Kaviani et al. 2020, Creatine supplementation in vegetarians, a review

Systematic review of creatine supplementation in vegetarians. Vegetarians and vegans have lower resting muscle creatine (roughly 10–15% lower for total creatine in the vastus lateralis, with free creatine ranging 7–26% lower across studies) and therefore tend to show a larger response to supplementation than omnivores, with greater gains via super compensation. Consistent across the included trials. Moderate to strong.