NSTK · 01.2026Independent supplement reference
NutriStack
Edition 1.0Updated August 1, 2026

Supplement × Prescription·Evidence index

Fish Oil and Naproxen: what the published research says

PubMed indexes 8 records that name Fish Oil and Naproxen together, either in the title or in an interaction, co-administration, or pharmacokinetic context. Each one is listed below with its study design and, where the abstract states one, the authors’ own conclusion, quoted and linked. This page reports that literature. It does not tell you whether to combine them.

Read this first

An evidence index, not guidance.

Every statement below is attributed to a named, dated, linked source.

This page lists published research relevant to Fish Oil and Naproxen. It deliberately does not state whether the combination is safe, whether it interacts, in which direction, at what dose, or how far apart to take them.

The research

8 studies naming Fish Oil and Naproxen.

Strongest relevance first: papers naming both substances in the title, then human trials and systematic reviews.

Dietary omega-3 fatty acid supplementation and naproxen treatment in patients with rheumatoid arthritis.

The Journal of rheumatology · 1992 · PMID 1464864

Clinical TrialRandomized Controlled Trial67 participants

“However, for duration of morning stiffness the deterioration was significantly less pronounced in Group 3 compared with Group 1. These effects might be ascribed to the dietary omega-3 fatty acid supplementation.”

Kjeldsen-Kragh et al. · From the abstract

Names both Fish Oil and Naproxen in its title.

Naproxen affects multiple organs in fish but is still an environmentally better alternative to diclofenac.

Aquatic toxicology (Amsterdam, Netherlands) · 2020 · PMID 32835849

Human subjects

“In summary, naproxen and diclofenac produce highly similar effects in fish but the environmental hazards and risks are clearly lower for naproxen. Hence, if there are concerns for environmental risks to fish with diclofenac, a substitution would be advisable when naproxen presents an adequate alternative from a clinical point-of-view.”

Näslund et al. · From the abstract

Names both Fish Oil and Naproxen in its title.

Chronic toxicity and endocrine disruption of naproxen in freshwater waterfleas and fish, and steroidogenic alteration using H295R cell assay.

Chemosphere · 2018 · PMID 29655108

Animal study

“The current detected levels of naproxen in ambient Korean rivers are far lower than the effective levels, however potential adverse effects cannot be ignored in some highly polluted areas. Endocrine disruption effects in fish warrant further investigation particularly for their ecological implications.”

Kwak et al. · From the abstract

Names both Fish Oil and Naproxen in its title.

The anti-inflammatory drugs diclofenac, naproxen and ibuprofen are found in the bile of wild fish caught downstream of a wastewater treatment plant.

Environmental science & technology · 2013 · PMID 23186122

Animal study

“None of the other studied compounds could be detected. The study shows that pharmaceuticals originating from wastewater treatment plant effluents can be traced to the bile of wild bream and roach living in a lake where diclofenac, naproxen, and ibuprofen are present as pollutants.”

Brozinski et al. · From the abstract

Names both Fish Oil and Naproxen in its title.

Fish oil supplementation in F1 generation associated with naproxen, clenbuterol, and insulin administration reduce tumor growth and cachexia in Walker 256 tumor-bearing rats.

The Journal of nutritional biochemistry · 2004 · PMID 15157942

Animal study

“In conclusion, chronic fish oil supplementation decreased tumor growth and partially recovered cachexia. This beneficial effect of fish oil supplementation was potentiated by treatment with naproxen plus clenbuterol plus insulin.”

Pinto et al. · From the abstract

Names both Fish Oil and Naproxen in its title.

Comparative in vitro hepatic clearances of commonly used antidepressants, antipsychotics, and anti-inflammatory agents in rainbow trout liver S9 fractions.

Aquatic toxicology (Amsterdam, Netherlands) · 2024 · PMID 39146846

Comparative StudyAnimal study

“Finally, we carried out intrinsic clearance assays with mixtures of diclofenac, ibuprofen, naproxen, levomepromazine, and sertraline to examine the impacts of EROD and BFCOD inhibitions on their in vitro CLINT in RT-S9. Our in vitro data suggests that the intrinsic clearances of ibuprofen, levomepromazine, and sertraline in rainbow trout can be significantly reduced as the result of P450 inhibition by pharmaceutical mixtures, whereas the clearances of diclofenac and naproxen…”

Pihlaja et al. · From the abstract

Names Fish Oil and Naproxen together in an interaction, co-administration, or pharmacokinetic context.

Limitations

What this evidence cannot tell you.

Search-based evidence indexes have real limits, and it is worth being explicit about them:

NutriStack

Track what you actually take.

NutriStack is a free iPhone app for organising a supplement routine: what you take, when, and what the published record says about it. Its exploratory interaction checker covers Fish Oil, Naproxen, and several hundred other substances.

The checker is a research and organisation tool, not a clinical decision aid, and its per-pair assessments are excluded from search until they pass claim-level review.

NutriStack is an informational and organizational tool, not a medical service, and not a substitute for professional advice. Always consult a qualified healthcare professional before starting, stopping, or changing any supplement or medication.