Hello. Thank you for posting your query at DoctorSpring.com
I understand your concern and appreciate that before using the product you want to know more about it.
Biocell collagen is extremely safe, and has passed a lot of clinical trials and its efficacy has been proved in each of them. It will be excellent for her joint, it also has great use in the skin, it can clear out pimples and has an anti-aging effect. Regarding joints, it will improve the cartilage strength, the tensile stregth, her mobility won't be impaired as before. So it is good that you did research and chose to buy it. It will be immensely beneficial.
Regarding allergic reaction, she should not have, because people who have used, have always recommended its usage to other people. In case she does experience some minor allergic reaction like rashes, Tab. Claritin 10 mg can be taken once at night and it will stop the allergic manifestations.
However, it is a very safe drug and can be taken without any anxiety.
Feel free to discuss further,
Regards