Marcos graduated from Middlesex University in 2005 with a first class honours BSc, having also been awarded a first-year scholarship, the Herb Society's national 'Best Third Year Student' prize and the Elsevier prize for Herbal Pharmacy. Since graduating, Marcos practiced at various places. From 2007-16 he practiced from Neal’s Yard Remedies in Covent Garden and Notting Hill. From 2009-13 Marcos and his colleague Lynne Hulka initiated a service providing complementary Western herbal medicine for people living with HIV (and other ailments) at Archway Clinic in North London; and from 2013-18 Marcos was a clinical supervisor and trainer on Middlesex University's herbal medicine BSc & MSc courses.
Marcos is also a student of renaissance and classical astrological techniques. He is currently conducting research on the effects of chocolate in sickle cell disease whilst writing his first book, on the medical history and usage of chocolate. He now practices from home in north London.