Pharmaceutical doses of the banned stimulant oxilofrine found in dietary supplements sold in the USA

In Vitro Activation of Human Adrenergic Receptors and Trace Amine-Associated Receptor 1 by Phenethylamine Analogues Present in Food Supplements

Pre-workout supplements are popular among sport athletes and overweight individuals. Phenethylamines (PEAs) and alkylamines (AA) are widely present in these supplements. Although the health effects of these analogues are not well understood yet, they are hypothesised to be agonists of adrenergic (ADR) and trace amine-associated receptors (TAARs). Therefore, we aimed to pharmacologically characterise these compounds by investigating their activating properties of ADRs and TAAR1 in vitro. The potency and efficacy of the selected PEAs and AAs was studied by using cell lines overexpressing human ADRα1A/α1B/α1D/α2a/α2B/β1/β2 or TAAR1. Concentration-response relationships are expressed as percentages of the maximal signal obtained by the full ADR agonist adrenaline or the full TAAR1 agonist phenethylamine. Multiple PEAs activated ADRs (EC50 = 34 nM-690 µM; Emax = 8-105%). Almost all PEAs activated TAAR1 (EC50 = 1.8-92 µM; Emax = 40-104%). Our results reveal the pharmacological profile of PEAs and AAs that are often used in food supplements. Several PEAs have strong agonistic properties on multiple receptors and resemble potencies of the endogenous ligands, indicating that they might further stimulate the already activated sympathetic nervous system in exercising athletes via multiple mechanisms. The use of supplements containing one, or a combination of, PEA(s) may pose a health risk for their consumers.

Prevalence of adulteration in dietary supplements and recommendations for safe supplement practices in sport

The prevalence of dietary supplement use among athletes continues to rise with 60-80% of athletes often reporting current or previous use of dietary supplements. While select dietary ingredients have been shown to improve acute performance and enhance training adaptations over time, it is important to still consider the risk vs. reward for athletes before opting to consume a dietary supplement. Previous work has indicated that certain dietary supplements may pose risks for inadvertent doping, may be susceptible to mislabelling, could be banned by certain governing bodies of sport, or pose health risks for certain populations. The purpose of the current narrative review is to summarize the prevalence of adulteration in dietary sport supplement products, outline the risks of inadvertent doping for athletes, and highlight best practices regarding safe supplementation strategies. Analytical studies have found anywhere from 14 to 50% of samples analyzed from dietary supplement products have tested positive for anabolic agents or other prohibited substances. It is important for the consumer to adhere to safe supplementation strategies, which include following serving size recommendations, cross-referencing ingredient profiles with the list of prohibited substances, choosing quality products that have been verified by a third-party certification program, and being cognizant of consuming multiple dietary supplement products with overlapping ingredient profiles. Once these practices have been considered, it is reasonable for an athlete to utilize dietary supplements as a strategy to optimize performance and health, with a low risk of failing a drug test (adverse analytical finding) and experiencing adverse events.

Notifications and Health Consequences of Unauthorized Pharmaceuticals in Food Supplements

Health concerns associated with the consumption of food supplements rise in parallel with the rise in the popularity and market availability of these products. In pursuit of data related to the unauthorized presence of pharmaceuticals in food supplements, the Rapid Alert System for Food and Feed (RASFF) database was searched for the 2011-2022 period. The most "popular" pharmaceuticals for the adulteration of food supplements were phosphodiesterase-5 inhibitors (235 records); anorexics and laxatives (76), including sibutramine and its active metabolite N-didesmethyl sibutramine, phenolphthalein and 2,4-dinitrophenol; stimulants, among which 1,3-dimethylamine (97), and synephrine (53) were the most numerous; nootropic drugs (24); anabolics and prohormones (16); and cannabinoid cannabidiol (14) (pending authorization as a novel food ingredient). Over 65% of notifications of interest were classified as serious risks, and over 80% of these were alert or border rejection notifications, mainly generated as a result of official control on the market. The alarming number of RASFF notifications should be considered a public health issue, demanding clear and targeted recommendation for action for the legislature and authorities. A harmonized nutrivigilance system should be considered as a tool to detect and scrutinize the adverse health effects of food supplements, along with measures to improve their safety, quality, and testing.

The Safety and Efficacy of Citrus aurantium (Bitter Orange) Extracts and p-Synephrine: A Systematic Review and Meta-Analysis

Synephrine has been used to promote weight loss; however, its safety and efficacy have not been fully established. The goals of our study were to give an overview of the safety and efficacy of p-synephrine, to systematically evaluate its efficacy regarding weight loss and to assess its safety, focusing on its cardiovascular side effects in a meta-analysis. PubMed, the Cochrane Library, Web of Science and Embase were searched for relevant studies. Only placebo-controlled, human clinical trials with synephrine intervention were included in the meta-analysis. The meta-analysis was reported according to the PRISMA guidelines using the PICOS format and taking into account the CONSORT recommendations. Altogether, 18 articles were included in the meta-analysis. Both systolic and diastolic blood pressure (DBP) increased significantly after prolonged use (6.37 mmHg, 95% CI: 1.02–11.72, p = 0.02 and 4.33 mmHg, 95% CI: 0.48–8.18, p = 0.03, respectively). The weight loss in the synephrine group was non-significant after prolonged treatment, and it did not influence body composition parameters. Based on the analyzed clinical studies, synephrine tends to raise blood pressure and heart rate, and there is no evidence that synephrine can facilitate weight loss. Further studies are needed to confirm evidence of its safety and efficacy.

Undeclared Doping Substances are Highly Prevalent in Commercial Sports Nutrition Supplements

Sports nutrition supplements have previously been reported to contain undeclared doping substances. The use of such supplements can lead to general health risks and may give rise to unintentional doping violations in elite sports. To assess the prevalence of doping substances in a range of high-risk sports nutrition supplements available from Dutch web shops. A total of 66 sports nutrition supplements - identified as potentially high-risk products claiming to modulate hormone regulation, stimulate muscle mass gain, increase fat loss, and/or boost energy - were selected from 21 different brands and purchased from 17 web shops. All products were analyzed for doping substances by the UK life sciences testing company LGC, formerly known as the Laboratory of the Government Chemist, using an extended version of their ISO17025 accredited nutritional supplement screen. A total of 25 out of the 66 products (38%) contained undeclared doping substances, which included high levels of the stimulants oxilofrine, β-methylphenethylamine (BMPEA) and N,β-dimethylphenethylamine (NBDMPEA), the stimulant 4-methylhexan-2-amine (methylhexaneamine, 1,3-dimethylamylamine, DMAA), the anabolic steroids boldione (1,4-androstadiene-3,17-dione) and 5-androstene-3β,17α-diol (17α-AED), the beta-2 agonist higenamine and the beta-blocker bisoprolol. Based upon the recommended dose and the potential variability of analyte concentration, the ingestion of some products identified within this study could pose a significant risk of unintentional doping violations. In addition to inadvertent doping risks, the prescribed use of 3 products (4.5%) could likely impose general health risks.

Racemic synephrine found in Citrus aurantium-listing pre-workout supplements suggests a non-plant-based origin

Multi-ingredient pre-workout supplements (MIPS) contain Citrus aurantium as a source of bioactive amines such as p-synephrine, but concerns regarding the authenticity of ingredients in some supplements as well as adverse effects from consumption have been raised. R-(-)-Synephrine is the predominant enantiomer in Citrus aurantium extracts while synthetic preparations are often racemic. The aims of this study were to develop a screening method to determine the ratio of synephrine enantiomers in pre-workout supplements listing Citrus aurantium and to assess the ingredient authenticity by directly comparing their ratios to that found in Citrus aurantium standardised reference materials (SRMs). Quantification of enantiomers in the supplements and SRMs was achieved using a validated, high-performance liquid chromatography-single quadrupole mass spectrometry (HPLC-UV-QDa) direct enantioseparation method with a cellobiohydrolase (CBH) column (100 × 4.0 mm, 5 μM) and UV detection at 225 nm. Citrus aurantium SRMs were found to have an average enantiomeric ratio of 94:6 (R:S) with total synephrine ranging from 5.7 to 90.2 mg/g. Within the pilot sample of pre-workout supplements tested, only 42% (5/12) had enantiomeric ratios consistent with the SRMs with total synephrine ranging from 0.03 to 91.2 mg/g. For the remaining supplements, four had racemic ratios of synephrine (0.14 to 5.4 mg/g), two lacked any detectable levels of synephrine, and one had solely the S-(+)-enantiomer (0.15 mg/g). These results bring the authenticity of labelling of some pre-workout supplements into question and highlight the need for more stringent labelling regulations and testing for dietary supplements.

Melatonin Use in Pediatrics: Evaluating the Discrepancy in Evidence Based on Country and Regulations Regarding Production

Melatonin manufacturers in the United States have begun producing melatonin products specifically targeted for use in the pediatric population. This paper aims to critically evaluate the evidence available regarding the use of melatonin in children based on where the clinical trials are performed and the regulations regarding the production of melatonin in that country. Melatonin is regulated differently around the world with the least amount of regulation placed on OTC supplements in the United States. The majority of studies evaluating melatonin use in the pediatric population are conducted with children who have comorbidities, such as autism spectrum disorder or attention-deficit/hyperactivity disorder. Evidence supporting the use of US formulations of melatonin in the otherwise healthy pediatric population is non-existent. Based on the lack of safety regulations in place in the United States and the lack of evidence regarding US melatonin products, they should be used sparingly in the otherwise healthy pediatric population, if they are used at all.

HPLC-UV-QDa analysis of Citrus aurantium-labelled pre-workout supplements suggest only a minority contain the plant extract

Bitter orange (Citrus aurantium) is a common ingredient in pre-workout supplements with purported weight-loss and performance-enhancing effects. Supplements listing Citrus aurantium or p-synephrine have been associated with reports of adverse cardiovascular events attributed to the active biogenic amines, p-synephrine, p-octopamine or p-tyramine. Additionally, questions have been raised as to the authenticity of the plant-derived active components listed on the supplement labels. The aim of this study was to determine the quantities of these amines in a sample of pre-workout supplements which specifically listed Citrus aurantium, and assess the authenticity of plant material by comparing the ratios of amines found to that found in Citrus aurantium standardized reference materials (SRM). The quantities of amines in the supplements and SRMs were determined using a validated high-performance liquid chromatography-single quadrupole mass spectrometry (HPLC-UV-QDa) method. In the Citrus aurantium SRMs the quantities of trace amines found ranged from 5.30 to 38.00 mg/g (synephrine) 0.14-0.35 mg/g (octopamine) and 0.15-1.90 mg/g (tyramine) with an average ratio of 100:1:5 (synephrine: octopamine: tyramine). Only 42 % (5/12) of the supplements tested had ratios consistent with that found in the SRMs. The average trace amine ratio in those supplements was 100:1:3 while the quantities of trace amines found ranged from 0.35 to 31.31 mg/g (synephrine); 0.005 - 0.10 mg/g (octopamine) and 0.01-1.51 mg/g (tyramine). For the remaining supplements, some did not contain any detectable levels of trace amines or only synephrine was detected with concentrations ranging from 0.003 - 0.95 mg/g. These results suggest a role for authenticity/quality assurance testing of pre-workout supplements and more stringent regulation of pre-workout supplements.

Lessons for Local Policy Initiatives to Address Dietary Supplement Use Among Adolescents: A Qualitative Study of Stakeholders' Perceptions

PURPOSE

Weight-loss and muscle-building dietary supplements can have adverse health consequences for youth. At a time, when the Food and Drug Administration is considering increasing oversight of dietary supplements, this study aimed to explore community stakeholders' perceptions about the use of and access to such supplements among adolescents and to identify challenges and opportunities to engage stakeholders with policy initiatives to curtail youth access to supplements at the local level.

METHOD

We conducted 32 key informant semistructured interviews in four municipalities in Massachusetts with purposefully selected participants representing three categories of community stakeholders who could contribute to policy agenda setting at the local level: policy professionals, youth service providers, and young adults aged 18-25 years who used weight-loss or muscle-building supplements as minors. Interviews were audio-recorded, transcribed, deidentified, and analyzed using thematic analysis approach, facilitated by Dedoose software.

RESULTS

Community stakeholders reported wide availability and easy access to dietary supplements. Most participants were unaware of health risks. Many stakeholders did not perceive the use of these products as an issue impacting youth in their communities. The challenges identified in engaging stakeholders were competing concerns on the policy agenda, limited capacity of stakeholders, and uncertainty about who is accountable for the problem.

CONCLUSION

This study indicates the need for complementary, multipronged approaches at the municipal level to address the problem of weak regulation and easy access to potentially dangerous weight-loss and muscle-building supplements for youth.

Acute Liver Failure Caused by Use of Fat Burner: A Case Report

Acute liver failure is a rare condition consisting of abrupt and extensive hepatocyte injury, leading to significant liver dysfunction associated with a high mortality. Liver transplantation is the most effective treatment in severe cases. The most common cause of acute liver failure in Western countries is drug-induced liver injury caused by prescription drugs and herbal and dietary supplements. Thermogenics, or fat burners, are a category of dietary supplements that claim to increase the resting metabolic rate, leading to weight loss. There are previous reports of acute liver failure associated with specific thermogenic formulations. We report the case of a 36-year-old male patient who developed jaundice 7 days after he started taking a thermogenic dietary supplement (Thermo Gun), with progressive deterioration of hepatic function and development of hepatic encephalopathy 19 days after the beginning of the symptoms. He had a Model for End-Stage Liver Disease score of 38 and fulfilled 4 of the King's College Criteria for poor prognosis in patients with acute liver failure. He underwent liver transplantation, receiving a graft from a cadaveric donor, and is alive with good liver graft function 2 years after the transplant. No possible causes for acute liver injury were identified other than the use of the supplement, which contained N-acetyl-L-tyrosine; 1,3,7-trimenthylxanthine; white willow; and 1-hydroxypholedrine. We found no previous reports in the literature of acute liver failure associated with those particular substances. This manuscript is compliant with the Helsinki Congress and the Istanbul Declaration.

Pharmacological profiles of compounds in preworkout supplements ("boosters")

Preworkout supplements ("boosters") are used to enhance physical and mental performance during workouts. These products may contain various chemical substances with undefined pharmacological activity. We investigated whether substances that are contained in commercially available athletic multiple-ingredient preworkout supplements exert amphetamine-type activity at norepinephrine, dopamine, and serotonin transporters (NET, DAT, and SERT, respectively). We assessed the in vitro monoamine transporter inhibition potencies of the substances using human embryonic kidney 293 cells that expressed the human NET, DAT, and SERT. The phenethylamines β-phenethylamine, N-methylphenethylamine, β-methylphenethylamine, N-benzylphenethylamine, N-methyl-β-methylphenethylamine, and methylsynephrine inhibited the NET and less potently the DAT similarly to D-amphetamine. β-phenethylamine was the most potent, with IC₅₀ values of 0.05 and 1.8 μM at the NET and DAT, respectively. These IC₅₀ values were comparable to D-amphetamine (IC₅₀ = 0.09 and 1.3 μM, respectively). The alkylamines 1,3-dimethylbutylamine and 1,3-dimethylamylamine blocked the NET but not the DAT. Most of the phenethylamines interacted with trace amine-associated receptor 1, serotonin 5-hydroxytryptamine-1A receptor, and adrenergic α_1A and α_2A receptors at submicromolar concentrations. None of the compounds blocked the SERT. In conclusion, products that are used by athletes may contain substances with mainly noradrenergic amphetamine-type properties.

Using the Dietary Supplement Label Database to Identify Potentially Harmful Dietary Supplement Ingredients

Over half of young adults, athletes, and Military Service Members self-report using at least one dietary supplement (DS) 1 or more times per week. DS may be consumed to improve health, provide more energy, increase muscle strength, and/or enhance performance. The United States Food and Drug Administration (FDA) has raised concerns regarding adulteration, safety, and adverse events associated with DS marketed for brain health and bodybuilding. Some DS products may compromise health as well as lead to a serious adverse event. The National Institutes of Health (NIH) Dietary Supplement Label Database (DSLD), available at https://dsld.nlm.nih.gov/, can be freely accessed and used by researchers, providers, and consumers alike to screen for potentially harmful DS. It was developed to serve the research community and as a resource for health care providers and the public. Herein we provide two examples of how the database can be used to identify DS ingredients of concern in products marketed for brain health and bodybuilding. The search for DS marketed for brain health returned 49 unique DS, and the search on DS marketed for bodybuilding returned 18 unique DS. Search results were cross-referenced with the Operation Supplement Safety High-Risk Supplement List, the FDA Tainted Products Marketed as Dietary Supplements list, the Natural Medicines database, and NIH Office of Dietary Supplements Fact Sheets. Three ingredients found in DS marketed for brain health and two ingredients in DS marketed for bodybuilding were identified as "of concern". Educational tools, including the DSLD, can help consumers and providers make informed decisions regarding DS.

Making Decisions About Supplement Use

The use of dietary supplements is widespread among athletes in all sports and at all levels of competition, as it is in the general population. For the athlete training at the limits of what is sustainable, or for those seeking a shortcut to achieving their aims, supplements offer the prospect of bridging the gap between success and failure. Surveys show, however, that this is often not an informed choice and that the knowledge level among consumers is often low and that they are often influenced in their decisions by individuals with an equally inadequate understanding of the issues at stake. Supplement use may do more harm than good, unless it is based on a sound analysis of the evidence. Where a deficiency of an essential nutrient has been established by appropriate investigations, supplementation can provide a rapid and effective correction of the problem. Supplements can also provide a convenient and time-efficient solution to achieving the necessary intake of key nutrients such as protein and carbohydrate. Athletes contemplating the use of supplements should consider the potential for both positive and negative outcomes. Some ergogenic supplements may be of benefit to some athletes in some specific contexts, but many are less effective than is claimed. Some may be harmful to health of performance and some may contain agents prohibited by anti-doping regulations. Athletes should make informed choices that maximize the benefits while minimizing the risks.

Dietary Supplements in Children

High-quality systematic reviews of use of herbal or homeopathic remedies in children often suffer from design flaws, such as not following PRISMA guidelines, inconsistent outcome measurements, and paucity of high-quality studies. Herbal remedies have modest demonstrated benefits with insufficient evidence to recommend any particular supplement. Homeopathic remedies have no role in treatment of pediatric conditions, and have been associated with great harm in infants given homeopathic teething products. Two types of herbal supplements are associated with high risk in adolescents, energy drinks and adulterated weight-loss products. Parents should be counseled about risks of these products.

Safety, Efficacy, and Mechanistic Studies Regarding Citrus aurantium (Bitter Orange) Extract and p-Synephrine

Citrus aurantium L. (bitter orange) extracts that contain p-synephrine as the primary protoalkaloid are widely used for weight loss/weight management, sports performance, appetite control, energy, and mental focus and cognition. Questions have been raised about the safety of p-synephrine because it has some structural similarity to ephedrine. This review focuses on current human, animal, in vitro, and mechanistic studies that address the safety, efficacy, and mechanisms of action of bitter orange extracts and p-synephrine. Numerous studies have been conducted with respect to p-synephrine and bitter orange extract because ephedra and ephedrine were banned from use in dietary supplements in 2004. Approximately 30 human studies indicate that p-synephrine and bitter orange extracts do not result in cardiovascular effects and do not act as stimulants at commonly used doses. Mechanistic studies suggest that p-synephrine exerts its effects through multiple actions, which are discussed. Because p-synephrine exhibits greater adrenergic receptor binding in rodents than humans, data from animals cannot be directly extrapolated to humans. This review, as well as several other assessments published in recent years, has concluded that bitter orange extract and p-synephrine are safe for use in dietary supplements and foods at the commonly used doses. Copyright © 2017 The Authors Phytotherapy Research Published by John Wiley & Sons Ltd.