A small daily dose of an inexpensive prescription medicine; briefly blocking the body's own opioid signals appears to quiet inflammatory signalling. The clearest human signal is in active Crohn's disease; for widespread muscle pain the picture is split, and lifespan claims rest entirely on worm and mouse work. Safety is reassuring; the serious hazard is blocked opioid pain relief. (Full Review)
| Marker | Target | Why |
|---|---|---|
| ALT | 10–26 U/L (women), 10–30 U/L (men) | Detects the dose-related liver enzyme rise documented at higher naltrexone doses |
| AST | 10–26 U/L | Paired with ALT to separate liver from muscle sources of enzyme release |
| hs-CRP | Below 0.5 mg/L | Tracks the systemic inflammation the drug is intended to lower |
| ESR | Below 10 mm/hour (men), below 15 mm/hour (women) | A higher baseline value tracked with larger benefit in the fibromyalgia pilot |
| TSH | 1.0–2.0 mIU/L | Detects over-replacement once autoimmune thyroid inflammation settles |
| Free T4 | 1.0–1.5 ng/dL | Confirms that a change in TSH reflects true thyroid status rather than assay drift |
| Urine opioid screen | Negative | Confirms opioid-free status before the first dose, preventing precipitated withdrawal |
| Fasting insulin | Below 5 µIU/mL | Baseline for the metabolic effects proposed from animal work |
| Symptom score (0–10 numeric rating scale) | No established target; track change from the individual's own baseline, treating a 2-point fall as meaningful | The only measure that determines whether treatment continues |
Cadence: Baseline work-up before the first dose. Liver enzymes and the inflammatory marker at 12 weeks, then annually; thyroid function every 6 to 12 weeks for anyone on replacement; symptom scores at 4 and 12 weeks, when the decision to continue or stop is made.