Across 3 studies, 2 reported beneficial small-sized effects and 1 reported a neutral effect, resulting in mixed evidence for vitamin C reducing gingival index. The only statistically significant finding came from a low-quality review of nano-bio fusion gel, not vitamin C alone. The median study duration is 180 days based on 1 study, but effects were not consistently significant, and the most-studied population includes patients with periodontitis or thin gingival phenotype.
Caveats: Evidence base is small (only 3 studies) — conclusions should be considered preliminary. Many of the included studies did not reach statistical significance — effect may be smaller than the predominant direction suggests. The only significant finding came from a narrative review of a combined gel formulation, not vitamin C alone, limiting direct applicability.
No adverse effects were observed, and 92.3% of participants reported high satisfaction.
from: Comparative Evaluation of Vitamin C and Injectable Platelet-rich Fibrin in the Managementlow for PD/GI
Both GI and PI improved significantly over time, with vitamin C showing a trend toward greater GI reduction (p = 0.053)
NBF gel may provide clinical benefits as an adjunct to non-surgical periodontal therapy, with reported improvements in plaque and gingival indices