Intelligent Muscle Sharp AMF 300 g

DMAA (1,3-dimethylamylamine)

DMAA (1,3-dimethylamylamine, methylhexanamine) is a synthetic stimulant that constricts blood vessels and raises blood pressure. It has been sold in pre-workout and weight-loss supplements and as a recreational stimulant¹.

DMHA (2-aminoisoheptane, octodrine) and DMBA

DMHA, also labelled 2-aminoisoheptane or octodrine (2-amino-6-methylheptane), is a synthetic aliphatic amine stimulant found in pre-workout and weight-loss supplements, sometimes alongside the related compound DMBA².

Yohimbine (yohimbe bark, rauwolscine)

Yohimbine is an alkaloid from the bark of the African tree Pausinystalia yohimbe. It blocks α2-adrenergic receptors, which increases noradrenaline release. Rauwolscine (alpha-yohimbine) is a closely related alkaloid.

Higenamine

Higenamine is a plant alkaloid that stimulates β2-adrenergic receptors, the same receptor family targeted by asthma bronchodilators. It is found in plants such as Nandina domestica³.

Synephrine (bitter orange, Citrus aurantium)

p-Synephrine is the main protoalkaloid of bitter orange (Citrus aurantium). It is structurally related to adrenaline and is used in weight-loss and pre-workout products⁴.

Beta-alanine

Beta-alanine is an amino acid that combines with histidine in muscle to form carnosine, which helps buffer acid during intense exercise⁵.

L-citrulline and citrulline malate

L-citrulline is an amino acid that the body converts to arginine, a precursor of nitric oxide, which widens blood vessels. Citrulline malate combines citrulline with malic acid⁶.

Agmatine sulfate

Agmatine is formed in the body from the amino acid arginine and acts as a signalling molecule in the nervous system. It is sold as agmatine sulfate in sports and nootropic products.

L-tyrosine

L-tyrosine is an amino acid that the body uses to make the neurotransmitters dopamine and noradrenaline. It is found in protein-rich foods; N-acetyl-L-tyrosine is a related form⁷.

Green tea extract (catechins, EGCG)

Green tea extracts are concentrated sources of catechins, mainly epigallocatechin gallate (EGCG), and usually contain caffeine.

Hordenine

Hordenine (N,N-dimethyltyramine) is a phenethylamine alkaloid found in barley and beer. It acts on the dopamine D2 receptor and is marketed in pre-workout and fat-burning products⁸.

Grape seed extract (OPC)

Grape seed extract is rich in oligomeric proanthocyanidins (OPCs), polyphenolic antioxidants.

Piperine (black pepper extract, BioPerine®)

Piperine is the pungent alkaloid of black pepper, added to supplements as a "bioavailability enhancer".

Octopamine and halostachine

Octopamine and halostachine (N-methylphenylethanolamine) are phenethylamine-type amines related to synephrine and adrenaline. They appear in weight-loss and pre-workout products⁹.

DMAA (1,3-dimethylamylamine)

No controlled trials show that DMAA improves athletic performance or weight loss. A pharmacokinetic study of a single 25 mg dose did not find meaningful changes in resting heart rate, blood pressure or body temperature¹⁰.

DMHA (2-aminoisoheptane, octodrine) and DMBA

There are no controlled human trials showing that DMHA improves exercise performance or weight loss.

Yohimbine (yohimbe bark, rauwolscine)

A small trial in professional soccer players found reduced body fat with yohimbine but no change in body mass, muscle mass or performance¹¹. Larger, independent trials are lacking.

Higenamine

There are no controlled human trials showing that higenamine improves exercise performance or weight loss. Analyses of US supplements found up to about 62 mg per serving, with labels that often did not state the amount³.

Synephrine (bitter orange, Citrus aurantium)

A review of human clinical studies reported small increases in energy expenditure and modest weight loss with bitter orange extract or p-synephrine products over 6–12 weeks, many in combination with other ingredients⁴.

Beta-alanine

The International Society of Sports Nutrition concludes that 4–6 g a day for at least 2–4 weeks raises muscle carnosine and improves performance in exercise lasting about 1–4 minutes⁵.

A meta-analysis found a significant overall ergogenic effect, with the size of the benefit depending on the type and duration of exercise¹².

L-citrulline and citrulline malate

A review of human studies found that citrulline supplementation raises plasma arginine, and that several studies report improved exercise performance or recovery, but the results are inconsistent⁶.

Agmatine sulfate

Controlled human research on agmatine for exercise performance is very limited. Published human data are mostly small studies and a long-term case report¹³.

L-tyrosine

A review found that tyrosine may support cognitive performance in short-term stressful or cognitively demanding situations, when these neurotransmitters are temporarily depleted, but found no consistent effect on physical exercise performance⁷.

Green tea extract (catechins, EGCG)

Evidence for weight loss from green tea extracts is limited and effects are small; no health claim is authorised¹⁴.

Hordenine

There are no controlled human trials of hordenine for exercise performance or weight loss. Human research concerns its absorption from beer, where plasma levels were too low for a direct effect on dopamine receptors⁸.

Grape seed extract (OPC)

A meta-analysis of 16 randomised controlled trials examined the effect of grape seed extract on blood pressure¹⁵.

Piperine (black pepper extract, BioPerine®)

A 2026 review of 22 human pharmacokinetic studies found that reports of enhanced nutrient absorption come mainly from manufacturer-affiliated studies, and that independent trials did not confirm enhancement for curcumin or resveratrol at supplement doses¹⁶.

Octopamine and halostachine

There are no controlled human trials showing benefits for weight loss or performance. Research concerns their detection and quantification in sports supplements⁹¹⁷.

DMAA (1,3-dimethylamylamine)

The single-dose study does not reflect repeated use, higher doses or combination with other stimulants and exercise¹⁰. Analyses of sports and weight-loss supplements have repeatedly found stimulants that were not declared, or quantities different from the label²¹⁸.

DMHA (2-aminoisoheptane, octodrine) and DMBA

The research concerns detection of these stimulants in supplements, not their effects. Analyses of sports and weight-loss supplements have repeatedly found stimulants that were not declared, or quantities different from the label²¹⁸.

Yohimbine (yohimbe bark, rauwolscine)

Evidence for fat loss or performance is limited to small studies. Supplement labels are often inaccurate: of 49 US yohimbine supplements tested, only 2 gave accurate information on both the quantity and the known adverse effects¹⁹.

Higenamine

Published research concerns supplement analysis rather than effects in humans³.

Synephrine (bitter orange, Citrus aurantium)

Most studies are small, short and use multi-ingredient products, and longer studies are needed to establish efficacy and safety⁴.

Beta-alanine

Effects on strength and on endurance exercise beyond about 25 minutes are not established⁵. A single serving taken before training does not reproduce the daily supplementation used in research.

L-citrulline and citrulline malate

Studies differ in dose, form (citrulline or citrulline malate, often with an unverified ratio) and exercise test, and many are small. The mechanism behind any performance effect is not established⁶.

Agmatine sulfate

There are no large randomised trials showing a performance benefit from agmatine in healthy people. Claims of better "pump" or focus are not established.

L-tyrosine

Most studies are small and use single doses in laboratory settings⁷.

Green tea extract (catechins, EGCG)

Results depend on caffeine content and extract type.

Hordenine

Supplement amounts are much higher than the amounts studied from beer, and their effects have not been studied⁸.

Grape seed extract (OPC)

Trials are small and use different extracts and doses¹⁵.

Piperine (black pepper extract, BioPerine®)

Piperine raises blood levels of other compounds mainly by inhibiting drug-metabolising enzymes (CYP3A4, CYP2C9) and P-glycoprotein, not by improving absorption¹⁶.

Octopamine and halostachine

Without human trials, effects and safe amounts are unknown. Analyses of sports and weight-loss supplements have repeatedly found stimulants that were not declared, or quantities different from the label²¹⁸.

DMAA (1,3-dimethylamylamine)

DMAA is a potent pressor agent. Cases of cerebral haemorrhage have been reported in adults after using DMAA¹.

DMHA (2-aminoisoheptane, octodrine) and DMBA

Human safety data are lacking. As a sympathomimetic amine, DMHA may raise heart rate and blood pressure; avoid combining it with other stimulants. Contaminated supplements have caused positive doping tests¹⁸.

Yohimbine (yohimbe bark, rauwolscine)

A review of poison-centre cases found that adverse events with yohimbine products had more serious outcomes than average exposures, including rapid heart rate, anxiety, high blood pressure and agitation²⁰. People with heart conditions, high blood pressure, anxiety disorders or taking antidepressants should not use yohimbine.

Higenamine

As a β2-agonist, higenamine may raise heart rate and cause palpitations, and its safety at supplement doses has not been established³.

Synephrine (bitter orange, Citrus aurantium)

The reviewed studies did not report serious adverse effects at the doses tested⁴, but combining synephrine with caffeine and other stimulants increases cardiovascular stress. People with high blood pressure, heart-rhythm disorders or taking stimulant or antidepressant medication should avoid it.

Beta-alanine

The only commonly reported side effect is paraesthesia, a harmless tingling of the skin that is more likely with larger single doses⁵.

L-citrulline and citrulline malate

Citrulline is generally well tolerated in the doses studied. Digestive discomfort has been reported, and people taking blood-pressure or erectile-dysfunction medication should ask a doctor, because citrulline raises arginine and nitric oxide production⁶.

Agmatine sulfate

A case report described 5 years of high daily agmatine intake without detected adverse effects¹³. One case report cannot establish safety for the wider population.

L-tyrosine

People taking MAO inhibitors or thyroid medication should not use tyrosine supplements without medical advice.

Green tea extract (catechins, EGCG)

EFSA concluded that intakes of 800 mg EGCG a day or more, taken as a food supplement, significantly increased liver transaminases, a sign of liver stress²¹. Green tea extracts have been linked to liver injury; take them with food and do not exceed the label serving.

Hordenine

Human safety data at supplement doses are lacking. It may interact with MAO inhibitors and other stimulants. Analyses of sports and weight-loss supplements have repeatedly found stimulants that were not declared, or quantities different from the label²¹⁸.

Grape seed extract (OPC)

Generally well tolerated; it may add to the effect of blood-thinning medicines.

Piperine (black pepper extract, BioPerine®)

Because it inhibits drug-metabolising enzymes, piperine can raise blood levels of prescription medicines, including drugs with a narrow therapeutic index. People taking medication should ask a pharmacist first¹⁶.

Octopamine and halostachine

These amines may raise heart rate and blood pressure, especially with caffeine and other stimulants.

Contains 1,3-dimethylamylamine (DMAA), a synthetic stimulant that is not authorised as a novel food in the EU and is on the WADA Prohibited List. Contains DMHA/DMBA, a synthetic stimulant that is not authorised as a novel food in the EU. Contains higenamine and/or octopamine, which are on the WADA Prohibited List. Contains yohimbe bark extract. Yohimbe bark and its preparations are prohibited in foods, including food supplements, in the EU (Regulation (EC) No 1925/2006, Annex III, Part A, as amended by Regulation (EU) 2019/650). Contains yohimbine. Isolated yohimbine is classified as a medicinal substance in several EU member states; its legal status depends on the country of sale.

DMAA (1,3-dimethylamylamine)

DMAA is not authorised as food or as a food supplement ingredient in the EU²² and is prohibited in competition by the World Anti-Doping Agency²²³.

DMHA (2-aminoisoheptane, octodrine) and DMBA

DMHA and DMBA are not authorised as novel foods in the EU²². Octodrine and related stimulants are prohibited in competition by the World Anti-Doping Agency¹⁸²³.

Yohimbine (yohimbe bark, rauwolscine)

Yohimbine is a pharmacologically active substance. Its use in food is regulated under Regulation (EC) No 1925/2006 and national rules²⁴, and several EU Member States treat it as a medicinal substance²⁵.

Higenamine

Higenamine is not an authorised food supplement ingredient in the EU²² and is prohibited at all times by the World Anti-Doping Agency as a β2-agonist¹⁸²³.

Synephrine (bitter orange, Citrus aurantium)

Bitter orange extracts are used in EU food supplements under national rules, which differ between Member States²⁶.

Beta-alanine

Beta-alanine is used in EU food supplements under national rules. No health claim is authorised¹⁴.

L-citrulline and citrulline malate

L-citrulline is used in EU food supplements under national rules. No health claim for citrulline is authorised in the EU¹⁴.

Agmatine sulfate

Agmatine sulfate is used in some EU food supplements under national rules. No health claim is authorised¹⁴. Whether a product needs novel food authorisation depends on its history of use²².

L-tyrosine

Amino acids such as L-tyrosine are used in EU food supplements under national rules. No health claim is authorised¹⁴.

Green tea extract (catechins, EGCG)

The EU restricts green tea extracts containing EGCG in foods under Regulation (EC) No 1925/2006 on the addition of other substances to foods²⁴²¹. No health claim for this ingredient is authorised in the EU¹⁴; it is sold under national food-supplement rules²⁶.

Hordenine

Hordenine is not an authorised food supplement ingredient in the EU; its status depends on novel food rules²².

Grape seed extract (OPC)

No health claim for this ingredient is authorised in the EU¹⁴; it is sold under national food-supplement rules²⁶.

Piperine (black pepper extract, BioPerine®)

No health claim for this ingredient is authorised in the EU¹⁴; botanical ingredients are sold under national food-supplement rules²⁶.

Octopamine and halostachine

They are not authorised food supplement ingredients in the EU²². Octopamine is prohibited in competition by the World Anti-Doping Agency²³.