Metabolism is the use of energy for growth, use and repair of tissues and maintenance of function (e.g. brain). It can be increased by increasing the muscle to fat ratio.
Arginine can increase the levels of growth hormone under low glucose levels. It also increases the dilation of blood vessels and with that blood flow. L-Citrulline is a precourser of arginine and has a larger effect on arginine levels.
The hypothalamus releases the releasing hormone of growth hormones. It is also involved in temperature regulation, which explains the large effect of temperature on growth hormone levels. Heat and therefore sauna can increase the level of growth hormone release. Under high heat, blood vessels dilate, the heart stroke rate increases. Sauna for 20-30... See more
When the levels of a hormone are too high, the brain will stop to produce stimulating hormones to stop the Production. It can be supplemented through Kelp and seaweed.
Thyroid can increase the glucose uptake by various tissues especially muscles and bones, which increases bone mineral density (especially important for 30+).
The releasing neurons signal to other neurons to trigger the release of stimulating hormones, which triggers the release of the hormone. The releasing hormone is coming from the brain.