Buying Melatonin: What Matters
Melatonin (CAS 73-31-4) is a widely traded bulk raw material, but it is not a simple commodity. The same molecular formula can be supplied as supplement grade, pharmacopoeial grade, cosmetic grade or reference standard, each with different specifications, documentation and regulatory implications. Buying well means matching the grade to your finished product and the market you sell into.
This guide explains the specifications that define melatonin quality, how to read a certificate of analysis, how to choose a grade, and the questions worth asking a supplier. For the chemistry and manufacturing background, see our main article on melatonin (CAS 73-31-4).
Step 1: Match the Grade to the Use
| Grade | Standard | Typical use |
|---|---|---|
| Supplement / nutraceutical | Food-supplement specification | Tablets, capsules, gummies |
| Pharmacopoeial / API | USP or Ph. Eur. monograph, GMP | Pharmaceutical products |
| Cosmetic | Cosmetic-ingredient specification | Skincare and personal care |
| Reference standard | Fully characterised, high purity | Analytical and research use |
Buying the wrong grade is the most common and most expensive mistake. A supplement-grade material will not satisfy a regulator expecting a pharmacopoeial monograph, and paying for API documentation you do not need wastes money.
Step 2: Read the Specification
Melatonin quality is defined by a small set of parameters. The table below lists what to look for, using a representative specification.
| Parameter | Why it matters | Typical value |
|---|---|---|
| Assay (HPLC, dried basis) | The headline purity figure | 99.0–101.0% |
| Identification | Confirms the material is melatonin | IR and/or HPLC vs reference |
| Loss on drying | Moisture; affects stability and weight | ≤ 0.5% |
| Residue on ignition | Inorganic residue | ≤ 0.1% |
| Heavy metals | Safety and compliance | ≤ 10 ppm (as Pb) |
| Related substances | By-products and impurities | Per monograph / customer |
| Residual solvents | Process solvents remaining in the product | Within applicable limits |
| Appearance / colour | Visible quality in a white powder | White to off-white |
Assay and related substances define purity far more usefully than a single headline number, and appearance matters because melatonin is a white powder in which trace colour is easily seen.
Step 3: Choose the Form and Packaging
- Form. Melatonin is normally supplied as a crystalline powder; particle size can be agreed where blend uniformity or tabletting behaviour matters.
- Packaging. Light-resistant, moisture-tight packaging is essential, because melatonin degrades under light. Fibre drums or cartons with inner liners are typical, with amber bottles for research quantities.
- Storage. Keep cool, dry and out of direct sunlight, both in your warehouse and in transit.
Step 4: Confirm the Regulatory Fit
Melatonin’s regulatory status varies sharply between markets, and this is the single most important commercial consideration:
- United States: sold as a dietary supplement; not an approved OTC drug.
- European Union: in many member states it is regulated as a prescription medicine, with restrictions on supplements and cosmetics.
- Elsewhere: classification ranges from supplement to medicine.
Before ordering, confirm that the material and its documentation are acceptable in the market where your finished product will be sold.
Supplier Checklist
- Grade and standard. Which grade, and does it meet your target market’s requirements?
- COA per batch. Will a certificate of analysis accompany each shipment, and can you see a recent example?
- Documentation. SDS, and GMP, non-GMO, halal or kosher statements where needed.
- Consistency. How is assay and colour controlled batch to batch?
- Particle size. Can the particle size be specified if blend uniformity is critical?
- Packaging. Is the packaging light-resistant and moisture-tight?
- Lead time, MOQ and Incoterm. Confirm the commercial terms.
Common Buying Mistakes
- Buying on price alone. A cheaper material with a weaker related-substances profile can fail finished-product testing, costing more than the saving.
- Ignoring regulatory status. Melatonin acceptable as a supplement in one market may be a prescription medicine in another.
- Overlooking colour and light protection. Poor packaging leads to degraded, discoloured material.
- Assuming grades are interchangeable. Supplement and API grades carry different documentation obligations.
- Neglecting storage. Light and heat degrade melatonin, so storage discipline is part of quality.
How PolyBlueChem Can Help
PolyBlueChem can supply melatonin (CAS 73-31-4) as a bulk raw material with the documentation appropriate to your application. We can provide current specifications and a COA, discuss the grade that fits your market, and quote packaging and shipping options. To request specifications, a sample or a quotation, contact the PolyBlueChem team.
Frequently Asked Questions
What should I look for when buying melatonin?
Match the grade to your use, check assay and related substances rather than a single purity figure, confirm the material meets your target market’s regulatory rules, and require a per-batch COA.
What is the CAS number of melatonin?
73-31-4.
Is supplement grade the same as API grade melatonin?
No. The molecule is identical, but API grade must meet a pharmacopoeial monograph and GMP requirements, while supplement grade is produced to a food-supplement specification.
What documents should come with a melatonin shipment?
At minimum a certificate of analysis and a safety data sheet; GMP and other statements are available for many grades where required.
How should melatonin be packaged and stored?
In light-resistant, moisture-tight packaging, stored cool and dry, away from direct sunlight and heat.