L-Serine
Compiled from published pharmacological and botanical literature. Not independently verified by Herbuno. Spotted an error or have a correction? Flag it below →
| Compound | L-Serine |
|---|---|
| Chemical class | Non-essential α-amino acid — hydroxymethyl side chain |
| CAS | 56-45-1 |
| Molecular weight | 105.09 g/mol |
| Biosynthesis | From 3-phosphoglycerate via the phosphorylated pathway (3-PGDH, PSAT, PSPH) |
| Key applications | One-carbon donor, glycine and cysteine precursor, sphingolipid and phospholipid synthesis |
| Claim strength | High for the one-carbon and sphingolipid biochemistry; Moderate for HSAN1 |
| Buy from Herbuno | L-Serine Powder |
| Origin | Processed / Sourced from India |
| MOQ | R&D 100 g / 250 g (subject to stock) · Pilot batch 1–5 kg · Bulk 10 kg, 25 kg and above |
| Lead Time | Dispatch within 72 hrs from stock · fresh-batch production (typically 50 kg+): 10 working days |
| Documentation | CoA & MSDS standard with every lot |
Name origin: From the Latin sericum, silk, because Emil Cramer isolated it in 1865 from silk protein hydrolysate — sericin is unusually rich in it. The hydroxymethyl side chain is what makes serine chemically versatile: it is a nucleophile, a phosphorylation site, a glycosylation site, and a one-carbon donor, which is a wider functional range than most amino acids carry.
Biochemical position: Serine is the hub of one-carbon metabolism rather than a peripheral participant. Serine hydroxymethyltransferase transfers serine's hydroxymethyl group to tetrahydrofolate, generating 5,10-methylenetetrahydrofolate and glycine, and that reaction supplies the bulk of the one-carbon units used for thymidylate and purine synthesis and for methionine remethylation. Serine is also the committed precursor of cysteine via cystathionine, of phosphatidylserine, of the entire sphingolipid class via serine palmitoyltransferase, and of D-serine, the co-agonist at the NMDA receptor glycine site.
Research trajectory: Serine's clinical literature is narrow but unusually specific. The best-characterised application is hereditary sensory and autonomic neuropathy type 1, where a mutation in serine palmitoyltransferase causes the enzyme to accept alanine and glycine in place of serine and generate neurotoxic deoxysphingolipids; high-dose L-serine reduces them by substrate competition. Serine deficiency disorders arising from 3-phosphoglycerate dehydrogenase deficiency are also treated with L-serine. A separate thread has examined high-dose L-serine in amyotrophic lateral sclerosis.
Commercial source: L-serine is produced by fermentation, typically using engineered Corynebacterium glutamicum or Escherichia coli, and is also obtained by enzymatic conversion from glycine and methanol. Historically it was recovered from protein hydrolysates, principally silk and sericin, which is worth noting for vegan positioning. Substrate and route determine certification eligibility and should be named.
Evidence for L-Serine Applications
Serine is the principal one-carbon donor, which is a stronger statement than it usually receives and the foundation of its biochemical importance. Serine hydroxymethyltransferase cleaves serine's hydroxymethyl group onto tetrahydrofolate, producing 5,10-methylenetetrahydrofolate and glycine. That folate-bound one-carbon unit supplies thymidylate synthesis, purine synthesis and the remethylation of homocysteine to methionine. Serine therefore sits upstream of nucleotide synthesis and of the methylation cycle simultaneously, and its supply constrains both more directly than glycine's does. Claim strength: High.
Serine is the committed precursor of the entire sphingolipid class, which gives it a structural role no other amino acid has. Serine palmitoyltransferase condenses serine with palmitoyl-CoA as the first and rate-limiting step of sphingolipid synthesis, producing the backbone for ceramides, sphingomyelin and the glycosphingolipids. These are central to membrane organisation, to the skin barrier, and to myelin. The pathway's dependence on serine specifically is what makes the HSAN1 mechanism work, and it is also the basis of interest in serine for barrier-function applications. Claim strength: High.
The HSAN1 application is the best-developed clinical evidence and the mechanism is unusually clean. In HSAN1, serine palmitoyltransferase carries a mutation that allows it to accept alanine or glycine in place of serine, generating 1-deoxysphingolipids which lack the normal hydroxyl group and are neurotoxic. Supplying high-dose L-serine competes for the enzyme and lowers deoxysphingolipid concentrations, and trials have reported reduced levels and stabilisation of neuropathy progression. Doses are substantial, in the range of several grams to tens of grams daily. This is a rare-disease therapeutic application rather than a supplement claim. Claim strength: Moderate, with a High-confidence mechanism.
The ALS work is interesting, early, and frequently overstated. High-dose L-serine has been examined in amyotrophic lateral sclerosis, partly on the rationale of competing with β-methylamino-L-alanine, a cyanobacterial non-protein amino acid that may be misincorporated into proteins in place of serine. Early-phase trials have reported tolerability and some signals on progression rate, but the work is small, the BMAA hypothesis itself remains contested, and no definitive trial has been completed. The honest statement is that it is an active research direction with no established outcome. Claim strength: Emerging.
D-serine and the NMDA receptor are a genuine mechanism, but the connection to oral L-serine is weak. D-serine, produced from L-serine by serine racemase, is the principal endogenous co-agonist at the NMDA receptor glycine site in the forebrain, and D-serine itself has been trialled in schizophrenia as an adjunct. Oral L-serine does not reliably raise brain D-serine, however, and the two should not be conflated in product positioning. A cognitive claim built on D-serine pharmacology does not transfer to an L-serine product. Claim strength: Emerging for L-serine; the D-serine pharmacology is separate.
Safety at supplemental doses is good and has been characterised at unusually high intakes. The HSAN1 and ALS trials have used doses far above typical supplement levels for extended periods with acceptable tolerability, which gives serine a better-characterised high-dose safety record than most non-essential amino acids. Gastrointestinal effects are the usual dose-limiting factor. No tolerable upper intake level has been established. Serine is a normal dietary constituent and endogenously synthesised, so deficiency does not occur outside the specific enzymatic disorders. Claim strength: Moderate.
Sourcing L-serine from Herbuno. We supply L-serine as a crystalline powder.
One specification point specific to this amino acid: historically L-serine was recovered from silk and sericin protein hydrolysates, so for vegan positioning require the production route named on the certificate rather than inferred. Fermentation or enzymatic conversion from glycine is the appropriate specification. All lots ship with CoA and MSDS; request a quotation for pilot or bulk volumes.
Dosage & Formulator Specification
L-serine is dosed as the free amino acid at 98 to 99%, with no salt conversion to apply. General supplemental doses are in the range of 500 milligrams to 3 grams daily; the clinical literature in HSAN1 and ALS has used far higher intakes, from several grams to tens of grams daily in divided doses, which is a different proposition entirely and should not be read across to a supplement format. There is no established requirement, since serine is synthesised endogenously from 3-phosphoglycerate and is abundant in dietary protein.
Formulation positioning should match the biochemistry rather than borrow adjacent literatures. The defensible statements are the one-carbon donor role, the glycine and cysteine precursor relationship, and the sphingolipid backbone function — all settled biochemistry. The HSAN1 and serine-deficiency applications are rare-disease therapeutics and cannot be used in supplement claims. The D-serine NMDA pharmacology belongs to D-serine, not to an oral L-serine product. A formulation positioned on sleep or cognition is working well ahead of the evidence.
Handling is straightforward. L-serine is freely soluble in water at around 36 grams per 100 millilitres at room temperature, stable to heat and across a broad pH range, and only mildly hygroscopic. It has a faintly sweet taste and is among the more palatable amino acids, which is useful at the gram-scale doses some applications require. Its hydroxyl group participates in Maillard reactions with reducing sugars, so thermally processed sugar-containing formats warrant the usual browning check, though serine is less reactive in this respect than lysine.
Co-formulation follows from the one-carbon chemistry. Serine's contribution to the folate one-carbon pool is only realised if folate is adequate, so a formulation positioned on methylation or nucleotide synthesis should carry folate, B12 and B6 alongside. Where serine is included as a cysteine precursor, the transsulphuration route requires methionine-derived homocysteine and B6-dependent cystathionine beta-synthase, so B6 adequacy is the relevant cofactor. Where the target is sphingolipid or barrier function, pairing with the relevant fatty acid substrate is coherent, though the combination has not been tested as such.
For analytical control, specify identity and assay by HPLC or ion-exchange chromatography with optical rotation confirming L-configuration, since D-serine is a distinct and pharmacologically active compound rather than an inert diluent and its presence should be limited and specified. Standard coverage includes heavy metals, residual solvents, microbiological limits, loss on drying and sulphated ash. For fermentation-derived material, specify residual host-cell protein and endotoxin and name the organism and substrate.
The production route deserves explicit specification for certification purposes, which is not true of most amino acids in this catalogue. L-serine was historically recovered by hydrolysis of silk and sericin, which are unusually serine-rich proteins, and material from protein hydrolysate routes has been traded. Silk is an animal-derived material, so for vegan positioning the route must be confirmed rather than assumed from a supplier's general certification portfolio. Fermentation using engineered Corynebacterium or Escherichia coli on a carbohydrate substrate, or enzymatic conversion from glycine and methanol, are the appropriate specifications, and the organism, substrate and any enzyme source should be named on the certificate.
Frequently Asked Questions — L-Serine
What does serine actually do that glycine does not?
It is the principal one-carbon donor. Serine hydroxymethyltransferase moves serine's hydroxymethyl group onto tetrahydrofolate, producing the folate one-carbon unit used for thymidylate and purine synthesis and for homocysteine remethylation — and glycine as a by-product. Serine also uniquely starts the entire sphingolipid class via serine palmitoyltransferase.
Is the ALS research a basis for a product claim?
No. Early-phase high-dose trials have reported tolerability and some progression signals, partly on the rationale of competing with the cyanobacterial amino acid BMAA, but the studies are small, the BMAA hypothesis is contested, and no definitive trial has completed. It is an active research direction with no established outcome, and ALS is a disease endpoint regardless.
Does L-serine raise brain D-serine?
Not reliably, and the two should not be conflated. D-serine is the principal endogenous co-agonist at the NMDA receptor glycine site and has its own trial literature as an adjunct in schizophrenia. Oral L-serine does not dependably translate into brain D-serine, so a cognitive claim built on D-serine pharmacology does not transfer to an L-serine product.
What should I specify beyond assay?
Optical rotation confirming L-configuration, with D-serine limited and specified — it is a pharmacologically active compound rather than an inert diluent, which is unusual for a D-isomer in this catalogue. Plus the production route, for the reason below.
Why does the production route matter here?
Because L-serine was historically recovered by hydrolysis of silk and sericin, which are unusually serine-rich, and protein-hydrolysate material has been traded. Silk is animal-derived, so vegan positioning needs the route confirmed on the certificate rather than inferred from a supplier's general certifications. Specify fermentation or enzymatic conversion from glycine.
What cofactors should accompany it?
Depends on the target. For methylation or nucleotide positioning, folate, B12 and B6 — serine's one-carbon contribution is only realised if folate is adequate. For cysteine precursor use, B6, since cystathionine beta-synthase depends on it. Serine on its own in a methylation formula is substrate without the machinery.