Hydroxy Tetramethylpiperidine Oxide
molecular structure · PubChem
AKA: Tanol, 4-Oxypiperidol, HyTEMPO, Nitroxyl 2, 1-Piperidinyloxy, 4-Hydroxy-2, 2, 6, 6-tetramethylpiperidine 1-oxyl
Synthetic
Antioxidant
Not Clean
1-Oxyl-2,2,6,6-tetramethyl-4-hydroxypiperidine; 1-Piperidinyloxy, 4-hydroxy-2,2,6,6-tetramethyl-; 1-λ1-Oxidanyl-2,2,6,6-tetramethylpiperidin-4-ol2,2,6,6-tetramethylpiperidine-1,4-diol; 4-Hydroxy-2,2,6,6-tetramethyl-piperidinooxy; 4-Hydroxy-2,2,6,6-tetramethylpiperidine 1-Oxyl Free Radical; 4-Hydroxy-2,2,6,6-tetramethylpiperidinoxy; 4-Hydroxy-2,2,6,6-tetramethylpiperidinoxyl; 4-HYDROXY-2,2,6,6-TETRAMETHYLPIPERIDINOXYL-; 4-Hydroxy-TEMPO; HTMPO; Hydroxy Tempo
Formula
C9H18NO2
Mol. Weight
172.24
CAS #
2226-96-2
Form
Powder
State
Pellets or Large Crystals; Dry Powder; Liquid; Other Solid
Functions
Antioxidant
Fights free radicals — the unstable molecules from UV, pollution, and stress that break down collagen and cause premature aging.
Neutralizes Free Radicals
Traditional Use
A modern synthetic antioxidant developed in the late 20th century specifically for cosmetic preservation and anti-aging formulations, with no traditional historical use.
Skin Types
●all-skin-types
Best For
General
Pregnancy & Breastfeeding Safe
Caution
The paper trail
🔬Peer-reviewednone on file
⚖️Regulatory0 listings
🛡️Safety-assessed2 reviews →
Counts, not a verdict. A listing isn't a study. The trail, you decide.
Verified Jun 2026
Data: PubChem · CosIng · EWG · CIR