The Food and Drug Administration of the United States has not approved micro-needle rollers for at-home use. A number of micro-needle derma rollers produced outside of the US are on the FDA's Import Alert red list, since their needles are classed for clinical use only. This doesn't necessarily mean they're unsafe, but it does mean the FDA doesn't think they're appropriate for at-home skin care. Several medical studies have proven the effectiveness of micro-needle treatments on acne scars.