Which supplements are truly a waste of money — a ranking based on the strength of evidence
Which supplements are really a waste of money: a summary based on the strength of evidence. u Bucha.
Poles spend over 5 billion PLN annually on dietary supplements — the market grows by several percent each year (Health Market, 2024). A significant portion of this amount goes to products whose efficacy does not exceed placebo in randomized studies. This ranking is not a list of "bad companies" — it is a review of substances whose strength of evidence is disproportionately low compared to marketing budgets. Knowing where not to spend money is just as valuable as knowing what works.
KEY INFORMATION
• Poles spend over 5 billion PLN annually on supplements (Health Market, 2024); a large portion lacks evidence of effectiveness.
• A supplement can be legally sold without demonstrating effectiveness — the requirement only pertains to safety.
• The ranking is based on Cochrane reviews, RCT meta-analyses, and EFSA assessments — not on user opinions.
• The goal is not to discredit the industry, but to assist in making informed spending decisions.
• Substances with the strongest evidence — in a separate article.
Methodology: how do we assess the strength of evidence?
The ranking is based on a hierarchy of medical evidence. At the top of the hierarchy are systematic reviews and meta-analyses of randomized controlled trials (RCTs) — if such exist for a given substance and indication. Below are individual RCTs, cohort studies, and case-control studies. At the bottom — in vitro studies, animal studies, and expert opinions. A substance with only in vitro studies and intensive marketing directed at consumers will rank high on the "waste of money" list.
| Evaluation Criteria | Weight | What we check |
|---|---|---|
| Quality of the highest available evidence | 40% | Metaanaliza RCT > pojedyncze RCT > obserwacyjne > in vitro |
| Size of clinical effect | 30% | Is the difference vs placebo clinically significant, not just statistically |
| Consistency of results across studies | 20% | Do different laboratories and research groups confirm the effect |
| Price / evidence ratio | 10% | Is the price proportional to the strength of evidence |
Important note: "lack of evidence of efficacy" is not the same as "evidence of lack of efficacy." Some substances on this list are simply poorly researched — it is possible that future studies will change the picture. Others have specific studies showing no effect vs placebo. We indicate this distinction for each item.
Ranking of supplements with the weakest evidence
Below is a compilation of supplements on which Poles spend significant money, but for which the strength of available evidence in human clinical studies is low or contradictory. The list does not exhaust the topic — it focuses on substances with the greatest discrepancy between popularity and evidence base.
| Position | Substance | Marketing promises | What research says | Evidence assessment |
|---|---|---|---|---|
| 1 | Detoks / „oczyszczanie organizmu” | Removes toxins, cleanses the liver | No RCT; the liver and kidneys naturally "detoxify" without supplements. | No evidence |
| 2 | Oral collagen (for skin) | Smooths wrinkles, hydrates skin | Weak meta-analyses; collagen is digested into amino acids, transport to skin is uncertain | Weak, inconsistent |
| 3 | General probiotics (without indication) | "Boost immunity", "regulate flora" | Effective for specific indications (diarrhea, IBS) and strains; "general" without indication — weak. | Depends on strain and indication |
| 4 | Multivitamins for healthy adults | Supplement deficiencies, protect against diseases | US Preventive Services Task Force (2022): no evidence of reducing heart disease, cancers | No benefits with a healthy diet |
| 5 | Glucosamine and chondroitin sulfate | Regenerates joint cartilage, reduces knee pain | NEJM meta-analysis (GAIT trial): not better than placebo for knee joint pain | Weak; large RCT study negative |
| 6 | Echinacea for colds | Shortens and prevents colds | Cochrane (2015): heterogeneous results; effect statistically insignificant or marginal | Weak, inconsistent |
| 7 | Green coffee extract | Accelerates fat burning, reduces weight | Cochrane (2011, update 2021): statistically insignificant or marginal effect due to poor quality of studies | Very weak |
| 8 | CLA fats for weight reduction | Burns fat, preserves muscle | Meta-analysis: weight reduction ~0.1 kg/week — clinically insignificant given the product price | Small effect, low clinical significance |
Price update: June 26, 2026
Detox and cleansing — why is it a marketing construct?
The leader of the ranking deserves a separate explanation. The concept of "detoxifying the body" does not exist in pharmacology or clinical physiology as a defined evidence-based procedure (Klein et al., JRSM, 2015). The liver — the only organ that actually detoxifies the blood — does so 24 hours a day through phase I and II enzymatic mechanisms of metabolism. The kidneys filter the blood and remove metabolic waste. The lungs exhale CO2. These organs do not need "supplemental support" in a healthy person.
The review by Klein and Ernst published in JRSM (2015) analyzed 15 clinical studies on "detox programs" — none met the methodological requirements of RCTs and none demonstrated a repeatable effect. The "detox" market is globally valued at billions of dollars solely based on marketing mechanisms, not clinical evidence.
We have noticed that "detox" as a concept operates in two completely different contexts. In clinical medicine, "detoxification" means treating poisoning from substances — alcohol, drugs, heavy metals — and is conducted in hospital settings using specific antidotes. In supplement marketing, "detox" is a metaphor for "cleansing", without any defined mechanism or measurable endpoint. These are two completely different words that sound the same.
Oral collagen — why might the effects be less than promised?
Collagen is one of the fastest-growing segments of supplements in Poland. The question about the biological mechanism is justified: since collagen is digested into amino acids (mainly glycine, proline, and hydroxyproline) in the intestines, what actually reaches the skin? Radioisotope studies have shown that collagen hydrolysates are indeed absorbed as short peptides (di- and tripeptides) and reach the dermis, where they may stimulate fibroblasts to produce endogenous collagen (Proksch et al., Skin Pharmacology and Physiology, 2014).
The problem lies not in the mechanism, but in the scale of the effect and the quality of the studies. The meta-analysis by Choi et al. from 2019 analyzed 11 RCTs on collagen supplements — most studies were funded by manufacturers, groups were small (under 100 people), and effects were measured subjectively. With such methodological limitations, the results are difficult to interpret (Choi et al., Nutrients, 2019). It does not say "collagen does not work" — it says "we do not yet know for sure, for whom, and at what dose".
We have noticed that questions about collagen mainly come from women over 40. This is understandable — collagen production decreases after the age of 25 by about 1% per year. But the honest answer to this question is: if you expect dramatic skin improvement in 30 days with collagen supplementation, you will probably be disappointed. If you view it as long-term support (6–12 months) while simultaneously protecting the skin from UV — the data is more promising.
Glucosamine — large study, negative result
The GAIT Trial (Glucosamine/chondroitin Arthritis Intervention Trial) is one of the largest independently funded studies of supplement vs placebo in history. It involved 1583 patients with knee pain due to osteoarthritis, divided into five groups (glucosamine, chondroitin, combination of both, celecoxib, placebo). The results were published in NEJM in 2006: the combination of glucosamine and chondroitin did not differ significantly from placebo in the primary endpoint (25% reduction in pain) (Clegg et al., NEJM, 2006).
This is not just any study — it is well-blinded, funded by the NIH (not by the manufacturer), and methodologically sound. Individuals with severe knee pain showed some tendency to respond to the glucosamine + chondroitin combination, but the subgroup sample was too small to draw definitive conclusions. For mild and moderate knee pain, the difference vs placebo was statistically insignificant.
Multivitamins for healthy adults — what does the USPSTF say?
The US Preventive Services Task Force, in its 2022 update, analyzed the evidence for multivitamins in the context of preventing cardiovascular diseases and cancers in healthy adults. Conclusion: insufficient evidence to recommend or discourage (USPSTF, 2022). The SELECT study (selenium + vitamin E) showed a slightly higher risk of prostate cancer in men taking vitamin E. The CARET study showed a higher risk of lung cancer in smokers taking beta-carotene.
This does not mean that multivitamins are harmful to everyone. At typical doses, they are safe. But "safe" is not the same as "effective". For a healthy person on a varied diet, a multivitamin is likely an expensive placebo. Exception: individuals with confirmed deficiencies of specific vitamins, older adults with limited absorption, pregnant women (folic acid) — here specific supplements have solid indications.
Echinacea and green coffee extract — what do Cochrane reviews say?
Echinacea makes this list for a specific reason: it is one of the most commonly purchased supplements "for immunity" in Poland and Germany, and the evidence base does not justify its popularity. The Cochrane review from 2015 included over 2000 participants from 24 studies — the results were so heterogeneous that the authors could not formulate a definitive conclusion (Karsch-Völk et al., Cochrane Database, 2015). Some studies showed a slight reduction in the duration of colds (by a few hours), while others showed no effect. Echinacea preparations differ in plant species (Echinacea purpurea vs. angustifolia vs. pallida), plant part (root, herb), and form (dried extract, tincture). The lack of standardization makes it impossible to draw general conclusions.
Green coffee extract (chlorogenic acid) has followed a similar path. Individual studies from 2011–2012 sparked a wave of interest — including a prominent recommendation in one of the popular television programs. Cochrane conducted a systematic review in 2011 and an update in 2021: the effect on body weight was on the verge of statistical significance and disappeared when adjusting for the methodological quality of the studies (Onakpoya et al., Gastroenterology Research and Practice, 2011). One of the prominent meta-analyses supporting green coffee extract was retracted from the scientific literature due to data errors. This is an extreme example, but it illustrates how a single "breakthrough" result can live a marketing life long after science has undermined it.
We have noticed that supplements in this category share a common pattern: a small study with a positive result reaches the media as a "breakthrough", then manufacturers cite this study for years — while subsequent, better-planned studies do not confirm the effect or correct its scale. The consumer does not have time to follow scientific updates. That is why databases like Examine.com, which update summaries regularly, are so useful — they aggregate the entire literature, not just a single favorable study.
How to approach purchasing supplements without wasting money?
Practical criteria for purchasing decisions that you can apply without delving into scientific details: first — look for a specific indication, not "general health". A supplement with studies confirming "generally strengthening" or "cleansing" effects has no specific indication. Second — check if the effect was demonstrated in human studies, not just in vitro or in rodents. Third — look for who funded the study: the manufacturer or an independent scientific institution. Studies funded by the manufacturer statistically have a higher chance of a positive outcome (Lexchin et al., BMJ, 2003).
One of the more useful resources is the list of health claims approved by EFSA. It includes substances for which the European regulator has determined that the evidence meets the minimum requirements to formulate a health claim. This does not mean that every substance on the EFSA list is a "miracle supplement" — but it means that the effect has been sufficiently well documented to pass rigorous regulatory assessment (EFSA, 2024). Substances not on this list should be treated with caution.
Frequently Asked Questions
How to check if a supplement has scientific evidence?
The best starting point is the PubMed database and Cochrane Library. Look for meta-analyses and RCT reviews for the specific substance and indication. Examine.com aggregates this data in an accessible way. The key question: was the effect demonstrated in a randomized and blinded study — not just in vitro or on mice?
Are "natural" supplements always safe?
No. Natural origin does not guarantee safety — many plants contain toxic compounds, and herbs can interact seriously with medications (e.g., St. John's Wort lowers the concentration of immunosuppressive drugs). A supplement legally available in Poland only needs to meet food safety requirements — it does not have to demonstrate efficacy like a drug (EFSA, 2024).
Which supplements have the strongest evidence of efficacy?
Supplements with the strongest evidence include: creatine, vitamin D (in case of deficiency), omega-3 fatty acids (triglycerides), magnesium (in case of deficiency), caffeine (endurance), melatonin (circadian rhythm). The list regulated by EFSA includes approved health claims — substances for which the evidence was sufficient for approval by the regulator.
Can juices and fortified drinks replace supplements?
Functional foods provide lower doses than typical supplements. A juice fortified with vitamin D delivers 1–2 µg/100 ml; a supplement with 50 µg is a completely different scale. They are not direct substitutes in cases of confirmed deficiency. For prevention in a healthy person on a good diet — fortified food may be sufficient.
Is it worth taking supplements preventively?
It depends on the substance. Vitamin D preventively in Polish conditions (low sun exposure) has strong grounds. Creatine for an athlete or an older person — justified. A multivitamin supplement for a healthy person on a varied diet — weak evidence in favor (USPSTF, 2022).
Why are supplements without evidence still legal?
Dietary supplements in Poland and the EU are subject to food law, not pharmaceutical law. The manufacturer does not have to prove efficacy — they only need to demonstrate safety for consumption and report the product to the Chief Sanitary Inspector. Health claims are regulated by EFSA: only approved claims can be placed on the label. The problem is that the overall marketing message (graphics, names, descriptions on the store page) is not directly regulated in the same way as the product label (EFSA, 2024).
Does Echinacea have any confirmed effects?
A Cochrane review from 2015 involving over 2000 participants showed inconsistent results between studies and did not allow for a definitive conclusion regarding the efficacy of echinacea in the prevention or treatment of colds. Different preparations (species, part of the plant, form) yield different results — they cannot be treated as equivalent. There is also a lack of data from well-designed large studies sponsored independently of manufacturers (Karsch-Völk et al., Cochrane, 2015).
This article is for informational and educational purposes. It contains internal links to products available in the u Bucha store. Prices and specifications may change — please check the current data on the product page before purchasing.
Author: Michał Waluk · Published: 2026-05-04 · Updated: 2026-05-04
