Molekula
L-(+)-Selenomethionine
Supplying 4,500+ customers in over 80 countries
ISO 9001:2015 & ISO 14001:2015 certified · Supplying laboratories and industry since 1999 · Listed pack sizes are a starting point — we manufacture, source and repack to the quantity you need
L-(+)-Selenomethionine is a selenium-containing amino acid used in nutritional supplements and biochemical research to study selenium metabolism and antioxidant functions. It is a white to off-white crystalline powder with a molecular formula of C5H11NO2Se and a molecular weight of 196.11 g/mol. It is classified as a hazardous substance with a signal word of Danger and must be stored at temperatures between -15 and -20 °C.
Molekula supplies L-(+)-Selenomethionine at ≥98% purity in 1 g packs, from £69.12 inc. VAT. It is made or sourced to order. Every batch ships with a certificate of analysis, and safety data sheets are available in 5 languages. Larger quantities, up to multi-tonne, are quoted on request.
Example image for illustration only. Other packaging and pack sizes are available.
Pricing & pack sizes
On backorder — expected to ship by 5 December 2026
These pack sizes aren't a limit. Molekula manufactures, sources and repacks to order — if you need 500 kg and only see 1 kg listed, . We quote from grams to multi-tonne.
Need a different size? Add the nearest pack and change the size in your basket — we price it at the same rate per unit.
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1 g — £57.60 per pack ex VAT · £69.12 inc. VAT
Need a different quantity or pack?
Tell us how much you need and when — drums, IBCs, sacks or a one-off bulk lot. We'll manufacture or source it and come back with a price.
Prices exclude VAT/sales tax and shipping.
Specifications
| Property | Value |
|---|---|
| Appearance | White to off white powder |
| Loss on Drying | ≤1.0% |
| Assay | ≥98% |
| Carbon (C) | 29.5% - 31.5% |
| Identification (IR) | Conforms to reference |
| Selenium (Se) | 37.2% - 42.9% |
| Nitrogen (N) | 6.6% - 7.6% |
Storage & handling
| Property | Value |
|---|---|
| Storage Temperature | -15 to -20 °C |
| Flash Point | 100 °C |
| Transport Class | 6.1 |
| Packing Group | III |
| Acidity | Neutral |
Literature values
Published physical properties of the substance, not batch specifications.
| Property | Value |
|---|---|
| Melting Point | 275 °C |
Source: PubChem CID 105024 (Human Metabolome Database (HMDB))
Identification
| Property | Value |
|---|---|
| SKU | 24764032 |
| CAS Number | 3211-76-5 |
| IUPAC Name | (2S)-2-amino-4-methylselanylbutanoic acid |
| Molecular Formula | C5H11NO2Se |
| Molecular Weight | 196.11 |
| Exact Mass | 196.9955 |
| SMILES | C[Se]CC[C@@H](C(=O)O)N |
| InChIKey | RJFAYQIBOAGBLC-BYPYZUCNSA-N |
| InChI | InChI=1S/C5H11NO2Se/c1-9-3-2-4(6)5(7)8/h4H,2-3,6H2,1H3,(H,7,8)/t4-/m0/s1 |
| PubChem CID | 105024 |
| UN Number | UN3283 |
| REACH Code | Y110 |
| HTS Code | 29319000 |
| Tariff Code | 2931900090 |
Safety & GHS
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Toxic
GHS06
-
Serious Health Hazard
GHS08
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Hazardous to the Environment
GHS09
Hazard statements
- H301 Toxic if swallowed
- H331 Toxic if inhaled
- H373 May cause damage to organs through prolonged or repeated exposure
- H400 Very toxic to aquatic life
- H410 Very toxic to aquatic life with long lasting effects
Precautionary statements
- P260 Do not breathe dust/fume/gas/mist/vapours/spray
- P273 Avoid release to the environment
- P280 Wear protective gloves/protective clothing/eye protection/face protection
- P284 Wear respiratory protection
- P301+310 IF SWALLOWED: Immediately call a POISON CENTER or doctor/physician
- P304+312 IF INHALED: Call a POISON CENTER or doctor/physician if you feel unwell
Documents
Safety Data Sheets (SDS)
Available in English, French, German, Italian, Spanish.
Certificate of Analysis (CoA) by batch
Enter a lot or batch number to retrieve the CoA for that specific batch. We can generate one from spec data if no PDF is on file.
Quality certificates
Molekula Group is certified to ISO 9001:2015 (quality) and ISO 14001:2015 (environmental management), audited by a UKAS-accredited body. Both certificates are valid to 17 May 2028.
Synonyms
- (2S)-2-amino-4-(methylseleno)butanoic acid
- (2S)-2-amino-4-methylselanylbutanoic acid
- (2S)-2-azaniumyl-4-methylselanylbutanoate
- (S)-2-Amino-4-(methylselanyl)butanoic acid
- (S)-2-Amino-4-(methylseleno)butanoic acid
- L-Selenomethioninum
- Selenium-L-methionine
- Seleno-L-methionine
- Selenomethionine-L
- SeMet
Frequently asked questions
What is L-(+)-Selenomethionine used for?
It is used as a selenium source in nutritional supplements and research applications, particularly in studies involving selenium metabolism and antioxidant activity.
What is the chemical formula and molecular weight of L-(+)-Selenomethionine?
The formula is C5H11NO2Se with a molecular weight of 196.11 g/mol.
How should L-(+)-Selenomethionine be stored?
It must be stored at temperatures between -15 and -20 °C to maintain stability and prevent degradation.
What grade of L-(+)-Selenomethionine is available?
We supply L-(+)-Selenomethionine with an assay of ≥98%, specified for appearance, loss on drying (≤1.0%), IR identification and carbon, nitrogen and selenium content.
Can Molekula supply L-(+)-Selenomethionine in bulk?
Yes, we can supply L-(+)-Selenomethionine in bulk quantities—please contact our sales team for pricing and availability.
What documentation comes with an order of L-(+)-Selenomethionine?
Each order includes a Certificate of Analysis (CoA) and Safety Data Sheet (SDS), compliant with regulatory standards.
Where can I buy L-(+)-Selenomethionine?
Directly from Molekula, which lists L-(+)-Selenomethionine in 1 g packs from £69.12 inc. VAT, with a certificate of analysis for every batch. Larger quantities are quoted on request. Molekula's offices: United Kingdom, France, Spain, Germany, Italy, United States and China.
Is L-(+)-Selenomethionine dangerous goods for shipping?
Yes. L-(+)-Selenomethionine ships as dangerous goods: UN3283, class 6.1, packing group III.
Ready to order or need a custom pack?
Tell us the product, grade, and quantity — Molekula usually responds within one working day with pricing and lead time.