L-Proline
L-Proline is a non-essential cyclic amino acid (technically an imino acid) that plays a structural role in collagen, elastin, and other fibrous proteins of connective tissue.
The molecule is unique among proteinogenic amino acids in having its alpha-amino group locked into a five-membered pyrrolidine ring, which imposes a kink on the peptide backbone and is the basis of the triple-helix geometry of collagen.
We source bulk L-Proline from top China manufacturers for our partners. The manufacturers are in Hebei and Jiangsu. For this ingredient the minimum order is 500 kg and a 20-foot container takes 11.25 MT, and a smaller requirement can ship in a combined container with other ingredients.
Please send the grade you need, the volume and your destination port, and we will come back with a solution and a price.
or call +86-21-6858 0751
- Minimum order
- 500 kg
- Qty in 20' FCL
- 11.25 MT
- Packaging
- 25 kg kraft paper bag with PE inner liner
- ISO 9001
- HACCP
- Halal
- Kosher
Specifications
Grades / Types Available: CP2020, EP11, USP2023
| Item | Specification |
|---|---|
| Appearance | White crystalline powder |
| Assay | ≥98.5% |
| Specific Rotation [α]D20 | -84.0° to -86.0° |
| Loss on Drying | ≤0.5% |
| Residue on Ignition | ≤0.1% |
| pH (5% solution) | 5.5–7.0 |
| Heavy Metals (as Pb) | ≤10 ppm |
| Arsenic | ≤1 ppm |
| Chloride | ≤0.02% |
| Total Plate Count | ≤1000 CFU/g |
| Transmittance (T430) (CP2020) | ≥98.0% |
| Appearance of solution (EP11) | clear & colorless |
| Ammonium (CP2020) | ≤0.02% |
| Sulfate (CP2020) | ≤0.02% |
| Iron (CP2020) | ≤10PPM |
| Other amino acids (CP2020) | ≤0.5% |
| Ninhydrin-positive substances (EP11) | Each impurity≤0.2% Total impurities≤0.5% |
| Endotoxin (CP2020) | <10EU/g |
| Moulds & Yeasts (CP2020) | ≤ 50 CFU/g |
Common Markets Grades
L-Proline is a white to off-white crystalline powder with a sweet taste.
Pharmaceutical grade meets USP and Ph. Eur. monographs at 98.5 to 101.0 percent assay on the anhydrous basis. It is used in amino acid infusion solutions, parenteral nutrition, and oral pharmaceuticals.
Food and supplement grade at 99 percent minimum is the standard offering for dietary supplements, sports nutrition, medical foods, and collagen support formulations. Specifications follow FCC monograph parameters for chloride, sulphate, ammonium, and heavy metals.
Biotechnology grade L-proline at 99.5 percent low-endotoxin is sold to cell culture media manufacturers, where proline supplementation supports growth of CHO cells and other mammalian production lines.
Applications
- Parenteral and enteral amino acid solutions
- Medical foods and nutritional therapy products
- Infant formula amino acid blends
- Collagen support and joint health supplements
- Sports nutrition and recovery formulations
- Cosmetic actives in anti-aging and skin-firming products
- Cell culture media for mammalian and microbial production
- Pharmaceutical excipient and stabiliser in protein formulations
- Reference standard in analytical and clinical laboratories
- Asymmetric synthesis chiral organocatalyst in fine chemicals
Brands Using L-Proline
Widely-distributed consumer products that list L-Proline on the ingredient label.
- NOW FoodsL-Proline 500 mg Veg Capsules ↗Vegetable capsules delivering 500 mg L-proline each.Label verified 2026-05-24
- Source NaturalsL-Proline ↗A free-form L-proline amino acid product.Label verified 2026-05-24
Brand names, product names and logos are the property of their owners. They appear here as published evidence that the ingredient is used, taken from the brand's own label or website. Their appearance is not an endorsement, and it does not mean the brand buys from us or from any manufacturer listed on this site.
China Manufacturers of L-Proline
Top L-Proline manufacturers in China.
Shijiazhuang Haitian Amino Acid Co., Ltd.11 ingredients in the directory
Wuxi Jinghai Amino Acid Co., Ltd.18 ingredients in the directory
Company names and logos are the property of the manufacturers themselves. They are listed here because our own directory records them as producing this ingredient. A listing is not an endorsement by them, and we do not represent them or speak on their behalf.
How We Help Source L-Proline
Direct Factory Sourcing
We run the whole process: selecting the manufacturer from the top Chinese food ingredient producers, negotiating the price, verifying quality, and coordinating the logistics. You deal with us instead of with several factories at once.
Original Packaging and Documents from the Manufacturer
The manufacturer sends your L-Proline out of its own factory in the original packing, through to your destination port. The COA, COO, MSDS, TDS and any certifications reach you from the manufacturer as well.
Free Samples and Lead Time
We send 100 to 500 g free for your own laboratory to test and you cover only the courier, usually within 2 to 3 working days. ETD is usually within 7 to 15 days once the order is confirmed, and we check that date against the factory's own manufacturing schedule before we give it to you.
Combined Shipment
We can load L-Proline together with other ingredients such as Glycine, L-Arginine and L-Leucine into one 20' FCL. If your quantity is small, we can also ship LCL.
Regulatory Status
L-Proline is recognised as a food-grade amino acid and approved for nutritional use in all major markets.
In the United States it is GRAS under 21 CFR 172.320 for use as a nutrient added to foods, with infant formula use governed by 21 CFR 107. The European Union authorises L-proline as a permitted amino acid in foods, food supplements, and infant formula under the relevant directives.
JECFA has evaluated L-proline and accepts it as a food-grade amino acid without numerical limit when used in accordance with good manufacturing practice. Codex includes it among the optional ingredients for infant formula.
USP and Ph. Eur. monographs govern pharmaceutical and parenteral use. Kosher and Halal certifications are routinely available from fermentation suppliers, and vegetarian-suitable certification is produced from non-gelatin sources.
Manufacturing Process
L-Proline is produced commercially by microbial fermentation.
Engineered Corynebacterium glutamicum and Escherichia coli strains convert glucose to L-glutamate and onward to L-proline through the proB-proA-proC pathway. Deregulation of gamma-glutamyl kinase, the rate-limiting and feedback-controlled enzyme, is the central metabolic engineering target for high-yielding production strains.
Kyowa Hakko, Ajinomoto, and several Chinese fermentation houses operate the main production capacity. Some smaller volumes are still recovered by extraction from acid hydrolysates of gelatin, which is naturally rich in proline and hydroxyproline at around 12 percent each.
Downstream recovery uses cation exchange chromatography, decolorisation with activated carbon, concentration under vacuum, crystallisation from aqueous ethanol, centrifugation, and drying. The product is finished as a free-flowing crystalline powder packed in 25 kg fibre drums or food-grade bags.
