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Cosmetic antioxidants

Tempol

Also known as Tanol, 4-Oxypiperidol, TMPN

CAS 2226-96-2Formula C9H18NO2Molar mass 172.25 g/molEC 218-760-9
GHS signal word: Danger. Pictograms: Corrosive, Harmful or irritant, Serious health hazard 64 suppliers listed
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Tempol chemical structure, C9H18NO2, CAS 2226-96-2
2D chemical structure

Key facts

What buyers check first

All properties
CAS number
2226-96-2
Formula
C9H18NO2
Appearance
Crystals from ether + Benzene
Melting point
71.5 ยฐC
HS code
293339
Category
Cosmetic antioxidants
Illustrative photo, 25 kg white woven sacks of powder on a pallet in a warehouse
Typical packagingIllustrative packaging image, not the actual product

What is Tempol?

Plain description, key identifiers and synonyms

4-hydroxy-TEMPO is a member of the class of aminoxyls that is TEMPO carrying a hydroxy substituent at position 4. It is a radical scavenger which exhibits anti-inflammatory and analgesic properties. It has a role as a catalyst, an antineoplastic agent, a radical scavenger, a hepatoprotective agent, a neuroprotective agent, an anti-inflammatory agent, an apoptosis inducer and a nephroprotective agent. It is a member of aminoxyls and a hydroxypiperidine. It is functionally related to a TEMPO.

Identifiers

Registry numbers, names and line notations, tap to copy

CAS number
2226-96-2 CAS number cross-checked
EC number
218-760-9
Molecular formula
C9H18NO2
UNII
U78ZX2F65X
INCI name
HYDROXY TETRAMETHYLPIPERIDINE OXIDE
InChIKey
UZFMOKQJFYMBGY-UHFFFAOYSA-N
InChI
InChI=1S/C9H18NO2/c1-8(2)5-7(11)6-9(3,4)10(8)12/h7,11H,5-6H2,1-4H3
SMILES (canonical and isomeric)
CC1(CC(CC(N1[O])(C)C)O)C

Synonyms

  • Tanol
  • 4-Oxypiperidol
  • TMPN
  • HyTEMPO
  • Nitroxyl 2
  • 1-Piperidinyloxy, 4-hydroxy-2,2,6,6-tetramethyl-
  • 4-Hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl
  • 2,2,6,6-Tetramethyl-4-hydroxypiperidinooxy
  • 2,2,6,6-Tetramethyl-4-piperidinol 1-oxyl
  • 2,2,6,6-Tetramethyl-4-piperidinol-N-oxyl
  • 4-Hydroxy-2,2,6,6-tetramethylpiperidinooxy
  • 4-Hydroxy-2,2,6,6-tetramethylpiperidinooxyl
  • 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl
  • 2,2,6,6-Tetramethyl-4-hydroxypiperidinooxy radical
  • 4-Hydroxy-2,2,6,6-tetramethylpiperidin-1-yl)oxidanyl
  • (4-hydroxy-2,2,6,6-tetramethylpiperidin-1-yl)oxidanyl
  • Piperidinooxy, 4-hydroxy-2,2,6,6-tetramethyl-
  • 2,2,6,6-Tetramethyl-4-piperidinol N-oxyl
  • 2,2,6,6-Tetramethyl-4-piperidinol-1-oxy
  • 2,2,6,6-Tetramethyl-4-piperidinol 1-oxide
  • 2,2,6,6-Tetramethylpiperidine-N-oxyl-4-ol
  • 2,2,6,6-Tetramethyl-4-oxypiperidine-1-oxyl
  • 2,2,6,6-Tetramethyl-4-piperidinol nitroxide
  • 2,2,6,6-Tetramethyl-4-hydroxypiperidin-1-oxyl
  • 2,2,6,6-Tetramethyl-4-hydroxypiperidyl 1-oxyl
Show all 39 synonyms
  • 4-Hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl
  • 4-Hydroxy-2,2,6,6-tetramethylpiperidinooxy radical
  • 4-hydroxy-2,2,6,6-tetramethyl-piperidin-1-oxyl
  • 4-Hydroxy-2,2,6,6-tetramethylpiperidinlyoxy
  • 1-Piperidinyloxy,4-hydroxy-2,2,6,6-tetramethyl-
  • 4-Hydroxy-2,2,6,6-tetramethylpiperidiney-1-oxyl
  • 2,2,6,6-Tetramethyl-4-hydroxypiperidine 1-oxide radical
  • 4-hydroxy-2,2,6,6-tetramethylpiperidinoxy radical
  • N-Oxyl-2,2,6,6-tetramethylpiperidine
  • 4-hydroxy-2,2,6,6-tetramethylpiperidinyl-1-oxy
  • nitroxide 4-hydroxy-2,2,6,6-tetramethylpiperidinyl-N-oxyl
  • nitroxyl-2 (2,2,6,6-tetramethyl 4-oxypiperidine)-1-oxyl
  • 4-hydroxy-1-oxyl-2,2,6,6-tetramethylpiperidine
  • 4-Hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy

Physical and chemical properties

Measured values and descriptors computed from the structure

Physical and chemical properties

Measured values, check the supplier specification for your grade

Appearance
Crystals from ether + Benzeneexp.
Melting point
71.5 ยฐCexp.

Values vary by grade. Ask suppliers for the COA or TDS of the batch you buy.

Computed descriptors

Calculated from the structure, useful for screening and formulation

Molecular weight
172.25 g/molcalc.
Exact mass
172.1338 Dacalc.
LogP (octanol/water)
1.35calc.
Topological polar surface area
43.37 ร…ยฒcalc.
Hydrogen bond donors
1calc.
Hydrogen bond acceptors
2calc.
Rotatable bonds
0calc.
Heavy atoms
12calc.
Rings
1calc.
Aromatic rings
0calc.
Fraction sp3 carbons
1calc.
Formal charge
0calc.
Stereocentres
0calc.
Lipinski rule of five
Passes (0 violations)calc.

Calculated for screening. Confirm critical figures with the supplier.

Murcko scaffold

The ring system that remains when every side chain is removed

Murcko scaffold of this chemical, C1CCNCC1

C1CCNCC1

1 ring, 6 atoms, the Piperidine ring system.

32,085 other chemicals share this scaffold

Safety and hazards

GHS classification summary, not a safety data sheet

GHS signal word
Danger
GHS05: Corrosive
Corrosive
GHS07: Harmful or irritant
Harmful or irritant
GHS08: Serious health hazard
Serious health hazard

Hazard statements

  • H302Harmful if swallowed.
  • H315Causes skin irritation.
  • H318Causes serious eye damage.
  • H319Causes serious eye irritation.
  • H335May cause respiratory irritation.
  • H373May cause damage to organs through prolonged or repeated exposure.
  • H412Harmful to aquatic life with long lasting effects.
Precautionary statements (23)
  • P260Do not breathe dust, fume, gas, mist, vapours or spray.
  • P261Avoid breathing dust, fume, gas, mist, vapours or spray.
  • P264Wash skin thoroughly after handling.
  • P264 + P265Wash skin thoroughly after handling. Do not touch eyes.
  • P270Do not eat, drink or smoke when using this product.
  • P271Use only outdoors or in a well-ventilated area.
  • P273Avoid release to the environment.
  • P280Wear protective gloves, protective clothing, eye protection and face protection.
  • P301 + P317If swallowed: Get medical help.
  • P302 + P352If on skin: Wash with plenty of water.
  • P304 + P340If inhaled: Remove person to fresh air and keep comfortable for breathing.
  • P305 + P351 + P338If in eyes: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
  • P305 + P354 + P338If in eyes: Immediately rinse with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
  • P317Get medical help.
  • P319Get medical help if you feel unwell.
  • P321Specific treatment (see supplemental first aid instructions on the label).
  • P330Rinse mouth.
  • P332 + P317If skin irritation occurs: Get medical help.
  • P337 + P317If eye irritation persists: Get medical help.
  • P362 + P364Take off contaminated clothing. And wash it before reuse.
  • P403 + P233Store in a well-ventilated place. Keep container tightly closed.
  • P405Store locked up.
  • P501Dispose of contents and container in accordance with local regulations.

GHS classification summary, not a safety data sheet (SDS). Classifications can differ by supplier, grade and concentration. Always check the supplier's SDS.

Full safety data and first aid

Tempol suppliers

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All 64 suppliers
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Where suppliers are based

64 suppliers in 12 countries

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Tempol price

Indicative price range per kg from live supplier offers

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Uses and applications

What the substance is used for, by industry and function

Spin label for EPR (electron paramagnetic resonance) studies, phase transfer dehydration catalyst, antioxidant, inhibitor of olefin-free radical polymerization.

Tempol, a water-soluble piperidine nitroxide derivative having nonspecific radical-scavenging and superoxide dismutase (SOD) activity, protects cultured aerobic, but not hypoxic, cells against radiation-induced killing.

Industrial uses: UV stabilizer, Processing aids not otherwise specified, Chemical reaction regulator, Antioxidant, Other, Intermediate, Sealant (barrier), Stabilizing agent.

Consumer uses: Sealant (barrier), Antioxidant, UV stabilizer, Other.

Cosmetic ingredient, INCI name HYDROXY TETRAMETHYLPIPERIDINE OXIDE(antioxidant)

Pharmacological actions

  • Antioxidants
  • Neuroprotective Agents
  • Protein Synthesis Inhibitors
  • Radiation-Protective Agents

Roles

  • anti-inflammatory agent
  • antimicrobial agent
  • antineoplastic agent
  • antioxidant
  • antiviral agent
  • apoptosis inducer
  • cardiovascular drug
  • catalyst
  • hepatoprotective agent
  • nephroprotective agent
  • neuroprotective agent
  • pharmaceutical
  • protective agent
  • radical scavenger

Functional uses

  • Antioxidant

Cosmetic functions

  • Antioxidant

Pharmacology

Topical Piperidine Nitroxide MTS-01 is a topical gel containing a cell permeable hydrophilic piperidine nitroxide with potential radioprotective and antioxidant activity. As a stable, free radical compound, MTS-01 may be able to protect cells against the damaging effects of reactive oxygen species (ROS), upon exposure to ionizing radiation and oxidative stress. The topically applied MTS-01 may protect normal tissue from radiation-induced toxicity, such as radiation dermatitis, during radiation therapy.

Regulatory status

Inventories, regulations and trade controls that list this substance

Health and food

  • EU cosmetic ingredient inventory

United States

  • TSCA inventory (USA)
    Status: Active in US commerce

HS code and trade data

Customs classification and reported world trade statistics

Global trade

World import and export statistics for the HS code Tempol is traded under.

HS 2933.39Indicative HS code

Heterocyclic compounds containing an unfused pyridine ring (whether or not hydrogenated) in the structureโ€ฆ

World exports in 2024
$9.16B
โˆ’17.9% vs 2023, imports $10.6B
2019 to 2024
Top exporters
  1. China21.5%
  2. India * partner reported12.3%
  3. Ireland11.6%
Top importers
  1. Germany14.2%
  2. United States12.8%
  3. Brazil10.1%

* Partner reported figures, a lower bound.

Reported customs values in USD, not prices.Full trade data

The HS code shown for Tempol is indicative (it was assigned by structure rules). Confirm the classification with your customs broker before shipping.

Frequently asked questions

Quick answers about Tempol, based on the data on this page

What is Tempol?

4-hydroxy-TEMPO is a member of the class of aminoxyls that is TEMPO carrying a hydroxy substituent at position 4. It is a radical scavenger which exhibits anti-inflammatory and analgesic properties.

What is the CAS number of Tempol?

The CAS registry number of Tempol is 2226-96-2.

What is the molecular formula and weight of Tempol?

The molecular formula of Tempol is C9H18NO2 and its molar mass is 172.25 g/mol.

What is Tempol used for?

Spin label for EPR (electron paramagnetic resonance) studies, phase transfer dehydration catalyst, antioxidant, inhibitor of olefin-free radical polymerization.

Is Tempol hazardous?

Tempol carries the GHS signal word "Danger". Main hazards: harmful if swallowed, causes skin irritation, causes serious eye damage. This summary is not an SDS, always read the supplier safety data sheet.

What is the HS code of Tempol?

Tempol is usually classified under HS code 293339 (Compounds containing an unfused pyridine ring (whether or not hydrogenated) in theโ€ฆ). This is indicative, confirm it with your customs broker before shipping.

Where can I buy Tempol?

CompoundList lists 64 suppliers of Tempol in China, United States, Germany, United Kingdom and 8 more. Send one free request to get and compare quotes. Your contact details stay private until you accept a quote.

Where can I buy Tempol in India?

1 supplier in India list Tempol on CompoundList. Filter the suppliers list by country and send a request to compare prices, grades and delivery times.

What is the price of Tempol?

Suppliers quote Tempol on request because prices depend on grade, purity, quantity and destination. A free request on CompoundList gets you several quotes to compare.

Guides for buyers

Practical guides that help when you source, ship or handle Tempol

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Data last updated 7 Oct 2026. Details may have changed, please confirm them with the supplier. Report an error on this page
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