At a Glance
- Glycerin, also called glycerol, is a three-carbon alcohol with the formula C3H8O3 and three hydroxyl groups.
- Most commercial glycerin is a co-product of oleochemical and biodiesel production, and a smaller share is made from propylene.
- Five routes produce it: saponification, transesterification, hydrolysis, propylene synthesis and fermentation.
- Crude glycerin needs refining before it suits cosmetic, food or pharmaceutical use.
- Glycerin is a polyol, not a sugar, although some sources group it with sugar alcohols.
- For buyers, grade, feedstock origin and test results matter more than the name on the label.
What You’ll Learn
Learn where glycerin comes from, how each production route works, and which grade fits your product.
Introduction
Formulators and buyers often ask what glycerin is made of before they approve a supplier. The answer affects purity, label claims, cost and the documents a supplier must provide. Glycerin, also called glycerol, is a simple three-carbon alcohol. It comes from vegetable oils, animal fats, propylene or fermentation.
This guide is for manufacturers in personal care, pharmaceuticals, food and industrial chemicals. It explains the chemistry, the sources and the five main production routes. It then compares crude, technical and USP grades so you can ask suppliers the right questions. Each section opens with a direct answer. For a naming comparison, read our guide to glycerol vs glycerin.
Crude glycerin from fats, oils and biodiesel is refined before it meets cosmetic or pharmaceutical specifications.
What Is Glycerin Made Of?
Glycerin is made of three carbon atoms, eight hydrogen atoms and three oxygen atoms. The glycerin formula is C3H8O3. Each carbon carries one hydroxyl group, so chemists call it a triol, or propane-1,2,3-triol. These hydroxyl groups make the molecule hydrophilic. That is why glycerin holds water and works as a humectant.
In vegetable oils and animal fats, glycerol is the three-carbon backbone that links three fatty acids into a triglyceride. The glycerin structure is a short propane chain with one hydroxyl group on each carbon. Glycerin composition is the same in every grade, and grades differ only in purity and impurities.
|
Property |
Value |
|
Molecular formula |
C3H8O3 |
|
Melting point |
18 °C (64 °F) |
|
Boiling point |
290 °C (554 °F), decomposes |
|
Density |
About 1.26 g/cm³ at 20 °C |
|
Solubility |
Miscible with water and ethanol |
Melting point, boiling point, density and solubility are from PubChem, which cites handbook and safety-card sources. Use your supplier’s certificate of analysis for any specific grade.
Is Glycerin a Sugar Alcohol?
Glycerin is a polyol, meaning a molecule with several hydroxyl groups. It is not a sugar and contains no sugar. It does resemble sorbitol and xylitol, which also carry several hydroxyl groups and taste sweet.
Classification Debate
Some food references and labels group glycerin with sugar alcohols because it is a sweet-tasting polyol. Stricter definitions reserve the term for polyols derived from sugars, and sources disagree on whether glycerol qualifies. Which wording applies on a label depends on the market and the regulator. Confirm label treatment with qualified regulatory review before you print a claim.
Where Does Glycerin Come From?
Most commercial glycerin is a co-product rather than the main output of a plant. Commercial glycerin is made from vegetable oils and animal fats, which release it when split or converted into other products. A smaller share is made from propylene. The route you buy from affects purity, cost and the label claims you can support.
Natural Sources
1. Vegetable Oils
Palm, coconut and soybean oils are the usual feedstocks for vegetable glycerin. Glycerin is released when these oils are hydrolysed or converted into soap or biodiesel. Buyers who need a plant-derived claim should ask for feedstock documentation.
2. Animal Fats
Animal fats and tallow also release glycerin during soap and fatty acid production. If you need vegetable origin, ask suppliers to state the feedstock in writing.
3. Biodiesel Production
Biodiesel plants react oils or fats with methanol and a catalyst. This yields biodiesel and crude glycerin as a co-product. Crude glycerin from this route needs refining before cosmetic or pharmaceutical use.
Synthetic Sources
1. Petrochemical Glycerin
Synthetic glycerin is made from propylene, a petroleum derivative. The route uses chlorination followed by hydrolysis over several steps. It supplies a minor share of the market. Read more about personal care uses of the finished ingredient.
2. Fermentation (Biotechnological)
Glycerol can also be made by fermenting sugars with microorganisms. Ask suppliers whether fermentation-derived material is available in the grade you need.
How Is Glycerin Made? Production Processes
Each manufacturing process starts from a different feedstock and delivers glycerin at a different purity. Saponification, transesterification and hydrolysis release it from fats and oils. The petrochemical and fermentation routes build it from other molecules. The route changes purity, cost and the refining needed afterward.
Crude glycerin from fats, oils and biodiesel still contains impurities such as water, salts, soaps and unreacted material. Refining steps such as distillation and carbon treatment remove them, along with colour and odour.
1. Saponification
- Used For: Soap and cosmetic industry
- Process: Triglycerides + Lye (NaOH or KOH) → Soap + Crude Glycerin
2. Transesterification
- Used In: Biodiesel industry
- Process: Triglycerides + Methanol (with catalyst) → Biodiesel + Crude Glycerin
3. Hydrolysis
- Used For: High-purity glycerin
- Process: Oils or fats are split with high-pressure water, separating glycerin and fatty acids.
4. Synthetic Petrochemical Path
- Used When: Natural feedstocks are scarce
- Process: Chlorination of propylene → Hydrolysis → Glycerin
5. Fermentation
- Eco-Friendly Alternative
- Process: Microorganisms such as yeast ferment glucose into glycerol
Grade decides where glycerin can be used, so check it before you compare prices. Published purity figures vary by source, so treat the ranges below as typical and check each supplier’s specification. An RSC Advances review reports about 60–80% glycerol in crude glycerol from biodiesel.
Grades of Glycerin: What Manufacturers Need to Know
|
Grade |
Purity (typical) |
Common applications |
Documents to request |
|
Crude glycerin |
About 60–80% |
Refining feedstock; some animal feed use |
Supplier specification and SDS |
|
Technical grade |
Varies by supplier |
Industrial and chemical uses |
TDS, COA and SDS |
|
USP/Pharmaceutical |
99.5%+ |
Food, cosmetics and pharma |
COA with assay, water, colour, heavy metals and DEG/EG results; TDS and SDS |
Sources report technical grade anywhere from about 95% to 99.5%, so ask for the assay in writing. Elchemy’s glycerine product page lists assay, water content, colour, heavy metals and DEG/EG limits among its shipment checks.
Need a USP or Ph.Eur. grade sample for testing? Request a Sample.
Industrial Applications of Glycerin
Glycerin is used wherever a formulation needs a humectant, a solvent or a sweetener. The applications below show how its properties fit each industry.
Pharmaceuticals
Glycerin is used in medicines as a humectant, solvent and sweetener. It appears in syrups, lozenges, creams and suppositories. Check the pharmacopoeia monograph that applies to your product before you specify a grade.
Cosmetics & Personal Care
Glycerin is listed in the EU cosmetics inventory as a humectant and solvent. Its three hydroxyl groups bind water, which helps skin care products hold moisture.
Food & Beverage
Glycerin is used in food as a humectant, thickener, solvent and sweetener. As a humectant, it helps products retain moisture. Check labeling rules for your target market before you make any sugar or glycemic claim.
Industrial & Chemical Manufacturing
Glycerol has been used in automotive antifreeze, although ethylene glycol largely replaced it. It is listed as a plasticizer. Nitrating glycerol produces nitroglycerin, which is used in explosives and, as glyceryl trinitrate, in angina treatment.
Tobacco Industry
Glycerin and propylene glycol are widely used as tobacco humectants. Rules on tobacco ingredients differ by market, so confirm requirements with qualified regulatory review.
Agriculture
Glycerol can replace part of the corn in animal feed as an energy source. Residual methanol and sodium in crude glycerin limit how much can be used. Feed regulations vary by region, so confirm the permitted grade and inclusion level with qualified review.
How to Source Glycerin for Your Product
Sourcing glycerin starts with the end use, because the grade and the paperwork depend on it. Define the application first. Then ask each supplier to document feedstock, grade and test results.
- Grade and assay against your specification, such as USP or Ph.Eur.
- Feedstock origin, stated in writing as vegetable, animal or synthetic.
- Test results, including water, colour, heavy metals and DEG/EG limits.
- Documents: certificate of analysis, technical data sheet and safety data sheet.
- Packaging format and delivery destination, such as drums, IBCs or ISO tanks.
Choose a refined vegetable-origin grade if your label or customer requires plant-derived material. Choose USP or Ph.Eur. grade if the product is for pharmaceutical, food or cosmetic use. Choose technical grade for industrial and chemical uses where food or pharmaceutical specifications do not apply. Treat crude glycerin as a feedstock for refining, not as a finished ingredient.
To compare grades and documents for your application, request a quote.
Frequently Asked Questions
1. Is glycerin natural or synthetic?
Both exist. Most commercial glycerin is a co-product of oleochemical and biodiesel production. It comes from vegetable oils or animal fats, so its feedstocks are natural. A smaller share is synthesized from propylene, and some is made by fermentation. Ask the supplier to state feedstock origin in writing.
2. Is glycerin an alcohol?
Yes, chemically. Glycerin has three hydroxyl groups, which makes it an alcohol. It is not ethanol, the alcohol in drinks, and pure glycerin contains no ethanol. Labeling rules for polyols differ by market, so check the requirements for your product and destination with regulatory review.
3. Is glycerin a sugar?
No. Glycerin is a three-carbon polyol, not a sugar. It tastes sweet, which is why some references group it with sugar alcohols. Its sweetness is mild, so confirm any sugar or sweetener claim against the labeling rules of your target market.
4. Is glycerin the same as glycerol?
Yes. Both names describe the same compound, C3H8O3. Glycerol is the chemical name, and glycerin or glycerine are the common commercial spellings. On an ingredient list, all three names mean the same material. For a buyer, the name matters less than the grade, the purity and the documents that come with the shipment.
5. Is glycerin allowed in food in the US?
US rules list glycerin as generally recognized as safe under good manufacturing practice, per 21 CFR 182.1320. That covers food use only. Cosmetic, pharmaceutical and other markets have separate rules. Confirm the requirements for your product and destination with qualified regulatory review.
Conclusion: Source Quality Glycerin with Elchemy
Glycerin is a three-carbon polyol, and most commercial supply is released from fats and oils or from biodiesel production. The route and the refining step decide the grade, the label claims you can support and the documents you receive.
Match the grade to your application. Ask each supplier for feedstock origin and test results. Confirm labeling rules for your market. That keeps specifications, claims and paperwork aligned before you place an order.
Comparing glycerine grades for a formulation? Request a Sample and review the certificate of analysis against your specification.
