CuratedFit
CURATEDFIT SUMMARY
Passes because this is as clean as a single-ingredient product gets, 100% L-Proline powder, nothing else in the formula, no capsule shell, no anti-caking agent, no filler. L-Proline is produced almost exclusively via bacterial fermentation industrially, using the same class of organisms (Corynebacterium, Brevibacterium) already established as favorable for lysine and leucine in this catalogue, distinct from glycine and methionine, which lean toward chemical synthesis.
WHAT IT IS
A pure powder providing 100% L-Proline, an amino acid the body uses as one of the primary building blocks in collagen synthesis, alongside glycine and lysine. Proline is also the metabolic precursor to hydroxyproline, one of the most abundant structural components of stable collagen fibers.
WHO IT IS FOR
Someone specifically supporting the body's own collagen production, most relevantly here, as one of three individually sourced amino acid building blocks (alongside glycine and lysine) paired with vitamin C in the Vegan Muscle Building basket's collagen-support tier, rather than a "vegan collagen" product, which is overwhelmingly proprietary-blend territory that fails this Standard's transparency criteria.
INGREDIENT BREAKDOWN
L-Proline
2 g
Free-form amino acid powder. A single, disclosed active with nothing else in the formula. Recommended intake is 2g daily, mixed into water or juice.
CERIFICATIONS
Informed Sport
Not Confirmed
Banned substance tested
Not Confirmed
GMP Certified
Certified
Heavy metals tested
Not Confirmed
BRCGS
Not Confirmed
FSSC 22000
Not Confirmed
CURATEDFIT STANDARD CHECK
Pass
As Natural As Possible
L-Proline is produced almost exclusively via bacterial fermentation industrially, the dominant commercial route, favorable by the same reasoning already applied to lysine and leucine.
Info
Contains What It Claims
No independent lab verification of the stated purity was found. Manufacturer stated.
Pass
Every Ingredient Earns Its Place
Single ingredient, no excipients of any kind.
Pass
No Insect-Derived Ingredients
No animal or insect-derived ingredients.
Pass
No Proprietary Blends
Single active ingredient, no blend.
Info
Allergen Declaration
No explicit allergen statement found beyond the ingredient list.
Pass
Sugar Content Declared
No sugar present.
Pass
Artificial Sweeteners and Flavorings
None present.
Info
Heavy Metals and Contaminants
Not disclosed on the page reviewed.
Pass
Banned Substance Risk Declared
A standard proteinogenic amino acid, not a banned substance.
Pass
Country of Manufacture Noted
Manufacturer states the product is made in the UK.
TRANSPARENCY NOTE
Proline's role in collagen synthesis is as a structural building block, alongside glycine and lysine, and as the metabolic precursor to hydroxyproline specifically, one of collagen's most abundant components. This completes the three-amino-acid building block set for the basket's collagen-support tier, paired with vitamin C (Sevenhills Camu Camu), which functions as the enzymatic cofactor required for the body to actually use these building blocks in collagen synthesis. Worth being precise about what this approach is and isn't: it supports the body's own collagen-building process, it doesn't supply collagen itself, which has no plant-based equivalent.
FREQUENTLY ASKED QUESTIONS
Why proline specifically, alongside glycine and lysine?
Collagen is unusually rich in these three amino acids relative to other proteins, and proline is additionally the precursor to hydroxyproline, a compound essential to collagen's structural stability. Supplying all three individually supports the body's own collagen-building process.
Is this the same as taking a "vegan collagen" product?
No, deliberately so. Most vegan collagen products are large, undisclosed proprietary blends, sometimes 15-20+ ingredients, that fail this Standard's transparency criteria. This approach sources the individual, disclosed building blocks instead.
Why powder instead of capsules?
The powder format here avoids capsule excipients entirely, resulting in a genuinely single-ingredient product with nothing added.
Last reviewed:
8/16/26
Peak Supps L-Proline Powder, Amazon UK product listing and Peak Supps UK product page, including manufacturer stated ingredient disclosure.
Sources:
Last updated:
8/16/26
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