Editorial process

• Daily serving of collagen, i.e. the 'collagen in collagen' content. We award a point for each full gram of collagen.
• Daily collagen content.
• Presence of laboratory studies and clinical trials:
  • 10 points.
• Presence of certification that the product is sustainably sourced or otherwise ethically, organically or controlled:
  • 5 points.
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The main ingredient in a collagen supplement is, of course, the collagen serum itself. The higher the quality, the better it is rated. Research suggests that fish collagen has better absorbability (Jafari et al, 2020), which we also take into account in the ranking:

• fish collagen gets 3 points (specifying e.g. a fish species gives 2 extra points for transparency),
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• if the raw material comes from a clearly identified manufacturer (e.g. Seagarden^®, VERISOL^®, NatiCol^®), we rank it higher (3 points),
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• the lower the molecular weight, the better the absorption and therefore the efficacy of (Bianchi et al., 2022):
  • 5 points for 2000 Da,
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  • 3 points for 3000 Da,
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  • 1 point for 4000 Da,
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For obvious reasons, if manufacturers do not provide this information, the assessment will assume that a product simply does not meet these criteria. Every effort is made to find and include all information; we regularly update the data as soon as there is more clearly defined information from a particular manufacturer. Completion of such data may mean changes to the rankings.

Additionally, we assume that currently the most basic collagen supplements should have some active substances in the formulation, such as vitamin C and hyaluronic acid. Vitamin C supports collagen synthesis and absorption (Bechara et al., 2022). Hyaluronic acid supports the body in the proper functioning of the skin and joints (Göllner et al., 2017). We also note the form of the sweetener:

• vitamin C is additionally scored (3 points),
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• hyaluronic acid similarly (2 points),
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• The presence of sugar or fructose is penalised slightly (-1 point; sugar is simply unnecessary calories. Great products, even with sugar, will defend themselves with no problem; if two products score the same, we consider the one without sugar to be better).

Today, all ratings are standardised to a grade on a five-point scale and rounded to one decimal place, with the lowest rating being 4.

This approach is due to the fact that:

• Although we include 30+ products in our rankings, the original review of the market gave us more than 100 products.We focused on the best of the best and/or the most popular products because we do not want to have 'less than good' supplements in the rankings (a rating of 4).
• The second reason for this approach is that we have a very low score.
• The second reason is that Collagen X may perform less well when it comes to, for example, skin, hair and nails, but be a very good option for joints. Our assessment is focused on the overall quality of the product, especially in terms of the main raw material, collagen, and sometimes may not take into account such a discrepancy. Narrowing the spread of ratings makes similar products perform similarly in scoring as well.
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As editors, we reserve the right to update data, modify product scoring criteria and add or remove products from the rankings. We want our rankings to be timely and to reflect our evolving understanding of the scientific data.

The order of the products in an article does not necessarily reflect the order resulting from the ratings. This is due, among other things, to the situation described above: the criteria are prepared in terms of evaluating the overall product against others, but may miss a specific application. A collagen that is rated 4.5 overall and would be in 8th position in the overall ranking, for example, may jump to third place in the joint collagen ranking.

How might this look in practice?

Let's take the example of an imaginary product, collagen Acme - Skin, Hair, Nails, 3000 mg. This hypothetical product is targeted at skin, hair and nails. It has a lower portion of collagen than many products, for which it gets 3 points (because 3g; other products typically get 5 points or 10). It has laboratory (+10 points) and clinical studies (+10 points); it also has vitamin C and hyaluronic acid (+3, +2). It is fish collagen (+3) in capsule form (the form of administration is neutral). In terms of quantitative evaluation, it would perform very average; however, in a summary that specifically looks at collagen supplements for skin, hair and nails, it could be an attractive option for buyers (e.g. people in their 20s who are not yet experiencing a significant loss in collagen synthesis and have a lower need for dietary supplementation). "Quantitatively" such a supplement comes off as average and this will also be its assessment. However, in the product description itself, these additional, "qualitative" factors will be taken into account and will give the evaluation an appropriate context (including a note, for example, that - unlike the competition - these tablets are smaller and easier to swallow, and the price is also attractive). What's more, in a comparison of collagen tablets, Acme's product could appear much higher, even catching a place in the top 5.

Conflict of interest

The Natu.Care brand sells its collagen product, Natu.Care Collagen Premium. Natu.Care also runs a health and beauty website that presents, among other things, collagen rankings. The Natu.Care brand's collagen rating comes out the best. Why? When creating the Natu.Care product, we followed criteria similar to those used in the rankings. Natu.Care chose to:

• fish collagen - due to its potentially better absorbability (Jafari et al, 2020),
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• use of a branded raw material (Nutricoll Seagarden^®) that has undergone clinical studies and has laboratory studies,
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• collagen molecular mass of 3000 Da (i.e. here it does not get full credit - 3 points instead of the maximum 5),
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• obtaining MSC certification,
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• portion of 5000 or 10 000 mg of collagen (5 000 is a common "best practice", 10 000 mg is one of the highest doses on the market; the 5000 variant therefore performs worse than the 10 000 variant due to the lower collagen content of the collagen),
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• addition of both vitamin C (+3 points) and hyaluronic acid (+2 points) in the composition,
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• the use of a sweetener in the form of steviol glycolide instead of sugar (no negative points).

In creating its own collagen supplement, the Natu.Care brand was therefore guided by quality factors: strong raw material, research, essential additives. Analogous criteria are used in the rankings. Thus, this understanding of the market translated into this rather than other composition and criteria.

In the future, if the Natu.Care brand were to launch beef collagen, it would be treated like other beef collagens in the rankings. Similarly, if the Natu.Care brand created a supplement with two grams of collagen, such a supplement would be ranked correspondingly lower.

Omega-3 rankings

The most important criterion in the rankings of supplements with omega-3 fatty acids is the quality and quantity of the main ingredient:

• total content of omega-3 fatty acids, EPA and DHA,
  • one point for every 100 mg,
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• the form of acids used,
  • the triglyceride form is ~1.7 times better absorbed than esters (Dyerberg et al., 2010), so we recalculate the omega-3 fatty acid content by such a multiplier,
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• 5 points,
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At the final stage, the score is converted to a scale of 4.0-5.0.

What this looks like in practice: imagine a product Acme Omega-3 500 mg that contains 500 mg of omega acids in ester form. It doesn't have laboratory tests, but it clearly states the species of fish from which it was extracted. 500 mg earns 5 points, 0 points for laboratory testing and 2 points for transparency. Raw number of points: 7. Compare it with an analogous product in the form of triglycerides, but without testing and transparent composition: 5 × 1.7 gives us 8.5. The two products perform similarly in the final evaluation: approximately 4.5 vs 4.4. For those considering purchasing one of these two products, the final decision comes down to a determination of preference: do they want a better absorbed supplement or a supplement that is potentially more trustworthy.

General product selection process

When compiling lists of recommended products, we first prepare a market analysis. Once we have compiled a list, in which we try to capture as many brands as possible, we select those product lines that meet our criteria.

When there are products in the list that particularly stand out, the editors forward the list to Natu.Care's management, with a request to bring them to the Natu.Care shop, even if they are competitors. For example, although Natu.Care offers its collagen, you will find nearly 30 other supplements with collagen from other brands - de facto competitors - in the shop that we consider worth promoting.

Interesting facts

• We have so far written over 200 texts.
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• For the purpose of the rankings, we have analysed over 500 products.
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• We have analysed over 5000 scientific studies.
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