Amino Acid
L-Proline
Also known as: Proline, Pro, L-Pro
L-Proline is a non-essential amino acid that serves as a structural component of collagen and elastin, and is involved in protein synthesis and tissue repair. It has limited direct clinical evidence as an isolated supplement, though adequate proline intake supports connective tissue health.
Last reviewed June 2026 · Evidence graded from peer-reviewed research, not editorial opinion. Educational only — not medical advice.
Every L-Proline product we have scored
| # | Product | Score | Per serving |
|---|---|---|---|
| 1 | Nutricost L-Proline Powder | 86 A- | $0.16 |
| 2 | BulkSupplements L-Proline Capsules | 84 A- | $0.20 |
| 3 | NOW Foods L-Proline | 84 A- | $0.20 |
| 4 | Pure Encapsulations Amino-NR | 79 B+ | $0.78 |
| 5 | NOW Foods Liquid Hyaluronic Acid - Mixed Berry | 77 B+ | $0.85 |
| 6 | Pure Encapsulations Ligament Restore | 76 B+ | $1.05 |
| 7 | Carlson Pro•Rite | 73 B+ | $0.42 |
| 8 | Integrative Therapeutics Pro-Biome | 70 B | $1.26 |
| 9 | Bluebonnet Nutrition ULTIMATE HAIR & NAIL FORMULA | 69 B | $1.35 |
| 10 | Carlson Cardio Complete | 68 B | $1.16 |
| 11 | Physician's Choice Women's Probiotic | 66 B- | $0.98 |
| 12 | Zhou Nutrition Pro-Clenz | 63 B- | $0.58 |
Scored on dose accuracy, form, label transparency and third-party testing. Per-serving cost is list price divided by servings per container. No brand pays to be listed or ranked.
Common questions
How much L-Proline should I take?
The typical range is 1,500–5,000 mg daily. Ongoing use typical for structural support; effects on skin and joint health may require 8–12 weeks
When should I take L-Proline?
Anytime; often combined with other collagen-supporting amino acids (glycine, hydroxyproline). May be taken with or without food.
Which form of L-Proline is best?
Powder (free amino acid).
Is L-Proline safe?
Commonly reported: Minimal; occasional mild GI upset at high doses.
Which L-Proline supplement scores highest?
Nutricost L-Proline Powder, at 86/100. Scored on dose accuracy, form, label transparency and third-party testing — no brand pays to be listed or ranked.
Primary uses
- Collagen synthesis support
- Joint and connective tissue health
- Skin health and elasticity
- Protein synthesis
- Wound healing support
How it works
- Acts as a structural amino acid in collagen (comprises ~10% of collagen)
- Substrate for hydroxylation to form hydroxyproline, critical for collagen cross-linking
- Participates in general protein synthesis
Dosage
- Typical range
- 1,500–5,000 mg daily
- Timing
- Anytime; often combined with other collagen-supporting amino acids (glycine, hydroxyproline)
- With food
- May be taken with or without food
- Duration
- Ongoing use typical for structural support; effects on skin and joint health may require 8–12 weeks
- Special populations
- Adequate dosing may support recovery in athletes; individual needs vary based on dietary protein intake
Forms
- Powder (free amino acid)· 70/100
Safety
Common side effects
- Minimal; occasional mild GI upset at high doses
Products containing L-Proline
Top-scoring supplements in our catalog that list L-Proline on the label. Each product is graded on Formulate's ingredient-level rubric — dose accuracy, form, transparency, and third-party testing.
Evidence notes
L-Proline is biochemically essential for collagen formation with strong mechanistic support, but isolated supplementation lacks robust RCT evidence demonstrating superior outcomes versus dietary protein intake. Most evidence is derived from collagen peptide studies that include multiple amino acids. Direct proline supplementation studies are limited.
Grade C: Mostly observational or small trials; mechanism is plausible but unproven at scale.
Related in Amino Acid
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Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider. Individual needs and risks vary — consult a professional before starting, stopping, or combining supplements, especially if you are pregnant or nursing, taking medication, or managing a health condition.