The Short Version
This claim is not supported by the available evidence. No peer-reviewed study links metformin's effects on HIV latency specifically to "blocking the DDIT4 gene." The primary literature describes metformin acting through AMPK/mTOR/mitochondrial pathways with mixed antiviral and proviral effects. Critically, DDIT4 is a negative regulator of mTORC1, so blocking it would increase mTOR activity—the opposite direction needed to promote HIV dormancy. The claim appears to stitch together unrelated biological facts into an unsupported causal chain.