Bioidentical hormones are derived from diosgenin, which is sourced from Mexican yams or soy. Personalised prescriptions are created then compounded under strict guidelines by the Specialist Pharmacy of which is overseen by the General Pharmaceutical Council and the Medicines and Healthcare products Regulatory Agency (MHRA). Compounding is widely used in areas of medicine such as paediatrics and dermatology because it allows the possibility for doses to be individualised.