Does Vitamin D Make Soccer Players Faster? A New Study Suggests It Depends
Vitamin D has become one of the more talked-about supplements in sports nutrition. The logic seems straightforward: vitamin D plays a role in muscle function, bone health, calcium regulation, and immune function—all things that matter to soccer players.
So if vitamin D is important for athletic performance, taking more of it should make you faster or more powerful, right?
Not necessarily.
A new randomized controlled trial involving professional female soccer players tested exactly that question. After eight weeks, players taking 4,000 IU of vitamin D3 per day did not improve their sprinting, repeated-sprint ability, or jumping performance more than players taking a placebo.
But there is an important wrinkle in those findings—and it may be the most useful part of the study for players and coaches.
Most of the athletes already had adequate vitamin D levels.
In other words, this may be less a story about vitamin D “not working” and more a story about why supplementation should address an actual need rather than simply be added in hopes of gaining a performance advantage.
Why Vitamin D Matters in Soccer
Soccer places unusual demands on the body.
A player may spend much of a match running at relatively low intensity, only to suddenly accelerate, sprint, jump, tackle, change direction, or battle for the ball. Speed and muscular power matter, although the researchers appropriately point out that soccer performance also depends on agility, reaction time, perception, and decision-making.
Vitamin D is potentially relevant because it participates in several physiological processes important to athletes, including skeletal muscle function, calcium regulation, immune function, and erythropoiesis—the process involved in producing red blood cells. But having a biological reason why vitamin D could matter is different from demonstrating that taking a supplement actually improves performance.
Previous research has been mixed, and the authors note that potential benefits appear more likely among athletes who begin with low vitamin D levels. Female soccer players are also particularly important to study because women remain underrepresented in sports nutrition and supplementation research.
That led researchers to put vitamin D to a fairly rigorous test.
What Did the Researchers Do?
The study included 18 professional female soccer players competing in Poland’s Women’s Ekstraliga, the country’s highest level of women’s soccer.
These weren’t casual players. They averaged about seven years of training experience and had been participating in at least five training sessions per week. Researchers randomly divided them into two groups of nine. For eight weeks:
- One group received 4,000 IU of vitamin D3 per day.
- The other received an identical-looking placebo.
Neither the players nor the investigators conducting the performance testing and analysis knew which players were receiving vitamin D until the analysis was completed.
Meanwhile, the players continued a substantial training schedule. They generally trained on the field daily for approximately two hours, completed strength and conditioning sessions twice per week, and eventually played league matches on weekends.
Before and after the intervention, researchers measured several things highly relevant to soccer performance.
Sprint speed
Players performed maximal 30-meter sprints, with times measured at both 5 meters and 30 meters.
The 5-meter time provides a useful window into acceleration, while the longer distance captures more of a player’s sprinting capability.
Repeated sprint ability
Players also completed the Running-Based Anaerobic Sprint Test (RAST): six maximal 30-meter sprints separated by 25 seconds of active recovery.
That is particularly interesting for soccer because players don’t simply sprint once. They repeatedly produce high-intensity efforts while recovering for relatively short periods.
Jump performance
Researchers measured bilateral and single-leg countermovement jumps using force plates, examining variables including jump height, peak power, and peak force.
They also collected blood samples and measured vitamin D metabolites and several hematological markers.
In short, this wasn’t simply a questionnaire asking players whether they felt faster. Researchers directly tested physical qualities relevant to soccer.
So, Did Vitamin D Make the Players Faster?
No—not compared with placebo.
There were no significant group-by-time differences for the 5-meter sprint, 30-meter sprint, repeated-sprint test, bilateral jump power, peak force, bilateral jump height, or most of the other performance measures. One isolated interaction involving left-leg jump height was considered exploratory rather than evidence of a vitamin-D effect.
Here’s where the study gets especially interesting.
The players did get better at several things.
For example, 30-meter sprint performance improved over time. Repeated-sprint performance improved too, along with several jump measures.
But those improvements weren’t unique to the vitamin D group.
Both groups were training.
The researchers therefore concluded that the improvements were more consistent with adaptations to the players’ training program than an effect of supplementation.
That’s an important lesson that extends well beyond vitamin D.
The Boring Thing Worked: Training
Athletes are constantly exposed to products promising marginal gains.
Supplements are especially attractive because they’re easy. Taking a capsule requires far less effort than completing another carefully designed training cycle.
But look at what happened here.
Players trained.
Players got faster.
Players improved their repeated-sprint ability.
And adding 4,000 IU of vitamin D per day did not produce additional measurable improvements compared with placebo.
For coaches, that’s a useful reminder about priorities.
Training remains the intervention doing most of the heavy lifting.
That doesn’t mean nutrition doesn’t matter. It means supplements shouldn’t automatically be treated as performance enhancers simply because a nutrient has an important physiological function.
But There’s a Big Catch: Most Players Weren’t Vitamin D Deficient
This is probably the most important qualification in the entire study.
At baseline, approximately one-quarter of the players had vitamin D concentrations at or below 30 ng/mL, while most were above that level.
So the study mostly tested this question:
Does giving relatively high-dose vitamin D to professional female players who mostly already have sufficient vitamin D make them faster or more powerful?
Based on this small study, the answer appears to be probably not.
That’s very different from asking:
Can correcting a genuine vitamin D deficiency improve performance or health?
This study cannot confidently answer that question.
There were too few vitamin-D-insufficient players to determine whether those athletes responded differently. The authors specifically call for larger trials involving female athletes with confirmed vitamin D insufficiency or deficiency.
That distinction matters enormously.
Think about it like hydration. Water is essential for performance. But that doesn’t mean an adequately hydrated player becomes progressively faster by drinking more and more water.
Correcting a deficiency and exceeding an adequate level are two different things.
Vitamin D may work similarly.
What This Means for Soccer Players
The takeaway shouldn’t be “vitamin D doesn’t matter.”
Instead, it should be:
Don’t assume taking more vitamin D will automatically improve your performance.
If your vitamin D status is already adequate, this study provides little reason to expect eight weeks of 4,000 IU/day to suddenly increase your sprint speed or jumping ability.
That shifts the question from: “Should I take vitamin D to become faster?”
to: “Do I actually have a vitamin D problem that needs to be addressed?”
That’s a much better question.
Players concerned about vitamin D—particularly during winter, periods of limited sun exposure, or because of individual nutritional or medical factors—should discuss testing and supplementation with an appropriate healthcare or sports-nutrition professional rather than treating supplementation as a DIY performance hack.
The researchers similarly argue for individualized supplementation based on baseline status and biochemical monitoring, rather than simply escalating doses for every athlete.
What This Means for Coaches
Several useful coaching lessons emerge.
1. Don’t confuse supplementation with performance training
If your goal is faster players, training speed is still the obvious place to start. Acceleration mechanics, maximal-speed exposure, strength development, repeated-sprint conditioning, adequate recovery, and progressive training loads all directly address the qualities you’re trying to improve. A supplement shouldn’t become a substitute for good programming.
2. Think “identify and correct,” not “more is better”
Nutrition should support training. If an athlete has a deficiency, identifying and appropriately correcting it may be important for health and potentially performance. But supplementing an athlete who is already sufficient may provide little additional benefit. That’s a fundamentally different philosophy from giving every player the same supplement.
3. Be especially thoughtful with youth players
This study involved adult professional female players from one team, not children or adolescents. The authors explicitly warn against directly extrapolating the findings to younger athletes, male athletes, recreational players, or athletes with confirmed vitamin D deficiency.
Youth coaches therefore shouldn’t read this study as evidence either for or against giving vitamin D supplements to their players.
Supplement decisions involving young athletes belong with parents, physicians, dietitians, and other appropriately qualified professionals—not the coach handing out pills in the locker room.
4. Remember that female athletes deserve better evidence
This study also highlights a larger issue in sports science. Professional women’s soccer has grown dramatically, but female athletes remain comparatively understudied in sports nutrition research. The researchers specifically identified that evidence gap as part of the reason for conducting the trial. Training and nutrition recommendations shouldn’t automatically assume that findings from male players transfer perfectly to female players. More research specifically involving female soccer players is needed.
There Are Important Limitations
This was a randomized, double-blind, placebo-controlled trial—a strong experimental design—but it was also very small.
There were only 18 players, with nine in each group. That means the study had limited ability to detect smaller effects. The researchers explicitly caution that a nonsignificant finding shouldn’t be interpreted as definitive evidence that vitamin D can never have an effect. The intervention also lasted only eight weeks.
Researchers didn’t systematically measure several factors that could influence vitamin D status or athletic performance, including dietary vitamin D and calcium intake, individual sunlight exposure, skin phototype, menstrual-cycle phase, hormonal contraceptive use, and menstrual dysfunction.
And because all participants came from one professional women’s team, we should be cautious about generalizing the findings to the entire soccer population.
So this isn’t the final word on vitamin D and soccer. It is one useful piece of a much larger puzzle.
The Bottom Line
After eight weeks, 4,000 IU of vitamin D3 per day did not provide an additional boost to sprint speed, repeated-sprint ability, strength, or jumping performance compared with placebo in these professional female soccer players.
But that doesn’t mean vitamin D is irrelevant.
About one-quarter of these elite players still had insufficient vitamin D status after the summer, suggesting that outdoor training alone doesn’t guarantee adequate levels for every athlete.
The practical lesson is more nuanced—and more useful: Optimize deficiencies. Don’t chase excess.
For players, supplements aren’t shortcuts to speed. For coaches, good training remains the foundation. And for both, nutrition decisions are probably best made by figuring out what an individual athlete actually needs rather than assuming that if some vitamin D is important, more must be better.
