Protocol

Low-dose naltrexone (LDN)

LDN · naltrexone low dose · low-dose naltrexone

There is no human trial of LDN with a longevity or healthspan endpoint. The only lifespan evidence is invertebrate: a 2024 iScience study reported a 17.6 percent median lifespan extension and improved mobility in C. elegans at 2.5 micromolar via SKN-1 (the worm NRF2 orthologue), with no benefit at high dose. That is a worm result, not a mammalian or human one. In humans the best-developed dataset is fibromyalgia pain, where a 2025 systematic review and meta-analysis of five RCTs found a significant reduction in pain scores but small samples and limited robustness. For long COVID a 2025 systematic review found zero RCTs, only four observational pre-post studies (n=155), with low certainty of evidence. A 2026 narrative review in Advances in Therapy covering 105 studies including 15 RCTs concluded that early positive uncontrolled findings were rarely replicated in placebo-controlled trials and that the literature is dominated by case reports and small feasibility studies prone to publication bias. What the evidence does NOT show: any effect on ageing biomarkers, biological age, mortality, or any healthspan outcome in humans. Anyone presenting LDN as a longevity intervention is extrapolating from a worm study and an anti-inflammatory mechanism story.

At a glance

Evidence
Preclinical
Singapore (HSA)
Not registered by HSA at low dose. The naltrexone-containing product identifiable in HSA's new drug approval listings is CONTRAVE (naltrexone 8 mg / bupropion 90 mg prolonged release), approved in 2022 as an anti-obesity preparation and classified prescription-only medicine. No HSA-registered product exists at the 1.5 to 4.5 mg LDN strength, so LDN in Singapore is a prescriber-initiated, extemporaneously compounded preparation: Amber Compounding Pharmacy (Singapore) states plainly that this dosage is not commercially available and that LDN is only available from a compounding pharmacy. Caveat: I could not verify from an HSA source whether standalone naltrexone 50 mg tablets are registered in Singapore, and I found no HSA guidance addressing low-dose naltrexone specifically.
Australia (TGA)
Naltrexone hydrochloride 50 mg oral tablets are TGA-registered on the ARTG (for example NALTREXONE GH, ARTG 128710, registered 2007; NALTREXONE ASTRON, ARTG 386567, registered 2023), indicated for alcohol dependence within a comprehensive treatment programme and as adjunctive therapy in maintenance of formerly opioid-dependent patients. Low-dose use is entirely off-label: no TGA-registered product exists at LDN strengths, so LDN must be extemporaneously compounded by a compounding pharmacy on a doctor's prescription and is not PBS-subsidised. National Custom Compounding, an Australian compounding pharmacy, states LDN "is considered an off-label therapy in Australia" and must be prescribed by a doctor. There is no TGA approval, and no Special Access Scheme pathway is involved, since off-label prescribing of a registered ingredient via compounding is a normal prescriber-responsibility route.
Offered at
No clinic on file

Singapore

Health Sciences Authority

HSA status
Not registered by HSA at low dose. The naltrexone-containing product identifiable in HSA's new drug approval listings is CONTRAVE (naltrexone 8 mg / bupropion 90 mg prolonged release), approved in 2022 as an anti-obesity preparation and classified prescription-only medicine. No HSA-registered product exists at the 1.5 to 4.5 mg LDN strength, so LDN in Singapore is a prescriber-initiated, extemporaneously compounded preparation: Amber Compounding Pharmacy (Singapore) states plainly that this dosage is not commercially available and that LDN is only available from a compounding pharmacy. Caveat: I could not verify from an HSA source whether standalone naltrexone 50 mg tablets are registered in Singapore, and I found no HSA guidance addressing low-dose naltrexone specifically.
In our SG set
Tracked in Singapore
SG clinics
None on file

Australia

Therapeutic Goods Administration

TGA status
Naltrexone hydrochloride 50 mg oral tablets are TGA-registered on the ARTG (for example NALTREXONE GH, ARTG 128710, registered 2007; NALTREXONE ASTRON, ARTG 386567, registered 2023), indicated for alcohol dependence within a comprehensive treatment programme and as adjunctive therapy in maintenance of formerly opioid-dependent patients. Low-dose use is entirely off-label: no TGA-registered product exists at LDN strengths, so LDN must be extemporaneously compounded by a compounding pharmacy on a doctor's prescription and is not PBS-subsidised. National Custom Compounding, an Australian compounding pharmacy, states LDN "is considered an off-label therapy in Australia" and must be prescribed by a doctor. There is no TGA approval, and no Special Access Scheme pathway is involved, since off-label prescribing of a registered ingredient via compounding is a normal prescriber-responsibility route.
In our AU set
Tracked in Australia
AU clinics
None on file
Evidence is not approvalAn evidence grade describes how strong the science is. A regulatory status describes whether a body has approved the intervention for an indication. They are different questions, answered separately above.

What it is

Plain-language explainer

Low-dose naltrexone is the opioid antagonist naltrexone taken at roughly 1.5 to 4.5 mg daily, about a tenth of the licensed dose used in addiction medicine. At that dose it is proposed to work by transient opioid receptor blockade, a rebound rise in endogenous endorphins, and antagonism of glial toll-like receptor 4 signalling, which is claimed to damp neuroinflammation. It is promoted in integrative and functional medicine for chronic pain, fibromyalgia, autoimmune disease and long COVID, and more recently, on much thinner ground, as a general anti-inflammatory geroprotector.

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Sources

What this profile is built on

  1. What is Low Dose Naltrexone? (LDN) · National Custom Compounding (Australia)
  2. NALTREXONE GH naltrexone hydrochloride 50mg film coated tablets blister pack (128710) · Therapeutic Goods Administration (TGA)
  3. NALTREXONE ASTRON naltrexone hydrochloride 50 mg tablet blister pack (386567) · Therapeutic Goods Administration (TGA)
  4. Naltrexone (ARX): approved Australian indications · healthdirect Australia
  5. New drugs approved for 2022 (includes CONTRAVE naltrexone/bupropion, POM) · Health Sciences Authority, Singapore
  6. Low Dose Naltrexone (LDN) 101 · Amber Compounding Pharmacy Pte Ltd, Singapore
  7. Low-dose naltrexone extends healthspan and lifespan in C. elegans via SKN-1 activation · iScience (2024), via PubMed Central
  8. Efficacy and safety of low-dose naltrexone (LDN) in fibromyalgia: a systematic review and meta-analysis · PubMed Central
  9. Effect of low dose naltrexone for long covid: a systematic review (no RCTs; low certainty) · medRxiv preprint, September 2025
  10. Low-Dose Naltrexone: What is the Evidence? A Narrative Review · Advances in Therapy (2026)
  11. LDN Research Trust: Australia prescriber and pharmacy registry · LDN Research Trust

Every entity profile on variis is sourced. Not medical advice.