The goal of this clinical trial is to evaluate if supplemental zinc can prolong the duration of benefit of botulinum toxin injections in cervical dystonia patients receiving care at the University of Florida. The main aims are: 1. To evaluate the efficacy of zinc citrate supplementation in prolonging the duration of symptom relief provided by botulinum toxin type A (Botox) injections in cervical dystonia patients. 2. To assess the safety and tolerability of zinc supplementation in this patient population. 3. To analyze the potential influence of zinc supplementation on the quality of life and functional outcomes in cervical dystonia patients receiving Botox. Researchers will compare zinc citrate to a placebo (a look-alike substance that contains no active drug) to see if zinc works to extend the effects of Botox. Participants will: Take zinc citrate or a placebo every day for 3 months, then cross over to the alternative treatment for another 3 months. Visit the clinic every 3 months for Botox injections, check ups and surveys.