What is Internal Alchemy (Neidan) in Taoism?

Important: Neidan practice requires guidance from a qualified teacher. Do not practice blindly. Study the theoretical foundation first through texts like The Seal of the Unity of the Three, then find a reputable Taoist temple or teacher.

Neidan uses the human body as the furnace, essence (jing), energy (qi), and spirit (shen) as the ingredients, to cultivate the "Golden Elixir" internally. External alchemy (Waidan) involved physical furnaces and minerals — historically problematic due to heavy metal poisoning. Neidan works through three stages: refining essence into energy → refining energy into spirit → refining spirit to return to Emptiness.

For modern people: Neidan is essentially a mind-body cultivation practice emphasizing breath regulation, visualization, and guarding the One. It has many parallels with modern mindfulness meditation. Beginners can start with standing meditation (zhan zhuang), sitting meditation, and breath work.