Fenformin
An older biguanide drug that had a powerful effect on lactate levels, causing safety concerns and influencing the initial hesitation to bring metformin to the US.
Videos Mentioning Fenformin

#123–Joan Mannick & Nir Barzilai: Rapamycin and metformin—longevity, immune enhancement, & COVID-19
Peter Attia MD
A cousin of Metformin that was more active against diabetes but associated with lactic acidosis, leading to Metformin's wider use.

#66 – Vamsi Mootha, MD: Aging, T2D, cancer, dementia, Parkinson’s—do all roads lead to mitochondria?
Peter Attia MD
A more potent drug related to Metformin that can cause fatal lactic acidosis, illustrating the importance of dosage/potency in complex I inhibition.

204 - Centenarians, metformin, and longevity | Nir Barzilai, M.D.
Peter Attia MD
An early, more potent and toxic form of metformin that caused side effects due to its strong mitochondrial action.

337- Insulin resistance masterclass: The full body impact of metabolic dysfunction, treatment & more
Peter Attia MD
An older biguanide drug that had a powerful effect on lactate levels, causing safety concerns and influencing the initial hesitation to bring metformin to the US.