Top 5 mejores suplementos para mejorar tu sistema inmunitario si entrenas fuerte

Top 5 best supplements to support your immune system if you train hard

March 17, 2026

TABLE OF CONTENTS

Training hard is powerful, motivating, and transformative…but it also takes a toll on your body if you do not take care of recovery. When you accumulate weeks of heavy training, too little sleep, or eat less than you need, it is easier for typical signs that something is wrong to appear: unusual fatigue, a drop in performance, and that “almost-cold” feeling that keeps coming back.

The good news is that you can protect your defenses with a simple, realistic strategy. And yes, supplements can help…but only when they fit your situation. Let’s take it step by step before showing you which supplements are best for improving your immune system.

Why training hard can take a toll on your defenses

Your immune system does not function at maximum capacity all day; it adapts. With demanding training, travel, stress, insufficient rest, or low energy availability, your body prioritizes survival and performance, and may allocate fewer resources to immunity.

In fact, in high-load situations (for example, long efforts such as marathons), an increased risk of respiratory infection symptoms has been observed in the following days (Sardeli et al., 2024). This does not mean that training is bad (quite the opposite—over the long term, it is usually protective); it means that when you push too hard, recovery matters more than ever.

And here’s the key point: before thinking about “the best supplement,” you’ll gain a lot by getting the basics right (sleep, training density, frequency, and volume).

First things first: sleep, energy, and stress (before taking supplements)

If your goal is a strong, stable immune system, your number-one supplement is usually sleep and recovery.

Sleep: Sleeping too little or poorly is associated with worse recovery and greater vulnerability to illness. In athletes, the impact of insufficient sleep on health and performance is frequently described, and prioritizing routines that protect sleep is recommended (Walsh et al., 2021).
Available energy (eating enough): When you eat less than your training demands (low energy availability), your body goes into conservation mode. In female athletes, even a short period of low energy availability has been shown to cause significant changes in stress and immune-response markers, as well as impair performance (Jeppesen et al., 2024). The IOC consensus on REDs also emphasizes that this situation can affect multiple systems, including the immune system (Mountjoy et al., 2023).

So, before spending money on supplements, you are going to do this:

You are going to ensure 7–9 hours of sleep (or at least improve consistency).
You are going to eat enough (especially around your workouts).
You are going to reduce stress when you can (breathing exercises, walks, clearing your schedule).

With that foundation, we can now talk about the best supplements for improving your immune system.

Vitamin D

Vitamin D is one of the most relevant nutrients for athletes for two reasons:

Many people have low levels, especially in winter or if they spend little time in the sun.
Its relationship with inflammation and immune markers has been studied.

In athletes, a systematic review of controlled trials analyzed vitamin D supplementation and pro-inflammatory markers, showing results that may be especially useful when a pre-existing deficiency is present (Saedmocheshi et al., 2024).

You should take supplements if:

If you suspect a deficiency (little sun exposure, winter, recurring fatigue), ideally get a blood test and professional guidance.
Avoid taking “megadoses” on your own. Vitamin D is fat-soluble, and abusing high doses is not a good idea.

That said, you should keep these two things in mind:

If your vitamin D levels are adequate, supplementation may provide little benefit.
If your levels are low, correcting this is usually a powerful change for your overall health (and potentially for your defenses).

Zinc

Zinc is not magic, but there is fairly solid evidence that it can shorten the duration of a cold when used correctly and promptly.

A recent Cochrane review concludes that zinc may reduce the duration of colds, although results vary and there is an increase in non-serious adverse effects, such as nausea or an unpleasant taste (Nault et al., 2024). In addition, the NIH technical summary also cites meta-analysis evidence showing a reduction in duration, with mixed results for prevention (National Institutes of Health, Office of Dietary Supplements, 2026).

There are some mistakes you should avoid, such as:

Taking high doses “all winter” is a bad idea.
Exceeding the recommended dose over the long term can cause problems, such as interfering with copper.
Zinc usually makes more sense as a short-term strategy at the onset of symptoms, not as an “eternal daily supplement.”

Vitamin C

Vitamin C is a classic. The evidence generally points to something very specific:

In the general population, it does not always reduce the incidence of colds.
But it may reduce duration and/or severity in some contexts, especially with regular use.

A more recent review/meta-analysis supports benefits from “standard” supplementation in reducing the duration of respiratory illness (Keya et al., 2022). And a 2023 paper reviews findings in which Vitamin C is associated with reduced cold severity in certain analyses (Hemilä, 2023).

This translates as follows in everyday life:

If your diet already includes enough fruit and vegetables, you may not need to add more.
If you eat few fruits and vegetables (very common when you are in a hurry), an extra supplement may be a simple help, especially during periods of greater stress and training load.

And keep in mind, Vitamin C cannot make up for sleeping five hours. It is better used as an extra, not as a foundation.

Probiotics

Here is a powerful idea: a large part of your immune system communicates with your gut. That is why probiotics have been studied so extensively in athletes with high training loads.

In athletes, a meta-analysis found that probiotic supplementation may reduce the overall severity of upper respiratory tract infection symptoms, with changes in some inflammatory markers (Łagowska et al., 2021). In addition, more recent reviews and methodological papers emphasize that results depend greatly on the strain, dose, duration, and type of athlete (Mohr et al., 2022; Aykut & Aykut, 2024).

This means that

There is no single “probiotic.” There are specific strains with specific studies.
If you choose one at random, you may notice little benefit.
If you choose it well and use it for a reasonable period, it can be an effective tool, especially if you are someone who catches colds easily when training hard.

They tend to be more effective when:

Periods of high training volume, stress, travel, and irregular sleep.
If you also have digestive discomfort (which is more common among athletes than it may seem, especially with high calorie intake).

Beta-glucans

Beta-glucans (especially from yeast) have been studied as immunomodulators. Recent literature continues to grow, with reviews describing them as promising for supporting immune defenses, although more consistent trials are still needed to establish the “perfect formula” (Habibullah et al., 2025; Edo et al., 2025).

Their functions:

They are an interesting option if you are looking for extra support during periods of high training load.
They are not essential for everyone.
If your budget is limited, I would normally prioritize: Vitamin D (if you are deficient), a well-chosen probiotic (if it suits you), and zinc occasionally.

Advanced immune support

Advanced Immune from Moremuscle is useful for improving your immune system if you train hard because it combines nutrients that cover precisely what is most depleted during intense exercise. During hard training, oxidative stress increases, inflammation rises, and your immune system becomes more vulnerable. This formula helps offset that:

Vitamin C → a powerful antioxidant. It reduces cellular damage, supports immune function, and promotes recovery.
Vitamin D3 → key to the immune response. Many athletes have low levels because they train indoors.
Zinc → essential for immune cells and muscle recovery. It is lost through sweat, so it is advisable to replenish it.
Selenium → another key antioxidant that protects against training-related stress.
Plant extracts (such as echinacea or reishi, if included) → help modulate the immune response and improve defenses against infections.
Synergistic formula → combines antioxidants + regulatory minerals + immune support, strengthening your defenses when your body needs it most (periods of heavy training, double sessions, calorie deficits, etc.).

In summary: if you train hard, your immune system becomes weaker; Advanced Immune provides the micronutrients that are depleted the most and strengthens your defenses while improving recovery and performance.

How to choose quickly.

Here’s a super-practical guide for everyone and every situation:

Yes, you catch a cold every time you increase your training volume.

Start by reviewing your sleep and calorie intake first (Walsh et al., 2021; Mountjoy et al., 2023).
You’ll consider a probiotic with supporting evidence and take it consistently (Łagowska et al., 2021; Mohr et al., 2022).

If it’s winter and you get little sunlight.

You’ll consider getting a Vitamin D blood test and correcting any deficiency if appropriate (Saedmocheshi et al., 2024).

If you notice symptoms “right now” (a strange throat sensation, the beginning of a runny nose).

You’ll consider taking zinc for a short time and cautiously (Nault et al., 2024; National Institutes of Health, Office of Dietary Supplements, 2026).

If your diet is a little low in vegetables.

You’ll improve the basics (2–3 fruits/day and “easy” vegetables), and if you don’t reach that, Vitamin C can help as a boost (Keya et al., 2022; Hemilä, 2023).

If you are under high stress, getting little sleep, and training hard.

You will reduce your training load for 3–7 days, prioritize sleep, and then decide on supplements. This is usually the most effective approach.

Conclusion

You will improve your immune system effectively when you combine recovery (sleep + energy + load management) with well-chosen supplements. If I had to sum it up: build a solid foundation first, then vitamin D if you are deficient, probiotics if they suit you, zinc only occasionally, and vitamin C as support if your diet falls short. Consistency, common sense, and a realistic plan.

Bibliography

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