@Nikkilee BCNA recommend a website that evaluates most supplements - vitamin , mineral and herbal - which I gather on here some GPs use as well . It’s free and can either be viewed as an app called Herbs or on the website
www.mskcc.org/cancer-care/patient -education/herbal-remedies-and - treatment
It is maintained by the Memorial Sloan Cancer centre in NYC and provides information for both patients and medical practioners.They research and monitor research with a focus on people with cancer.They look at a supplements purported uses and contraindications etc
You can place a topic of interest eg skin/ nails whereupon it uploads supplements that are said to be effective for your reading as well as enabling you to search by supplement name eg biotin.
Please be aware it should not replace the advice of your medical team but might provide further reading from which you can formulate questions to ask your team.