Now, as a Registered Dietitian Nutritionist, I am familiar with L-arginine: it is an amino acid, one of the building blocks of protein; it is conditionally non-essential, which means that your body can usually make enough of it to meet your needs. But if you break your leg or have major surgery to recover from you may need additional amounts to help you heal. It is also used to promote dilation of the blood vessels and may be important in reducing inflammation in the body.
Having said all of that, I don’t know of any peer-reviewed randomized controlled double blinded human research that even suggests arginine supplementation will promote weight loss.
Arginine is readily available in a number of food sources both plant and animal including dairy products (e.g., cottage cheese, ricotta, milk, yogurt, whey protein drinks), beef, pork (e.g., bacon, ham), gelatin , poultry (e.g. chicken and turkey light meat), wild game (e.g. pheasant, quail), seafood (e.g., halibut, lobster, salmon, shrimp, snails, tuna), wheat germ and flour, lupins, buckwheat, granola, oatmeal, peanuts, nuts (coconut, pecans, cashews, walnuts, almonds, Brazil nuts, hazelnuts, pinenuts), seeds (pumpkin, sesame, sunflower), chickpeas, cooked soybeans, Phalaris canariensis (canaryseed or alpiste).
Losing (and maintaining) weight loss will never be as easy as we would like. Weight loss schemes and supplements represent a multi-billion dollar industry in the U.S. alone. Shame on Dr. Oz for once again giving credence and wide exposure to just another fad.