Thermogenesis is the process of increasing heat production in tissues. It's critical for maintaining a stable weight, adapting to cold environments (cold acclimatization) and maintaining body temperature in hibernating animals. Serbian researchers found that rats fed
L-arginine supplements showed increased levels of brown adipose tissue and uncoupling proteins, both of which increased thermogenic or heat-producing capacity of tissues.
Brown fat is a highly thermogenic tissue that isn't very significant in humans. The arginine promoted brown fat buildup and the formation of uncoupling proteins both of which triggered thermogenesis. Humans have little brown fat, but have the ability to make uncoupling proteins and generate heat.