Protein and collagen: what are you actually buying?

Same shelf, same scoop, two tubs that sound like cousins. One is protein, which you can also get from lunch. The other is collagen: a protein too, technically, but sold on a skin-and-joints story that has very little to do with building muscle. Before either goes in the basket, let's see what's actually in each tub and what the trials have measured.

Do you need either tub? Probably not as a matter of necessity. Many adults in the Netherlands already eat well above the official protein norm, and Voedingscentrum says active people can reach sports-nutrition ranges with ordinary food, so a powder is a convenience rather than a requirement. When total protein is adequate, whey and soy gave similar training results in the trials we found. Some other plant proteins are less well tested, and one large review found slightly smaller muscle gains with them. Collagen is a different product. It can't stand in for ordinary protein, its best evidence is for knee osteoarthritis pain, its skin results look weaker once you account for who paid for the trials, and its tendon evidence is small.

How much protein is the norm, and how much do active people use?

The Dutch Health Council (Gezondheidsraad, 2021) follows EFSA: an average requirement of 0.66 g of protein per kilogram of body weight a day, and a recommended amount of 0.83 g/kg for adults (Gezondheidsraad, Voedingsnormen voor eiwitten, 2021). For a 70 kg adult that's about 58 g a day. The Council sets no upper limit for healthy people, notes that many people eat well above the norm, and says its norms are aimed at people with average physical activity, not extreme sport or chronic illness. Protein supplies about 15% of energy in the Dutch diet on average, and 16% in adults.

For people who train, sports guidance goes higher:

• Source: Voedingscentrum (Dutch nutrition centre); Range: 1.2 to 2 g/kg a day for dedicated strength athletes; 1.4 g/kg for endurance athletes; Who it describes: Page read 8 October 2026; gives 84 to 140 g a day as the example for a 70 kg strength athlete
• Source: International Society of Sports Nutrition position stand (2017); Range: 1.4 to 2.0 g/kg a day; Who it describes: "Sufficient for most exercising individuals"
• Source: Morton et al. meta-analysis of 49 trials, 1,863 participants (2018); Range: About 1.6 g/kg a day; Who it describes: Above this, extra protein from supplements added no further gain in fat-free mass during resistance training

(ISSN position stand, Jäger et al., 2017; Morton et al., 2018, British Journal of Sports Medicine.) These describe what exercising people eat or what trials found useful, not instructions. The ISSN also suggests spreading protein out: about 0.25 g/kg, or 20 to 40 g, per meal-sized dose.

When a powder is just convenience

Voedingscentrum is refreshingly direct: a protein shake isn't necessary if you exercise, though it can be a practical way to add protein quickly. It says dedicated strength athletes can get 84 to 140 g from food (extra quark or yoghurt, a cup of milk, chicken, tofu, nuts or beans), and that shakes and bars are intended for very intensive athletes who can't manage enough protein from ordinary food (Voedingscentrum, protein shakes; Voedingscentrum, extra protein for sport).

That doesn't contradict the trials. Morton's analysis found that protein supplements helped gains in muscle size and strength during prolonged resistance training, with a smaller effect in older participants. It tested adding protein, and a powder is one way of adding it. Whether you need that depends on what you already eat. If you eat a plant-based diet, the Dutch advice is to eat more protein: Voedingscentrum cites the Health Council as advising vegans about 30% more, roughly 1.08 g/kg, because plant proteins are on average lower in quality (Voedingscentrum, proteins).

"Protein quality": what PDCAAS and DIAAS actually score

Protein quality is about two things: how much of each essential amino acid a protein supplies, and how much of it you digest. Two scoring systems turn that into a number.

• PDCAAS compares a protein's amino acids with a reference pattern and corrects for digestibility using a single figure for the whole protein, with scores capped at 1.0.
• DIAAS, recommended to replace PDCAAS by the FAO's 2011 expert consultation (report published 2013), uses digestibility of each amino acid at the end of the small intestine, and doesn't cap scores. A whey protein isolate's lowest amino acid ratio is above 1, so its score can exceed 100% (Moughan and Lim, 2024, Frontiers in Nutrition).

Much of the DIAAS data comes from animal studies (the FAO report itself noted that human data were insufficient), and the numbers differ between studies. One pig study found that PDCAAS-style values may overestimate the quality of pea concentrate and soy isolate compared with DIAAS (Mathai et al., 2017, British Journal of Nutrition). We haven't printed a list of scores here, because the tables floating around online mix methods and species.

What the amino acid analyses do show is a pattern. A research group analysed commercial plant protein isolates and found, on average, less leucine, lysine and methionine than animal proteins (leucine 7.1% of protein versus 8.8%), with big differences between plant sources. They concluded that blends of plant proteins, or of plant and animal protein, can come close to an animal profile (Gorissen et al., 2018, Amino Acids). Leucine matters because the ISSN suggests a protein dose should contain roughly 0.7 to 3 g of it.

A worked label example: from percentage to leucine

Orangefit and Upfront are the two fitness brands used as examples on this page; we haven't tested their products, and the details are supplier information that can change. Orangefit's public Dutch product page for its vegan Protein (read 8 October 2026) lists pea protein isolate, natural flavouring, xanthan gum and stevia. For the vanilla flavour it gives 26 g per shake, 99 kcal and 21 g of protein, which is roughly 81% protein by weight. Its amino acid table gives leucine at 5.6 g per 100 g of powder, so a 26 g shake supplies about 1.5 g of leucine (our calculation from the page's table), inside the range the ISSN suggests, and about 7% of the protein. The same table lists methionine at 0.8 g and cysteine at 0.7 g per 100 g. The page itself claims that Orangefit Protein is "a complete protein source with all amino acids" and that yellow split pea is the most complete plant protein source; those are supplier claims.

Upfront's whey pages (read 8 October 2026) describe a 1 kg whey bag with 33 portions and a clear whey with "19 gram" of protein per portion and 32 portions per bag, both called "good absorbable" protein. We quote those descriptions only. A label comparison needs the full nutrition table for the flavour you'd buy, and the quantity to check is protein per portion, not powder per portion.

Whey, soy, pea: what training trials found

Here's what the whey, soy and pea comparisons show:

• Study: Hevia-Larraín et al., 2021; What was compared: 19 habitual vegans (soy protein top-up) vs 19 omnivores (whey top-up), both set to about 1.6 g/kg a day (groups weren't randomised to diet), 12 weeks of resistance training in young men; Result: No differences between groups in lean mass, muscle size or strength gains (Sports Medicine)
• Study: Babault et al., 2015; What was compared: 161 young men, 12 weeks, 25 g twice a day: pea protein, whey or placebo, training of the arm muscles; Result: Pea and whey both increased biceps thickness more than placebo and didn't differ from each other. Funded by Roquette, the pea protein maker; three authors worked for the funder (J Int Soc Sports Nutr)
• Study: Banaszek et al., 2019; What was compared: 15 people, 8 weeks of functional training, 24 g whey or pea; Result: No group differences; a pilot study too small to rule much out (Sports)

Pooled reviews give a more mixed picture, and it's worth setting them side by side. A 2025 meta-analysis of 43 randomised trials (30 of them pooled) found that plant protein produced slightly less muscle mass than animal protein overall, a small effect, and larger in under-60s. Soy matched milk protein, but trials of non-soy plant proteins (rice, chia, oat, potato) favoured animal protein, though that rests on only five trials. There was no difference in strength or physical performance (Reid-McCann et al., 2025, Nutrition Reviews; funded by a Northern Ireland government department). A 2026 analysis limited to trials of six months or longer (18 trials, 1,893 adults, mostly soy) found no significant differences in body composition or strength. Its article processing charge was paid by Danone's research arm, and one author affiliation is a Danone research centre (Yimam et al., 2026, Frontiers in Nutrition).

Putting it together: soy has the most evidence of matching whey. Pea has fewer, smaller trials, and the larger one was paid for by a pea protein producer. Blends are plausible on amino acid grounds but we didn't find long trials of the specific blends sold in tubs. If you eat enough protein overall, the evidence we found doesn't show that the source decides your training results.

Collagen: a different kind of protein

Collagen is the main structural protein in skin, tendon, cartilage and bone, and supplements are made by breaking animal collagen (bovine, porcine or marine) into short peptides. After someone eats collagen hydrolysate, a collagen-derived dipeptide (a cyclic form of prolyl-hydroxyproline) shows up in their blood, peaking after about two hours, in a small pilot study (Shigemura et al., 2018, Nutrients). That's where the "it survives digestion" story comes from. Peptides in blood tell you about absorption. They don't tell you what collagen does for skin or joints; that needs trials with outcomes.

Collagen also isn't a complete protein. By the standard PDCAAS method it lacks one essential amino acid, tryptophan, so it can't replace your ordinary protein. A modelling study estimated collagen peptides could still make up part of a typical diet's protein without breaking the amino acid balance; one author does research work for a supplement maker whose products include collagen peptides (Paul et al., 2019, Nutrients). In a head-to-head comparison for muscle building, a 2021 review found collagen peptides didn't improve muscle protein synthesis compared with higher-quality protein of the same nitrogen amount (Khatri et al., 2021, Amino Acids). So collagen is a separate purchase, not a cheaper whey.

Skin: the shelf's favourite promise

• A 2023 meta-analysis of 26 randomised trials (1,721 people) found hydrolysed collagen improved skin hydration, and flagged biases in the trials it included (Pu et al., 2023, Nutrients).
• A 2025 meta-analysis of 23 trials (1,474 people) looked at funding. Taken together, trials showed improvement in hydration, elasticity and wrinkles. But trials not funded by pharmaceutical companies found no effect, and the high-quality trials found no significant effect. The authors concluded there is currently no clinical evidence to support collagen supplements for preventing or treating skin ageing (Myung and Park, 2025, American Journal of Medicine).
• In 2013 EFSA's panel looked at the evidence one manufacturer submitted for a specific collagen hydrolysate and skin elasticity. It concluded a cause-and-effect relationship hadn't been established. That opinion concerns one product and one set of studies, not all collagen (EFSA Journal 2013;11(6):3257).

Joints: where collagen does best

For knee osteoarthritis the picture is better. A 2024 meta-analysis of 35 randomised trials (25 of them in the pain analysis) found collagen derivatives had small-to-moderate effects on pain (standardised mean difference −0.35) and function (−0.31) compared with controls, and no increase in adverse events (Liang et al., 2024, Osteoarthritis and Cartilage). A smaller 2023 analysis of collagen peptides found a pain benefit in four trials of 507 patients, but all four were at high risk of bias (Lin et al., 2023, J Orthop Surg Res). These are people with diagnosed osteoarthritis, not healthy people hoping to prevent it. None of these reviews split results by funder, so the funding question stays open for knee osteoarthritis.

Tendons: early days

A 2026 systematic review of eight small trials (257 people, nearly all men) combined collagen with resistance or jump training. Tendon cross-sectional area grew more with collagen in three of four trials measuring it, and tendon stiffness improved only in the trials using 15 to 30 g a day (about 5 g showed within-group changes only). Collagen made no extra difference to muscle strength (Buchalski et al., 2026, Journal of Functional Morphology and Kinesiology). That's promising for researchers, but small and short.

Collagen claims you'll meet on the tub

• "Collagen drops after your twenties, so replace it" is a story about the body, not a trial result.
• "Marine is better than bovine" (or the reverse): the 2023 skin meta-analysis found no significant difference in elasticity results by collagen source, though only one trial used bovine collagen, so it can't say much about bovine versus marine.
• Peptides in blood and cell experiments are mechanism, not outcome.
• Doses vary by outcome. A 2021 review linked 15 g a day to raised collagen synthesis rates (Khatri, above), so about 15 g is the figure you'll often see for skin and joints. The tendon review found stiffness improved only in trials using 15 to 30 g a day, with about 5 g showing within-group changes only. Those are what the studies used, not recommendations.

Upfront's collagen product page (read 8 October 2026) describes collagen as the most common protein in the body, important for the structure of bones, tendons, joints and skin, and lists two variants, one labelled "100% Collageen" and one flavoured. Its text states no health benefit. For any collagen tub, the label questions are the animal source, the grams of collagen peptides per portion, and what else is in it.

Before you scoop: the safety bits

• Protein: the Health Council found too little suitable research on kidney function to draw a conclusion, set no upper limit, and notes its advice doesn't cover chronic illness. If you have kidney disease or another condition, ask your doctor before changing protein intake.
• Whey comes from milk and collagen from bovine, porcine or fish sources, so check the allergen line.
• Collagen trials reported no more adverse events than controls in the osteoarthritis meta-analysis, but the underlying evidence is not strong enough to say much more. We found no collagen trial data for pregnancy or breastfeeding.
• Check the full ingredient list for sweeteners and other additives, particularly if you add several products.

So, what goes in the basket?

1. Work out your protein from food first, using the norm (0.83 g/kg) or sports ranges, and see if you're short before buying powder.
2. If you use powder, compare protein per portion, the amino acid table if there is one, and what else is in the tub.
3. Whey and soy have the best match in trials; other plant proteins are less tested, and blends haven't been studied for most brands.
4. Treat collagen as its own product: possible help for knee osteoarthritis pain, uncertain for skin, early for tendons, and not a protein replacement.

For reading the rest of the label, see our label guide, and check medicine interactions if you take prescription medication.

Where to read next

The same shelf holds plenty more. Neighbouring guides:

• Creatine: strength, running and the actual question, for which kinds of effort creatine helps and where the kidney, hair and focus questions stand.
• Electrolytes: what is in the mix?, for sodium, potassium, magnesium and chloride explained, the overdrinking risk and a worked label example.
• Vitamin D in the Netherlands and Europe, for Dutch and EU advice by group, EFSA's upper limit and what blood-test levels mean according to named guidelines.
• Magnesium forms: what's actually different?, for how magnesium forms differ in magnesium per gram, absorption and gut effects.

Written by Smart Supplements with AI assistance from the sources linked in the text. It has not been reviewed by a clinician.

Last updated: 12 October 2026

This article is for informational purposes only and is not intended as medical advice. Always consult a healthcare professional before starting any new supplement, especially if you take prescription medication.