Evidence supporting the use of: Collagen
For the health condition: Stretch Marks

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Synopsis

Source of validity: Scientific
Rating (out of 5): 2

Collagen is commonly cited in both topical and oral products marketed for the prevention or treatment of stretch marks (striae distensae). The rationale is that collagen is a major structural protein in the skin, providing strength and elasticity. During rapid stretching of the skin—such as in pregnancy or weight gain—collagen and elastin fibers can rupture, contributing to the formation of stretch marks. Scientific interest has thus focused on whether supplementing collagen, either by ingestion or topical application, can support the skin’s structure and minimize stretch marks.

The scientific evidence for collagen’s efficacy in stretch marks is limited and mixed. Some small clinical studies suggest that oral hydrolyzed collagen supplements may improve skin elasticity and hydration, potentially offering modest benefits for skin appearance. However, direct evidence showing a reduction or prevention of stretch marks is sparse. A few studies on topical formulations containing collagen have been conducted, but collagen molecules are generally too large to penetrate the skin, limiting their effectiveness when applied topically. Most benefits from topical products may be due to other ingredients or improved skin hydration rather than collagen itself.

In summary, while the biological rationale exists and preliminary studies suggest possible benefits for overall skin quality, robust clinical trials directly supporting collagen’s effectiveness for stretch marks are lacking. The evidence is therefore weak to moderate, and collagen’s use for this purpose is more supported by plausibility and emerging science than by strong, conclusive data.

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