Magnesium Stearate
Magnesium stearate is the excipient you want as little of as possible. At half a percent it stops a press sticking; at three it can cost you tablet hardness and dissolution rate. Almost every practical question about this product is really a question about how much, and for how long you blend it.
Chelora Chemicals supplies magnesium stearate to pharmaceutical, nutraceutical and food manufacturers worldwide, in vegetable and bovine origin grades, with a batch COA, GHS safety data sheet and the origin statements your QA file needs.
Product identity
- CAS Number
- 557-04-0
- Compendial name
- Magnesium Stearate
- Molecular formula
- C₃₆H₇₀MgO₄
- Molecular weight
- 591.24 g/mol
- EC / EINECS
- 209-150-3
- Food additive number
- E470b
- Pharmacopoeias
- USP-NF · Ph. Eur. · JP · IP · BP
- HS Code
- 2915 70*
* Confirm the exact HS heading with your customs broker — fatty-acid metal salts can sit under a different subheading depending on the destination tariff schedule and the declared end use.
What Magnesium Stearate is used for
Magnesium stearate is a white, very fine, light and bulky powder, noticeably greasy between the fingers — the magnesium salt of stearic and palmitic acid. In practice it is never a single compound but a mixture, which is why the monograph specifies magnesium content and fatty-acid composition rather than a simple assay.
Its role is lubrication in solid dosage manufacture: added at the final blending stage, it spreads over particle surfaces and cuts friction between the compact and the die wall, so tablets eject cleanly and capsule machines dose consistently. It also appears as an anti-adherent and glidant, and in food and cosmetics under E470b.
Where it sits among lubricants
- Magnesium stearate (this product) by far the most effective lubricant per unit weight, and the industry default.
- Sodium stearyl fumarate less hydrophobic and gentler on dissolution; the usual choice where magnesium stearate is incompatible.
- Stearic acid a weaker lubricant, used where the alkaline magnesium salt would attack the active.
- Calcium stearate similar chemistry, less common in pharmaceutical use.
Nearly every tablet formulation uses one of these — see the full excipient range.
Appearance and handling character
The material is extremely light, with a very low bulk density, which makes it dusty to handle and prone to floating in a blender rather than dispersing. It is practically insoluble in water and in ethanol, and it is not classified as a hazardous substance. The practical handling questions are dust control, accurate low-level weighing, and — above all — controlling blend time.
| Parameter | Typical value |
|---|---|
| Appearance | White, fine, light, bulky powder; greasy to touch |
| Identification | Conforms |
| Magnesium content (dried) | 4.0 – 5.0% |
| Stearic acid | 40.0% min |
| Stearic + palmitic acid | 90.0% min |
| Loss on drying | 6.0% max |
| Chloride | 0.1% max |
| Sulphate | 1.0% max |
| Microbial limits | TAMC ≤ 1000 cfu/g · TYMC ≤ 500 cfu/g |
Important: the figures above are indicative of compendial-grade material and are offered for planning only. The batch certificate of analysis is the governing document. Origin, magnesium content and specific surface area are what most affect performance — tell us your requirement and we will quote against it.
| Property / option | Value |
|---|---|
| Physical state | Fine powder at ambient |
| Melting point | ≈ 88 °C |
| Bulk density | ≈ 0.15 – 0.20 g/cm³ |
| Water solubility | Practically insoluble |
| Origin options | Vegetable (palm) · bovine |
| Specific surface area | Reported per batch on request |
Published melting points for magnesium stearate vary with hydrate form and fatty-acid composition. Treat the figure as orientation, not as a specification.
Where our customers put this excipient to work
One job, at a fraction of a percent, in almost every solid dosage form made anywhere.
Tablet lubrication
Added at final blending, typically at 0.5–1%, to cut die-wall friction so tablets eject cleanly without sticking or picking.
Capsule filling
Keeps powder moving through dosators and tamping pins, giving consistent fill weight at speed on an encapsulator.
- Typically 0.5–1% of fill weight
- Lower levels than tableting
- Capsule-grade specification available
Roller compaction
Used sparingly to keep ribbon from sticking to the rolls, usually at a lower level than in the final blend.
- Split addition common
- Over-lubrication risk is higher here
- Technical desk review of your route
Anti-adherent & glidant
Improves flow and stops powder adhering to punch faces, particularly on embossed or deeply concave tooling.
- Punch sticking remedy
- Often paired with colloidal silica
- Formulation guidance available
Nutraceutical tablets
Large, heavily compressed supplement tablets are exactly where lubrication problems show up first, and where vegetable origin is usually required.
- Vegetable (palm) grade standard
- Halal, kosher and vegan statements
- Food-grade E470b specification
Cosmetics & personal care
Used as a binder and texturiser in pressed powders and colour cosmetics, where the greasy feel is a formulation asset.
- Cosmetic-grade specification available
- Vegetable origin standard
- Bulk quantities available
How we supply Magnesium Stearate
Chelora Chemicals is a supplier and sourcing partner, not a manufacturer. On a lubricant whose performance depends on physical form as much as chemistry, owning no plant means we are never defending our own grade — we route your order to the producer whose surface area and origin actually match your blend.
We place your order with whichever qualified producer best matches your origin requirement, your compendial requirement, your price point and your delivery window.
We keep a second qualified source on this line. A lubricant change is felt immediately on the press, so we would rather you qualify the alternate in advance than discover the difference mid-campaign.
- Origin confirmed before we quote. Vegetable or bovine is a labelling and regulatory question as much as a technical one, and we settle it in the first reply.
- Specific surface area available on request. It is the number that predicts lubrication efficiency, and the monograph does not require it — so we ask for it.
- Compendial coverage confirmed first. USP-NF, Ph. Eur., JP or IP — we establish which monographs your filing cites before the quote, not after.
- Full regulatory statement pack. BSE/TSE, origin, allergen, elemental impurity and nitrosamine risk statements with the consignment.
- We will raise incompatibility before you order. If your active is acid-sensitive we say so, even when it means recommending a different lubricant entirely.
- Change notification taken seriously. If a source plant changes anything that touches your filing, you hear about it from us first.
Packed the way your plant receives it
At 1% of a formulation a bag lasts a long time, so the pack has to survive repeated opening as well as transit. Tell us how it will be dispensed and we will quote the right format.
Multiwall paper bags
Kraft bags with an inner PE liner on shrink-wrapped pallets — the standard format and the lowest cost per kilo.
Fibre drums, lined
Lined fibre drums for dispensaries that open the same container many times over several months.
Volume-optimised loading
This is an unusually light powder, so we plan the container around volume rather than weight to keep your freight per kilo down.
Trial / sample quantities
Small sealed packs dispatched so your formulation team can run blend and compression trials before committing to a source.
Incoterms to suit you
Quoted on the Incoterm your purchasing team works to, with export documentation filed before the booking is made.
Campaign despatch
We hold contracted quantity and release it against your production calendar instead of landing a year's usage at once.
Benign powder, unforgiving blend window
Magnesium stearate is not classified as hazardous and is used in food and cosmetics as well as medicine. Its difficulty is not toxicological at all — it is that the same property making it a good lubricant makes it capable of ruining a batch if over-blended. The summary below is orientation only — the safety data sheet supplied with your consignment is the authoritative document.
Hazard position
GHSNot classified as a hazardous substance or mixture.DUSTNuisance dust; may cause mechanical irritation to eyes and the respiratory tract.ATEXCombustible organic powder with a very low bulk density — dust precautions apply.SLIPSpilled powder is slippery underfoot even when dry.
The combustible-dust point deserves more weight here than on a denser excipient. A very light, fatty powder forms airborne clouds readily, and your process-safety team should treat enclosed handling accordingly. Always read the SDS issued with your specific batch.
Practical handling notes
- Fix the blend time and hold it. Three minutes and eight minutes give measurably different tablets from the same blend — this belongs in the batch record, not in operator judgement.
- Sieve before adding. The powder agglomerates into soft lumps that a tumble blender will not break up, leaving some tablets under-lubricated and others over.
- Add last, blend gently. Low shear and short time; a high-shear step after lubricant addition is the classic cause of soft tablets.
- Watch low-level weighing accuracy. At 0.5% of a batch, a weighing error that looks trivial is a large proportional error.
- Clean spills dry. The powder is slippery and floats; vacuum rather than sweep or hose.
Storage
- Cool, dry, tightly closed store. Ordinary warehouse conditions; keep well below the melting range and out of direct sun.
- Keep the liner sealed between dispensings. A bag opened weekly for a year needs a liner that can actually be re-closed.
- Keep away from strong odours. A fatty powder picks up volatile compounds readily and carries them into the dosage form.
- Segregate from strong acids and oxidisers. Standard practice for a fatty-acid salt.
- Shelf life typically 36 months. In sealed original packing. Re-test against your specification after extended storage.
Handling & PPE
- Standard GMP powder handling. Local exhaust at dispensing points, gloves, safety glasses and a dust mask where airborne powder is generated.
- Dust extraction at dispensing. This powder becomes airborne more readily than almost anything else in the dispensary.
- Static control on transfer. Earthed equipment where the material is conveyed pneumatically.
- Check incompatibility before formulating. It is alkaline; acid-sensitive actives need a different lubricant, not a lower level of this one.
- Dispose of as ordinary non-hazardous waste. Subject to your local waste classification.
Transport
Magnesium stearate is not a regulated dangerous good and ships as general cargo by road, sea and air. We issue the commercial, compendial and origin documentation with every consignment — ask us for the full document pack when you plan the shipment.
What travels with every consignment
On this excipient the origin statement is as important as the assay. A compliant batch without a clear BSE/TSE position is still a batch your QA cannot release.
Certificate of Analysis
Batch-specific magnesium content, fatty-acid composition, LOD, chloride, sulphate and microbial limits against the monographs you cite.
Origin & BSE / TSE statement
Explicit confirmation of vegetable (palm-derived) or bovine origin, with the BSE/TSE position stated in writing rather than inferred.
GHS Safety Data Sheet
Full 16-section SDS in GHS format, issued in the language your destination requires, confirming the unclassified status in writing.
Specific surface area
Available on request as an additional test — the figure that actually predicts lubrication efficiency between two compliant lots.
Halal, kosher & vegan
Certification and allergen statements supplied with the consignment — straightforward on vegetable grade, and the usual reason it is specified.
Retained & pre-shipment samples
Pre-shipment samples carry the same COA as the commercial lot, so what your laboratory qualifies is exactly what arrives.
A fatty film, one molecule at a time
Magnesium stearate lubricates by shearing into thin layers that transfer onto whatever it touches. Understanding that explains both why it works so well and why it is so easy to overdo. The steps below are the general industrial pattern, not a process disclosure.
Source the fatty acid
Stearic and palmitic acid are obtained from vegetable oil, usually palm, or from tallow — and that choice defines the grade.
React with a magnesium salt
Precipitation or fusion with a magnesium source forms the metal soap, fixing the magnesium content.
Dry and mill
Drying and milling set particle size, surface area and hydrate form — the physical properties that govern lubrication.
Shear into a film in use
In the blender, the platelets shear and transfer onto particle surfaces. The longer this runs, the more complete the coating becomes.
Why physical form matters more than assay
Two lots can both meet the monograph exactly and behave very differently on your press:
- Specific surface area drives efficiency. A high-surface-area lot coats more particle surface per kilogram, so it lubricates better and over-lubricates sooner at the same percentage.
- Hydrate form affects the melting behaviour. Anhydrous, mono- and dihydrate forms differ in how they shear and spread, and the monograph does not distinguish them.
- Blend time is a formulation variable. Lubrication, hardness and dissolution all move together with mixing time — which is why it belongs in the batch record as a fixed parameter.
- Alkalinity is a stability question. With an acid-sensitive active, the issue is not lubrication at all; it is degradation over shelf life.
That is why we will get you surface area data on request and flag incompatibility before you order, and why the batch COA is shared for approval before dispatch rather than sent with the invoice.
| Material | Character / use |
|---|---|
| Magnesium stearate CAS 557-04-0 — this product | Most effective · hydrophobic · alkaline |
| Sodium stearyl fumarate CAS 4070-80-8 | Gentler on dissolution |
| Stearic acid CAS 57-11-4 | Weaker · non-alkaline |
| Calcium stearate CAS 1592-23-0 | Similar chemistry, less common |
We supply across the excipient range — see the full excipient range. Send your formulation and we will confirm the grades before quoting.
What actually moves the price of this product
Knowing what drives the quote helps you time a purchase and read whether an offer is realistic.
Palm and tallow markets
Vegetable grade tracks palm stearin, which has its own agricultural and biofuel-driven cycle quite separate from petrochemicals.
- Palm oil cycles can be sharp
- Vegetable commands a premium over tallow
- We flag feedstock-driven moves in the quote
Origin requirement
Vegetable grade with full traceability costs more than bovine, and sustainably certified palm costs more again.
- Specify origin explicitly at enquiry
- Certified sustainable palm available
- Documentation drives part of the price
Freight on a very light powder
With a bulk density around 0.15 g/cm³ this material cubes out a container far before it weighs out.
- Always compare on landed cost
- Container utilisation drives the number
- We quote FOB, CIF, CFR or DDP as you prefer
Grade and compendial coverage
Food, cosmetic and pharmaceutical grades come from related plants at different prices and documentation levels.
- Never cross-shop grades on price alone
- Pharma grade carries the statement pack
- We will say when a lower tier will do
Source qualification lead time
A lubricant change shows up immediately in tablet hardness and dissolution, so requalification is the real cost of a supply gap.
- We hold a second qualified source on this line
- Qualify the alternate before you need it
- Ask us about dual-source contracts
Nutraceutical and cosmetic demand
Supplements and colour cosmetics draw on the same vegetable-grade material as pharma and can tighten availability.
- Ask us what adjacent demand is doing
- Long-term contracts lock in supply
- We hold inventory on vegetable grade
| If your situation is… | Specify |
|---|---|
| Standard tablet lubrication | Vegetable grade, 0.5–1% |
| Capsule filling | Vegetable grade, 0.5–1% of fill |
| Sticking on embossed tooling | Higher surface area grade, same level |
| Dissolution already marginal | Lowest workable level, short blend time |
| Acid-sensitive active | Sodium stearyl fumarate instead |
| Vegan / halal product | Vegetable (palm) grade with origin statement |
Not sure which row you are in? Describe your press, your API and your current blend time and our technical desk will help — including telling you when the answer is less lubricant rather than a different one.
Support that goes beyond shipping the pallet
What our technical desk will do
- Establish the origin requirement first. Vegetable or bovine decides labelling, certification and price, and it is the first question we ask.
- Ask about your API's acid sensitivity. If magnesium stearate is the wrong lubricant for your formulation, we would rather tell you than sell you a drum of it.
- Get you surface area data. It is not a monograph test, which is exactly why it is worth asking for when two compliant lots behave differently.
- Flag the blend-time variable. Most lubricant complaints trace back to mixing, not to material, and we will say so before suggesting a source change.
Regulatory & compliance notes
- Excipient change control is yours to manage. Tell us which products this feeds and we will treat source changes as notifiable rather than routine.
- Origin documentation is market-specific. Some markets require explicit vegetable-origin declaration on the label; confirm your position before you order.
- Compendial monographs differ in detail. USP-NF, Ph. Eur., JP and IP are close but not identical; we confirm coverage rather than assuming harmonisation.
- Sustainable palm certification is available. Where your market or customer requires it, ask and we will source against it.
None of the above is legal advice — your own regulatory affairs team owns the final compliance position for your import and your filing. What we commit to is accurate product identity data, a clear origin statement and complete documentation to work from.
From enquiry to delivered pallet
Send the specification
Origin (vegetable or bovine), the pharmacopoeias you cite, any surface-area requirement, quantity, pack preference and destination port.
Receive a firm quote
Pricing, lead time, packing and Incoterm confirmed in writing within 24 hours — our sourcing desk is staffed around the clock.
Qualify and approve
Sample dispatched with the origin and statement pack for your blend trials. Batch COA shared for approval before release.
Ship and track
Freight booked, export documents issued, and the consignment tracked through transit and clearance to your plant.
What buyers ask us about Magnesium Stearate
What is magnesium stearate used for?
Why does over-blending cause problems?
What is the difference between vegetable and bovine grades?
How much should I use?
What is it incompatible with?
Does particle size or specific surface area matter?
What is the minimum order quantity?
How should we store it?
Do you manufacture this yourself?
Request pricing on Magnesium Stearate
Send your origin requirement, the pharmacopoeias you cite, quantity, pack format and destination port. Our sourcing desk is available 24 hours a day, 7 days a week, and comes back with pricing, lead time and packing options.