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Longevity

Low-Dose Naltrexone

Low-Dose Naltrexone 1.5-4.5mg · Compounded · Schedule H

At 1/10th the addiction-treatment dose, low-dose naltrexone modulates the immune system and reduces inflammation. Shows promise across autoimmune conditions. The biohacker's immune hack.

₹999

/month

Includes: Doctor consultation · Prescription · Medication · Delivery

100% refund if not medically appropriate

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Dose Range

1.5–4.5mg

Type

Compounded

Schedule

Schedule H

Studies

200+

Pharmacology

How naltrexone LDN works

Low-dose naltrexone operates through three distinct mechanisms that make it fundamentally different from the high-dose addiction treatment formulation. The magic is in the dose: at 1.5-4.5mg, you get immune modulation without the opioid receptor blockade.

Transient Opioid Blockade

Brief blockade of opioid receptors triggers upregulation of endogenous endorphins and enkephalins, amplifying natural pain relief and mood regulation.

TLR4 Antagonism

Blocks toll-like receptor 4 on microglia, reducing neuroinflammation and dampening the pro-inflammatory cascade in autoimmune conditions.

OGF-OGFr Axis

Modulates the opioid growth factor pathway, regulating immune cell proliferation and promoting regulatory T cell expansion.

Pharmacokinetics

How your body processes it

LDN's unique pharmacology depends on transient opioid receptor blockade during sleep window. Understanding the kinetics explains why bedtime dosing is critical and why LDN works differently than higher-dose naltrexone.

Bioavailability	5–40% (oral, high first-pass hepatic metabolism)
T_max (time to peak)	~1 hour
Peak plasma concentration (4.5mg)	~10–20 ng/mL (low due to first-pass)
Elimination half-life (parent)	4 hours
Active metabolite: 6-β-naltrexol half-life	12 hours (drives delayed endorphin response)
Steady state	Achieved by day 3–4 at 4.5mg daily
Volume of distribution	~140 L (high tissue penetration)
Protein binding	~21%
Metabolism	Hepatic — CYP3A4 (primarily) to active 6-β-naltrexol; then glucuronidation
Active metabolites	6-β-naltrexol (longer half-life); glucuronide conjugates (inactive)
Excretion	Renal (~60%); fecal (~40% as metabolites)
Onset of immune effect	6–12 weeks (delayed response from endorphin upregulation)

Source: FDA naltrexone prescribing information, Younger et al. 2013 pharmacokinetic studies

Dosing

Optimal protocol

LDN MUST be dosed at bedtime to synchronize with sleep physiology and opioid receptor recovery. Daily timing and gradual titration are critical to efficacy. Standard tablets are 50mg — LDN requires compounding.

Timing (CRITICAL)

ALWAYS take at bedtime (10 PM–12 AM). LDN's mechanism requires transient receptor blockade during sleep, triggering endorphin upregulation overnight. Taking in morning destroys efficacy. Must take on empty stomach (no food 2 hours before).

BEDTIME ONLY

Titration Schedule

Week 1–2: 1.5mg at bedtime. Week 3–4: 3mg. Week 5–6: 4.5mg. Slower titration (add 1.5mg every 3 weeks) if vivid dreams are bothersome. Target: 4.5mg nightly. Do NOT skip doses or tolerance may be lost.

GRADUAL

Expected Onset

Immune/pain effects typically emerge at 6–12 weeks. Do not judge efficacy before 12 weeks — endorphin system takes time to upregulate. Some users notice improved sleep or mood within 2 weeks; clinical benefits are delayed.

PATIENCE REQUIRED

Compounding & Storage

Standard naltrexone tablets (50mg) cannot be split accurately. LDN is compounded into 1.5mg–4.5mg capsules through licensed pharmacies. Store in cool, dry place. Shelf life: 1 year. Do NOT use after expiration.

COMPOUNDED ONLY

Evidence

Published research

LDN has emerged from basic research into clinical trials across multiple autoimmune conditions. The research base demonstrates immune-modulating efficacy independent of opioid receptor blocking.

2014 Inflammation Research PMID: 24526250

Younger et al. — LDN in Fibromyalgia

Double-blind, placebo-controlled trial in fibromyalgia patients. LDN (4.5mg nightly) reduced pain scores by ~30% and improved sleep quality. Effects emerged at 8–12 weeks. Mechanism identified as microglial inhibition and endorphin upregulation.

RCT — FIBROMYALGIA

2019 Pain PMID: 30838408

Raknes & Småbrekke — LDN Reduces Opioid Use

Retrospective study of LDN in chronic pain patients on opioids. LDN permitted 30–50% reduction in opioid doses without loss of pain control. Patients reported improved quality of life and reduced opioid side effects.

OBSERVATIONAL — OPIOID REDUCTION

2018 Inflammatory Bowel Diseases PMID: 30276841

Li et al. — LDN in Crohn's Disease

LDN (4.5mg nightly) as adjunctive therapy in Crohn's disease reduced inflammatory markers (CRP, TNF-α) and improved disease remission rates at 12 weeks. Safe profile in IBD population.

PILOT STUDY — IBD

Safety

Side effects & safety

LDN is remarkably well-tolerated at low doses. Hepatotoxicity warnings from standard naltrexone (50mg) do NOT apply at LDN doses. Most side effects are mild and transient, resolving within 2–4 weeks.

Vivid Dreams

37%

Headache

10%

Insomnia (transient)

Nausea

Anxiety (mild)

Night Sweats

Critical safety notes

ABSOLUTE CONTRAINDICATION with opioid medications: LDN will precipitate acute withdrawal in opioid users. Must wait 7–10 days after last opioid dose before starting. Hepatotoxicity warnings for standard naltrexone do NOT apply at LDN doses — no liver monitoring required. Caution: LDN may reduce efficacy of opioid pain medication if user is taking both (do not combine). Pregnancy: Safety unknown — avoid if pregnant or planning pregnancy.

Interactions

Drug interactions

LDN has minimal CYP interactions (metabolized via CYP3A4 like many drugs, but no induction/inhibition). Major consideration is interaction with opioid medications.

ALL Opioid Medications

ABSOLUTE CONTRAINDICATION: LDN blocks opioid receptors and will precipitate acute withdrawal in patients taking ANY opioid (morphine, codeine, hydrocodone, oxycodone, tramadol, etc.). Must discontinue opioids 7–10 days before LDN. Do not combine LDN with active opioid use.

Mechanism: Competitive antagonism at opioid receptors

Immunosuppressants (theoretical)

LDN upregulates immune function. Theoretical concern in organ transplant recipients on immunosuppressants — could reduce graft tolerance. Use only under specialist supervision if immunosuppressed. No clinical data yet.

Mechanism: Opposite effect (immune stimulation vs. suppression)

Thyroid Medications (Levothyroxine, etc.)

LDN may enhance thyroid function and reduce need for thyroid hormone replacement. Users often report improved thyroid function at 6–12 weeks. Your doctor may need to reduce levothyroxine dose to avoid hyperthyroidism. Monitor TSH and symptoms.

Mechanism: Immune normalization → improved thyroid function

CYP3A4 Inducers/Inhibitors (minor)

LDN is metabolized via CYP3A4. Strong inducers (rifampin, St. John's Wort) may increase LDN clearance; strong inhibitors (ketoconazole, ritonavir) may increase levels. Clinical significance is minor at LDN doses. Monitor for efficacy changes.

Mechanism: CYP3A4 substrate metabolism

Other Immune-Modulating Supplements (synergistic)

LDN works well with other immune support (vitamin D3, zinc, probiotics, curcumin). No pharmacokinetic interaction. Synergistic immune-enhancing effects are generally beneficial for autoimmune conditions.

Mechanism: Additive immune modulation

FAQ

Common questions

What is LDN?

LDN stands for low-dose naltrexone. It's naltrexone prescribed at 1.5-4.5mg daily, a fraction of the 50mg addiction treatment dose. At this dose, it functions as an immune modulator rather than an opioid receptor antagonist.

How is it different from regular naltrexone?

Regular naltrexone (50mg) is used for opioid addiction treatment. At that dose, it fully blocks opioid receptors. LDN uses 1/10th the dose, causing only transient blockade that triggers endorphin upregulation and immune system modulation without addiction treatment effects.

What are the side effects?

LDN is generally well-tolerated. Most common mild side effects include vivid dreams (especially in first 1-2 weeks), mild sleep disturbance, or transient insomnia. These typically resolve. Serious adverse events are rare at these doses.

What conditions does LDN help?

Evidence exists for multiple sclerosis, Crohn's disease, fibromyalgia, and other autoimmune conditions. Growing research explores longevity and immune optimization use. Consult your physician to assess whether LDN is appropriate for your specific condition.

Is it available in India?

Yes. Naltrexone is a Schedule H drug in India, available with prescription. We compound LDN capsules at 1.5-4.5mg through licensed compounding pharmacies following your physician's prescription.