Niacin improves organ function and survival following hemorrhagic shock. Rats and mice where bled 60% of their blood volume, and replaced with Ringers lactate solution to induce hemorrhagic shock ( deprive tissue of oxygen and blood ). After 10 minutes of shock the animals where split into 3 groups and injected with nicotinic acid, NMN or DMSO, at 3 levels of dosing. Niacin at 10mg/kg, which was the highest dose given, had by far the best level of survivability. Rats, given NMN even at a 5x higher dose than niacin at 50mg/kg did not achieve a survival rate to the level observed in the 10mg/kg or the even 5mg/kg treated mice. Use of GPR109A knockout mice confirmed that the niacin GPR109A receptor plays a major role in the survivability enhancing effect of niacin.