IngredientsMarine protein is a broad term encompassing the proteinaceous fractions — intact proteins, hydrolysates, and bioactive peptides — derived from organisms of marine origin. Marine organisms including fish, seaweed, shellfish, microalgae, crustaceans, cephalopods, and mollusks, as well as their by-products, constitute vital reservoirs of proteins and bioactive peptides. In the context of dietary supplementation, the most commercially significant forms are:
Fish collagen is almost exclusively type I collagen, which constitutes roughly 80% of collagen in human skin and is the dominant structural protein in tendons, ligaments, and bone. Marine collagen is known for its low molecular weight, which makes it easier for the body to absorb compared to collagen derived from other sources, such as bovine or porcine collagen.
Marine organisms also have special structures and constitute nearly half of the worldwide biodiversity, with activities including antioxidant activity, antimicrobial activity, anticancer activity, antihypertensive activity, and anti-inflammatory activity. In general, bioactive peptides often have 3 to 20 amino acid residues, and their biological activities are based on their amino acid composition and sequence. The collagen tripeptide motif glycine-X-Y (where X is often proline and Y is often hydroxyproline) is the predominant structural unit. The tripeptide glycine-X-Y, along with the dipeptides proline-hydroxyproline and hydroxyproline-glycine, appears especially crucial for bioactivity, possibly with variations in the amino acid composition contributing to the unique molecular and biological properties of collagen peptides derived from aquatic sources.
Variations in activities and structures of marine peptides are pronounced because of the high taxonomic diversity among and within the five major groups of marine organisms used as food — fish, algae, bivalves, cephalopods, and crustaceans — spanning four kingdoms of living organisms. Unlike peptides from other sources, many marine-derived peptides are more resistant to proteolysis by gastrointestinal proteases, because of the steric factors derived from their unusual structures (branched, cyclic and possessing both D and L amino acids).
Marine proteins are regarded as nutritionally complete. Their nutritional value is similar to that of meat and egg proteins and, in particular, the high contribution, compared to meat, of the essential amino acids lysine, methionine, and threonine is of great interest. All analyzed marine species had a high content of high-quality protein, with all indispensable amino acids above the reference value pattern for adults and children.
Marine fish provide a rich source of bioactive compounds such as proteins and peptides. The bioactive proteins and peptides derived from marine fish have gained enormous interest in nutraceutical, pharmaceutical, and cosmeceutical industries due to their broad spectrum of bioactivities, including antioxidant, antimicrobial, and anti-aging activities.
Marine-sourced proteins and peptides have garnered considerable scientific attention owing to their diverse range of biological activities, such as antioxidant, antihypertensive, antidiabetic, anticoagulant, antibacterial, anti-inflammatory, anticancer, and immunomodulatory effects.
Beyond protein, marine sources supply associated micronutrients. They may supply high-quality animal protein for people in densely populated countries, along with essential micronutrients, including vitamins A, D, and B, and minerals such as iodine, zinc, calcium, phosphorus, iron, and selenium.
Collagen Peptides (Type I Tripeptides, Pro-Hyp, Hyp-Gly): Hydrolysis disrupts the triple-helix spatial organization of native collagen, releasing bioactive, small peptides that are widely distributed throughout the body, including the joints, with effects on mesenchymal cells such as chondrocytes and synoviocytes similar to those on dermal and subcutaneous fibroblasts. The principal mechanism is indirect: ingested peptides act as signaling molecules to dermal fibroblasts, stimulating endogenous collagen and extracellular matrix synthesis rather than acting as direct structural substrates.
ACE-Inhibitory Peptides: ACE-inhibitory peptides may function by competitively inhibiting the active site of ACE, blocking the conversion of angiotensin I to angiotensin II. Additionally, peptides may affect ACE activity by modifying enzyme structure or interfering with substrate recognition. Aside from their function as ACE inhibitors, marine peptides have a wide range of pharmacological properties. Certain peptides have antioxidant capabilities that protect cardiovascular tissues from oxidative stress-induced damage. Others have antihypertensive effects via regulating vascular tone or reducing endothelial dysfunction, which complements their ACE-inhibitory activities.
Antioxidant Peptides: Increased exposure of amino acids can be attained by food processing, fermentation or gastrointestinal digestion. The in vitro antioxidant activity of marine protein hydrolysates has been shown for several fish species, mollusks, crustaceans, and microalgae. The link to a beneficial health outcome in humans is, however, still on a theoretical level. Bioactive peptides, especially those derived from fish hydrolysates, exhibit the ability to mitigate oxidative stress by lowering levels of reactive oxygen species (ROS).
Antimicrobial and Immunomodulatory Peptides: Antimicrobial peptides mainly consist of 12–45-amino acid chains with positive charge and are mainly based on amphipathic secondary structures, like α-helices and β-sheets. Seacure® is packaged as an "intestinal health promoting" product. These preparations work on animal gastric-damaging models and induce epidermal growth factor-like responses, stimulating the proliferation of epidermal and epithelial tissues.
Marine protein, derived from sources such as fish, shellfish, seaweed, and other oceanic organisms, has a rich history of use in traditional medicine and nutritional therapies. Across many coastal cultures, marine protein has been esteemed not only as a dietary staple but also for its medicinal properties. In ancient Chinese medicine, for example, fish and seaweed were regularly incorporated into remedies designed to strengthen the body, boost vitality, and support recovery from illness. Similarly, indigenous populations along the Pacific Rim have long utilized fish broth and seaweed infusions to promote healing, believing them to fortify the blood and improve joint health.
The consumption of fish varied by the wealth and location of the household. In the Greek islands and on the coast, fresh fish and seafood (squid, octopus, and shellfish) were common. They were eaten locally but more often transported inland. Sardines and anchovies were regular fare for the citizens of Athens. They were sometimes sold fresh, but more frequently salted.
According to the FAO, seafood offers a means of nutrition that can complement cereal-based diets, providing micronutrients, such as long-chain polyunsaturated omega-3 fatty acids, that are not often found in other food sources.
Fermentation of fish for preservation and concentration of protein has ancient roots across East and Southeast Asia. Katsuo-bushi (fermented and dried skipjack tuna), long used in Japanese cuisine for both nourishment and flavour, has been investigated pharmacologically for its ACE-inhibitory peptide content. Spontaneously hypertensive rats fed a standard chow supplemented with tuna hydrolysate, Katsuo-bushi, for seven weeks, experienced reduced blood pressure.
Athletes have historically harnessed the nutritional advantages of various marine products to enhance their performance and recovery. Among these, fish-based products have been particularly popular. Fish oil supplements, rich in omega-3 fatty acids, have been widely used to reduce inflammation, improve joint health, and support cardiovascular function in athletes. Additionally, marine protein supplements, often derived from sources like fish and shellfish, offer a concentrated source of essential amino acids, aiding in muscle repair and growth.
Skin health is the most extensively studied application of marine protein supplements, particularly hydrolyzed fish collagen peptides.
Fish collagen peptides have been shown to significantly reduce crow's feet and periorbital wrinkles in women. Further, hydrolyzed collagen supplementation was reported to improve skin elasticity and moisture while reducing evaporation.
Kim et al. designed a randomized, double-blind, placebo-controlled trial to evaluate the efficacy of low-molecular-weight collagen peptide (LMWCP) with a tripeptide (Gly-X-Y) content on human skin hydration, wrinkling, and elasticity. Compared with the placebo group, the LMWCP group had higher skin-hydration values after 6 weeks and 12 weeks, and two parameters out of three of the skin elasticity in the LMWCP group were significantly higher after 12 weeks. During the study period, none of the subjects presented adverse symptoms. These results suggested that LMWCP could be used as a healthy food ingredient to improve human skin conditions.
A trial observed a significant reduction in nasolabial wrinkles after three months of oral collagen supplementation, as measured by the VISIA skin analysis system (+35% compared to baseline). Over twelve weeks, skin elasticity improved by 23% compared to the placebo group, with hydration rising by 14%, radiance by 22%, and skin firmness by 25%, based on self-reported skin quality visual analogue scores. Results were particularly positive in women aged 45–54 years. More recently, in a 2023 double-blind, placebo-controlled clinical trial, a ninety-day oral intake of hydrolyzed marine collagen from fish cartilage was associated with noticeable and significant reductions in wrinkles in the frontal and nasolabial areas, as well as the periorbital skin.
The same meta-analysis that found significant effects carried an important qualifier: studies funded by supplement manufacturers consistently showed significant benefits across all measured outcomes, while independent studies produced more modest results. This doesn't mean marine collagen supplements are ineffective. It means the evidence is most reliable for modest improvements in hydration and elasticity with consistent daily use over 8–12 weeks, rather than dramatic wrinkle reversal.
A separate 2021 clinical trial found that oral collagen peptides improved skin hydration by increasing natural moisturizing factor (NMF) content in the stratum corneum, but did not produce significant changes in skin elasticity or thickness. The hydration benefit appears more consistently across studies than the structural benefit.
One study of freshwater collagen demonstrated that supplementation was safe and well tolerated in a healthy female population, with a similar number of adverse events between groups; none were classified as probably related or related to the supplement, and all blood safety parameters for the complete blood count, electrolytes, and liver and kidney markers were within normal clinical ranges.
Evidence quality: Multiple RCTs support modest to moderate benefits for skin hydration and elasticity over 8–12 weeks. Meta-analytic evidence is complicated by industry funding bias. The mechanistic pathway (peptide signaling to fibroblasts, not direct structural deposition) is reasonably well established, but long-term effects remain underexplored.
Marine protein-based dietary supplements targeting hair loss have been the subject of a programme of controlled clinical research.
One multisite study assessed the value of a dietary marine-extract based dietary supplement in premenopausal women with subclinical hair thinning or hair loss conditions. This multi-site, randomized double-blind, placebo-controlled clinical trial was conducted with impact on hair shedding rate and hair fiber diameter (assessed by phototrichogram) as primary end points. A total of 96 eligible female subjects were enrolled aged 21–55 years of age from Asian, Caucasian, and Hispanic ethnic backgrounds. This study showed that hair shedding was significantly reduced in the first 3–6 months of daily consumption of the oral supplement. Moreover, phototrichogram image analysis revealed a statistically significant increase in the mean vellus-like hair diameter after 6 months.
Following an initial pilot study, five randomized, double-blind studies assessed the effectiveness of the oral marine supplement for promoting hair growth. Each study was approved by one or more institutional review boards. Together, these studies demonstrated the ability of oral marine supplements to increase the growth of terminal and vellus hairs, increase the diameter of terminal and vellus hairs, and decrease hair loss. This product was found to be beneficial for men as well as women.
Studies have additionally assessed the role of marine proteins on hair loss. A 2015 study randomized female participants with self-reported hair thinning to receive either an oral supplement containing marine proteins and glycosaminoglycans (N = 30) or a placebo supplementation (N = 30).
Whole hydrolysates of marine-derived proteins have been applied in food/feed preparations, serving functions including preventing hair loss. Although all these activities have been verified by clinical trials, there are several problems with using whole protein hydrolysates.
Evidence quality: Several RCTs with a consistent direction of effect support the use of marine protein complexes for hair thinning. However, many trials involve a single proprietary formulation (Viviscal®), which combines marine protein with other nutrients (e.g., biotin, zinc, vitamin C), making it difficult to isolate the contribution of marine protein alone. Risk of bias from industry sponsorship is a limitation.
Focus on health benefits from marine resources has traditionally been on the long chain omega-3 fatty acids. However, emerging evidence points out that other nutrients, such as peptides and proteins also play a major role. A review sums up preclinical and clinical trials on the cardioprotective effects of marine protein and peptides.
The increased harvesting of low-trophic marine organisms has made it relevant to map antihypertensive peptides from these resources for use in functional foods, dietary supplements, or drug synthesis. The ongoing prevalence of adverse reactions associated with currently utilized antihypertensive medications has elevated the importance of researching novel antihypertensive peptides. Most of the research conducted in this field is predominantly biochemical, with a lesser emphasis on cell-based assays, animal models, and clinical trials. Biochemical in vitro assays for ACE inhibitory activity are commonly used to investigate antihypertensive potential, since these assays are affordable, timesaving, and readily accessible.
In three studies lasting for two months, spontaneously hypertensive rats (SHR) were fed standard animal chow where 20% of the feed was either fish protein or casein protein. The blood pressure in the SHR eating fish protein was significantly reduced compared to that in those eating the casein protein. However, when this was investigated in rats with diabetes, no effect on blood pressure was observed.
Although ACE-inhibitory peptides from marine sources are weaker in ACE inhibition than synthetic drugs, the peptides derived from fish sources are often consumed in a diet. Some of the peptides found have been previously described as revealing antihypertensive activity in vivo in spontaneously hypertensive rats. These results provide a basis for further clinical animal and human studies.
The translation of marine peptides from laboratory research to clinical applications has the potential to provide safer and more effective alternatives to traditional ACE inhibitors in CVD management. Clinical trials and preclinical research have shown that some marine-derived peptides may decrease blood pressure and improve cardiovascular function in animal models and humans.
Extensive research has been conducted on mussels, examining them in both fermented and hydrolyzed forms. Blue mussel meat was subjected to a 6-month fermentation process and a decapeptide that exhibited a notable increase in ACE inhibitor activity was identified and isolated from the sauce. This decapeptide significantly reduced blood pressure in SHRs after oral administration compared to control rats receiving a saline control solution. It is worth noting that the observed decrease, while significant, was not as effective as the drug Captopril.
Evidence quality: Preclinical animal evidence is substantial and mechanistically coherent. Human clinical evidence for blood pressure reduction from marine protein peptides is preliminary and limited in scale. Most clinical findings derive from small trials. The valyl-tyrosine dipeptide from sardine muscle hydrolysate represents one of the better-studied human-tested antihypertensive peptides. No large-scale RCTs have established cardiovascular event reduction in humans. Evidence in this area should be considered preliminary.
Clinical studies showed that collagen peptides are involved in cartilage matrix synthesis and treatment with the peptides reduced pain in osteoarthritic patients. They are thus potential therapeutic agents for osteoarthritis and osteoporosis.
Collagen peptides isolated by enzymatic digestion from fish, bovine, and porcine skin, as well as from chicken and bovine cartilage have drawn particular interest for the treatment of patients with osteoarthritis. Several clinical trials showed that marine collagen peptides were safe and provided an improvement in terms of pain and functions in such patients.
A systematic literature search was conducted following PRISMA guidelines. Multiple databases were searched for RCTs published up to May 2023 that focused on the analgesic outcomes and adverse events associated with collagen peptides or hydrolyzed collagen in patients with osteoarthritis. Quality was assessed using the Cochrane ROB 2.0 tool and GRADE criteria. Four trials involving 507 patients with knee osteoarthritis were included and analyzed using the random-effects model. All these trials were considered to have a high risk of bias.
Due to their high systemic bioavailability after oral intake, hydrolyzed marine collagens are widely distributed throughout the body, including the joints, with effects on other mesenchymal cells such as chondrocytes and synoviocytes similar to those on dermal and subcutaneous fibroblasts.
Evidence quality: There is a growing body of RCT evidence suggesting collagen peptides (across various animal sources, with some fish-derived data) may reduce knee pain in osteoarthritis. However, the meta-analysis found high risk of bias across all included trials, and the best-supported data are for bovine collagen peptides, not exclusively marine-derived products. Evidence for marine collagen specifically in osteoarthritis is suggestive but not conclusive.
The purpose of one RCT was to determine whether a marine protein hydrolysate given as a supplement can prevent age-related loss of muscle mass and loss of physical function in frail elderly.
This double-blinded, randomized, controlled trial is one of the first registered studies to evaluate the effects of a supplement of marine protein hydrolysate (MPH) on measures of physical function and strength. Eighty-six older adults received nutritional supplements containing 3 g of MPH or a placebo for up to 12 months. Short Physical Performance Battery (SPPB), grip strength, and gait speed were measured at baseline, 6 months, and 12 months. No difference was found between the intervention and control groups in mean change in SPPB or regarding time trend in SPPB, grip strength, or gait speed.
The aim of this trial was to evaluate the effects of marine protein hydrolysate (MPH) supplements on physical function and strength in the elderly. This is one of the first long-term studies of MPH and age-related changes in muscle health.
Evidence quality: The most rigorously conducted human RCT of marine protein hydrolysate for sarcopenia found no statistically significant benefit on physical performance measures at a dose of 3 g/day over 12 months. The evidence for this indication is currently negative in the most direct human trial. The dose used may have been insufficient to observe effects, and higher-protein dietary contexts may obscure benefit in well-nourished older adults.
Marine collagen peptides (MCPs) obtained by enzymatic digestion of fish skin have been shown to exert several health effects mainly in two directions: metabolic disorders and skin/bone repair. They positively affected glucose and lipid metabolism in patients with type II diabetes mellitus, improved lipid metabolism in obese people, and possessed hypotensive and lipid normalising action in patients with primary hypertension.
A study was conducted to explore the therapeutic benefits of marine collagen peptides (MCP) from fish hydrolysates on Chinese patients diagnosed with type 2 diabetes mellitus (DM2). The study involved 100 diabetic patients and 50 healthy individuals. The diabetic patients were randomly assigned to either a treatment group or a control group. For three months, the treatment group received 13 g of MCP every day. Blood samples were collected from all participants before treatment, at 1.5 months, and at 3 months after treatment to assess glucose and lipid metabolism. The researchers also measured serum levels of highly sensitive C-reactive protein, nitric oxide, bradykinin, prostacyclin, and lipids.
Evidence quality: Preliminary human clinical data suggest potential benefits for glycaemic and lipid markers in diabetic patients, but trials are small, often single-centre, and lack independent replication. This area should be considered exploratory.
Seacure® is a commercial dietary supplement product obtained from proteolysis of Pacific whiting proteins by fermentative yeast. They are packaged as "intestinal health promoting" product. They work directly on animal gastric-damaging models and induce epidermal growth factor-like responses, stimulating the proliferation of epidermal and epithelial tissues.
Peptides, due to their capacity to engage with cellular receptors, enzymes, and ion channels, are crucial for the regulation of several physiological processes. The adaptability of peptides derived from marine sources renders them a viable field for research and prospective use.
Evidence quality: Evidence for gut/intestinal effects of marine protein products is largely confined to in vitro and animal models. Robust human clinical evidence is lacking.
Despite evidence showing clear associations between oxidative stress and CVDs, epidemiological data on antioxidant intake and disease prevention are inconclusive. Natural antioxidant intake from foods has been proven beneficial, whereas analyses with antioxidant supplementation have been proven unfavorable or even resulting in adverse effects in preventing all-cause mortality. One study has been published focusing on the effect of marine proteins on oxidative stress and antioxidative status.
Recently, development and research of nutraceuticals based on marine collagen peptides (MCPs) have been growing due to their high homology with human collagens, safety, bioavailability through gut, and numerous bioactivities. The major concern regarding safety of MCPs intake relates to increased risk of oxidative stress connected with collagen synthesis and to ROS production by MCPs-stimulated phagocytes.
Evidence quality: In vitro antioxidant activity is well-documented for multiple fish species and marine organisms, but translation to meaningful in vivo antioxidant effects in humans has not been clinically demonstrated. Human evidence in this domain remains limited and indirect.
Dosages reported in published studies vary considerably by indication and product formulation. The following are drawn directly from study reports:
Dosage forms include: oral capsules, powder (dissolved in water or mixed into food), tablets, and liquid concentrates. Duration in studies ranges from 3 weeks to 12 months.
A well-designed study demonstrated that freshwater-derived marine collagen supplementation was safe and well tolerated in a healthy female population; none of the reported adverse events were classified as probably related or related to the supplement, and all blood safety parameters for the complete blood count, electrolytes, and liver and kidney markers were within normal clinical ranges.
Seafood allergens are usually heat stable and cannot easily be destroyed through cooking. Some people can tolerate tinned fish (intensely heat treated) yet are unable to tolerate the same fish when freshly cooked. People with seafood allergy react to proteins in the seafood, not to iodine in the fish or shellfish.
Fish is one of the top eight food allergens recognized worldwide. If a person has a fish allergy or seafood sensitivity, marine collagen supplements could potentially trigger an allergic reaction. The allergens in fish are primarily proteins called parvalbumins, which are found in fish muscle tissue. Marine collagen is extracted from fish skin and scales, not muscle, which theoretically contains lower levels of these specific allergenic proteins. However, cross-contamination during processing is possible, and some individuals with severe fish allergies may still react to trace amounts of fish proteins.
Individuals with fish allergies should avoid marine collagen products, as they can provoke allergic responses ranging from mild symptoms like itching and rashes to severe reactions such as anaphylaxis.
Another significant concern is the potential for heavy metal contamination. Fish can accumulate harmful substances like mercury, lead, and arsenic due to environmental pollution. Regular consumption of contaminated marine collagen could pose serious health risks, including neurological damage. To mitigate this risk, it is crucial to choose products that undergo rigorous testing for heavy metals and contaminants.
Shellfish allergies and fish allergies are different. Shellfish allergies involve crustaceans like shrimp, crab, and lobster, or mollusks like clams and oysters. The protein allergens present in one seafood group can be very different to those in other seafood groups. Consumers and clinicians should distinguish between species-specific products, as a known allergy to finfish does not necessarily preclude use of shellfish-derived products, and vice versa, though caution is warranted in either case.
Marine-derived ACE-inhibitory peptides carry a theoretical interaction risk with antihypertensive medications, particularly ACE inhibitors and angiotensin receptor blockers, due to additive blood pressure-lowering potential. Although ACE-inhibitory peptides from marine sources are weaker in ACE inhibition than synthetic drugs, the peptides derived from fish sources are often consumed in a diet. This suggests a low but non-zero potential for additive hypotensive effects at high supplemental doses.
Excess collagen can cause digestive upsets such as bloating, constipation, or diarrhea. Even without a known allergy, some people may develop a sensitivity or intolerance to marine collagen, manifested by digestive disorders such as nausea, bloating, or diarrhea.
The major concern regarding safety of MCPs intake relates to increased risk of oxidative stress connected with collagen synthesis (likewise in fibrosis) and to ROS production by MCPs-stimulated phagocytes. This theoretical concern has led some researchers to combine marine collagen peptides with antioxidants in formulations, though whether this is clinically necessary has not been established.
Health conditions that Marine protein may help support.
Body systems that Marine protein may help support.
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