Vitamin D deficiency is common in older adults and associated with such as falls, fractures, reduced muscle strength, and functional decline. Globally, the rapidly increasing population aged 80 years and older is characterized by frailty, multimorbidity.Vitamin D deficiency risk is increased by reduced sun exposure, limited mobility, nutritional inadequacy, polypharmacy, and social inequalities. In our country, despite the inability to routinely measure vitamin D levels in primary care and the frequent prescription of vitamin D at prophylactic doses, uncertainties persist regarding optimal serum threshold values and the appropriateness of routine supplementation in elderly populations. Social disadvantages makes it essential to clarify the existing evidence in order to support equitable, humanistic, and patient-centered decision-making in family medicine.The aim of this review is to evaluate current evidence on vitamin D levels and prophylactic supplementation in frail adults aged 80 years and older in order to support evidence based and patient centered decision making in primary care.A literature review was conducted using PubMed. Articles published within the last five years were identified using the keywords “vitamin D” OR “25-hydroxyvitamin D” AND “aged 80 and over.” Review and systematic review studies were included.The reviewed literature reports a high prevalence of vitamin D deficiency among adults aged 80 years and older.Evidence supporting routine vitamin D supplementation inconsistent. Some reviews report potential benefits of supplementation in selected high-risk and frail subgroups, such as individuals with osteoporosis, previous falls or fractures, limited outdoor activity.In contrast, routine supplementation has not demonstrated consistent improvements in clinically meaningful outcomes.Clarifying current evidence is essential to support equitable, humanistic, and patient-centered decision-making in family medicine.Current evidences do not support routine supplementation for all patients in this group.Therefore, decisions regarding vitamin D supplementation should be guided by individual risk profiles rather than routine practice. Vitamin D levels below 20 ng/mL indicate deficiency, while levels ≥20–30 ng/mL are generally considered sufficient, with ≥30 ng/mL in frail older adults. Supplementation with 800–1000 IU/day is commonly recommended.Individualized dosing based on clinical risk factors and serum monitoring remains essential in this group.