A bit on my personal observations of alchemy.
I find Mantak Chia's stuff somewhat helpful, but very limited. He claims that he had read "all" the taoists books required for understanding the ideas and there is no sense in reading them again, as what he proposes is a sort of condensed essential taoist teachings presented in a practical material.
However, I think the opposite: a very limited way in which his teachings are presented may limit your natural development.
He admits that there is a problem with exceess of heat when doing his energy alchemical excercises. Indeed there is - according to my understanding this is because the whole theory on which these excercises are based is limited. It mainly focuses on qi circulation and alike stuff. He won't achieve what ancient taoists achieved IMHO. I.e. there is a big need to not stop just on his understanding of taoism. Most of his books which I saw present a short introduction (which is good, btw, but as stated - overly short and lacks in references) to a subject, but then he fulfills the material with the "do this, do that tutorials". Better understanding of taoist alchmy IMHO can be found in the direct Eva Wong's translations to English on taoism and alchemy.
I found a solution to his problem while practising similar alchemical excercises. Season and place where you live have a different sorts of energy and air (qi or prana is tightly related to energy, as this is how qi / prana comes into the Earth's atmosphere - from the cosmos), depending on what the season or where the place is on the planet. What is missing to me in the Mantak's practice is the fact that it does not take into account some higher energies, which e.g. Lao Tzy or other taoists referred to, basically of shen. Shen for instance balances the energy, including heat, providing necessery cold. Cold energy helps also in rejuvenating the body, but it has to be balanced with the "hot" qi energy. This is just my observation.
Bookmarks