B12 can be taken by humans - if you are going to try it use the methylcobalamin version as that is the most easily absorbed. I do take internet sites with a pinch of salt as you don't know what/who is behind them. B12 methylcobalamin is good for nerve problems. Even if it doesn't work, the low toxicity means it shouldn't cause any harm.
This from a Podiatry site:
Can Vitamin B12 (Methylcobalamin) Supplementation Have An Impact For Diabetic Neuropathy?
Increasingly, we have identified the role of vitamin B12 in diabetic neuropathy and the need to supplement B12 in the patient with diabetes. Metformin, the most commonly utilized drug for the treatment of diabetes, is associated with worsening of diabetic neuropathy due to the inhibition of folic acid and B12 absorption as a result of the effects of metformin.10
Authors have demonstrated that the malabsorption of B12 and decreased folate levels associated with metformin result in an increased homocysteine level and increased risk of neuropathy.11,12 The administration of B12 may be associated with a reversal of these effects. Homocysteine, when elevated, results in endothelial damage and decreased blood flow to peripheral nerve tissue by thrombus formation within the vascular supply to the nerve. In addition, homocysteine impairs the coupling of arginine and oxygen for the formation of nitric oxide, which is necessary to maintain vascular supply and normal nerve function.13 Cobalamin deficiency, which is exacerbated by the utilization of metformin, increases risk of neuropathy. B12 supplementation can be helpful in the reversal of this deficiency and neuropathy.
In addition to those patients utilizing metformin, researchers have demonstrated that vitamin B12 deficiency and folate deficiency are associated with increased levels of homocysteine, increased oxidative stress secondary to low levels of glutathione, and decreased total antioxidant activity.14 Bailey and colleagues noted that cobalamin deficiency is common and the majority of cases are subclinical.15 In addition, they have suggested that cobalamin serum testing is unreliable.
Solomon demonstrated that functional B12 deficiency is common in the elderly and common in 62 percent of patients with diabetic neuropathy.16 In these patients, normal serum cobalamin levels were associated with markers for B12 deficiency such as elevated levels of methylmalonic acid and the presence of neuropathy. Solomon showed that the administration of cobalamin reversed the effects of functional B12 deficiency in many patients.
Wyckoff and Ganji demonstrated that vitamin B12 deficiency may exist even in the presence of patients who presumably have a "large intake" of B12.17 They further demonstrated that classic markers of B12 deficiency such as macrocytic anemia are not reliable markers for B12 deficiency.
The administration of methylcobalamin at 1,500 mcg per day has been associated with normalization of hemoglobin A1c and improved motor conduction velocity, thereby suggesting that vitamin B12 therapy may be helpful in the reversal of diabetic motor neuropathy, or symptoms such as cramping.18 Others have demonstrated that the administration of methylcobalamin at 1,500 mcg daily was associated over three months with relieved muscle cramping, improvement in motor conduction velocity, reduction in neuropathic pain and improvement in two point discrimination, suggesting nerve regrowth.19
Yaqub and co-workers have demonstrated that methylcobalamin improves not only sensory but autonomic nerve dysfunction symptoms as well.20 With reference to autonomic neuropathy, multiple studies have demonstrated the reversal of autonomic signs, autonomic symptoms and the normalization of autonomic nerve dysfunction with the administration of methylcobalamin.21,22 Authors have also described a potential neuroprotective effect together with reversal of symptomatic sensory and autonomic neuropathy.23-26</size>
