Fish oil supplements, rich in omega-3 fatty acids EPA and DHA, are widely used to support skin health in the UK. These essential fatty acids help maintain skin barrier function and may modulate inflammatory processes in conditions such as psoriasis and atopic dermatitis. Whilst fish oil is available over-the-counter, evidence for its dermatological benefits remains mixed, and it is not licensed by the MHRA for treating skin disorders. The NHS recommends obtaining omega-3s primarily through dietary sources, particularly oily fish. This article examines the evidence-based benefits, safe usage, and important precautions surrounding fish oil supplementation for skin health.

What Is Fish Oil and How Does It Support Skin Health?

Fish oil is a dietary supplement derived from the tissues of oily fish such as mackerel, salmon, sardines, and anchovies. It is particularly rich in omega-3 polyunsaturated fatty acids, primarily eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These long-chain omega-3 fatty acids are formed inefficiently in the body from alpha-linolenic acid (ALA) and are primarily obtained from oily fish in the diet.

Omega-3 fatty acids play a role in maintaining skin barrier function and regulating inflammatory processes. EPA and DHA are incorporated into cell membranes throughout the body, including keratinocytes and other skin cells, where they influence membrane fluidity and cellular signalling. The anti-inflammatory properties of omega-3s are particularly relevant to skin health, as they can modulate the production of pro-inflammatory mediators such as prostaglandins and leukotrienes.

The skin barrier, composed of lipids, proteins, and corneocytes, relies on adequate fatty acid content to maintain its integrity and prevent transepidermal water loss. When omega-3 levels are low, the skin may become more susceptible to dryness, inflammation, and impaired healing. Fish oil supplementation aims to increase omega-3 intake by providing a concentrated source of EPA and DHA.

Whilst fish oil is widely available as an over-the-counter supplement in the UK, it is important to recognise that it is not classified as a medicine by the MHRA for dermatological indications. The NHS recommends eating at least one portion (140g) of oily fish per week as part of a balanced diet. The evidence supporting fish oil use for skin conditions varies in quality and strength, and patients should maintain realistic expectations about potential benefits. Fish oil should be viewed as a complementary approach rather than a primary treatment for diagnosed skin disorders.

Evidence-Based Benefits of Fish Oil for Skin Conditions

Research into fish oil's effects on skin health has focused on several dermatological conditions, though the evidence base remains mixed and generally of low certainty. For inflammatory skin conditions, omega-3 supplementation has shown some promise, particularly in conditions characterised by excessive inflammation.

Psoriasis has been the subject of multiple studies examining fish oil supplementation. Some clinical trials have demonstrated modest improvements in scaling, erythema, and pruritus when fish oil is used as an adjunct to conventional therapy. The proposed mechanism involves EPA competing with arachidonic acid in inflammatory pathways, potentially reducing the production of pro-inflammatory eicosanoids. However, systematic reviews indicate that whilst some patients may experience benefit, the effects are generally modest and variable. Neither NICE guidance (CG153) nor British Association of Dermatologists guidelines recommend fish oil as a treatment for psoriasis.

Atopic dermatitis (eczema) research has yielded inconsistent results. Whilst the theoretical rationale is sound—omega-3s may help restore skin barrier function and reduce inflammation—clinical trials have not consistently demonstrated significant improvements in eczema severity scores. Some studies suggest potential benefits in reducing disease severity or topical corticosteroid use, but others show no significant effect. NICE Clinical Knowledge Summaries for atopic eczema do not include omega-3 supplements in management recommendations.

Photoprotection represents another area of interest. Laboratory studies suggest that omega-3 fatty acids may offer some protection against UV-induced skin damage by reducing inflammatory responses and oxidative stress. However, this evidence is limited to small studies, and fish oil supplementation should never replace appropriate sun protection measures such as sunscreen, protective clothing, and following NICE guidance on skin cancer prevention.

Acne vulgaris has been investigated in smaller studies, with some suggesting that omega-3 supplementation may reduce inflammatory lesions, though evidence remains preliminary. NICE guideline NG198 on acne management does not include omega-3 supplements among recommended treatments.

For general skin hydration and ageing, observational data suggests an association between higher omega-3 intake and improved skin barrier function and reduced signs of photoageing, though robust interventional studies are limited. These associations should not be interpreted as proving causality.

How to Use Fish Oil Supplements Safely for Skin

When considering fish oil supplementation for skin health, patients should approach it systematically and safely. Dosage considerations vary, but typical supplements contain 250–1000 mg of combined EPA and DHA per capsule. For general health, the NHS recommends eating at least one portion of oily fish weekly (approximately 140g per portion) to provide adequate omega-3 intake for most people.

There is no established UK-recommended dose of fish oil specifically for skin health. If choosing to supplement, patients should follow the dosage instructions on product labels. Some studies investigating inflammatory skin conditions have used higher doses (2–4 grams daily), but such amounts are not licensed for skin conditions and should only be taken under medical supervision, particularly for individuals on anticoagulant medications.

Quality and purity are important considerations when selecting fish oil supplements. In the UK, look for products that:

• Display clear EPA and DHA content per serving

• Have been tested for contaminants such as heavy metals, PCBs, and dioxins

• Carry quality assurance marks or third-party testing certification

• Are stored appropriately to prevent oxidation (in dark, cool conditions)

Timing and administration can affect tolerability. Taking fish oil capsules with meals may reduce gastrointestinal side effects and improve absorption. Some individuals find that refrigerating capsules or choosing enteric-coated formulations minimises fishy aftertaste or reflux.

Patients should be aware that benefits, if they occur, develop gradually. Unlike topical treatments that may show effects within days, oral omega-3 supplementation typically requires several weeks to months of consistent use before any skin improvements might be noticed, and responses vary considerably between individuals.

Before starting supplementation, patients with existing skin conditions should consult their GP or dermatologist, particularly if they are already receiving treatment. Fish oil should complement, not replace, evidence-based therapies recommended by healthcare professionals. Those with fish allergies should avoid fish oil. People with shellfish-only allergies may be able to use fish oil products that are free from shellfish proteins (check product labelling). Algae-based omega-3 supplements provide an alternative source of DHA and EPA for those who cannot take fish oil.

Potential Side Effects and Precautions

Whilst fish oil is generally well-tolerated, patients should be aware of potential adverse effects and important precautions. Common side effects include:

• Gastrointestinal symptoms: fishy aftertaste, reflux, nausea, loose stools, or abdominal discomfort. These are usually mild and can often be minimised by taking supplements with food or switching to enteric-coated preparations.

• Fishy breath or body odour: occasionally reported, particularly with higher doses.

• Mild bleeding tendency: omega-3 fatty acids have antiplatelet effects, which may slightly prolong bleeding time, though clinically significant bleeding is rare at standard supplemental doses.

Drug interactions require careful consideration. Fish oil may enhance the effects of anticoagulant and antiplatelet medications, including warfarin, aspirin, clopidogrel, and direct oral anticoagulants (DOACs). Patients taking warfarin should have their INR monitored when starting or stopping fish oil supplements. All patients on anticoagulants should consult their GP before starting fish oil supplementation, as additional monitoring may be necessary.

Individuals with fish allergies should avoid fish oil supplements. Those with shellfish allergies may be able to take fish oil products that are specifically labelled as free from shellfish proteins, but should check product information carefully. Algal-based omega-3 supplements provide an alternative for those who cannot take fish oil.

Pregnancy and breastfeeding considerations are important. Whilst omega-3 fatty acids are beneficial during pregnancy for foetal development, pregnant women should avoid high-dose supplements and fish oil derived from fish liver (such as cod liver oil) due to excessive vitamin A content, which may be harmful to the unborn baby. The NHS advises pregnant women to avoid shark, swordfish and marlin completely, limit oily fish to two portions weekly, and restrict tuna intake (no more than two tuna steaks or four medium-sized cans per week). Women who are breastfeeding should also limit oily fish to two portions weekly.

When to seek medical advice: Patients should contact their GP if they experience:

• Unusual bruising or bleeding

• Severe gastrointestinal symptoms

• Allergic reactions (rash, swelling, breathing difficulties)

• Worsening of existing skin conditions despite supplementation

It is important to emphasise that fish oil supplementation should not delay appropriate medical assessment for skin conditions. Persistent or worsening dermatological symptoms warrant professional evaluation to exclude conditions requiring specific medical treatment. Fish oil may serve as a complementary approach within a broader skin health strategy that includes appropriate skincare, sun protection, and evidence-based medical therapies when indicated.

Suspected adverse reactions to fish oil supplements should be reported through the MHRA Yellow Card Scheme (yellowcard.mhra.gov.uk).

Frequently Asked Questions