IngredientsTriglycerides (TG) are lipids comprised of three fatty acids attached to a glycerol molecule; their main function is to store energy as fat in the adipose tissue. They are formally known by multiple synonymous names: triacylglycerols (TAG), triacylglycerides, and, in older literature, neutral fats. Triglycerides, commonly referred to as triacylglycerols, are a vital class of lipids present in living things; in numerous cells and tissues, they act as the main energy storage molecules. Glycerol and three fatty acids combine to produce triglycerides, which are hydrophobic and insoluble in water due to the ester linkages that result from their composition.
Triglycerides consist of a glycerol backbone and three fatty acid chains. The glycerol molecule is a trihydric alcohol with three hydroxyl groups (βOH), and the fatty acids are long hydrocarbon chains with a carboxyl group (βCOOH) at one end. The fatty acids are covalently bonded to the glycerol through ester linkages, resulting in the formation of triglycerides.
Fatty acids are stored for future use as triglycerides (TG; also termed triacylglycerides, TAG) in all cells, but primarily in adipocytes of adipose tissue. Triglycerides constitute molecules of glycerol to which three fatty acids have been esterified. The fatty acids present in triglycerides are predominantly saturated fatty acids. The fatty acids incorporated into triglycerides are all activated to acyl-CoAs through the action of various acyl-CoA synthetases.
Triglycerides are most meaningfully classified in dietary and clinical contexts by the chain length of their constituent fatty acids:
Fatty acids can be saturated, meaning they have no double bonds between the carbon atoms, or unsaturated, containing one or more double bonds. Saturated fatty acids tend to be solid at room temperature, while unsaturated fatty acids are typically liquid. The balance of these types of fatty acids in a triglyceride impacts its functionality in metabolic processes and its behavior under different physiological conditions.
Triglyceride is the main dietary lipid, and nearly 90β95% of the energy produced by fat is derived from TG.
There are limited natural sources that contain medium-chain triglycerides; these include coconut oil, palm kernel oil, and bovine milk. Naturally, MCTs are found in coconut oil, palm kernel oil, and also in milk fat. Coconut oil contains a larger fraction of lauric acid than other MCFA. Long-chain triglycerides dominate all commonly consumed plant and animal fats, including olive oil, sunflower oil, soybean oil, lard, tallow, and fish oil. The fatty acid composition of a triglyceride is largely decided by its source, which can be a plant or animal source. Triglycerides from plant sources are generally liquid at room temperature because they contain MUFA/PUFA.
In the context of dietary supplementation, triglycerides are encountered in several distinct forms:
Naturally, MCTs are found in coconut oil, milk fat, and palm kernel oil, and they are synthetically produced by esterification and interesterification reactions. Due to their numerous health benefits, MCT is used as a functional or nutraceutical oil in various food and pharmaceutical formulations.
Triglycerides β as the dominant constituent of all animal and vegetable fats β have been central to human nutrition throughout recorded history. Rendered animal fats (lard, tallow, suet, ghee), olive oil, sesame oil, and coconut oil have been used in cooking, medicine, and ritual across ancient Mesopotamian, Egyptian, Greco-Roman, Indian (Ayurvedic), and East Asian traditions. These preparations were ingested as dietary staples and employed topically and as carriers for medicinal herbs, but they were not conceptualized in biochemical terms prior to the 19th century.
The modern understanding of fats as glycerol esters of fatty acids was established through the work of Michel-Eugène Chevreul in the early 19th century, who demonstrated between 1813 and 1823 that soaps resulted from saponification of glyceride fats and proposed the structural framework that would come to be called triglycerides.
Differences in physical properties of medium-chain triglycerides led, since the 1960s, to the use of MCTs to improve various lipid absorption disorders and malnutrition. More than half a century has passed since MCTs were first used in the medical field. It has been reported that they not only have properties as an energy source but also have various physiological effects, such as effects on fat and protein metabolism.
In clinical practice, MCT-based formulas were introduced primarily to manage fat malabsorption in conditions such as cystic fibrosis, short-bowel syndrome, lymphangiectasia, and other disorders characterized by impaired long-chain fatty acid transport. The rationale was that MCTs are absorbed directly into the portal venous system rather than the lymphatic system, bypassing the need for chylomicron formation.
A relatively large ingestion of MCTs can be partially converted into ketone bodies, which can be used as a component of "ketone diets" in the dietary treatment of patients with intractable epilepsy, or in the nutritional support of terminally ill patients. The MCT-based ketogenic diet for epilepsy was developed in the 1970s by Peter Huttenlocher as an alternative to the classic Wilder-Russell ketogenic diet of the 1920s, offering better palatability with more dietary flexibility.
Japan was the first country to use designer lipid as a healthy cooking oil which does not result in fat accumulation when taken into diet. These are available as cooking oil under the brand name Resetta in Japan since 2000.
Triglycerides are critical lipids as they provide an energy source that is both compact and efficient. Due to their hydrophobic nature, triglyceride molecules can pack together densely and so be stored in adipose tissue. To be transported in the aqueous medium of plasma, triglycerides have to be incorporated into lipoprotein particles along with other components such as cholesterol, phospholipid, and associated structural and regulatory apolipoproteins.
Triglyceride molecules represent the major form of storage and transport of fatty acids within cells and in the plasma. The liver is the central organ for fatty acid metabolism. Fatty acids accrue in the liver by hepatocellular uptake from the plasma and by de novo biosynthesis. Fatty acids are eliminated by oxidation within the cell or by secretion into the plasma within triglyceride-rich very low-density lipoproteins. Notwithstanding high fluxes through these pathways, under normal circumstances the liver stores only small amounts of fatty acids as triglycerides.
The calories that you eat, but your body does not need right away, are changed by the body into triglycerides and stored in fat cells. When your body needs energy, it releases the triglycerides.
There are three major pathways for the synthesis of triglycerides: the glycerol-3-phosphate (G3P) pathway, the dihydroxyacetone phosphate (DHAP) pathway, and the monoacylglycerol pathway. The glycerolipidβfatty acid cycle consists of both lipid synthesis (lipogenesis) and lipid metabolism (lipolysis) segments and serves to generate complex bioactive lipids that control many biological processes. These biological processes include, but are not limited to, the synthesis, secretion, and function of insulin.
The distinctive physiological properties of MCTs relative to LCTs arise from their more rapid hydrolysis and unique absorptive pathway. Unlike LCTs, MCTs are hydrolyzed more rapidly by pancreatic lipases, are absorbed directly into the portal circulation, and do not require carnitine-mediated transport to enter mitochondria for beta-oxidation. Medium-chain triglycerides contain medium-chain fatty acid esterified to the glycerol backbone. These MCFA have a shorter chain length and are quickly metabolized in the body, serving as an immediate energy source.
MCTs not only have properties as an energy source but also have various physiological effects, such as effects on fat and protein metabolism. The enhancement of fat oxidation through ingestion of MCTs has led to interest in the study of body fat reduction and improvement of endurance during exercise. Recently, MCTs have also been shown to promote protein anabolism and inhibit catabolism, and applied research has been conducted into the prevention of frailty in the elderly.
MCTs are substantially more ketogenic than LCTs. When consumed in sufficient quantity, MCTs are oxidized in the liver to produce ketone bodies β primarily beta-hydroxybutyrate (Ξ²-HB) and acetoacetate β which can cross the blood-brain barrier and serve as an alternative fuel for neurons. This property underlies the use of MCT oil in cognitive support and epilepsy management. MCT oil is more ketogenic than long-chain triglycerides. Therefore, the MCT ketogenic diet (MCTKD) allows more carbohydrate and protein food, which makes the diet more palatable than the classic ketogenic diet (CKD). The MCTKD is not based on diet ratios as is the CKD but uses a percentage of calories from MCT oil to create ketones.
Serum TGs are the main components of chylomicrons and very low-density lipoproteins (VLDLs). VLDLs and chylomicrons can permeate the arterial intima and selectively deposit, eventually causing the accumulation of cholesterol in the arterial intima and plaque formation.
Triglycerides are enriched in chylomicrons and very low-density lipoprotein (VLDL), and lipolysis by lipoprotein lipase (LPL) is a critical step in the catabolism of these triglyceride-rich lipoprotein particles.
Evidence level: Moderate; systematic review and meta-analysis support a modest effect.
Research has indicated that consuming medium-chain triglycerides (MCT) may be more satiating than consuming long-chain triglycerides (LCT), potentially causing a reduction in energy intake. However, not all studies have demonstrated this acute reduction in energy intake and it has yet to be fully systematically reviewed.
Seventeen studies (291 participants) were included in one systematic review, of which 11 were included in the energy intake meta-analysis. Synthesis of combined data showed evidence of a statistically significant moderate decrease in ad libitum energy intake after both acute and chronic ingestion of MCT compared to LCT when assessed under laboratory conditions (mean effect size: β0.444, 95% CI β0.808, β0.080, p < 0.017), despite little evidence of any effect of MCT on subjective appetite ratings or circulating hormones. The current evidence supports the notion that MCT decreases subsequent energy intake, but does not appear to affect appetite.
A 2024 systematic review and meta-analysis examining MCT effects on weight loss in individuals with overweight or obesity found: diets enriched with MCTs are more effective in achieving weight reduction (WMD: β1.53%; 95% CI: β2.44, β0.63; p < 0.01), particularly those containing pure MCTs (WMD: β1.62%; 95% CI: β2.78, β0.46; p < 0.01).
An earlier meta-analysis of RCTs (2015) specifically focused on MCTs comprised of C8:0 and C10:0: it was designed to compare the effects of MCTs to long-chain triglycerides (LCTs) on weight loss and body composition in adults, with changes in blood lipid levels as secondary outcomes. Randomized controlled trials of more than 3 weeks' duration conducted in healthy adults were identified by searching multiple databases until March 2014 with no language restriction. Thirteen trials (n=749) were identified.
Evidence level: Preliminary to moderate; RCT and meta-analytic evidence exists but is mixed and often limited by small sample sizes.
The rationale for MCT use in cognitive decline is that impaired brain glucose metabolism appears to be a potential pathogenic feature of mild cognitive impairment (MCI), and MCT supplementation can increase circulating ketone bodies as a means to beneficially modulate brain homeostasis in subjects with MCI.
A small pilot RCT enrolled six participants with MCI: participants received 56 g/day of either MCTs or placebo for 24 weeks; serum Ξ²-hydroxybutyrate concentrations, apolipoprotein-E4 status, and cognitive assessments were carried out. Due to the small number of participants, only the raw scores were examined. Intake of MCT oil increased serum ketone bodies and improved memory, while intake of placebo did not show improvement in any of the cognitive measures tested. Consumption of 56 g/day of MCTs for 24 weeks increases serum ketone concentrations and appears to be a candidate for larger randomized controlled trials.
A meta-analysis of human studies on MCTs in MCI/AD reported: MCTs can induce mild ketosis and may improve cognition in patients with mild cognitive impairment and Alzheimer's disease. However, risk of bias of existing studies necessitates future trials.
A second systematic review and meta-analysis concluded that: while clinical trials have been conducted to explore the potential use of MCT for improvement of cognitive functioning in MCI and AD patients, results have been controversial and inconclusive.
A 15-month double-blind, placebo-controlled crossover trial with an open-label extension: This trial of community-dwelling moderateβsevere AD subjects suggests a stabilization of cognition with exposure to continuous daily nutritional ketones (in the form of MCT oil) over a 9-month period. Larger studies are needed to confirm this response, and to look at other stages of AD, including mild cognitive impairment.
In an open-label study in a Japanese population, 3 months of supplementation with 20 g MCT (C8) improved cognitive assessment scores in APOE4-negative (but not in APOE4-positive) AD patients with higher baseline scores, but failed to improve cognition in individuals with more advanced progression of the disease.
A double-blind RCT in healthy older adults using 18 g/day of MCT oil (6 g three times daily): dietary MCT supplementation showed a significant improvement in gait balance, although neurobehavioral cognitive changes were expected to be difficult to detect in healthy elderly participants.
A 2025 large RCT (280 participants with MCI) tested MCTs alone and in combination with DHA: this randomized, double-blind, placebo-controlled trial evaluated effects of MCT and DHA supplementation, alone or in combination, on MCI patients. A total of 280 MCI participants were randomly assigned to the placebo group, MCT group (14 g/d octanoic acid + 10 g/d capric acid), DHA group (800 mg/d) and MCT + DHA group, 70 individuals per group for 12 months. Cognitive function was assessed at baseline, 6 months, and 12 months.
One analysis also examined brain network connectivity: after MCT supplementation, the connectivity in one of eight brain networks β the dorsal attention network (DAN) β was 59% higher compared to the placebo group, which was also associated with better scores in some cognitive tests.
Evidence level: Moderate; supported by RCTs and a Cochrane review in the context of pediatric epilepsy.
The medium-chain triglyceride (MCT) ketogenic diet is used extensively for treating refractory childhood epilepsy.
The ketogenic diet (KD) is one of the most effective therapies for drug-resistant epilepsy. The efficacy of the MCT ketogenic diet (MCTKD) is as excellent as the classic KD (CKD), which has been documented in several subsequent retrospective, prospective, and randomized studies. MCT oil is more ketogenic than long-chain triglycerides. Therefore, the MCTKD allows more carbohydrate and protein food, which makes the diet more palatable than the CKD.
A case report documented: a 43-year-old man with a history of nonsurgical partial epilepsy who had previously failed multiple trials of antiepileptic drugs. MCTs were added to his regular diet in the form of pure oil; he experienced a significant daily seizure reduction of 96% compared to baseline after introduction of MCT oil.
A well-known form of the ketogenic diet is the MCT-diet, which consists mainly of medium-chain triglycerides. The body of evidence has been synthesized in Cochrane and prospective studies, with the MCT diet demonstrating comparable efficacy to the classic ketogenic diet, though direct comparative RCT data remain limited.
Evidence level: Strong for association; causal role of lowering TG on outcomes remains debated.
Approximately 25β50% of the population worldwide exhibits serum triglycerides β₯150 mg/dL, which are associated with an increased level of highly atherogenic remnant-like particles, non-alcoholic fatty liver disease, and pancreatitis risk. High serum TG levels could be related to cardiovascular disease, which is the most prevalent cause of mortality in Western countries.
Hypertriglyceridemia has been associated with an increased risk of cardiovascular disease and pancreatitis. A severe elevation of triglycerides increases the risk for pancreatitis and requires lowering by lifestyle change and pharmacotherapy.
Interest in triglyceride-rich lipoproteins (TRLs) has for long been rather low, but recent results demonstrating that TRLs are causally associated with atherosclerotic cardiovascular disease (ASCVD) have generated major interest in these lipoproteins.
A systematic review and meta-analysis found that hypertriglyceridemia is associated with increased risk of cardiovascular death, MI, cardiovascular events, and possibly acute pancreatitis. Pooled estimates showed increased odds of cardiovascular events by 37% (odds ratio of 1.37).
Despite these associations, the clinical evidence for treatment of HTG specifically improving outcomes is less definitive: multiple studies have shown that mild to moderate hypertriglyceridemia is an independent risk factor for cardiovascular disease, but data do not show definite evidence that cardiovascular disease risk diminishes with the treatment of hypertriglyceridemia.
Evidence level: Strong for severe hypertriglyceridemia as a cause; emerging evidence links even moderate elevations to risk.
Triglycerides are a major source of energy, while high plasma triglycerides are a risk factor for various diseases and premature death. Severely elevated plasma triglycerides are a well-established cause of acute pancreatitis with high mortality, likely due to the presence of elevated levels of chylomicrons and large very low-density lipoproteins in plasma.
The release of excess free fatty acids and lysolecithin from chylomicrons in pancreatic capillaries is linked to the causation of pancreatitis. Hyperviscosity from increased chylomicrons leads to acidosis and ischemia in the capillary beds. This leads to the activation of pancreatic lipases, lipolysis, and release of toxic free fatty acids, which cause inflammation, cytotoxic injury, and pancreatitis. The risk of pancreatitis correlates with the level of triglycerides and markedly increases with levels above 500 mg/dL. In most instances, pancreatitis can be prevented by keeping triglyceride levels below 250β500 mg/dL.
Recent observational and genetic studies indicate that mild to moderate hypertriglyceridemia is causally related to increased risk of acute pancreatitis, most likely as a marker of future severe hypertriglyceridemia. Current guidelines do not mention individuals with mild to moderate hypertriglyceridemia, even though newer evidence suggests an unmet medical need.
MCTs, paradoxically, have a clinical application in the management of severe hypertriglyceridemia: MCTs have been clinically effective in treating patients with severe hypertriglyceridemia associated with familial hyperchylomicronemia. The reasoning is that MCTs, unlike LCTs, do not require chylomicron packaging for transport, thus removing the substrate that drives hypertriglyceridemia in this condition.
Evidence level: Moderate for associations; interventional data are more limited.
In the setting of overnutrition and obesity, hepatic fatty acid metabolism is altered, commonly leading to the accumulation of triglycerides within hepatocytes, and to a clinical condition known as non-alcoholic fatty liver disease (NAFLD).
The regulation of triglyceride metabolism is influenced by various factors, including nutritional status, hormonal signaling, and genetic factors. Dysregulation of these processes can lead to metabolic disorders such as obesity and type 2 diabetes. Hypertriglyceridemia, characterized by elevated levels of triglycerides in the bloodstream, is frequently associated with metabolic disorders. Among these, obesity stands out as one of the most prevalent conditions linked to high triglyceride levels.
The triglyceride-glucose (TyG) index, which combines fasting triglyceride and glucose measurements, has emerged as a biomarker of insulin resistance. An umbrella review covering 95 associations from 29 meta-analyses, investigating associations between TyG index and 30 health outcomes, found that 83 (87.4%) associations were statistically significant (p < 0.05). Based on the AMSTAR tool, 16 (55.2%) meta-analyses were high quality. The certainty of the evidence, assessed by the GRADE framework, showed that 6 (6.3%) associations were supported by moderate-quality evidence.
Evidence level: Preliminary; association-based only, causal direction unclear.
One study sought to quantitatively summarize the clinical data comparing peripheral blood triglyceride concentrations between patients with major depressive disorder (MDD) and healthy controls (HCs). Thirty-eight studies measuring the concentrations of peripheral blood TG in 2,604 patients with MDD and 3,272 HCs were included. Meta-analysis results indicated that TG levels were significantly higher in patients with MDD than in HCs (SMD = 0.31, 95% CI: 0.16 to 0.46, p < 0.01). The direction of causation β whether elevated TG precede or follow depression β has not been established, and this association should be interpreted with caution.
Evidence level: Weak to insufficient; inconsistent findings across studies.
The enhancement of fat oxidation through ingestion of MCTs has led to interest in the study of body fat reduction and improvement of endurance during exercise. A systematic review on MCT supplementation and endurance performance in healthy populations examined parameters including oxygen consumption, respiratory exchange ratio, fat oxidation, carbohydrate oxidation, lactate, ketones, glucose, glycerol, and rate of perceived exertion, with inconsistent results across trials. The evidence does not support MCT supplementation as a reliable ergogenic aid under current protocols.
Evidence level: Observational; strong associations, limited interventional data.
Hypertriglyceridemia is highly prevalent among patients with chronic kidney disease (CKD) and plays a critical role in both the progression of nephropathy and the increased risk of cardiovascular events. The underlying pathophysiology involves metabolic disturbances of triglyceride-rich lipoproteins, leading to lipid accumulation within renal cells. This accumulation triggers lipotoxicity, oxidative stress, and inflammatory cascades that ultimately contribute to renal fibrosis.
Based on the sourced literature, triglycerides β both as endogenous biomarkers and as supplemented ingredients β are relevant to the following systems:
The following dosages are those reported in cited peer-reviewed clinical sources only:
There has been literature which documents the associated gastrointestinal side effects from the MCT ketogenic diet, such as diarrhea, vomiting, bloating, and cramps. Side effects were more frequently diarrhea (50%), and in a larger study of 86 AD participants randomized to receive a proprietary blend of MCT powder/emulsifier, GI events were reported in 49% of the MCT group, diarrhea in 24%, versus GI events in 27% of the placebo group and diarrhea in 14%. GI intolerance is dose-dependent and is the principal dose-limiting factor in clinical use of MCT oil.
MCT consumption may have a beneficial impact on weight management; however, some studies point to a negative impact of MCT oil consumption on cardiovascular disease risk. One study examined the effects of MCT oil consumption, as part of a weight loss diet, on metabolic risk profile compared to olive oil in 31 men and women completing a 16-week weight loss program. The results showed that MCT oil consumption at a level of approximately 18β24 g/d does not have detrimental effects on cardiovascular disease risk factors after taking into consideration body weight. These data suggest that a distinction must be made when discussing the cardiovascular health effects of saturated fats, as those of medium chain length do not seem to confer adverse health effects.
However, discrepant findings exist: some studies reported similar increases in total cholesterol and LDL cholesterol after medium-chain fatty acid and palm oil consumption. Additional research is needed to comprehensively evaluate the effects of MCTs on body weight, weight loss, and CVD risk.
Significant increases in fasting plasma triglyceride concentrations have been observed in subjects consuming β₯40% of their energy in the form of MCTs. This is clinically relevant for individuals with pre-existing hypertriglyceridemia.
The risk of pancreatitis correlates with the level of triglycerides and markedly increases with levels above 500 mg/dL. In most instances, pancreatitis can be prevented by keeping triglyceride levels below 250β500 mg/dL.
Common disorders that can elevate triglyceride levels include poorly controlled diabetes, obesity, pregnancy, renal disease, hypothyroidism, and HIV. Common drugs that increase triglyceride levels are ethanol, oral estrogens, glucocorticoids, retinoids, beta blockers, thiazide and loop diuretics, protease inhibitors, and atypical antipsychotics.
The refined fatty acid caprylic acid (C8) from MCT oil meets GRAS (Generally Recognized as Safe) FDA exemption, GRAS Reference (FEMA No.) 2799.
Robust data about interactions between medium-chain triglycerides and common cardiometabolic medications are lacking. Many patients who ask about MCT oil are already on statins, fibrates, prescription omega-3s, or glucose-lowering drugs. Whether MCT oil meaningfully alters drug metabolism, drug potency, or the risk profile in combination with these therapies remains speculative.
In the setting of overnutrition and obesity, hepatic fatty acid metabolism is altered, commonly leading to the accumulation of triglycerides within hepatocytes, and to a clinical condition known as non-alcoholic fatty liver disease (NAFLD). Since MCTs are primarily metabolized in the liver through portal circulation, individuals with pre-existing hepatic disease warrant clinical evaluation before use.
Health conditions that Triglycerides may help support.
Body systems that Triglycerides may help support.
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