The food supplement market can feel like a dense jungle—full of exotic promises, bright packaging, and tempting claims. Buyers, lured by bold statements about the almost magical power of products to provide a burst of energy, induce sleep instantly, improve memory, or even rejuvenate and turn back the biological clock, are often bitterly disappointed when the advertising promises deflate and their expectations remain unfulfilled.

In this information noise, how can you distinguish between scientifically-backed benefits and blatant marketing? The good news is that with the right tools, you can make informed decisions about the products you use to support your well-being.

This guide is like a map and compass. Step by step, we will show you how and where to look for reliable information, how to distinguish high-quality scientific evidence from the results of early studies, and what to pay attention to when choosing a specific product.

Key messages

• Start with science, not marketing. The most reliable sources of information are scientific databases like PubMed, not brand websites or popular blogs.

• Not all studies are equally valuable. Learn to distinguish the highest level of evidence, such as systematic reviews, from preliminary laboratory studies on animals. The results of the latter are not always confirmed in humans.

• A trustworthy brand is transparent. Look for information about manufacturing standards (GMP certificate), third-party testing, and a clear ingredient list without mysterious "proprietary blends."

• Avoid miraculous promises. Be especially wary of products that promise rapid and dramatic effects, rely solely on emotional testimonials, or do not specify the exact dosages of active ingredients.

• Consultation with a doctor or pharmacist is essential. No general guidelines can ever replace the advice of a healthcare professional who has your medical history in front of them. If you are taking prescription medications, only a doctor can give qualified advice on supplements, tailored to your individual situation.

Our approach: how we select information

We believe the path to good health is paved with knowledge, not guesswork. Therefore, we are sharing the principles we follow ourselves when seeking answers. Our thinking is based on reliability, authoritativeness, and expertise — principles also applied by search engines like Google.

• Expertise. We delve into peer-reviewed scientific research and consult with experts in science and medicine. It is important for us to understand not only what works, but why.

• Authoritative sources. We base our knowledge on information from the world's most respected health institutions, such as the U.S. National Institutes of Health (NIH) Office of Dietary Supplements, the European Food Safety Authority (EFSA), or the World Health Organization (WHO).

• Reliability. Our goal is to be a trustworthy guide. We aim to help you sift through the marketing noise by providing a balanced and unbiased framework to understand what the scientific evidence truly says about the health benefits of supplements.

Step 1: Where to find reliable information about supplements

A proper search begins not with "Google," but with specialized, unbiased sources. This will help you avoid marketing tricks and get immediate access to reliable data.

Most reliable information sources:

• PubMed. This is like a giant online medical encyclopedia administered by the U.S. National Library of Medicine. Here you will find millions of scientific articles on almost any ingredient or supplement. It is the best starting point.

• Google Scholar. An excellent tool for broadly searching scientific literature, from articles and dissertations to books.

Sources to approach with caution:

• Popular health blogs. Although they can sometimes be useful for a general understanding, they often simplify or misinterpret scientific data. Therefore, they should not be your primary source of information; it's always worth checking their conclusions in reliable, science-based sources.

• Brand websites. Remember, their goal is to sell. Information here will be presented in the most favorable light.

• Social media and influencers. This is the least reliable source. Their recommendations are often based on promotional agreements, not science.

Step 2: How to understand scientific evidence

Not all studies are equally weighty. Imagine a pyramid of evidence: the higher the level, the more reliable the data.

• The gold standard: systematic reviews and meta-analyses. This is the highest level of analysis, where scientists collect and summarize the results of all high-quality studies conducted on the same topic. This is the most reliable way to find out what science says about a particular supplement.

• High level: randomized controlled trials. These are studies involving people where one group receives the test supplement and another receives a placebo (a substance with no effect). This allows for an objective evaluation of the supplement's effectiveness.

• Medium level: observational studies. These studies observe large groups of people and look for connections between their lifestyle (e.g., diet) and health. They can show a correlation, but do not prove causation.

• Initial level: animal trials and laboratory studies. This is an important first step, but their results are not always confirmed in humans.

Step 3: How to evaluate a brand

Once you are sufficiently familiar with a certain ingredient, it's time to evaluate the product itself and its manufacturer. A reliable brand will always be transparent.

What to look for:

• Third-party laboratory tests. This is an essential feature of high-quality supplements. When choosing a product, look for evidence that it has been tested by an independent laboratory that has confirmed its purity and that it is not contaminated with heavy metals, harmful bacteria, or fungus.

• Good Manufacturing Practices (GMP) certificate. This is one of the most important quality certificates in supplement manufacturing. A GMP certificate means that the factory where the supplement was produced meets the strictest international quality and safety standards and is regularly inspected by authorities.

• Clear label. Avoid products with proprietary blends, which hide the exact doses of the ingredients. A reliable manufacturer will always state the precise amount of each ingredient.

Step 4: Consult a specialist

No information on the internet can replace a conversation with your doctor or pharmacist. Before starting any new supplement, be sure to consult with at least one of these specialists.

This is important because a healthcare professional can:

• Assess whether the supplement is necessary and appropriate for you.

• Check if it will interact with medications you are taking.

• Recommend a safe and effective dose.

• Help monitor your body's reaction.

Practice: how to learn about popular ingredients

Let's apply the steps we've discussed in practice. We will examine three popular ingredients: melatonin, L-theanine, and Rhodiola rosea.

Melatonin

1. Search. In the PubMed database, we search for phrases like "melatonin" or "melatonin insomnia."

2. Evidence. There is strong scientific evidence (many systematic reviews) that melatonin is effective for circadian rhythm disorders, such as when traveling across several time zones. However, the evidence for treating general insomnia is weaker. Studies show that melatonin may help you fall asleep faster, but it does not have a significant effect on total sleep duration.

3. Brand evaluation. When choosing a melatonin supplement, the dose is most important. Studies show that even very small doses (0.3-1 mg) are effective. A reliable manufacturer will offer a product with a clearly stated, small dose and have third-party tests confirming purity, as some studies have shown large discrepancies between the amount of melatonin listed on the label and the actual amount.

4. Consultation. This is especially important because in many EU countries higher doses of melatonin are a prescription drug. It is necessary to consult a doctor or pharmacist for the appropriate dose.

L-Theanine

1. Search. In Google Scholar or PubMed, we search for the ingredient itself or for phrases related to its effects, such as "L-theanine caffeine interaction" or "L-theanine caffeine cognitive performance."

2. Evidence. There are numerous high-quality clinical trials with humans confirming the synergistic effect of L-theanine and caffeine. Studies show that caffeine provides energy and alertness but can cause anxiety or jitters in some people. L-theanine acts as its partner — it promotes relaxation and increases alpha wave activity in the brain without causing drowsiness. Scientific articles note that the combination of these two substances helps achieve a state of "calm focus": attention and concentration improve, while the undesirable effects of caffeine are reduced. This is one of the scientifically-backed reasons why green tea (a natural source of both substances) is valued for its positive effect on mental activity.

3. Brand evaluation. When choosing a supplement with a combination of L-theanine and caffeine, it is important to pay attention to their ratio. Studies show that the optimal ratio is often about 2:1 in favor of L-theanine, for example, 200 mg of L-theanine and 100 mg of caffeine. A reliable manufacturer clearly indicates the amounts of both substances. Some products do not include caffeine at all, so that people taking L-theanine can enjoy their usual cup of coffee without additional effects.

4. Consultation. Although L-theanine is considered a very safe substance, its combination with caffeine may not be suitable for people sensitive to stimulants, as well as those with heart problems or high blood pressure. It is necessary to consult a doctor before use.

Rhodiola rosea

1. Search. In PubMed, we search for "Rhodiola rosea", or more specifically "Rhodiola rosea stress" or "Rhodiola rosea fatigue."

2. Evidence. Such a search finds many studies and even several systematic reviews confirming the effectiveness of rhodiola as an adaptogen. Adaptogens are substances that help the body cope with physical and psychological stress. Scientific research shows that it can help reduce fatigue and improve mood during times of stress.

3. Brand evaluation. When choosing a rhodiola supplement, standardization is essential. Look for a product whose label indicates the exact amount of active compounds — rosavins (usually 3%) and salidrosides (usually 1%). This is an indicator of quality and effectiveness.

4. Consultation. Like other adaptogens, rhodiola can have a stimulating effect. It is necessary to consult a doctor, especially if you have anxiety disorders or are taking antidepressants.

Summary: be an informed consumer

To successfully navigate the world of food supplements, we must cultivate a healthy skepticism and rely on facts. By prioritizing scientific sources, understanding the differences in research quality, evaluating brand transparency, and always consulting with a healthcare professional, you can know exactly what you need and choose the right products for your wellness journey, regardless of the marketing noise.

Such an approach will allow you to make decisions that are not only evidence-based but also safe and beneficial for your health.

Frequently asked questions

• Why can't I just trust the reviews on the product website? Reviews on a brand's website may be filtered, leaving only positive ones. While customer experience is an important indicator, it remains subjective and does not replace scientific evidence about a product's effectiveness and safety. Look for reviews on independent platforms to get a more objective picture.

• What is the difference between a proprietary blend and clear labeling? Clear labeling indicates each ingredient and its exact dose. A "proprietary blend" lists the ingredients but only provides the total weight of the entire mixture, hiding the amount of each component. This can be a sign that the product contains only a symbolic, ineffective amount of the main ingredients.

• If a supplement is all-natural, does that mean it's safe? Not necessarily. Natural is a marketing term, not a guarantee of safety. Many natural substances can have strong effects, cause side effects, or interact with medications. The safety of any supplement depends on the specific compound, the dose, and your health condition. This is precisely why it is so important to consult a doctor.

• How can I quickly check if a PubMed study is of high quality? When you find a study, review its title and abstract. Look for keywords such as randomized controlled trial, systematic review, or meta-analysis, which indicate higher-quality evidence. You can also use filters in the search results to see only these strongest types of studies.