A precursor substance refers to something that comes before or leads to the creation or development of something else. It is like a starting point or an ingredient that is used to make something. Full definition
«We know insects can't synthesize hormones, so they must obtain precursor substances from their food,» Pupo said. (sciencedaily.com)
The successful approach may involve careful, timed delivery of natural precursor substances like pregnenalone or DHEA that support your body's own ability to produce hormones. (greensmoothiegirl.com)
Some bodybuilders use drugs such as anabolic steroids and precursor substances such as prohormones to increase muscle hypertrophy. (en.wikipedia.org)