Compare
Side by side.
| Low-dose naltrexone | Metformin | |
|---|---|---|
| Evidence | GRADE C | GRADE B |
| Category | other | metabolic |
| Status | Rx / compounded | Rx |
| Typical cost | $25–$60 / mo | $5–$20 / mo |
| Mechanism | Briefly blocks opioid receptors, which may trigger a rebound in endorphins, and may calm microglial (immune) cells in the nervous system. | Lowers glucose production by the liver and improves insulin sensitivity. It mildly affects mitochondrial energy signaling (AMPK), which may mimic some effects of caloric restriction. |
| Human evidence | Small RCTs in fibromyalgia and Crohn's disease show signals; larger trials are mixed. Not studied for lifespan. | Observational data suggest diabetics on metformin may have outcomes comparable to non-diabetics. The TAME trial is designed to test aging outcomes but has not reported. Some data suggest it can blunt exercise adaptations in older adults. |
| Side effects | Vivid dreams · Insomnia · Headache | GI upset, diarrhea · Vitamin B12 deficiency with long use · Rare lactic acidosis (kidney impairment) |
Not medical advice — talk to a licensed clinician. Content is educational, reflects published literature, and is not a recommendation to start, stop or change any treatment.