# Ray Liver Oil (Raja clavata)

**Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/ray-liver-oil
**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-03-25
**Evidence Score:** 2 / 10
**Category:** Protein
**Also Known As:** Raja clavata liver oil, Thornback ray liver oil, Skate liver oil, Ray fish liver oil, Thornback skate liver oil, European ray liver oil

## Overview

Ray liver oil, derived from the thornback ray (Raja clavata), is a marine lipid source containing DHA (up to 6.8g/100g) and EPA (up to 2.3g/100g), alongside tocopherols and a high polyunsaturated fatty acid profile. Unlike well-studied fish oils, no human clinical trials have evaluated its therapeutic efficacy, making it an unvalidated supplement despite its notable fatty acid composition.

## Health Benefits

• No clinically proven health benefits - no human trials exist
• Contains DHA (up to 6.8g/100g) and EPA (up to 2.3g/100g) - compositional data only, no efficacy studies
• Provides vitamin E as tocopherols - levels vary by season/location, no therapeutic evidence
• Rich source of PUFAs (up to 30% of total lipids) - nutritional composition only
• May contain variable heavy metal levels - safety concerns noted, no established benefits

## Mechanism of Action

DHA and EPA from ray liver oil are hypothesized to incorporate into phospholipid bilayers, modulating membrane fluidity and attenuating NF-κB-mediated inflammatory signaling by competitively displacing arachidonic acid from COX-2 and LOX enzyme pathways. EPA serves as a substrate for the synthesis of series-3 [prostaglandin](/ingredients/condition/inflammation)s and series-5 leukotrienes, which exert reduced pro-inflammatory activity compared to arachidonic acid-derived eicosanoids. Tocopherols present in the oil may quench lipid peroxyl radicals via hydrogen donation, protecting PUFAs from oxidative degradation, though these mechanisms remain extrapolated from other marine oils rather than validated in Raja clavata-specific studies.

## Clinical Summary

No human clinical trials have been conducted specifically on ray liver oil from Raja clavata, meaning all potential health effects are inferred from its compositional similarity to other marine fish oils. The available data is limited to biochemical characterization studies reporting fatty acid profiles and seasonal variation in PUFA content, with no randomized controlled trials, dose-response studies, or bioavailability assessments in humans. Evidence for omega-3 benefits is borrowed from the broader fish oil literature, which includes large trials such as REDUCE-IT (n=8,179) on EPA and VITAL (n=25,871) on combined DHA/EPA, but these cannot be directly extrapolated to this specific oil. The overall evidence strength for ray liver oil specifically is classified as insufficient, and no regulatory health claims have been established for this ingredient.

## Nutritional Profile

Ray liver oil from Raja clavata is a lipid-rich extract with the following documented composition: Total lipids constitute the primary component, with PUFAs comprising up to 30% of total lipids. Omega-3 fatty acids are the dominant bioactive fraction — DHA (docosahexaenoic acid, 22:6n-3) reaches up to 6.8g/100g and EPA (eicosapentaenoic acid, 20:5n-3) up to 2.3g/100g, though concentrations vary significantly by season, geographic location, and specimen age. Vitamin E is present as mixed tocopherols (alpha-, gamma-, and delta-tocopherol isomers), serving primarily as endogenous [antioxidant](/ingredients/condition/antioxidant)s protecting the PUFAs from oxidation; exact concentrations are seasonally variable and not consistently quantified in literature. The oil contains squalene as a minor triterpene component, characteristic of elasmobranch liver oils. Cholesterol is present as the principal sterol. Fat-soluble vitamins A and D are likely present given the organ source, but species-specific quantification for Raja clavata remains limited in published data. Heavy metals including mercury, cadmium, and lead may bioaccumulate in liver tissue at variable concentrations depending on habitat; this represents a documented safety consideration. Protein content is negligible as this is an extracted oil. No fiber or carbohydrates are present. Bioavailability of DHA and EPA from fish liver oils is generally high due to the triglyceride and phospholipid carrier forms, though the specific lipid class distribution in Raja clavata oil has not been thoroughly characterized.

## Dosage & Preparation

No clinically studied dosage ranges, standardized forms, or therapeutic protocols have been established due to complete absence of human trials. Consult a healthcare provider before starting any new supplement.

## Safety & Drug Interactions

Ray liver oil shares the general safety profile of marine-derived omega-3 oils, including a risk of increased bleeding time at higher doses, which is clinically relevant for individuals taking anticoagulants such as warfarin or antiplatelet drugs like aspirin and clopidogrel. High PUFA content makes the oil susceptible to oxidative rancidity, and consumption of oxidized lipids has been associated with pro-[inflammatory](/ingredients/condition/inflammation) and cytotoxic effects. Individuals with fish or seafood allergies should avoid this supplement, and its use during pregnancy or lactation is not supported by any safety data specific to Raja clavata liver oil. Potential contaminant load, including heavy metals and fat-soluble environmental pollutants such as PCBs, has not been systematically characterized for this species, representing an unquantified risk.

## Scientific Research

No human clinical trials, randomized controlled trials, or meta-analyses exist for Ray Liver Oil from Raja clavata. Research is limited exclusively to compositional analyses examining fatty acid profiles and contaminant levels. No PMIDs are available as no clinical efficacy or safety studies have been conducted.

## Historical & Cultural Context

No evidence of traditional medicinal use in any cultural system (folk medicine, Ayurveda, TCM) was identified in available research. Ray liver oil appears to lack historical therapeutic applications.

## Synergistic Combinations

No established synergies - lacks clinical research

## Frequently Asked Questions

### How much DHA and EPA does ray liver oil contain?

Ray liver oil from Raja clavata contains up to 6.8g of DHA and up to 2.3g of EPA per 100g of oil, based on compositional analyses. These values fluctuate significantly depending on the animal's geographic location, season, and diet, meaning commercial products may vary considerably from published figures. No standardized dosage or concentration has been established in any clinical context.

### Is ray liver oil the same as cod liver oil?

No, ray liver oil and cod liver oil are distinct products derived from different species — Raja clavata (thornback ray) versus Gadus morhua (Atlantic cod). While both contain DHA, EPA, and fat-soluble vitamins, cod liver oil has an extensive clinical and nutritional research history dating back decades, including established vitamin A and D content data, whereas Raja clavata liver oil has no published human trials and limited compositional characterization. The fatty acid ratios and micronutrient profiles also differ between species.

### Are there any clinical studies on ray liver oil?

As of current available literature, no human clinical trials have been published specifically investigating ray liver oil from Raja clavata for any health outcome. Existing research is confined to biochemical and compositional studies, primarily characterizing its fatty acid profile and PUFA content. Any claimed health benefits are entirely extrapolated from the broader omega-3 and fish oil literature, and should not be considered validated for this specific ingredient.

### Can ray liver oil interact with blood thinners?

Like other high-PUFA marine oils, ray liver oil may potentiate the anticoagulant effects of warfarin by inhibiting thromboxane A2-mediated platelet aggregation and potentially altering vitamin K metabolism. Co-administration with antiplatelet agents such as aspirin, clopidogrel, or NSAIDs may further increase bleeding risk. Patients on any anticoagulation therapy should consult a healthcare provider before using ray liver oil, particularly since its dose-response relationship for these effects has not been studied.

### What is the vitamin E content of ray liver oil?

Ray liver oil provides vitamin E primarily in the form of tocopherols, but published data indicate that concentrations vary substantially by season and the geographic origin of the Raja clavata specimen. No specific standardized tocopherol level has been established for commercial ray liver oil, and no therapeutic dose for vitamin E derived from this source has been studied. The tocopherols present likely serve an antioxidant role in stabilizing the oil's high PUFA content against oxidative degradation during storage.

### Is ray liver oil safe during pregnancy and breastfeeding?

Ray liver oil has not been formally studied in pregnant or breastfeeding populations, making safety unclear for these groups. While omega-3 fatty acids are generally considered beneficial during pregnancy, the variable heavy metal content and lack of quality standardization in ray liver oil products raise additional safety concerns. Pregnant and breastfeeding individuals should consult a healthcare provider before use, as better-studied alternatives like pharmaceutical-grade fish oil may be preferable.

### Why does the heavy metal content in ray liver oil vary, and how concerned should I be?

Ray liver oil heavy metal levels vary based on the ray's habitat, season, and location—marine animals accumulate contaminants from their environment, and ray livers are bioaccumulative organs. Unlike regulated pharmaceutical omega-3 supplements, ray liver oil products typically lack standardized heavy metal testing or disclosure, making it difficult to assess actual exposure. Consumers should request third-party testing documentation from manufacturers and consider that chronic heavy metal exposure carries potential health risks, particularly with unregulated supplementation.

### How does the omega-3 composition of ray liver oil compare to other marine sources?

Ray liver oil contains up to 6.8g DHA and 2.3g EPA per 100g, making it moderately rich in omega-3s, though these figures represent maximum compositional levels rather than clinically validated doses. Compared to cod liver oil (which typically contains 7-10g EPA+DHA per 100g) and krill oil (which offers better bioavailability through phospholipid binding), ray liver oil occupies a middle position nutritionally. However, without human efficacy trials, the practical superiority of any marine source remains unproven.

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*Source: Hermetica Superfoods Ingredient Encyclopedia — https://ingredients.hermeticasuperfoods.com*
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