose is low enough that almost all patients tolerate it, while still being a therapeutically meaningful dose. The first week is primarily for confirming tolerance—particularly for sleep effects, which can include vivid dreams in some patients.

Week 2: 3.0 mg daily

If 1.5 mg was tolerated without significant side effects, the dose increases to 3 mg nightly. This is the dose where many patients begin to notice early effects, particularly on sleep quality and mood.

Week 3: 4.5 mg daily

The dose advances to 4.5 mg nightly, the target dose used in the majority of published LDN trials. Most clinical effects emerge over the following weeks at this dose.

Week 4 and beyond: 4.5 mg daily (or individualized)

For most patients, 4.5 mg becomes the maintenance dose. Clinical effects on pain, inflammation, fatigue, and quality of life typically develop over the next 4–12 weeks. Patients who do not respond after 8–12 weeks at 4.5 mg often try variations on the standard regimen (different timing, divided dosing, or alternative dose levels) before discontinuing.

When to Slow the Titration

For patients with sensitivity to medications, autonomic disorders (POTS, dysautonomia), severe ME/CFS, or significant prior medication intolerance, a slower titration may be more appropriate:

• Week 1: 0.5mg daily
• Week 2: 1.0mg daily
• Week 3: 1.5mg daily
• Week 4: 2.0 mg daily
• Week 5:  2.5mg daily
• Week 6+ Continue increasing by 0.5mg every 1-2 weeks to target

This "low and slow" approach can take 6–10 weeks to reach target but substantially reduces the rate of patients discontinuing due to side effects.

LDN Dosing by Condition

The "right" LDN dose can vary meaningfully by the condition being treated. The following table summarizes the doses used in the major clinical trials and current clinical practice for each major indication.

Fibromyalgia

• Typical effective dose: 4.5 mg/day
• Range reported in studies: 3–4.5 mg/day
• Notes: Strongest evidence base; standard titration schedule applies

Crohn's disease

• Typical effective dose: 4.5 mg/day
• Range reported: 3–4.5 mg/day
• Notes: Often used as adjunct to standard IBD therapy

Ulcerative colitis

• Typical effective dose: 4.5 mg/day
• Range reported: 3–4.5 mg/day
• Notes: Less developed evidence than Crohn's; same dosing applies

Multiple sclerosis

• Typical effective dose: 3–4.5 mg/day
• Range reported: 1.5–4.5 mg/day
• Notes: Used as symptomatic management; not a disease-modifying therapy replacement

Long COVID

• Typical effective dose: 1–4.5 mg/day
• Range reported: 0.5–4.5 mg/day
• Notes: Often requires slower titration; a meaningful subset of patients respond at lower doses than the fibromyalgia population

ME/CFS (myalgic encephalomyelitis / chronic fatigue syndrome)

• Typical effective dose: 1.5–4.5 mg/day
• Range reported: 0.25–6 mg/day
• Notes: Highly individualized; many patients are sensitive to dose increases and benefit from slower titration

CRPS and neuropathic pain

• Typical effective dose: 4.5 mg/day
• Range reported: 0.1–6 mg/day
• Notes: A 2024 observational study found effective doses ranged widely; individualization is key

Major depressive disorder (adjunctive)

• Typical effective dose: 1 mg twice daily
• Range reported: 1–4.5 mg/day
• Notes: The original 2017 randomized trial used 1 mg twice daily; some clinicians use the standard 4.5 mg/day schedule instead

Chronic pelvic pain and endometriosis

• Typical effective dose: 4.5 mg/day
• Range reported: 1.5–4.5 mg/day
• Notes: Emerging evidence; standard titration schedule applies

Hashimoto's thyroiditis

• Typical effective dose: 3–4.5 mg/day
• Range reported: 1.5–4.5 mg/day
• Notes: Mixed evidence; standard titration schedule applies

Important context on the dose ranges. A 2024 observational study in Pain Research of 41 patients with chronic musculoskeletal pain found that effective LDN doses ranged from 0.1 mg/day to 6 mg/day, with substantial inter-patient variability [1]. The authors concluded that the maximally effective dose is "idiosyncratic" and recommended dose titration to establish individual response rather than fixed dosing.

This finding is important. The 4.5 mg "standard" dose is the most studied, but it is not necessarily optimal for every patient.

Morning vs Nightly Dosing

Most LDN protocols have historically used nightly dosing, primarily by convention dating back to Dr. Bernard Bihari's original 1980s observations. Current clinical evidence does not establish a single optimal timing—both work, and the choice depends mostly on side effects and patient preference.

Nightly dosing (most common):

• Default starting approach for most patients
• May produce vivid dreams or sleep disturbance, particularly in the first 1–2 weeks
• These side effects usually resolve with continued use

Morning dosing:

• Equal efficacy to nightly dosing in clinical observation
• Preferred for patients who experience persistent vivid dreams or sleep disruption
• May be better tolerated by patients with ME/CFS or autonomic disorders who are sensitive to evening dosing

Divided dosing (twice daily):

• Some patients respond better to split doses (e.g., 1.5 mg morning + 1.5 mg evening, or 2.25 mg twice daily)
• More common for ME/CFS, chronic fatigue, and pain conditions where shorter dose intervals appear to maintain steadier effects
• Used in the 2017 randomized depression trial (1 mg twice daily) [2]

A reasonable approach: start with nightly dosing as the default, and switch to morning dosing if sleep issues persist after 2–3 weeks. Consider divided dosing if neither timing produces adequate response.

LDN Formulations: Capsule, Liquid, and Troche

LDN is not commercially available at therapeutic dosages—the FDA-approved naltrexone tablets are 50 mg, far higher than off-label use requires. As a result, LDN must be prepared by a 503A compounding pharmacy in custom strengths.

The main formulation options:

Compounded Capsules

The most common formulation. Available in custom strengths including 0.5 mg, 1 mg, 1.5 mg, 3 mg, 4.5 mg, and other amounts. Generally well-absorbed orally with predictable pharmacokinetics. Most clinical trials have used capsule formulations.

Practical advantages: Familiar, easy to dose, predictable absorption, widely available from compounding pharmacies.

Limitations: First-pass metabolism through the liver reduces bioavailability somewhat; for patients with significant GI dysfunction (e.g., severe Crohn's, gastroparesis), absorption may be variable.

Compounded Liquid

Liquid formulations allow finer dose adjustments—useful for slow titration starting at 0.25 or 0.5 mg, and for patients who need doses outside standard capsule strengths. Same pharmacokinetics as capsules.

Practical advantages: Highly flexible dosing, useful for sensitive patients.

Limitations: Refrigeration may be required; some patients find the taste unpleasant.

Troches (Sublingual Lozenges)

LDN troches dissolve under the tongue, allowing absorption through the oral mucosa rather than passing through the GI tract. This bypasses first-pass liver metabolism and produces faster onset and potentially more predictable absorption.

Practical advantages:

• Faster onset (typically 15–30 minutes vs 60+ minutes for capsules)
• More predictable absorption, particularly useful for patients with GI dysfunction
• May allow lower effective doses due to higher bioavailability
• Useful for patients who cannot tolerate capsules

Limitations:

• Generally higher cost than capsules
• Requires holding under tongue for 5–10 minutes, which not all patients prefer
• Less widely available

Bioavailability differences mean that troche doses are not directly equivalent to capsule doses on a milligram basis. Patients switching between formulations should expect a brief titration to find the equivalent effective dose.

For a complete treatment of troche delivery and its mechanistic advantages, see our research review on LDN troche delivery.

What to Do When Standard Dosing Isn't Working

A meaningful subset of patients do not respond well to the standard 1.5 mg → 3 mg → 4.5 mg nightly schedule. Several variations are worth considering before concluding that LDN is not effective:

1. Try Different Timing

Switch from nightly to morning dosing, or vice versa. This single change resolves issues for many patients, particularly those with persistent vivid dreams (try morning) or those with daytime fatigue from the medication (try nightly).

2. Switch to Divided Dosing

Split the daily total into two doses (morning + evening). Patients with shorter half-life response or those who feel the medication "wears off" before the next dose often do better with split dosing.

3. Adjust the Target Dose

The 4.5 mg standard is a population average, not an individual prescription. Some patients respond best at lower doses (1.5–3 mg/day), others at higher doses (up to 6 mg/day in some clinical observation). Trial-and-error with the prescribing clinician can identify the individual optimal dose.

4. Change the Formulation

Patients on capsules who have not responded after 8–12 weeks may benefit from a switch to troches, which provide more predictable absorption and bypass first-pass metabolism. Conversely, patients on troches who experience irritation or absorption inconsistency may do better on capsules.

5. Reassess Tolerance and Side Effects

Persistent side effects may be limiting the dose patients can tolerate. Slower titration, dose reduction, or formulation change can sometimes resolve these issues and allow the patient to reach a therapeutic dose.

6. Consider Whether LDN Is Appropriate

Some patients will not respond to LDN regardless of dose or formulation. Across major indications, response rates are typically 40–70%, meaning 30–60% of patients do not benefit. Patients with no response after 3–4 months of adequate trial across dose variations generally discontinue.

Dosing in Special Populations

Older Adults

LDN is generally safe in older adults at standard doses. Some clinicians use slightly slower titration (advancing every 2 weeks rather than weekly) to confirm tolerance, but the target dose of 4.5 mg/day is typically maintained.

Patients with Renal Impairment

Naltrexone is metabolized primarily by the liver, not the kidneys, so significant renal dose adjustment is generally not required. Patients with severe renal disease should still be evaluated individually by the prescribing clinician.

Patients with Hepatic Impairment

LDN is metabolized in the liver. Patients with significant hepatic impairment may require dose adjustment or close monitoring. Acute hepatitis is a contraindication.

Pregnancy and Breastfeeding

Insufficient safety data exists for LDN during pregnancy or breastfeeding. The medication is generally avoided in both situations.

Patients on Opioids

Concurrent opioid use is the primary contraindication for LDN. Patients taking prescription opioids for pain management cannot start LDN without first transitioning off the opioid, with sufficient washout time (typically 7–10 days for short-acting opioids, longer for long-acting). The opioid blockade, even at low doses, can precipitate withdrawal.

Patients on partial agonists like buprenorphine or tramadol require careful evaluation by the prescribing clinician before LDN can be considered.

Patients on Other Medications

LDN has relatively few significant drug interactions. Most antidepressants, anti-inflammatories, biologics, DMARDs, and chronic disease medications are compatible with LDN. The prescribing clinician should review all concurrent medications, but the typical patient on multiple medications can usually take LDN safely.

How Long Does It Take LDN to Work?

This depends on the condition and what improvement is being measured:

• Sleep changes (often the first to shift): 1–3 weeks
• Mood improvements: 2–6 weeks
• Pain reduction (fibromyalgia, chronic pain): 4–8 weeks
• Inflammatory bowel disease activity: 6–12 weeks
• Fatigue (ME/CFS, long COVID): 4–16 weeks
• Autoimmune disease symptoms: 8–24 weeks

Patients should generally trial LDN at target dose for at least 8–12 weeks before concluding it is not effective for their condition. For ME/CFS and autoimmune conditions specifically, longer trials (16–24 weeks) are often appropriate before discontinuation.

Cost of LDN

Compounded LDN is relatively affordable compared with most chronic disease medications:

• Capsules (typical 4.5 mg, 30-day supply): $30–$60/month
• Liquid: $35–$75/month
• Troches: $50–$120/month
• Insurance coverage: Variable; many insurance plans do not cover compounded LDN, but cash prices are manageable for most patients

Out-of-pocket costs are typically lower than name-brand medications for similar indications (e.g., pregabalin for fibromyalgia, biologics for IBD).

For a comparison of how LDN dosing fits into broader treatment cost considerations, see our LDN benefits guide.

Frequently Asked Questions

What is the typical dose of low-dose naltrexone?

Most patients take 4.5 mg once daily, reached through a standard 3-week titration starting at 1.5 mg. Effective doses range from 0.5 mg to 6 mg per day depending on the individual and the condition being treated, with 4.5 mg being the most widely used and most studied target dose.

How do I titrate LDN?

The standard titration is 1.5 mg in week 1, 3 mg in week 2, and 4.5 mg in week 3 and beyond. For sensitive patients, a slower titration starting at 0.5 mg and increasing by 0.5 mg every 1–2 weeks can be used.

Should I take LDN in the morning or at night?

Both work. Nightly dosing is the traditional default and is used in most clinical trials. Morning dosing is preferred for patients who experience vivid dreams or sleep disturbance on nightly dosing. Some patients do best with divided dosing (twice daily).

What is the maximum dose of LDN?

The standard maximum is 4.5 mg/day, though some patients respond better at 6 mg/day or in divided regimens up to 9 mg/day total. Above approximately 6 mg/day, the medication begins to behave more like its standard 50 mg dose, losing the unique low-dose effects.

Can I take more than 4.5 mg of LDN?

In some cases, yes—but only under physician supervision. The standard target dose is 4.5 mg, and increasing beyond this does not reliably increase benefit. Some patients with refractory symptoms or severe pain conditions are tried at 6 mg/day, but doses meaningfully higher than this approach the threshold where LDN's unique mechanisms begin to fade.

What if I miss a dose?

A missed dose of LDN is generally not a significant issue. Most patients simply take the next dose at the regular time the following day. There is no need to "make up" for a missed dose with a double dose.

How long does LDN take to start working?

For sleep and mood, 1–3 weeks. For pain conditions like fibromyalgia, typically 4–8 weeks at target dose. For autoimmune and inflammatory conditions, the full effect may take 3–6 months. Most clinicians recommend at least 8–12 weeks at 4.5 mg/day before concluding LDN is not working.

What's the best LDN dose for fibromyalgia?

4.5 mg daily, reached through standard titration, is the dose most studied in fibromyalgia trials and the most common effective dose. Some fibromyalgia patients respond at lower doses (3 mg/day); a smaller subset benefits from slightly higher doses (6 mg/day).

What's the best LDN dose for Crohn's disease?

4.5 mg daily, consistent with the doses used in published trials and current clinical practice. Some IBD specialists use divided dosing (2.25 mg twice daily) for patients with severe symptoms.

What's the best LDN dose for long COVID?

Long COVID patients often benefit from slower titration and lower initial target doses. Many start at 0.5–1 mg and titrate slowly to 3–4.5 mg/day. A meaningful subset of long COVID patients respond at lower doses (1–3 mg/day) than the fibromyalgia population.

Why do some studies use 4.5 mg and others use different doses?

The 4.5 mg dose was used in Dr. Bernard Bihari's original observations and has been carried forward as the standard in most trials. Other doses (1 mg twice daily for depression, 3 mg for some MS protocols, lower doses for very sensitive patients) reflect refinements based on specific conditions and patient populations. A 2024 observational study found that effective doses are highly individual and can range from 0.1 to 6 mg/day.

Does LDN dose need to be adjusted with body weight?

Generally no. Unlike many medications, LDN is typically dosed at a fixed amount (4.5 mg) regardless of body weight, because the relevant pharmacological window is not strictly proportional to body mass. Individual variation in metabolism is more important than body weight in determining the effective dose.

How do I know if my LDN dose is right?

The most reliable indicator is clinical response: improvements in the symptoms LDN is being used to treat (pain, sleep, fatigue, inflammation, mood). If symptoms have not improved after 8–12 weeks at 4.5 mg, the dose, timing, or formulation can be adjusted.

Is it better to take LDN as a capsule, liquid, or troche?

Capsules are the most studied and most common formulation. Troches offer faster onset and may be more reliable for patients with GI absorption issues. Liquid is useful for highly individualized dosing. All three formulations are effective; the choice depends on individual preference, absorption considerations, and cost.

Can I stop LDN suddenly, or do I need to taper?

LDN does not require tapering. The medication can be stopped at any time without withdrawal effects. Some patients prefer to taper to assess whether symptoms return, but a hard stop is also safe.

How Healthspan Approaches LDN Dosing

The Healthspan LDN Protocol provides physician-supervised LDN with individualized dose titration based on the patient's condition, prior medication tolerance, and clinical response. Our approach includes:

• Baseline assessment of condition, concurrent medications, and contraindications
• Personalized starting dose and titration schedule (standard 1.5 mg increments, slow titration, or other variations as appropriate)
• Capsule formulation by default, with troche option available where indicated
• Follow-up assessment at 6 weeks and beyond to evaluate response and adjust dose if needed
• Coordination with other prescribers for patients managing multiple conditions

For patients who may benefit from troche delivery specifically, our LDN Troche Protocol offers the same physician oversight with the sublingual formulation.

Conclusion

The "standard" 1.5 → 3 → 4.5 mg titration schedule works well for the majority of LDN patients, and 4.5 mg daily remains the most evidence-supported maintenance dose across most conditions. But the current understanding of LDN dosing is more nuanced than a single number. Effective doses are individual. Timing matters. Formulation matters. Slow titration matters for sensitive patients. And the difference between a successful LDN trial and a failed one often comes down to whether the dose was adjusted thoughtfully across these variables, not just whether 4.5 mg was tried for 12 weeks.

For patients considering LDN, the practical implications are: start with the standard schedule, give it adequate time at target dose, and work with a prescribing clinician willing to individualize the regimen if standard dosing doesn't produce the expected response. For most patients, this approach finds the dose that works—and for those it doesn't, the lack of response is usually attributable to the underlying biology rather than to inadequate dose optimization.

Related Research

• Low-Dose Naltrexone Benefits: An Evidence-Based Guide to LDN's Clinical Uses
• The Multidimensional Benefits of Low-Dose Naltrexone: Pain, Fatigue, and Mental Health
• LDN Troche Delivery: A Research Review
• LDN for Long COVID: A Comprehensive Relief Guide
• Understanding LDN's Impact on Chronic Inflammatory Diseases
• Low-Dose Naltrexone in Chronic Disease Management: A Healthspan Review
• Low Dose Naltrexone for Autoimmune Disease: Hype or Legit?