SHEET /m/naproxen · PubChem CID 156391 · CAS 22204-53-1 · REV 2026.07
Naproxen from source
C14H14O3 · 230.26 g/mol
(S)-Naproxen · Naprosyn · (+)-Naproxen · Equiproxen
Also sold as Aleve from source
chemical compound
Fig. 1 · 2D structure RDKit
C[C@@H](C1=CC2=C(C=C1)C=C(C=C2)OC)C(=O)O
Where you'll find it
Not yet mapped to everyday foods or products.
Still in your system computed
Naproxen clears on a half-life of 14 h. Every 14 hours, half of what's left is gone. Put in what you had:
The dose makes the poison inferred
A reported mouse oral LD50 for Naproxen is 1,234 mg/kg, the dose lethal to half the animals tested. Scaled by body mass alone:
“The dose makes the poison” is a cross-species estimate shown as neutral science, not a threshold anyone should act on. Real toxicity depends on the person, not body mass alone.
Signature properties
Toxicity & hazards
Toxicity · LD50
1,234 mg/kg · low toxicity · LD50 mouse oral from source
The dose lens above scales this to a body weight.
3 more reported values
- 435 mg/kgLD50 · iv · mouse
- 475 mg/kgLD50 · other · mouse
- 500 mg/kgLD50 · other · mouse
Keep roaming
Where Naproxen leads
Naproxen is the long-acting NSAID: chemically close to ibuprofen but cleared far more slowly, with a half-life near fourteen hours. One dose lasts most of a day, and it lingers long after the pain is gone.