Boron

Calcium fructoborate, a natural sugar-borate ester found in fresh fruits and vegetables, is a source of soluble boron. 

Also known as: Calcium fructoborate

examine.com

ConsumerLabs

Wikipedia

pubMed

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4930945/

https://www.livestrong.com/article/501243-what-is-calcium-fructoborate/

https://www.lifeextension.com/Magazine/2018/4/Boron-An-Overlooked-Micronutrient/Page-01

https://www.lifeextension.com/Protocols/Immune-Connective-Joint/Osteoarthritis/Page-01