What's on the label is the measured result — net peptide mass, not gross powder weight, plus RP-HPLC purity, on a lot-numbered COA for every batch.
Net peptide mass and RP-HPLC purity — a lot-numbered COA for every batch.
Net peptide mass + HPLC purity, per lot.
PCAC will review 7 peptides for the 503A bulks list, BPC-157, KPV, TB-500, MOTS-c, Emideltide, Semax, Epitalon. Read our briefing →
PCAC will review 7 peptides for the 503A bulks list. Read →
FDA PCAC reviews 7 peptides in July. Read →
Cyanocobalamin (68-19-9) or Methylcobalamin (13422-55-4) form
Overview
Vitamin B-12 (cobalamin) is a cobalt-containing organometallic vitamin essential for methionine synthase activity and methylmalonyl-CoA mutase activity in mammalian metabolism. Supplementation is widely used in compounding pharmacy, med-spa lipotropic-injection protocols, and clinical contexts including pernicious-anemia management. B-12 exists in four biologically relevant forms that differ by the ligand at the cobalt center: cyanocobalamin (the synthetic / supplemental form, with -CN), methylcobalamin (the cytoplasmic methyl-donor form, with -CH₃), hydroxocobalamin (the photochemically-generated -OH form, used clinically for cyanide poisoning), and adenosylcobalamin (the mitochondrial form, with a 5'-deoxyadenosyl group). The choice between forms matters operationally: cyanocobalamin is cheaper and shelf-stable but requires intracellular conversion to active forms; methylcobalamin is directly active but more expensive and somewhat less stable in solution. PeptideXpo supplies Vitamin B-12 in both cyanocobalamin (CAS 68-19-9) and methylcobalamin (CAS 13422-55-4) forms; specify the form at order placement. Hydroxocobalamin and adenosylcobalamin are available on request through OEM service. Both standard and aqueous-solution formats are available. The release packet specifies the exact form and salt on every batch, buyers should always confirm the form on the COA before clinical use, since the forms are not interchangeable for all indications.
Who buys this, and why
Custom-blend buyers are almost always OEM clients building a branded product around a specific ratio of two or more peptides. The development workflow is collaborative: ratio target, analytical method to verify it, stability protocol in the chosen carrier, and packaging selection are all defined in the OEM brief before the first commercial run. Sample-stage volumes are usually 5-10 g of finished blend; commercial MOQ depends on the components.
Primary buyer fit: 503A / 503B compounding pharmacies, medical aesthetic clinics and med spas, and regional distributors and re-sellers.
Specifications
Documentation available on request
Regulatory note
Specify exact B-12 form (cyano vs. methyl vs. hydroxo vs. adenosyl) at order placement. Confirm form and salt via batch COA, the forms are not interchangeable for all clinical indications.
Frequently asked questions
Cyanocobalamin is the cheaper, more shelf-stable form most commonly used in supplements and in standard injectable preparations. It requires intracellular conversion to the active methylcobalamin and adenosylcobalamin forms, which is a normal metabolic step that most patients handle without issue. Methylcobalamin is the cytoplasmic active form, directly usable without conversion, preferred in clinical contexts where the patient has impaired methylation cycle function (some MTHFR variants) or where the prescriber wants to bypass the conversion step. For most med-spa lipotropic and routine supplementation protocols, cyanocobalamin is fine; for prescription-strength neurological or methylation-cycle-impaired contexts, methylcobalamin is preferred.
All four cobalamin forms (cyano, methyl, hydroxo, adenosyl) are photosensitive, exposure to visible and UV light initiates photochemical degradation of the corrin ring system that defines cobalamin chemistry. The cobalt center is also susceptible to oxidation under non-protected conditions. The combination produces measurable potency loss in solid lyophilized material over months at room temperature, and faster loss in solution. Refrigerated storage (2-8 °C) combined with light protection (amber vials or opaque packaging) keeps lyophilized B-12 stable for the standard 24-month shelf life. Reconstituted solutions for med-spa or clinical use should remain in the original container until just before administration; transferring to standard clear-glass syringes for extended hold accelerates degradation.
Med-spa lipotropic protocols commonly dose B-12 at 1,000-5,000 μg per intramuscular injection, administered 1-2 times weekly. The 1 mg/mL solution format supports easy aspiration into the 1-5 mL syringe range typical for IM injection; the 10 mg lyophilized vial format supports reconstitution into custom dosing volumes for clinics requiring larger doses or fractional administration. Methylcobalamin doses are often somewhat lower (500-2,000 μg) because the form is directly active without the conversion step that cyanocobalamin requires. PeptideXpo's B-12 is supplied as a bulk active for med-spa, compounding-pharmacy, and research workflows, buyers should reference their state-board or destination-market regulatory framework for clinical dosing limits.
Related peptides
