Vitamins B3, B12 and D May Help Alleviate Neuropathic Corneal Pain

Study shows that vitamins B3, B12 and D could be potentially integrated into treatment of NCP, with future research needed aimed to establish optimal treatment protocols, including dosing regimens, treatment duration and administration methods for each vitamin. Photo: Christopher Luft, OD. Click image to enlarge. Neuropathic corneal pain (NCP) is a complex condition often resistant to standard dry eye therapies. Given the established role of vitamins in various neuropathies and associations between vitamin deficiencies and NCP, supplementation represents a potential therapeutic avenue that hasn’t been adequately investigated, some suggest. In a recent study, researchers investigated the potential of vitamins B3, B12 and D. The findings were reported in Eye and Vision.Preclinical studies suggest that nicotinamide riboside, a form of vitamin B3, can alleviate neuropathic pain by increasing nicotinamide adenine dinucleotide (NAD+) levels, offering neuroprotective, antioxidative and anti-inflammatory effects. “Vitamin B3 belongs to the water-soluble B complex group, and this molecule is hypothesized to ameliorate NCP through multiple pathways, with one key mechanism being the increase in blood NAD+ levels,” the authors wrote in their paper.Regarding anti-inflammatory mechanisms, a clinical study showed that three weeks of daily oral administration of 1g nicotinamide riboside in 12 adult male patients significantly downregulated serum inflammatory cytokine levels of interleukin (IL)-6, IL-5 and IL-2. Thus, vitamin B3 may exert therapeutic effects in NCP through several mechanisms, including antioxidative effects and anti-inflammatory action, the authors explained in their paper.Clinical studies found that B12 can improve NCP symptoms, particularly in deficient patients, through neurodegenerative, antioxidant and antinociceptive mechanisms. “Preclinical studies showed that topical application of 0.05% vitamin B12 eyedrops four times daily for 10 days stimulated corneal re-epithelialization and corneal nerve regeneration in rat models compared to vehicle-treated models,” the authors wrote in their paper.Vitamin B12 has also been shown to improve nerve conduction velocity and subsequent wound healing, alleviating neuropathic pain in diabetic neuropathy patients in several studies. “Additionally, vitamin B12 supplementation suppressed aberrant spontaneous neuronal activity in dorsal root ganglia of rodent models, effectively mitigating associated allodynia and hyperalgesia, demonstrating its anti-allodynic properties,” the authors explained in their paper.Case reports show that correcting vitamin D deficiency can lead to symptom resolution in NCP. On a molecular level, vitamin D has been shown to downregulate the synthesis of nitric oxide, a retrograde transmitter that stimulates nociceptive hypersensitivity. “Additionally, in vitro studies on human lung fibroblasts showed that exposure to 1μm vitamin D over 24 hours modulated the T-cell response and inhibited fibroblast-derived PGE2 synthesis, an important mediator in pain pathways,” the authors wrote in their paper. “Other studies have further postulated vitamin D’s role in modulating the synthesis and release of serotonin and dopamine, key neurotransmitters involved in pain processing.” For advice on how to understand and recognize neuropathic corneal pain, see this feature. The therapeutic effects of vitamin D may also be attributed to its antioxidative properties, as evidenced by its upregulation of key antioxidant enzymes like superoxide dismutase, catalase and glutathione peroxidase through the neutralization of reactive oxygen species. “Furthermore, vitamin D has also demonstrated its neurotrophic capability, stimulating nerve growth factor expression in both peripheral and central dorsal root ganglion neurons innervating the skin and the hippocampus, respectively,” the authors explained in their paper. “This suggests its possible neuroregenerative effects in improving sensory neuron function in NCP.”The authors concluded that vitamins represent a promising candidate for integration into NCP treatment, but that supplementation should be represented in larger, well-powered studies to further establish its therapeutic relevance. “While substantial progress remains to be made, we propose that sustained investigative efforts will deepen our understanding of the condition and provide further validation for emerging therapeutic strategies, including vitamin supplementation,” the authors wrote in their paper. “Future research should also aim to establish optimal treatment protocols, including dosing regimens, treatment duration and administration methods for each vitamin.”Click here for the journal source. Jie Chow B, Yu M, Liu C, et al. Vitamin abnormalities in neuropathic corneal pain. Eye and Vision. October 12, 2025. [Epub ahead of print.]This article was developed by the editorial staff in conjunction with experts in the field. In the process, AI may have been among the editorial tools used to meet the goals of human editors, who approved all content.