Vanadium is a trace mineral with the symbol V. Scientists speculate that our bodies might need small amounts of vanadium, it may even play a role in normal bone growth. However, at high doses vanadium is toxic. It’s use as a dietary supplement is controversial. As a bodybuilding supplement it is used to increase insulin sensitivity, especially in the form of vanadyl sulfate (inorganic compound of vanadium).
Bioavailability and Absorption
Several studies reported that vanadium is poorly absorbed from gastrointestinal tract (from less than 1% to 10%) [14,15]. One other study reported a bit better absorption between 12.5% and 16.8% . Next generation vanadium includes complexes such as bis(glycinato)oxovanadium (BGOV) and bis(picolinato)oxovanadium (BPOV), which are claimed to possess greater absorption and bioavailability than the sulfate salt . This organic complexes are recognised as safer, more absorbable and are able to deliver therapeutic effect up to 50% greater than the inorganic forms .
Vanadium and Glucose Metabolism
In diabetic rats, blood glucose levels have been found to be normalized by administration of vanadyl or vanadate complexes (such as Bis Picolinato Oxo Vanadium [complex of vanadium and picolinic acid]) . Other studies also report potent insulin-potentiating activity by oxovanadium complexes when administered to both type I and type II diabetic animals [3,4]. Data by Wanny Basuki et al.  indicates that hypoglycemic effect by oxovanadium(IV) complexes is caused by activation of insulin signaling pathway (by direct phosphorylation of IRS-1 and activation of PI3-K, leading to GLUT4 translocation to plasma membrane ) and enhancement of glucose utilization.
Bis(picolinato)oxovanadium (IV) complex was confirmed to be potent , orally active and long-term acting insulin-potentiating vanadyl complex [7,8] in rats. Human studies are lacking for this complex. Bis(ethylmaltolato)oxovanadium(IV) (BEOV) has been selected for phase 1 and 2 clinical trials . Pharmaceutical efficacy and bioavailability of BEOV is superior over inorganic vanadyl sulfate . BEOV at 20 mg daily for 28 days is associated with reductions in fasting blood glucose .
Decreased fasting blood glucose levels by vanadyl sulfate administration have also been reported by three very small clinical trials [2,10,11]. However, with quite a few promising animal studies, human trials are far from definitive. In a well-conducted systematic-review  based on a comprehensive search, authors concluded that there is no good evidence that oral vanadium supplementation improves glycaemic control in patients with diabetes. Therefore, it cannot be recommended for such treatments.
Furthermore, studies in patients with impaired glucose tolerance  and obese patients without diabetes  also reported no efficacy of vanadium supplementation.
More large-scale clinical trials should be done (especially with oxovandium complexes) before any firm conclusions can be drawn.
Can it Improve Muscle Growth?
Vanadium is also marketed as a supplement that promotes muscle growth in weight training. Its usage as a sport performance enhancer has not been proven and Talbott et al.  suggest that bodybuilders who take it merely experience a placebo effect. J. P. Fawcet and assistants  reported no benefit at all from 12 week vanadyl sulphate administration to 31 bodybuilders. One very early study by Jandhyala and Hom  suggested that vanadyl sulfate might acutely stimulate amino acid transport into skeletal muscles.
Side Effects and Toxicity of Vanadium
At low/common concentrations vanadium is non-toxic and likely safe . Prolonged consumptions of high doses of vanadium is unsafe and not recommended as it can cause serious liver and kidney damage . Common side effects from vanadium salts also include gastrointestinal discomfort and decreased body weight gain . However, 100 mg of vanadium given to noninsulin-dependent diabetes milletius patients, which is roughly 10.000 times more than recommended, for 4 weeks exhibited no serious side effects . Most short-term human clinical trials with vanadium salts reported minimal toxicity . Kidney toxicity has been reported in the phase 2 clinical trial with Bis(ethylmaltolato)oxovanadium (IV) .
Organic vanadium compounds were recognised as much safer than inorganic vanadium salts .
As vanadium might lower blood sugar, people with diabetes should regularly monitor their blood sugar for signs of hypoglycemia.
(Other Common Names: Atomic number 23, Orthovanadate, Pentoxyde de Vanadium, Sulfate de Vanadyl, Vanadate, Vanadio, Vanadium Pentoxide, Vanadyl, Vanadyl Nicotinate, Vanadyl Sulphate, Metavanadate, Métavanadate)
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