Potential risks of dietary supplements for weight loss containing synephrine and caffeine available in Portugal
Palabras clave:
Caffeine, Citrus aurantium, Dietary supplements, Synephrine, Toxicity, Weight LossResumen
Objective
Caffeine and synephrine are normally included in weight loss products due to their claimed thermogenic effects. We aimed to determine the amount of caffeine and synephrine in dietary supplements available on websites that could ship to Portugal. We also aimed to check if levels comply with those recommended by health and food authorities.
Methods
This observational study conducted a search on platforms selling dietary supplements and examined their labeling. The inclusion criteria were supplements containing both synephrine and caffeine, regardless of quantity or use. The exclusion criteria were products in which only one of the components was present or in which the formula and ingredient amounts were not fully described on the label.
Results
Within the established inclusion and exclusion criteria, 20 dietary supplements were found. Supplements contained synephrine in the form of bitter orange extract (Citrus aurantium). A median of 153 mg (95% CI: 40-334) was found for the extract. The estimated synephrine levels for those extracts were a median of 11 mg (95% CI: 6-20). Regarding caffeine, the median for content was 200
mg (95% CI: 176-250), though the real value is higher, given the presence of several vegetable sources of caffeine. Moreover, 65% of supplements exceed the limits recommended by the German Federal Institute for Risk Assessment for synephrine levels, and 30% exceed 200mg of caffeine.
Conclusion
It was possible to conclude that 65% and 30% of dietary supplements exceed the levels recommended by food security agencies for synephrine and caffeine, respectively, which might carry potential health risks for the consumer.
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Gutierrez-Hellin J, Aguilar-Navarro M, Ruiz-Moreno C, Munoz A, Amaro-Gahete FJ, Posada-Ayala M, et al. Effect of p-Synephrine on Fat Oxidation Rate during Exercise of Increasing Intensity in Healthy Active Women. Nutrients. 2022;14(20):4352. doi: https://doi.org/10.3390/nu14204352
Gutierrez-Hellin J, Del Coso J. Effects of p-Synephrine and Caffeine Ingestion on Substrate Oxidation during Exercise. Med Sci Sports Exerc. 2018;50(9):1899-906. doi: https://doi.org/10.1249/MSS.0000000000001653
Guest NS, VanDusseldorp TA, Nelson MT, Grgic J, Schoenfeld BJ, Jenkins NDM, et al. International society of sports nutrition position stand: caffeine and exercise performance. J Int Soc Sports Nutr. 2021;18(1):1. doi: https://doi.org/10.1186/s12970-020-00383-4
Clark NW, Wells AJ, Coker NA, Goldstein ER, Herring CH, Starling-Smith TM, et al. The acute effects of thermogenic fitness drink formulas containing 140 mg and 100 mg of caffeine on energy expenditure and fat metabolism at rest and during exercise. J Int Soc Sports Nutr. 2020;17(1):10. doi: https://doi.org/10.1186/s12970-020-0341-4
Rodak K, Kokot I, Kratz EM. Caffeine as a factor influencing the functioning of the human body-friend or foe? Nutrients. 2021;13(9):3088. doi: https://doi.org/10.3390/nu13093088
Agostoni C, Canani RB, Fairweather-Tait S, Heinonen M, Korhonen H, La Vieille S, et al. Scientific Opinion on the safety of caffeine. Efsa J. 2015;13(5):4102. doi: https://doi.org/10.2903/j.efsa.2015.4102
Ruiz-Moreno C, Del Coso J, Giraldez-Costas V, Gonzalez-Garcia J, Gutierrez-Hellin J. Effects of p-Synephrine during exercise: a brief narrative review. Nutrients. 2021;13(1):233. doi: https://doi.org/10.3390/nu13010233
Rossato LG, Costa VM, Limberger RP, Bastos ML, Remiao F. Synephrine: from trace concentrations to massive consumption in weight-loss. Food Chem Toxicol. 2011;49(1):8-16. doi: https://doi.org/10.1016/j.fct.2010.11.007
Fernández-Cabal J, Avilés-Betanzos KA, Cauich-Rodríguez JV, Ramírez-Sucre MO, Rodríguez-Buenfil IM. Recent developments in citrus aurantium L.: an overview of bioactive compounds, extraction techniques, and technological applications. Processes. 2025;13(1):120. doi: https://doi.org/10.3390/pr13010120
Gutierrez-Hellin J, Baltazar-Martins G, Rodriguez I, Lara B, Ruiz-Moreno C, Aguilar-Navarro M, et al. p-Synephrine, the main protoalkaloid of Citrus aurantium, raises fat oxidation during exercise in elite cyclists. Eur J Sport Sci. 2021;21(9):1273-82. doi: https://doi.org/10.1080/17461391.2020.1817154
Stohs SJ, Ratamess NA. Effects of p-synephrine in combination with caffeine: a review. Nutr Diet Suppl. 2017;9:87-96. doi: https://doi.org/10.2147/Nds.S144761
Direção Geral de Alimentação e Veterinária. Suplementos alimentares – DGAV 2025. Lisboa: DGAV; 2025 [cited 2025 Mar 6]. Available from: https://www.dgav.pt/alimentos/conteudo/generos-alimenticios/regras-especificas-por-tipo-de-alimentos/suplementos-alimentares/
The Business Research Company. Weight Loss Supplements Global Market Report 2023. United Kingdom: TBRC; 2023 [cited 2024 Jul 15]. Available from: https://www.thebusinessresearchcompany.com/report/weight-loss-supplements-global-market-report
Marques JNAV, Capela JP. Potential health risks surrounding ingredients of pre-workout and postworkout dietary supplements: a thorough label analysis. Rev Nutr. 2022;35:e200148. doi: https://doi.org/10.1590/1678-9865202235e200148
Bundesinstitut für Risikobewertung. Health assessment of sports and weight loss products containing synephrine and caffeine. Germany: Bundesinstitut für Risikobewertung; 2012. Report No.: BfR Opinion No. 004/2013.
Canada H. Guidelines for the use of synephrine in natural health products Canada: Health Canada; 2010 [cited 2024 Jul 15]. Available from: https://www.canada.ca/en/health-canada/services/drugs-healthproducts/natural-non-prescription/legislation-guidelines/guidance-documents/notice-use-synephrine.html
Canada H. Synephrine, Octopamine and Caffeine, Health Risk Assessment (HRA) Repor. Canada; 2011. Report No.: 172091.
ANSES. Dietary supplements for weight loss containing p-synephrine France: ANSES; 2014 [cited 2024 Jul 15]. Available from: https://www.anses.fr/en/content/dietary-supplements-weight-loss-containingp-synephrine
Benjamim CJR, Junior FWS, Porto AA, Rocha EMB, Santana MD, Garner DM, et al. Bitter orange (Citrus aurantium L.) Intake before submaximal aerobic exercise is safe for cardiovascular and autonomic systems in healthy males: a randomized trial. Front Nutr. 2022;9:890388. doi: https://doi.org/10.3389/fnut.2022.890388
Stohs SJ, Ray SD. Review of published bitter orange extract and p-synephrine adverse event clinical study case reports. J Diet Suppl. 2020;17(3):355-63. doi: https://doi.org/10.1080/19390211.2019.1577936
de Jonge MLL, Kieviet LC, Sierts M, Egberink LB, van der Heyden MAG. Review of case reports on adverse events related to pre-workout supplements containing synephrine. Cardiovasc Toxicol. 2023;23(1):1-9. doi: https://doi.org/10.1007/s12012-022-09777-z
Kliszczewicz B, Bechke E, Williamson C, Green Z, Bailey P, McLester J, et al. Citrus Aurantium and caffeine complex versus placebo on biomarkers of metabolism: a double blind crossover design. J Int Soc Sports Nutr. 2019;16(1):4. doi: https://doi.org/10.1186/s12970-019-0271-1
Ratamess NA, Bush JA, Stohs SJ, Ellis NL, Vought IT, O’Grady EA, et al. Acute cardiovascular effects of bitter orange extract (p-synephrine) consumed alone and in combination with caffeine in human subjects: a placebo-controlled, double-blind study. Phytother Res. 2018;32(1):94-102. doi: https://doi.org/10.1002/ptr.5953
Haller CA, Duan M, Jacob P, 3rd, Benowitz N. Human pharmacology of a performance-enhancing dietary supplement under resting and exercise conditions. Br J Clin Pharmacol. 2008;65(6):833-40. doi: https://doi.org/10.1111/j.1365-2125.2008.03144.x
Cohen PA, Avula B, Katragunta K, Travis JC, Khan I. Presence and quantity of botanical ingredients with purported performance-enhancing properties in sports supplements. JAMA Netw Open. 2023;6(7):e2323879. doi: https://doi.org/10.1001/jamanetworkopen.2023.23879
Walpurgis K, Thomas A, Geyer H, Mareck U, Thevis M. Dietary Supplement and Food Contaminations and Their Implications for Doping Controls. Foods. 2020;9(8):1012. doi: https://doi.org/10.3390/foods9081012
Esposito G, Sciuto S, Martello E, Pezzolato M, Bozzetta E. Disclosing frauds in herbal food supplements labeling: a simple lc-ms/ms approach to detect alkaloids and biogenic amines. J Food Prot. 2023;86(10):100152. doi: https://doi.org/10.1016/j.jfp.2023.100152
New Zealand Medicines and Medical Devices Safety Authority. Minutes of the 30th meeting of the Medicines Classification Committee. New Zealand: MEDSAFE; 2003 [cited 2024 Jul 15]. Available from: https://www.medsafe.govt.nz/profs/class/Minutes/2001-2005/mccMin26Nov03.htm.
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Derechos de autor 2025 Catarina Martins Cepêda, João Paulo Capela
Esta obra está bajo una licencia internacional Creative Commons Atribución 4.0.
