Abstract: Metformin is a widely prescribed anti-diabetic medicine that also reduces body weight. There is ongoing debate about the mechanisms that mediate metformin’s effects on energy balance. Here, we show that metformin is a powerful pharmacological inducer of the anorexigenic metabolite N-lactoyl-phenylalanine (Lac-Phe) in cells, in mice and two independent human cohorts. … Lastly, mediation analyses support a role for Lac-Phe as a downstream effector of metformin’s effects on body mass index in participants of a large population-based observational cohort, the Multi-Ethnic Study of Atherosclerosis. Together, these data establish Lac-Phe as a critical mediator of the body weight-lowering effects of metformin.

Dr. Dominic D'Agostino recommends L-carnitine. Are you concerned about issues such as described in this phase 2, prospective, double blinded, randomized, placebo-controlled, two-center trial of people with metabolic syndrome (but not on a ketogenic diet): https://nutritionandmetabolism.biomedcentral.com/articles/10.1186/s12986-022-00661-9