Low-Dose Naltrexone dosage

Protocol

1. 1

   Measure the dose

   Typical Low-Dose Naltrexone dose is 4.5 mg. Use a weight-based calculator for individual adjustments.

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2. 2

   Set the frequency

   Administer once daily, typically at bedtime. Half-life of 4 hours anchors the dosing interval.

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3. 3

   Cycle if needed

   No formal cycling; some practitioners run 1 to 2 week washouts to assess benefit attribution

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4. 4

   Monitor for side effects

   Watch for: vivid dreams; sleep disruption; headache; mild GI upset. Stop or reduce dose if tolerability breaks down.

Why this dose

Brief mu-opioid receptor antagonism proposed to trigger compensatory upregulation of endogenous opioids; secondary TLR4 antagonism on microglia and immune cells contributes to anti-inflammatory effect.

The typical 4.5 mg dose is the figure most commonly used in published protocols for Low-Dose Naltrexone. Treat the label as a starting point: body weight, training status, sleep, diet, and concurrent medications all shift the effective dose-response curve in real users.

How to administer

Low-Dose Naltrexone is administered via the oral route. Oral dosing is straightforward: take with water, with or without food unless specifically noted.

Onset of action runs around 1 hour after administration. Peak effect lands near 1.5 hours post-dose. Plan the administration window so that peak effect lines up with whatever outcome you are dosing for, whether that is training, sleep, or symptom coverage.

Half-life note: Naltrexone half-life ~4 hours; active metabolite 6-beta-naltrexol ~13 hours; brief plasma exposure aligns with proposed rebound mechanism

Cycling and tolerance

No formal cycling; some practitioners run 1 to 2 week washouts to assess benefit attribution

Effects to expect at typical dose

• Off-label use at 1.5 to 4.5 mg, roughly one-tenth the FDA-approved 50 mg addiction-treatment dose
• Proposed mechanisms include brief opioid receptor blockade triggering rebound endogenous opioid release, plus TLR4 antagonism
• Compounded prescription only; insurance rarely covers; cash prices 20 to 80 USD per month
• Younger 2013 reported ~30% pain reduction in fibromyalgia at 4.5 mg in a small crossover trial
• Smith 2011 reported endoscopic improvement in active Crohn's disease (n=40 placebo-controlled)
• Vivid dreams affect 20 to 40% in first 2 weeks; manageable by switching to morning dosing

Side effects and interactions

Common side effects

• vivid dreams
• sleep disruption
• headache
• mild GI upset
• fatigue (early)

Notable interactions

• opioid analgesics (oxycodone, morphine, codeine) (major): blocks analgesic effect; precipitates withdrawal in dependent users
• tramadol (major): blocks opioid component of analgesia
• thyroid hormone replacement (minor): may alter dose requirements after immune modulation; monitor TSH

Lists above cover commonly reported and well-characterized items. They are not exhaustive: review the full Low-Dose Naltrexone profile and discuss with a clinician familiar with your medication list before starting, particularly if you are on prescription therapy or have a chronic condition.

Regulatory snapshot

WADA status

allowed

DEA / Rx

Rx only (not a controlled substance)

Pregnancy

Insufficient data; not routinely recommended

Legal status

Off-label compounded prescription (naltrexone is FDA approved for opioid and alcohol use disorder at 50 mg)

Do not use if

• concurrent opioid use
• acute hepatitis or liver failure
• opioid dependence
• pregnancy (insufficient data)

Related research