Benefits
Carbohydrate and glucose handling: laboratory and animal evidence only
In test tube and animal studies, mangiferin slows carbohydrate-digesting enzymes (alpha-glucosidase and alpha-amylase) and switches on AMPK, a cellular energy sensor, in muscle and liver cells. An animal meta-analysis of 19 preclinical studies found lower blood glucose in animals. Human data do not match this yet: in the one 12 week randomized trial (97 overweight adults with high blood fats, 150 mg/day mangiferin), there was no difference between mangiferin and placebo in fasting blood sugar or insulin, although a calculated insulin resistance index did improve. It is not a substitute for diabetes medication.
Anti-inflammatory and antioxidant protection
In laboratory studies mangiferin scavenges free radicals and dampens the NF-kB inflammatory pathway, lowering signaling molecules such as TNF-alpha, IL-6 and IL-1 beta. This comes from a narrative review of laboratory and animal work rather than from human trials. The one human trial cited here reported lipid, glucose and insulin outcomes, not inflammatory markers, so it is unknown whether these effects happen in people at supplement doses.
Lipid profile and cardiovascular support
The human evidence here is real but narrow. In a 12 week double-blind randomized trial of 150 mg/day mangiferin in 97 overweight adults already diagnosed with high blood fats, triglycerides and free fatty acids fell and HDL cholesterol rose compared with placebo. In that same trial there was no difference in total cholesterol or LDL cholesterol, so a claim about lowering cholesterol or LDL is not supported. The trial tested generic mangiferin rather than Melostacio, and it was run in people with a diagnosed lipid condition, so the results may not apply to healthy consumers.
Mechanism of action
AMPK activation and alpha-glucosidase inhibition (laboratory and animal studies)
In cell and animal studies, mangiferin activates AMP-activated protein kinase (AMPK), which moves the glucose transporter GLUT4 to cell membranes and increases glucose uptake, and it also blocks the intestinal enzyme alpha-glucosidase, which slows carbohydrate digestion. This is a proposed mechanism, not a proven human effect: the single human trial cited on this page found no change in fasting blood sugar or insulin compared with placebo.
Clinical trials
Randomized, double-blind, placebo-controlled trial of 150 mg/day of generic mangiferin (not the Melostacio brand) for 12 weeks in 97 overweight adults who had been diagnosed with high blood fats. Main outcomes were blood lipids, blood sugar and insulin. (Na et al. 2015, Sci Rep, PMID 25989216)
97 overweight adults with diagnosed hyperlipidemia (high triglycerides or high total cholesterol). Not healthy consumers, and not people with type 2 diabetes.
Triglycerides and free fatty acids dropped and HDL cholesterol rose compared with placebo, and a calculated insulin resistance index improved. There was no difference between the groups in total cholesterol, LDL cholesterol, fasting blood sugar or insulin. Limitations: this is a single trial, it used generic mangiferin rather than Melostacio, and it was run in people already diagnosed with a lipid condition, so the results may not carry over to healthy people or to other mango leaf extracts.