Marine Collagen Extra is The Protein Works’ capsule-based collagen supplement, designed for people who want a quick, convenient collagen hit without powders or shakers. It combines marine collagen with vitamin C, zinc, and selenium in a simple two-capsule daily serving. The convenience factor is real. But there is a significant problem with this product that we need to address straight away: the collagen dose is far too low to match the levels used in published clinical research.
What Is It?
Marine Collagen Extra is a capsule supplement containing Type I marine collagen peptides alongside vitamin C (80mg per serving), zinc (10mg), and selenium (55mcg). Each daily serving is two capsules delivering a total of 1,000mg (1g) of marine collagen. The capsules come in three pack sizes: 60, 120, and 180 capsules, lasting 30, 60, or 90 days respectively at the recommended two-per-day dose.
The added vitamin C, zinc, and selenium follow the same co-factor approach used across The Protein Works collagen range. Vitamin C is essential for collagen synthesis, zinc supports skin cell renewal, and selenium protects against oxidative stress. This multi-nutrient approach is a genuine differentiator from marine collagen capsules sold by brands that provide collagen alone.
The Dose Problem
Here is the issue that dominates any honest assessment of this product. At 1,000mg (1g) per serving, Marine Collagen Extra delivers a fraction of the collagen dose used in clinical research. The majority of published studies on collagen supplementation use doses between 2.5g and 15g daily. Some skin-focused studies have shown benefits at 2.5g to 5g. Joint health research typically uses 5g to 10g. At 1g per day, you are well below even the lowest clinically studied dose.
This is not a problem unique to The Protein Works. Collagen capsules in general struggle with dosing because you can only fit so much powdered collagen into a standard capsule. But it does mean you would need to take five to ten capsules daily to reach the 5g to 10g range used in research, which rather defeats the convenience argument and would burn through a 60-capsule pack in less than two weeks.
For comparison, The Protein Works’ own Clear Collagen 360 powder delivers 15g per serving at a lower cost per day. Hunter and Gather’s bovine powder delivers 13g. Ancient + Brave True Collagen delivers 5g. Even at the budget end, you would get a clinically meaningful dose from virtually any collagen powder for less money than taking enough of these capsules to match it.
Sourcing and Quality
The Protein Works describes the collagen as marine-sourced without specifying the species of fish, the waters of origin, or whether the fishery holds any sustainability certifications such as MSC or ASC. There is no information about the extraction method or independent testing for heavy metals, which is particularly relevant for marine collagen given the potential for mercury and microplastic contamination in fish-derived products.
Ancient + Brave’s Wild Collagen uses MSC-certified sustainably caught fish from the North Atlantic and provides full traceability. Hunter and Gather’s Marine Collagen comes from wild-caught deep-sea fish and carries independent lab testing for contaminants. The Protein Works offers none of this detail, which is disappointing for any marine supplement and especially concerning given the environmental and contamination questions that surround marine sourcing.
What Do Real Customers Say?
On Amazon UK, Marine Collagen Extra holds a 4.3 out of 5 rating from 63 reviews. That is a decent score but noticeably lower than the 4.6 and 4.7 ratings that Hunter and Gather and Ancient + Brave collagen products typically achieve on the platform. The most common positive feedback centres on convenience, with reviewers appreciating the simple two-capsule daily routine. Some users report improvements in skin and nail condition after several weeks of use.
The negatives are predictable given the dose issue. A number of reviewers note they are unsure whether the product is actually doing anything, which is consistent with the 1g daily dose sitting below clinically studied levels. Others mention the capsules are on the larger side.
The Protein Works brand overall holds a 4.7 out of 5 Trustpilot rating from 46,600+ reviews, but this reflects the broader product range rather than collagen specifically. There’s zero doubt The Protein Works are one of the best supplements companies out there, it’s just the collagen dose in this specific product that we’re unsure hits the mark.
Pricing
| Pack Size | RRP | Typical Sale | Per Serving (2 caps) |
|---|---|---|---|
| 60 capsules (30 days) | £12.99 | £9.99 | 33p (sale) |
| 120 capsules (60 days) | £22.99 | ~£14.99 | ~25p (sale) |
| 180 capsules (90 days) | £31.99 | ~£19.99 | ~22p (sale) |
At face value, the per-serving cost looks remarkably cheap. But this is misleading because the serving delivers only 1g of collagen. If you were to take enough capsules to reach 5g (the minimum dose with meaningful clinical support), you would need 10 capsules per day, turning the 60-capsule pack into a six-day supply at an effective daily cost of roughly £1.67 on sale. At that rate, Clear Collagen 360 at 44p per 15g serving is dramatically better value.
How It Compares
Against dedicated marine collagen powders, this product simply cannot compete on dose. Ancient + Brave Wild Collagen delivers 4g of MSC-certified marine collagen per serving. Hunter and Gather Marine Collagen delivers 10g per serving with full batch testing.
Even budget marine collagen capsules from brands like Nutravita typically provide 1,200mg to 1,500mg per serving, marginally above this product’s 1,000mg but still well below clinical thresholds.
The added vitamin C, zinc, and selenium do provide a modest advantage over single-ingredient marine capsules. But you can buy a standalone vitamin C tablet for pennies and pair it with any properly dosed collagen powder for far better results.
Who Should Buy This?
In all honesty, this is very difficult to recommend. The collagen dose is too low to align with clinical research, the marine sourcing lacks transparency, and there is virtually no customer feedback to suggest real-world effectiveness. The only scenario where it makes sense is as a minimal top-up for someone already getting collagen from other dietary sources and who values the convenience of a two-capsule-a-day routine over any measurable collagen dose.
If you want marine collagen, Hunter and Gather’s Marine Collagen Powder or Ancient + Brave Wild Collagen are significantly better options. If you want the convenience of capsules specifically, consider that you would need to take the equivalent of an entire day’s capsule allowance several times over to reach a meaningful dose, at which point the convenience argument collapses entirely.
Our Verdict
Marine Collagen Extra is the weakest product in The Protein Works collagen range by a considerable margin. The 1g dose sits well below the 2.5g to 15g range used in clinical research, the marine sourcing is unspecified, and with only a single customer review there is no real-world evidence of effectiveness.
The added vitamins are a nice touch, but they cannot compensate for a collagen dose that is unlikely to deliver the benefits most buyers are looking for. Your money is far better spent on a properly dosed collagen powder, including The Protein Works’ own Clear Collagen 360.
BEST ALTERNATIVE: Protein Works Clear Collagen 360
- Premium hydrolysed bovine collagen peptides
- 480g pack size lasts a long time
- Enhanced with vitamin C and hyaluronic acid
- Natural & unflavoured for versatile mixing
- Award-winning Gold Innovation formula
Frequently Asked Questions
Is 1,000mg of marine collagen enough?
Most published research on collagen supplementation uses doses between 2.5g and 15g daily. At 1g (1,000mg), Marine Collagen Extra falls below the lowest dose with meaningful clinical support. Some studies have shown modest skin benefits at 2.5g, but even that would require five capsules per day rather than the recommended two.
What type of collagen is in Marine Collagen Extra?
Type I marine collagen peptides. Type I is the most abundant collagen in the human body and the type most studied for skin, hair, and nail benefits. Marine collagen naturally contains predominantly Type I.
Is the marine collagen sustainably sourced?
The Protein Works does not specify the fish species, waters of origin, or whether the fishery holds any sustainability certifications such as MSC or ASC.
Can I take more than two capsules per day?
The recommended serving is two capsules. Taking more would increase the collagen dose but would also increase your intake of vitamin C, zinc, and selenium, which could exceed recommended daily limits at very high capsule counts. If you want a higher collagen dose, a powder supplement is a more practical and cost-effective approach.
How does this compare to The Protein Works Clear Collagen 360?
Clear Collagen 360 delivers 15g of bovine collagen per serving at approximately 44p on sale. Marine Collagen Extra delivers 1g of marine collagen per serving at approximately 33p on sale. Per gram of collagen, the powder is dramatically cheaper and delivers a clinically relevant dose in a single serving.
Are there any side effects?
Marine collagen is generally well tolerated. People with fish or shellfish allergies should avoid marine collagen supplements. Some users of marine collagen products report a mild fishy aftertaste, though capsule formats minimise this compared to powders.
Medical Disclaimer: This article is for informational purposes only and does not constitute medical advice. Consult your GP or a qualified healthcare professional before starting any new supplement, especially if you have underlying health conditions, take medications, or are pregnant or breastfeeding. Individual results may vary.
Affiliate Disclaimer: This article may contain affiliate links. If you purchase products through these links, we may earn a small commission at no additional cost to you. This helps support our website and allows us to continue providing helpful content. Our reviews remain honest and unbiased regardless of affiliate relationships.
I started this site after spending weeks trying to figure out which collagen actually works. Now I test products, read the studies, and share honest reviews so you can skip the research phase and get straight to results.