As Nigeria’s aging population increases, older adults living in poverty face growing threats to their psychological well-being. This study examines the role of formal social networks such as government programs, non-governmental organizations and faith-based initiatives in alleviating mental stress, defined as persistent psychological distress characterized by anxiety, loneliness and emotional strain, distinct from clinically diagnosed mental illness. Using Social Capital Theory as a guiding framework, the review explores how bonding, bridging and linking social capital influence the ability of formal networks to reduce financial insecurity, social isolation and health-related vulnerabilities. Traditional family caregiving structures are weakening due to rapid urbanization and economic pressures, leaving many older Nigerians unsupported. Although formal initiatives like the National Social Safety Nets Project exist, their effectiveness is limited by delayed disbursements, poor coordination and cultural stigma surrounding mental health. Strengthening the National Senior Citizens Centre as a coordinating body, expanding culturally relevant community-based care and integrating informal support systems are identified as crucial steps forward. Without such reforms, the continued neglect of this population risks worsening mental health outcomes, straining public health resources, and undermining intergenerational solidarity. This review offers actionable insights for improving older adult-care systems in Nigeria and provides guidance for other low-resource settings confronting similar demographic transitions.