A meta-analysis by He et al.[1] looked at three randomized controlled trials (RCTs) that compared daily supplementation with medium-chain triglycerides (MCTs) to long-chain triglycerides (LCTs) in their effects on blood lipids. The results showed that MCTs didn’t have a statistically significant effect on total cholesterol, LDL, or HDL. However, they did help lower triglycerides. It’s important to note, however, that the MCTs used in these three RCTs were specifically caprylic acid (an 8-carbon fatty acid) and capric acid (a 10-carbon fatty acid).[2][3][4] The studies didn’t include other MCTs, such as caproic acid (6-carbon) or lauric acid (12-carbon), and the meta-analysis did not identify any such studies, so we don’t know how those might compare.
Other research suggests lauric acid — an MCT with a 12-carbon fatty acid chain length — may actually raise cholesterol levels. For example, a meta-analysis by Mensink et al.[5] reviewed RCTs where 1% of dietary carbohydrates were replaced with different saturated fats, including lauric acid and LCTs like myristic acid (14-carbon), palmitic acid (16-carbon), and stearic acid (18-carbon). The findings showed that lauric acid, like myristic and palmitic acids, increased both total cholesterol and LDL cholesterol. However, this analysis didn’t directly compare lauric acid to other MCTs. Furthermore, no RCTs have directly tested how MCTs with different chain lengths — like caproic, caprylic, capric, and lauric acids — affect blood lipids. Still, based on the available evidence, it seems that lauric acid (12-carbon) may behave differently than the shorter-chain MCTs by raising total cholesterol and LDL.