Evidence Files

Meldonium: How a Latvian Cardiac Drug Became the Most Famous Banned Substance in Sports

Thousands of athletes took meldonium and risked their careers for it. A review in the *British Journal of Sports Medicine* describes the performance benefit as "quite speculative and discussed without sound scientific evidence". That is the strange heart of this story: a substance banned for an advantage nobody has managed to measure.

Published: 20 June 2026

Verdict

TRICK (weak evidence)

We searched PubMed and Cochrane Library for clinical evidence on meldonium. There are 309 publications and 22 randomised controlled trials, so something was studied. The flagship cardiac trial, MILSS I, enrolled 512 patients with stable angina and found 35 extra seconds of exercise time on a bicycle ergometer versus placebo — significant at only one of four doses, in a phase 2 study run at the institute in Riga where the drug was invented. On athletic performance, a review in the British Journal of Sports Medicine notes that despite widespread use, clinical trials are few and the performance benefit is speculative.

What it is and where it came from

Meldonium was developed in Soviet Latvia in the 1970s by chemist Ivars Kalviņš at the Institute of Organic Synthesis in Riga. The mechanism: it blocks an enzyme in the carnitine biosynthesis pathway, shifting cellular metabolism away from fatty acid oxidation toward glucose — theoretically more oxygen-efficient under ischemic conditions.

The drug is manufactured by Latvian company Grindeks and marketed as Mildronate. It's registered in Latvia and several post-Soviet countries for heart failure, angina, and myocardial infarction recovery. It's not approved in the EU as a whole, not in the US, not in most of Western Europe.

WADA banned it not because there was solid evidence it enhanced performance, but because of the sheer number of athletes testing positive and a suspicion that it might. The ban came first; the performance evidence was assumed — and still hasn't arrived.

What the science actually says

Meldonium is the rare drug that became world-famous before anyone established what it does.

The flagship cardiac trial is worth 35 seconds on a bicycle. In MILSS I — 512 patients with stable angina across 72 centres — adding meldonium to standard therapy increased exercise time by 35.2 seconds versus placebo. Statistically significant, and also exactly the kind of effect size worth picturing literally before paying for a course
The effect appeared at one dose, and the dose-response isn't linear. 100 mg and 300 mg were indistinguishable from placebo; 1000 mg performed best; and at 3000 mg the increase was smaller than at 1000 mg. For a drug with a claimed mechanism, that pattern argues for caution rather than confidence
It was a phase 2 study. Phase 2 exists to decide whether a large confirmatory phase 3 trial is warranted. In the years since, no large independent phase 3 trial has established clinical benefit
On sport, the review is blunt. The British Journal of Sports Medicine review states that despite widespread use there are only a few clinical studies, and that the benefit for performance enhancement is quite speculative and discussed without sound scientific evidence
The rest of the literature is geographically concentrated. Heart failure trials were published largely in Russian, Georgian and Ukrainian journals, with no independent replication outside that circle

The scandal was about doping — the doping evidence never arrived

What the testing showed

At the 2015 European Games in Baku, meldonium turned up in 66 of 762 urine samples (8.7%), across athletes competing in 15 of 21 sports. Only 23 of 662 (3.5%) had declared using it — most concealed it. The authors described this as widespread and inappropriate use of a prescription drug in an otherwise healthy population.

What the efficacy research showed

Nothing conclusive. Meldonium was banned because of how many people were taking it and a suspicion of benefit, not because the benefit was demonstrated. The 2017 review calls the belief in performance enhancement speculative. Thousands risked their careers for an edge nobody measured.

Frequently asked questions

Does meldonium actually improve endurance?

There is no convincing evidence that it does. The review in the British Journal of Sports Medicine states directly that the performance benefit is speculative and discussed without sound scientific backing. Meldonium's popularity in sport is a case study in how a rumour of an effect spreads faster than any test of it.

Why did WADA ban it, then?

Because of prevalence, not proven effect. Meldonium sat on WADA's monitoring programme in 2015, and testing at the European Games found it in 8.7% of samples while only 3.5% of athletes had declared it. The ban was a response to widespread concealed use of a prescription drug by healthy athletes.

Does it help the heart?

The best evidence in its favour is MILSS I: added to standard angina therapy, it increased cycling exercise time by 35 seconds. That is a real, measured, and very modest result from a phase 2 trial. It is not a foundation of ischaemic heart disease treatment — that role belongs to drugs with demonstrated effects on heart attacks and mortality.

Can you take meldonium for general fatigue or low energy?

No study supports that, in athletes or anyone else. Persistent fatigue has specific causes worth identifying: anaemia, thyroid disorders, sleep apnoea, depression, chronic sleep deprivation. A course of a drug without a diagnosis mainly postpones that search.

Are meldonium and Mildronate the same thing?

Yes. Meldonium is the international non-proprietary name of the substance; Mildronate is the brand name of the Latvian company Grindeks, which developed it. The same compound appears under other trade names in pharmacies across the post-Soviet region.

Our Conclusion

Meldonium is neither a fraud nor a sugar pill: the pharmacology is real and the best trial found a measurable effect. That effect is 35 extra seconds on a bicycle ergometer, in a phase 2 study run where the drug was invented. The doping story is the more instructive half. Thousands of athletes took meldonium for years and risked their careers for an advantage that, as a review in the *British Journal of Sports Medicine* puts it, remains speculative and unsupported by sound evidence. If meldonium has been prescribed to you for angina or after a heart attack, the question worth asking is precise: which of my medications are proven to reduce the risk of heart attack and death, and am I on all of them? Meldonium can be an addition to that therapy. It cannot be a substitute for it.

Sources

Every claim in this article rests on a primary publication. Links go to the publisher's site or to PubMed, the US National Library of Medicine database.

This article is for informational purposes only and does not constitute medical advice. Trick or Treatment analyses the presence of clinical studies in open scientific databases — PubMed and Cochrane Library. The absence of studies in these databases does not automatically mean a drug is ineffective, but it does mean its effectiveness has not been confirmed by evidence-based medicine standards. Any treatment decisions should be made together with your doctor.