Acacia rigidula, also known as Vachellia rigidula, is an ingredient with an intriguing and controversial history. Acacia rigidula extract is commonly named as an ingredient in pre-workout and weight loss supplements, and has seen increased popularity in the last few years due in part to the banning of ingredients like ephedra and DMAA.
Acacia Rigidula Alkaloids
The Acacia rigidula story is a compelling read. Many plant species, including Acacia, are known to contain a class of plant alkaloid known as trace amines. Trace amines resemble, and some are able to be converted into, neurotransmitters and neurotransmitter-like substances by the body's metabolic processes. Research stretching back to the 1960s identified low levels of four such alkaloids in Acacia rigidula – N-methyl- β-phenethylamine, tyramine, N-methyltyramine and hordenine (1). These relatively benign alkaloids are naturally present in a many foods, particularly aged cheeses and fermented foods like soy sauce and wine, and they are produced by a large number of animals, plants and microbes. Trace amines act as mild nervous system stimulants, increasing heart rate, blood pressure, metabolic rate, and many people believe they have mood boosting properties.
Acacia Rigidula Controversy
In the late 1990s, goat farmers noted that some of their animals exhibited difficulty in walking after consuming Acacia rigidula, which prompted a Texan research team to perform a full analysis on the compounds present in the plant, to determine a potential cause. The results were alarming.
On top of the four known alkaloids, scientists found another forty chemicals in the plant, including nicotine, powerful hallucinogens, and what was touted as the first instance of a naturally occurring plant amphetamine (1).
Acacia Rigidula Supplements
In spite of these findings, Acacia rigidula was not banned, but actually became a popular inclusion in pre workout and fat loss supplements after ephedra was outlawed. Over time, this attracted the attention of the US Food and Drug Administration (FDA), who commissioned a full safety study (2).
The story takes another turn at this point. This second, more thorough study debunked the results of the previous analysis by finding only low levels of the four relatively benign trace amines which had been known to scientists for close to half a century. None of the other forty compounds identified in the Texan study were detected. It is now widely believed that the results of the Texan investigation came about due to contamination (2).
But it doesn't end there – The FDA also tested 21 supplements that claimed to contain Acacia rigidula, and found that almost half contained a synthetic amphetamine analogue called BMPEA, the implication being that the manufacturers had adulterated their product with this illegal substance (2). There have since been a number of instances where manufacturers have attributed the presence of synthetic compounds to a natural extract that contains either a natural analogue of the synthetic compound, as in this case, or contains the compound at greatly reduced levels, like DMAA, which is present in trace amounts in some species of geranium.
Is Acacia Rigidula Legal in Australia?
At present, it is listed as a 'Novel Food' on a list held by Food Standards Australia New Zealand (FSANZ), which is a requirement for it to be sold in this country (3). FSANZ is currently investigating products claiming to contain Acacia Rigidula due to safety concerns recently raised by the media. It is hoped that the safety of this botanical extract will soon be legally established. Acacia Rigidula extract is still sold legally in the United States.
Acacia Rigidula Alternatives
A good quality, unadulterated Acacia rigidula extract has a number of benefits which lend it to inclusion in pre-workout and fat burner supplements. There are a number of plant-derived ingredients that contain the same, or similar trace amines to those found in Acacia rigidula, which represent a great alternative.
Bitter orange or Citrus aurantium – This extract contains a number of tyramine derivatives which are very similar to, and related to, those found in Acacia rigidula. These include synephrine and octopamine. Like Acacia, it has been widely touted as an alternative to DMAA, and has similar stimulatory effects on the nervous system and metabolism. Bitter orange is found in a number of pre-workouts and weight loss products.
Phenylethylamine or PEA – This is another naturally occurring plant alkaloid which is naturally produced from the amino acid phenylalanine. PEA is thought to stimulate the body's production of noradrenaline and dopamine, stimulatory neurotransmitters which can boost the mood.
N-methyltyramine – This is one of the four alkaloids found in Acacia rigidula, and it is often included as a stand alone ingredient in pre workouts and fat loss supplements. Like PEA, it can stimulate noradrenaline production, causing increased heart rate and blood pressure, and it can also prolong the action of neurotransmitters like dopamine and serotonin, which are involved in mood and focus.
Green Tea Extract – Green tea has more benefits than you can count. It is often mentioned for its powerful antioxidant properties, but it also contains a number of powerful natural alkaloids, like epigallocatechin gallate (EGCG), which have been hailed for their ability to boost the metabolism, enhance mood, and lift energy levels.
Caffeine – Caffeine is the world's most popular plant alkaloid, and with good reason. Not only does it provide you with a quick shot of focus-enhancing energy, but it can speed up your metabolism, help suppress the appetite, and as any coffee drinker knows, it can make you feel really good!
(1)Beverly A. Clement, Christina M. Goff, and T. David A. Forbes. Toxic amines and alkaloids from acacia rigidula. Phytochemistry Volume 49, Issue 5, 5 November 1998, Pages 1377-1380.
(2) Pawar RS, Grundel E, Fardin-Kia AR, Rader JI. Determination of selected biogenic amines in Acacia rigidula plant materials and dietary supplements using LC-MS/MS methods. J Pharm Biomed Anal. 2014 Jan;88:457-66.
(3) Food Standards Australia. Record of views held in response to enquiries. http://www.foodstandards.gov.au/industry/novel/novelrecs/Documents/novel-food-record-of-views.pdf. Accessed April 17 2015.