The honest truth about collagen supplements: what works and what doesn't
by Bo van Rijzewijk
The collagen supplement market is worth billions. Most of it is overpriced, underdosed, and relies on consumers not reading the label carefully.
Here's what the science actually says.
What collagen supplements are supposed to do
Collagen is the most abundant protein in your body. It forms the structural matrix of your skin, joints, bones, and connective tissue. After your mid-20s, your body produces progressively less of it — roughly 1% less per year. The visible effects on skin — loss of elasticity, increased fine lines, slower wound healing — are a direct result of this decline.
The theory behind collagen supplementation is straightforward: provide the body with the amino acids it needs to rebuild collagen, and it will do so. The key amino acids are glycine, proline, and hydroxyproline — which are found in high concentrations in collagen peptides.
Does it actually work?
Yes — but with important caveats about dose, source, and form.
The clinical evidence for collagen supplementation is stronger than many people realise. A 2019 systematic review published in the Journal of Drugs in Dermatology analysed multiple randomised controlled trials and found consistent evidence for improved skin elasticity, hydration, and collagen density after 8–12 weeks of supplementation at 10g per day.
The word "hydrolised" matters
Raw collagen is a large molecule that cannot be absorbed intact through the gut. For a collagen supplement to work, the collagen must be hydrolised — broken down into smaller peptides through enzymatic processing. These smaller peptides (typically 2–5 amino acids in length) are absorbed efficiently through the intestinal wall and transported to the dermis.
Products that list "collagen" without specifying "hydrolised" or "collagen peptides" may contain a form that cannot be effectively absorbed. This is the most common way that cheap collagen products underdeliver.
The dose problem
The effective dose in clinical studies is consistently around 10g of hydrolised collagen peptides per day. Many products on the market contain 1–5g per serving — a fraction of the studied dose — and price themselves as premium products. Read the label.
KLÄR Collagen Peptides contains 10g of hydrolised marine collagen per serving. One scoop, once a day.
Marine vs. bovine
Collagen supplements come from two primary sources: marine (fish) and bovine (cow). Both have been studied and both show efficacy. Marine collagen has a slightly smaller peptide size on average, which may improve absorption marginally — though the clinical difference is modest.
Marine collagen is also the more sustainable and traceable option when sourced responsibly. KLÄR uses sustainably sourced marine collagen with full supply chain traceability.
The role of Vitamin C
This is often overlooked: Vitamin C is an essential cofactor in collagen synthesis. Without adequate Vitamin C, your body cannot efficiently convert the amino acids from collagen peptides into new collagen fibres.
This is why KLÄR Collagen Peptides includes 80mg of L-Ascorbic Acid per serving — 100% of the daily recommended value. It's not marketing. It's biochemistry.
The bottom line
Collagen supplementation works — at 10g per day, hydrolised, with consistent use over 8–12 weeks. Most products on the market are underdosed or poorly formulated. Read the label before you buy.