Proline
Collagen-rich amino acid that restored mitochondrial function in senescent stem cells in a 2024 study.
Summary
Debbie writes that proline levels drop sharply in senescent cells and that restoring proline in a 2024 cell study induced mitophagy, improved mitochondrial function and reversed several signs of senescence in mesenchymal stem cells. Human studies she found mostly use gelatin or collagen (high in proline) and show increased collagen synthesis, plus better healing of hard-to-heal wounds in the elderly with a proline-containing supplement. She added proline to her stack, noting there aren't many studies on supplementing L-proline alone.
In her January 2026 stack. After a couple of doses she noticed vivid dreams and good sleep, adding "Could be coincidental."From Proline for Restoring Mitochondrial Function
The evidence
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Human trial
In a randomized trial in elderly people, an oral supplement of proline with vitamins C, A, E, zinc and arginine significantly improved hard-to-heal wounds.
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Human trial
In resistance-trained middle-aged men, 15-30 g of vitamin C-enriched collagen increased connective tissue collagen synthesis and proline levels.
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Human trial
In a clinical trial, 15 g of vitamin C-enriched gelatin (high in proline) increased collagen synthesis.
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Cell
In a 2024 cell study, restoring proline in senescent mesenchymal stem cells induced mitophagy, improved mitochondrial function, and reduced DNA damage, inflammatory cytokines and signs of senescence.
Doses used in studies
Amounts reported in the research, not dosing recommendations.
| Dose | Context |
|---|---|
| 15 g vitamin C-enriched gelatin | Clinical trial on collagen synthesis |
| 15-30 g vitamin C-enriched collagen | Resistance-trained middle-aged men |
| 5% of the diet | Animal safety study with no observed adverse effects |
Cautions
- Animal data: no adverse effects at 5% of the diet, but injecting rats with high levels for two weeks caused mild oxidative stress.
- Very high proline levels (from rare genetic defects) can cause seizures and psychosis; she doesn't expect a moderate supplement to do this but flags it in case of neurological changes.
- Higher proline biosynthesis is linked to cancer progression; talk with your oncologist before adding it if you have cancer.