Natural alternative to Metformin

Dr. Lam, my adult son is taking Metformin. I'm worried about the acidosis that is causes. His blood sugar is almost where it should be. I would like to know what you think is a good suppliment/s to take instead. I'm not asking for a paticular brand. Just looking for a healthy alternitive to Metformin. He was 280 pds, has lost weight and now weighs 246pds and still trying to lose weight. He works out at the gym and eats healthy now. He has been on Metformin for about 5 months. Tweet