Intertek, a leading provider of quality and safety services to a wide range of industries around the world, reviewed the safety of p‑synephrine, the dominant amine in Advantra Z, a patented bitter orange extract and the industry’s leading natural thermogenic ingredient, supporting p-synephrine dosages up to 60 mg. Intertek’s report is among six formally recorded documents in less than two years to support these specific dosing guidelines.
The report issued by Intertek on Sept. 13, 2012, states, "Although p-synephrine and caffeine have been assumed to produce similar clinical effects, but through different mechanisms, recent data regarding the isoform of synephrine present in C. aurantium[bitter orange] extracts and from receptor binding studies indicates that p-synephrine is unlikely to have significant effects on inotropy, vasoconstriction or blood pressure." The report concludes that the following dosages are "not likely to cause adverse effects" when used as directed:
- Up to 60 mg p-synephrine alone or 40 mg in combination with 320 mg of caffeine
- If taken as divided doses spaced out over the course of the day, 70 mg of p-synephrine alone or 60 mg p-synephrine in combination with 320 mg caffeine
Comparable findings also were published in International Journal of Medical Sciences (September 2012), Health Canada Natural Health Products Directorate (May 2011), Phytotherapy Research (April 2011), American Botanical Council’s HerbalGram (February 2011), and Journal of Functional Foods (November 2010).
"This is a particularly significant endorsement of the safety of Advantra Z and p‑synephrine," said Bob Green, president of Nutratech Inc., exclusive distributor of Advantra Z. "Intertek is a highly respected organization, known for its cautious and conservative approach to ingredient usage."
Green also said that a major mass-market retailer has already lifted its synephrine dosing restrictions based on Intertek’s findings. As a result, he expects many popular diet, fitness and energy brands will increase the p-synephrine potencies in their formulas accordingly—especially as other national dietary supplement retailers follow suit.
To prepare the report, Intertek evaluated scientific information and data obtained from literature searches, regarding to the safety of p-synephrine and caffeine, and of the use of these ingredients in combination products, citing 71 references.
The Intertek report advised product labeling that recommends usage by healthy individuals, clearance from a physician, incorporation of an initial scale-up "tolerance period," and maximum usage of eight weeks. The report notes that consumption of p‑synephrine/caffeine is contraindicated in children, women who are pregnant and nursing, and people who have various medical conditions or take certain medications.