Body and drug basics
Systemic vs local
Last updated
Systemic means a substance is circulating in the blood and can reach the whole body. Local means it stays largely where it was put and acts there. Rubbing something into skin or placing it into a single joint aims for local; anything entering the bloodstream in quantity is systemic. The line between the two is not clean, because substances applied locally can still be absorbed into circulation to some degree.
Why it matters here
The route of administration entries on this site are largely about this distinction, and it decides whether the rest of the body is exposed at all. It is also why a laboratory result obtained on one tissue does not describe what happens everywhere else.
What it is not
Local does not mean contained. Applying something to one spot does not guarantee it stays there, and how much crosses into the bloodstream depends on the substance and the tissue, and is frequently not documented at all for a given product.
Also called
- systemic
- local
- systemic vs local
- local vs systemic
- systemic effect
- local effect
- topical vs systemic
- site of action
Compounds carrying this term
None on file yet. This term is in the controlled vocabulary but no compound record currently uses it — which is a statement about our coverage, not about the term.