What is meldonium?
Meldonium, also called mildronate, MET-88 or THP (3-(2,2,2-trimethylhydrazinium)propionate), is a synthetic compound that lowers tissue carnitine. A 1988 paper from the Institute of Organic Synthesis in Riga, Latvia, now the Latvian Institute of Organic Synthesis, described it as a novel inhibitor of gamma-butyrobetaine (GBB) hydroxylase, an enzyme of carnitine biosynthesis (Simkhovich et al., 1988).
A 2017 review describes it as registered in most Baltic countries (Schobersberger et al., 2017). It has no US FDA approval, and the World Anti-Doping Agency (WADA) has prohibited it since 2016. Disguised Alpha supplies meldonium dihydrate in capsules, 60 per bottle, at the strength listed on the product page, for laboratory research use only. Nothing on this page is guidance for use in people.
Meldonium reference data
| Property | Value |
|---|---|
| Name | Meldonium dihydrate (meldonium) |
| Also called | Mildronate, MET-88, 3-(2,2,2-trimethylhydrazinium)propionate (PubChem CID 123868); THP (in the 1988 paper); mildronate dihydrate (PubChem CID 6918082) |
| Structure | Inner salt (zwitterion), (CH₃)₃N⁺-NH-CH₂-CH₂-COO⁻: a trimethylhydrazinium group on a propanoate chain, plus two water molecules in the dihydrate. It resembles GBB with NH in place of one CH₂. |
| Compound class | Inhibitor of carnitine biosynthesis and transport (GBB hydroxylase and OCTN2); a metabolic modulator in WADA class S4.4 |
| Molecular formula | C₆H₁₈N₂O₄ (dihydrate); C₆H₁₄N₂O₂ (meldonium) |
| Molecular weight | 182.22 g/mol (dihydrate); 146.19 g/mol (meldonium) |
| Form | Capsules, 60 capsules per bottle, strength per capsule as listed on the product page |
| Testing | Third-party tested, with the certificate for each lot published on the product page and in the COA portal |
Capsule format, count and storage are from the product page, which lists no formula or weight. Those figures, the structure and the aliases other than THP are from PubChem CID 6918082 (dihydrate) and CID 123868 (meldonium). Meldonium is about 80 percent of the dihydrate's mass. For quantitative work, check the identity test and labeled amount on your lot's certificate.
See it beside the other compounds on this site in the peptide molecular weight reference table.
What the research covers
Published work on meldonium falls into five areas. Each summary below states the model used. A 2017 review noted that few clinical studies exist despite wide use (Schobersberger et al., 2017).
Carnitine biosynthesis and the shift away from fatty-acid oxidation
The 1988 Riga paper described meldonium as a noncompetitive inhibitor of GBB hydroxylase from rat liver. Rats given 150 mg/kg orally for 10 days had 63.7 percent less free carnitine and 74.3 percent less long-chain acylcarnitine in the heart, and fatty-acid oxidation fell (Simkhovich et al., 1988). An Oxford crystal structure showed meldonium competing with GBB in the enclosed active site of this enzyme, which completes carnitine biosynthesis, and the enzyme also oxidized it as a substrate (Leung et al., 2010).
Riga researchers also call meldonium the most potent clinically used inhibitor of the carnitine transporter OCTN2 (Liepinsh et al., 2017). In an independent Oxford study, 3 weeks at 100 mg/kg a day raised cardiac pyruvate dehydrogenase flux 3.1-fold in diabetic rats and 1.2-fold in controls, suggesting more glucose oxidation (Savic et al., 2021). Models: enzyme preparations and rats.
Cardiac ischemia models in rats
Rats given 200 mg/kg a day for 10 days before 45 minutes of coronary occlusion and 2 hours of reperfusion had infarcts covering 43 percent of the area at risk, against 57 percent in controls (p=0.004), with no difference in heart rate, arterial pressure or arrhythmias (Sesti et al., 2006). Two of its four authors co-wrote the 1988 Riga paper.
In hearts isolated from rats given 100 mg/kg for 14 days, L-carnitine fell 69 percent, GBB rose 6-fold and infarcts were smaller; with L-carnitine added, carnitine, mitochondrial fatty-acid respiration and infarct size showed no significant change (Kuka et al., 2012). In rats with heart failure after coronary ligation, a Japanese company laboratory reported that MET-88 at 100 mg/kg a day extended median survival from 79 to 103 days and prevented left ventricular cavity expansion, similar to captopril (Hayashi et al., 2000). Models: rats and isolated rat hearts.
Clinical studies in angina, heart failure and stroke
MILSS I, a randomized, double-blind, placebo-controlled phase 2 trial led from Riga, enrolled 512 people with stable angina at 72 centers in 4 countries, adding placebo or one of four daily amounts of mildronate to standard care for 12 weeks. The primary endpoint, change in total time on a bicycle ergometer stress test, did not differ from placebo at the two lowest amounts, rose at the third (p=0.002) and rose less at the highest (Dzerve et al., 2011).
In a randomized trial published in Russian, 65 people with heart failure after myocardial infarction received basic therapy alone or with trimetazidine or meldonium dihydrate for 6 months. Both drugs lowered functional class, but only trimetazidine raised ejection fraction, and the authors preferred it (Vasiuk et al., 2007).
In a Chinese double-blind phase II trial in 227 people with acute ischemic stroke, mildronate and the active comparator cinepazide showed no significant differences in modified Rankin Scale scores at 3 months or in NIHSS and Barthel Index scores at 15 days (Zhu et al., 2013). Models: human trials.
The anti-doping record
WADA placed meldonium in its 2015 Monitoring Program and added it to the Prohibited List from 1 January 2016; its summary of the 2016 changes cites evidence of its use by athletes. At the Baku 2015 European Games, 66 of 762 athlete urine samples (8.7 percent) contained meldonium, while only 23 of 662 tested athletes had declared it (Stuart et al., 2016).
In early 2016, laboratories reported an unusually high number of samples with high concentrations (Rabin et al., 2019), and WADA's 2016 testing figures list 515 adverse analytical findings for meldonium, 71 percent of all findings in class S4. Model: anti-doping surveillance data.
Detection and elimination studies
In 10 healthy volunteers studied by a Cologne anti-doping group, urine stayed above the 10 ng/mL quantification limit for up to 65 days after a single oral amount and 117 days after 6 days of repeated amounts, with nonlinear, biphasic excretion (Görgens et al., 2017).
In an open-label study first-authored by a WADA scientist, 32 athlete volunteers received one of two daily amounts for 3 weeks; blood levels reached steady state within several days, and elimination ran over several months (Rabin et al., 2019). In mice, carnitine or GBB given during washout sped elimination but the diuretic furosemide did not; the Riga authors tied the long elimination to OCTN2 uptake into muscle and slow diffusion out (Liepinsh et al., 2017). Models: healthy volunteers and mice.
Key studies
- Simkhovich BZ, et al. "3-(2,2,2-Trimethylhydrazinium)propionate (THP): a novel gamma-butyrobetaine hydroxylase inhibitor with cardioprotective properties." Biochem Pharmacol. 1988. PMID 3342076. DOI 10.1016/0006-2952(88)90717-4. Rats: lower heart carnitine.
- Sesti C, et al. "Mildronate, a novel fatty acid oxidation inhibitor and antianginal agent, reduces myocardial infarct size without affecting hemodynamics." J Cardiovasc Pharmacol. 2006. PMID 16633095. DOI 10.1097/01.fjc.0000211732.76668.d2. Rats: smaller infarcts.
- Leung IK, et al. "Structural and mechanistic studies on γ-butyrobetaine hydroxylase." Chem Biol. 2010. PMID 21168767. DOI 10.1016/j.chembiol.2010.09.016. Crystal structure: competes with GBB.
- Zhu Y, et al. "Efficacy and safety of mildronate for acute ischemic stroke: a randomized, double-blind, active-controlled phase II multicenter trial." Clin Drug Investig. 2013. PMID 23949899. DOI 10.1007/s40261-013-0121-x. 227 adults: no significant difference from cinepazide.
- Stuart M, et al. "Meldonium use by athletes at the Baku 2015 European Games." Br J Sports Med. 2016. PMID 27015859. DOI 10.1136/bjsports-2015-095906. 762 urine samples: 8.7 percent positive.
- Rabin O, et al. "Meldonium long-term excretion period and pharmacokinetics in blood and urine of healthy athlete volunteers." Drug Test Anal. 2019. PMID 30328291. DOI 10.1002/dta.2521. 32 volunteers: elimination over months.
Handling and storage of meldonium dihydrate capsules
General laboratory practice for this material:
- Store the sealed capsules at 15 to 25°C in the original sealed container, away from moisture and direct light (storage guidance on the product page).
- Capsules ship in a sealed bottle or a resealable pouch, depending on the batch; close it fully after each opening.
- Avoid heat. The dihydrate holds water of crystallization, and a University of Latvia study examined how particle size, relative humidity and sample history affect its dehydration kinetics (Bērziņš and Actiņš, 2014).
- Record the lot number and keep its certificate with your notes. Check its identity test and labeled amount before quantitative work.
- For identity checks, compare analytical data with C₆H₁₈N₂O₄ and 182.22 g/mol (dihydrate) or C₆H₁₄N₂O₂ and 146.19 g/mol (meldonium).
Frequently asked questions
What is meldonium?
Meldonium, 3-(2,2,2-trimethylhydrazinium)propionate, is a synthetic GBB hydroxylase inhibitor that lowered heart carnitine and fatty-acid oxidation in rats (Simkhovich et al., 1988) and also blocks the carnitine transporter OCTN2 (Liepinsh et al., 2017).
Is meldonium the same as mildronate?
Yes. Meldonium is the international nonproprietary name; PubChem CID 123868 lists mildronate and MET-88 as synonyms. Older papers use mildronate (Sesti et al., 2006) or MET-88 (Hayashi et al., 2000).
What is meldonium dihydrate?
It is meldonium crystallized with two molecules of water: C₆H₁₈N₂O₄, 182.22 g/mol (PubChem CID 6918082). Meldonium itself is about 80 percent of that mass.
Is meldonium approved by the FDA?
No. Drugs@FDA data, searched through the FDA's openFDA interface, list no product containing meldonium or mildronate, and the European Medicines Agency's medicines data list no centrally authorized meldonium medicine (both checked October 2026).
Is meldonium banned by WADA?
Yes. The 2026 WADA Prohibited List names meldonium under S4.4.3, in class S4 (hormone and metabolic modulators), prohibited at all times as a non-Specified substance. The same S4.4 class names AICAR and MOTS-c as AMPK activators, and trimetazidine.
How should meldonium dihydrate capsules be stored?
Keep them sealed in the original container at 15 to 25°C, away from moisture and direct light, as listed on the product page.
Where can researchers buy meldonium?
Disguised Alpha sells meldonium dihydrate for laboratory research in capsules, 60 per bottle, at the strength listed on the product page, with each lot's third-party certificate published there: Meldonium Dihydrate.
Related compounds and guides
- Mexidol research guide
- AICAR research guide
- MOTS-c research guide
- SS-31 research guide
- NAD+ research guide
- COA portal: every published certificate, by lot
This product is for research use only. It has not been evaluated for safety or effectiveness in humans. Not for human consumption. All products are intended for laboratory research purposes only.