The science-to-practice supplementation gap in European elite soccer

To evaluate supplement potential and practice in this context, an international team of sports performance researchers reviewed soccer-specific supplement research combined with survey data on how practitioners implement supplementation strategies in elite professional sport.

“We found that elite soccer teams across Europe consistently use supplements like creatine, caffeine and protein, yet other supplements with strong evidence, such as nitrates, sodium bicarbonate and tart cherry, remain underused,” said Ralf Jäger, PhD, managing member of consulting company Increnovo and author on the paper. “It highlights a clear science-to-practice gap between what’s proven and what’s actually applied at the club level.”

Published in the Journal of Functional Morphology and Kinesiology, the review brought together researchers from the University of Bologna, Manchester City Football Club, Laboratoire Sport, Expertise and Performance INSEP, University of Study of Bari and Increnovo.

What the science says

For their literature review, the researchers searched the PubMed, EMBASE, Scopus and Web of Science databases from March 2024 to March 2025 to identify studies published in English and conducted in soccer players. The aim of the selection was to go beyond empirical findings and include studies that conceptually discussed the role of dietary supplements in soccer performance.

According to the studies reviewed, acute caffeine ingestion consumed 60 minutes before a 90-minute soccer-specific simulation substantially improved jump height and passing accuracy. Short-term supplementation (20 g/day for 5 days) with creatine may improve agility and used to enhance performance for either training or competitive periods, preventing and minimizing performance declines during busy match schedules. Protein supplementation was linked to improved maximum and average running speed, sprint times and even concentric and eccentric isokinetic peak torque of the knee extensors and flexors.

The review also assessed other supplements with less studied performance endpoints, including beta-alanine, sodium bicarbonate and tart cherry.

Despite mixed results, beta-alanine may help soccer players by increasing muscle carnosine levels and reducing proton accumulation—primary contributors to fatigue during high-intensity exercise. Buffering effects are relevant for modern soccer activities such as pressing, curved sprints, rapid tactical changes, and repeated jumping tasks. The researchers noted that “beta-alanine should be considered an emerging supplement with potential” but that further investigation is needed before it can be recommended for routine use in soccer.

Sodium bicarbonate also enhances buffering capacity, with researching indicating the potential to improve sprint performance and agility in elite soccer players. A recent consensus statement from the International Olympic Committee recommends ingesting 200 to 400 mg/kg body mass of sodium bicarbonate with a small, carbohydrate-dense meal approximately 120 to 150 minutes before exercise.

“Although the precise physiological mechanisms underlying its ergogenic effects remain unclear, meta-analyses have reported performance improvements of approximately 2–3% across various metrics, including power output, speed, work capacity and time to exhaustion, during single and repeated bouts of high-intensity exercise lasting 1–10 min," the researchers reported. They noted, however, that sodium bicarbonate is often combined with other supplements for synergistic effects, making it difficult to discern which supplement contributed to a specific benefit.

Tart cherry juice is being studied as a recovery aid for athletes due to its antioxidant and anti-inflammatory properties, which may help reduce exercise-induced stress and improve readiness for training and competition. However, research in soccer players shows mixed results, with some studies finding benefits for recovery and others not, possibly due to differences in study design and participant characteristics. Despite limited evidence, many soccer players use tart cherry concentrate after evening matches, as emerging research suggests it may also improve sleep quality and duration, which is important for recovery.

Supplementation in practice

The researchers also drew from a survey of 50 practitioners who worked with elite soccer players for more than two years.

These included physicians, nutritionists, heads of performance, sport scientists and strength and conditioning coaches across across the five highest-ranked European soccer leagues, with the largest proportion coming from the Italian Serie A (30%), followed by the English Premier League (25%), Spanish La Liga (20%), German Bundesliga (15%), and French Ligue 1 (10%).

“The uniqueness lies in collecting real-world data directly from top European clubs,” Dr. Jäger said. “Most studies are done in labs; this one shows how performance nutrition is truly applied inside professional locker rooms and training facilities.”

The 20-question survey based on the 5-point Likert scale investigated the perceptions, attitudes and practices regarding dietary supplement use in elite soccer. It collected information on the types of supplements used or recommended, as well as details on formulation, dosage and timing strategies.

Most practitioners were interested in performance supplements and a majority of those used those supplements in their practice. All practitioners who recommended creatine did so in the monohydrate form. Protein powders were regularly used by players as well, with 85% of practitioners recommending protein supplementation post-exercise, often combined with carbohydrates and creatine. Caffeine supplementation was typical for match days, usually consumed 30 to 60 minutes before kick-off via energy shots or gummies

“Supplements with strong and consistent evidence, such as creatine and caffeine, were widely implemented, whereas those with emerging or mixed evidence, such as beta-alanine, tart cherry and sodium bicarbonate, were only partially integrated into daily routines,” the researchers noted.

Regarding perceptions of efficacy and safety, 63.5% of practitioners believed that such supplements are both effective and safe.

Exploring the science-to-practice gap

These findings suggest that while scientific evidence provides the groundwork for supplementation efficacy and its connection to soccer performance, the translation of this evidence into elite soccer settings is limited. This is possibly due to gaps in practitioner knowledge, lack of familiarity with certain supplements or practical barriers to implementation.

“Although the scientific literature identifies several supplements with robust ergogenic or recovery benefits, the survey reveals a notable gap between controlled research findings and applied practice in elite soccer,” the researchers reported.

The review highlighted several factors as barriers to the adoption of supplements like beta-alanine, tart cherry and sodium bicarbonate, including gastrointestinal tolerance, individual preferences, cultural beliefs and logistical barriers (e.g., dosing complexity and timing).

“Sodium bicarbonate, despite meta-analytic evidence supporting its benefits for repeated high-intensity exercise, was recommended by only 24% of practitioners,” the researchers noted. “While gastrointestinal side effects and the complexity of timing protocols are frequently cited in the literature as barriers to its use, our findings also highlight a broader challenge, that evidence from research is not always effectively disseminated to or integrated by practitioners, which may contribute to the low adoption of this supplement in applied settings.”

Dietary nitrate and tart cherry have both shown potential to beneficially impact exercise tolerance and recovery but were used less frequently. Glycerol may serve as a hyperhydration strategy in hot environments but was recommended by less than 15% by practitioners.

Beyond a limited dissemination of scientific evidence, other factors can be a significant barrier to supplement adoption, including religious and cultural expectations.

For example, Muslim players observing Ramadan abstain from eating and drinking from dawn to dusk, which may impact supplement planning. Country of origin can also influence nutritional norms. English players consumed substantially more protein than Dutch or Scottish players.

A study of Spanish First Division Soccer League Club players also found nutritional intake and eating patterns often varied depending on the athletes playing position. Here, understanding preference can inform the development of personalized supplementation plans.

“What stood out most was how culture, logistics and practicality, taste, gut comfort, player routines, still shape supplement use as much as science,” Dr. Jäger said. “Bridging that human-science gap is where the biggest progress in performance nutrition will happen. And as a youth coach and lifelong soccer fan, it was fascinating to see firsthand how different teams, from the French National Team to Manchester City, approach nutrition at the highest level.”

Source: Journal of Functional Morphology and Kinesiology. doi: doi.org/10.3390/jfmk10040408 “From Science to Dressing Room: Dietary Supplements for Elite Soccer Performance”. Authors: Tindaro Bongiovanni et al.