Health, fitness and the supplement aisle. An independent South African desk.
Collagen · Answer
No. Collagen is an incomplete protein because it contains almost no tryptophan, an essential amino acid, and it is low in leucine. As a sole protein source its quality score is effectively zero. In South Africa, use collagen for connective-tissue goals if you wish, but rely on whey, eggs, meat, dairy or soya for muscle protein.
A complete protein supplies all nine essential amino acids in useful amounts. Collagen is rich in glycine, proline and hydroxyproline, which suit connective tissue, but it has essentially no tryptophan and is low in leucine, the amino acid that most strongly switches on muscle protein synthesis. Protein-quality scores such as PDCAAS and DIAAS are effectively zero for collagen when it is the only protein. Whey, by contrast, is one of the highest-scoring proteins; Mathai and colleagues (2017) found whey and milk protein highest on DIAAS, ahead of soy and pea.
| Collagen peptides | Whey protein | |
|---|---|---|
| Tryptophan | Almost none | Present |
| Leucine (share of protein) | Low | About 10 to 11% |
| Protein quality (DIAAS) | Effectively zero as sole protein | Highest of common sources |
| Best use | Connective-tissue goals (emerging evidence) | Muscle building, daily protein targets |
It adds nitrogen and calories, but it should not be counted as a full-quality serving. If you are aiming for 1.4 to 2.0 g of protein per kg a day (the ISSN range for people who train), get the bulk from complete sources and treat collagen as a small bonus. The per-meal target of roughly 0.25 to 0.4 g/kg with 2 to 3 g leucine cannot be met with collagen alone; see whey isolate vs concentrate for the complete-protein options.
Yes. They do different jobs. A shake with 25 g of whey and 10 g of collagen gives a complete protein plus connective-tissue amino acids, but the whey is doing the muscle work. Do not replace whey with collagen to save money: per gram of powder, collagen is not cheaper. As of October 2026, ATP Fitness Hydrolysed Collagen costs about R104 per 100 g (910 g for R950, ATP shop), while ATP's Unflavoured Whey Protein Concentrate is R80 per 100 g (1 kg for R800) and Primal Whey Isolate is R93.33 per 100 g (750 g for R700, Dis-Chem Living Fit). ATP does not publish protein per serving, so we compare price per 100 g of powder only.
Collagen products often list 9 to 15 g of "protein" per serving by nitrogen content (for example, Biogen Peptan lists 9.0 g and The Harvest Table Bovine lists 15 g per serving). That figure is correct as grams of protein but says nothing about quality. South African testing has found label overstatement in some protein supplements: Schönfeldt and colleagues (2019) found 5 of 70 products had 42% to 80% less protein than claimed. If you buy a "protein" product containing collagen, check the amino acid profile.
For muscle, see our best whey protein and best whey isolate comparisons. Anyone with kidney disease, pregnant women, under-18s and people on regular medication should follow their doctor or dietitian's advice before adding protein powders, and anyone allergic to beef or fish should avoid the matching collagen.
| Product | Size | Price (source, date) | Servings | R per 10 g | R per 100 g powder | Sweeteners |
|---|---|---|---|---|---|---|
| ATP Fitness Hydrolysed Collagen | 910 g | R950 (ATP Fitness shop, 2026-10) | 91 | R10.44 | — | None |
| ATP Fitness Unflavoured Whey Protein Concentrate | 1 kg | R800 (ATP Fitness shop, 2026-10) | — | — | R80.00 | None |
| Primal Whey Isolate (750 g) | 750 g | R700 (Dis-Chem Living Fit, 2026-10) | — | — | R93.33 | sucralose |
| ATP Fitness Unflavoured Whey Protein Isolate | 800 g | R900 (ATP Fitness shop, 2026-10) | — | — | R112.50 | None |
Educational information, not medical advice. Speak to a doctor, pharmacist or registered dietitian before using supplements if you are pregnant or breastfeeding, under 18, taking medication, or living with kidney, liver or heart disease. Prices were observed in October 2026 and are not offers.