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.
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
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.
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