- Acacia Rigidula extract was a popular ingredient in pre-workouts and weight loss supplements between 2010 & 2017
- It attracted controversy due to concerns about amphetamine derivatives
- Acacia Rigidula was commonly used as a substitute for the banned ingredient DMAA
- The plant contains alkaloids with stimulant effects & potential weight loss benefits
- There was a risk of adulteration & false-positive drug test results
- The legal status of Acacia Rigidula as a supplement ingredient varies by country
- In The United States & Australia Acacia Rigidula is illegal & banned from retail sale
- Acacia Rigidula legal alternatives are available that may produce similar type effects
Acacia Rigidula extract gained popularity as an ingredient in pre-workouts & weight loss supplements, but controversies arose regarding its potential amphetamine derivative content. Native to America & Mexico, Acacia Rigidula is a tree whose leaves were used for extraction. Scientific analysis revealed alkaloids with stimulant effects, which led to claims of improved mental focus & an increased metabolic rate for weight loss. Adulteration concerns and the possibility of false-positive drug test results add to the complexity of its use. The legal status of Acacia Rigidula differs between countries.
What is Acacia Rigidula?
Acacia Rigidula Extract was an ingredient used in a number of pre-workouts and weight loss supplements in the period 2010 through 2017. It was hailed by many people as an alternative to DMAA, as such it attracted some controversy due to the notion that it may have contained amphetamine derivatives.
Where does Acacia Rigidula come from?
Acacia rigidula, also known as Vachellia rigidula, Chaparro Prieto or Blackbrush Acacia is a tree that is native to the south of America and Mexico. The extract used in supplements was prepared from the leaves of this plant.
Acacia Rigidula Controversy
Acacia Rigidula is a plant with a controversial history. In the late 1990s, it was noticed that consuming the leaves of Acacia rigidula, a common forage crop for goats being raised in the area, caused the animals to experience incoordination and difficulty walking. This led a scientific team to perform a thorough chemical analysis of the plant in an attempt to pinpoint a cause.
The plant was previously known to contain four alkaloids with mild effects - N-methyl-β-phenethylamine, tyramine, N-methyltyramine, and hordenine - but this new research appeared to show that the plant contained another forty chemicals, including methamphetamine and a number of amphetamine derivatives not previously found in nature, powerful hallucinogens, and even nicotine (1).
Over the years, supplement manufacturers, banned from the use of stimulants like Ephedra and DMAA in their products, turned to Acacia Rigidula in light of its supposed similar properties, and it became a fixture in a number of fat loss and pre-workout supplements. This eventually led, in 2013, to a US FDA investigation of the plant as well as a number of products containing Acacia Rigidula extract (2). The study found only the same four previously known and relatively benign alkaloids in the plant. This raised the strong suspicion that the earlier analysis had been contaminated or incorrectly interpreted, a position backed by the fact that the study was the only known instance where amphetamines had been found to naturally occur in a plant.
Further adding to the controversy, the study found significant differences between the chemical profile of Acacia Rigidula and many of the products that claimed to contain this extract. β-Methylphenethylamine, a synthetic compound and amphetamine analogue was found in 9 of the 21 samples surveyed, and the strong implication was made that many supplement manufacturers who are claiming Acacia Rigidula as an ingredient are adulterating their products with synthetic chemicals (2).
Acacia Rigidula Benefits
The plant alkaloids in Acacia Rigidula (N-methyl-β-phenethylamine, tyramine, N-methyltyramine, and hordenine) belong to trace amines. These substances structurally resemble neurotransmitters, like dopamine, serotonin and noradrenaline.
Trace amines are common in most foods because they are produced by animals, plants and microbes. When eaten, these compounds may exert some non-psychoactive stimulant effects on the body, including increased blood pressure and heart rate. Some people claim Acacia Rigidula improves mental focus.
This class of chemicals is known to increase basal metabolic rate. Synephrine (known as bitter orange) is a tyramine metabolite closely related to the other Acacia Rigidula alkaloids. Ingestion of synephrine has been shown to have positive effects on weight loss, particularly in overweight and obese people (3). It is likely that Acacia Rigidula extract would have a similar effect.
Acacia Rigidula Benefits for Bodybuilding
Acacia Rigidula may have had a mild stimulant and focus-enhancing effect that made it a worthwhile inclusion in pre-workout supplements.
An increased metabolic rate enhances weight loss. This would have been advantageous to anyone trying to get their body fat percentage down, an attribute which has been realised by many manufacturers of fat metabolisers who have included Acacia Rigidula on their list of ingredients.
Acacia Rigidula Side Effects, Safety & Negatives
The active ingredients in Acacia Rigidula, tyramine and analogues, have been strongly implicated in migraine and cluster headaches. People who are prone to these afflictions are often placed on low tyramine diets to control the frequency and intensity of this crippling condition, so supplements containing Acacia Rigidula are unsuitable for this section of the population (4). Similarly, this extract should be avoided by those taking a class of drugs called Monoamine Oxidase Inhibitors. These active ingredients in Acacia Rigidula are metabolised by an enzyme in the body called Monoamine Oxidase (MAO), and inhibitors of this enzyme (MAOIs) are often used in the treatment of certain types of depression. The combination of high levels of tyramine and MAOIs is known to cause a hypertensive crisis, a serious and severe elevation of the blood pressure which can cause symptoms such as organ failure and haemorrhage, and can be fatal (5).
There is the possibility that Acacia Rigidula may give false positive results on a drug test, due to structural similarities to a number of substances that are banned in competition. While all the substances in Acacia Rigidula are legal, N-methyl-β-phenethylamine is an amphetamine analogue and may be detected as such on less sophisticated tests. Elite athletes may wish to avoid Acacia Rigidula, as tyramine and its derivatives are directly metabolised to Octopamine, an amine that is banned in competition by WADA (6).
As the FDA report 2013 showed, products labelled Acacia Rigidula were often adulterated with synthetic substances, including amphetamines. While this risk could have been mitigated by purchasing from large & trusted brands, the potential to unintentionally consume a product that contains an illegal drug with a number of dangerous side effects is very present (2). While there is some work on the positive effects of tyramine metabolite, synephrine (bitter orange) on weight loss, there is currently no scientific research into the metabolic effects of Acacia Rigidula consumption in humans.
In spite of these negatives, there is quite a bit of anecdotal evidence pointing to the idea that Acacia Rigidula extract is quite successful in promoting weight loss, & most people will not experience any side effects from the responsible use of a pure extract of this popular botanical.
Acacia Rigidula Recommended Dose & Ingredient Timing
There is no recommended therapeutic dose for Acacia Rigidula, any amount given would also depend on the purity of the extract.
Acacia Rigidula Supplements
Acacia Rigidula was commonly found in fat burners. It was also used as a replacement for the banned stimulant DMAA in a number of strong pre-workout supplements.
Is Acacia Rigidula Legal or Banned?
In the United States as of 2016, it is illegal to advertise, retail or sell Acacia Rigidula as a dietary supplement ingredient.
In the United States, Acacia Rigidula is considered a new dietary ingredient that must meet certain requirements to be lawfully marketed in the country. Consequently, products containing Acacia Rigidula that do not meet these requirements are deemed adulterated. Further, it is listed as a "Department of Defence Prohibited Dietary Supplement Ingredient".
In Australia as of 2017, Acacia Rigidula was also made illegal for advertising, retail & sale.
For further information please refer to "Notice under subsection 42ZCZN/42ZCZP of the Therapeutic Goods Regulations 1990 (the Regulations), March 2017".
Acacia Rigidula Alternatives
A good quality, unadulterated Acacia rigidula extract has a number of benefits that 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 that 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 that 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 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 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!
The use of Acacia Rigidula in dietary supplements has generated both interest & controversy. While anecdotal evidence suggests weight loss benefits & minimal side effects for most individuals, concerns about amphetamine derivatives, potential adverse effects, & adulteration existed. The legal status of Acacia Rigidula varies, with the United States and Australia implementing restrictions on its marketing and sale.
It is crucial for consumers to exercise caution, understand their respective country's legalities & consult with a healthcare professional before considering the use of Acacia Rigidula-containing products.
(1) Beverly A Clement, Christina M Goff, 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) Stohs SJ, Preuss HG, Shara M. A review of the human clinical studies involving Citrus aurantium (bitter orange) extract and its primary protoalkaloid p-synephrine. Int J Med Sci. 2012;9(7):527-38.
(4) D'Andrea G1, D'Amico D, Bussone G, Bolner A, Aguggia M, Saracco MG, Galloni E, De Riva V, Colavito D, Leon A, Rosteghin V, Perini F. The role of tyrosine metabolism in the pathogenesis of chronic migraine. Cephalalgia. 2013 Aug;33(11):932-7
(5) Flockhart DA. Dietary restrictions and drug interactions with monoamine oxidase inhibitors: an update. J Clin Psychiatry. 2012;73 Suppl 1:17-24.
(6) PISANO JJ, et al. Identification of p-hydroxy-alpha-(methylaminomethyl) benzyl alcohol (synephrine) in human urine. J Biol Chem. (1961)