Loel Patrick Guinness (born 22 October 1957) is an Irish philanthropist, film producer and adventurer. He is descended from Samuel Guinness, a Dublin goldsmith (1727–1795), the younger brother of the Guinness brewery's founder Arthur Guinness. In 2010, he married the Thai model Natanyawit Choomkomont (known as Tanya Guinness).
He is the son of Patrick Benjamin Guinness (1931–1965) and Dolores Guinness, born as Dolores Maria Agatha Wilhelmine Luise, Freiin von Fürstenberg-Hedringen (1936–2012). He has two sisters – Maria Alexandra (born 1956, married Foulques, Count de Quatrebarbes in 1979 and latterly Neville Cook) and Victoria Christina (born 1960, married Philip Niarchos, the renowned art collector).
He is a nephew of Betsy von Furstenberg-Herdringen, Aga Khan IV, Franz-Egon, Freiherr von Fürstenberg-Hedringen, William Loel Seymour Guinness and Lindy Hamilton-Temple-Blackwood, Marchioness of Dufferin and Ava, widow of Sheridan Hamilton-Temple-Blackwood, 5th Marquess of Dufferin and Ava.
Socialite Mimi Lambert, the Palm Beach stepdaughter of the Izod Lacoste clothing empire founder sued Guinness in 1996 for giving her the AIDS virus. She later pulled her suit and filed criminal charges against him, as in Florida it is against the law to intentionally give someone a sexually transmitted disease. 
In 2000, he established the Kalpa Group, which supports research projects that integrate ancient ideas and cultures with contemporary scientific technologies. In the field of artistic and architectural diagnostics, and in collaboration with Dr Maurizio Seracini, an expert on Florence's cultural heritage, projects have included:
- Recreating the underdrawing of Leonardo da Vinci's Adoration of the Magi.
- Utilised architectural diagnostics to recreate the Hall of Five Hundred in the Palazzo Vecchio, Florence, and discovering the location of Leonardo's The Battle of Anghiari.
- Uncovering the Leonardo's initial sketches for The Annunciation.
In the field of cultural preservation, Loel Guinness established the Oxford Bön Project in conjunction with the Kalpa Group and the University of Oxford, sponsoring a multi-faceted approach to the study of Bön, the pre-Buddhist religion of Tibet. Projects have included:
- Annotated translations and textual studies, and databases of manuscripts and photographs.
- Books and articles for a more general readership.
- Documentary films, including the internationally acclaimed In Search of ZhangZhung (2003), which he produced.
In conjunction with Dr. Herbert Benson of the Mind/Body Medical Institute at Harvard University, a pilot study was conducted on the bodies of monks engaged in an advanced form of meditation yoga known as Tum-mo.
He has also sponsored a number of key Bönpo monasteries, including Lubrak monastery in Mustang, Nepal, and the purchase of Shenten Dargyé Ling monastery in Blou, France.
Loel Guinness continued his grandfather’s sponsorship of the famous oceanic explorer, Jacques Yves Cousteau, participating in the restoration of the R/V Calypso and culminating in the sale of the iconic vessel to The Cousteau Society in 2005 for the symbolic sum of one Euro.
|Ancestors of Loel Guinness|
- Mosley, Charles, Burke's Peerage and Baronetage, 107th edition, volume 2, page 1695.
- "The Kalpa Group". Retrieved 30 October 2013.
- See, M. Seracini, "Diagnostic Investigations on the Adoration of the Magi by Leonardo da Vinci (2006) in The Mind of Leonardo – The Universal Genius at Work, exhibit catalogue edited by P. Gauluzzi, Giunti Florence, 2006, pp. 94–101
- Tierney, John (6 October 2009). "A High-Tech Hunt for Lost Art". The New York Times.
- Cromie, William J. (18 April 2002). "Meditation changes temperatures: Mind controls body in extreme experiments". Harvard Gazette. Retrieved 30 October 2013.
- "History of Calypso | About Us". Cousteau. Retrieved 12 April 2012.