Cod liver oil has genuine benefits for skin health, backed by research spanning decades. Its unique combination of omega-3 fatty acids, vitamin A, and vitamin D gives it a broader nutrient profile for skin than standard fish oil supplements, and each of those components acts on the skin through different pathways. The evidence is strongest for reducing skin inflammation, offering modest UV protection, and supporting wound healing, though the size and quality of the studies vary depending on which skin condition you look at.
What Makes Cod Liver Oil Different from Regular Fish Oil
Cod liver oil and fish oil both supply omega-3 fatty acids, but that is roughly where the overlap ends. Regular fish oil is extracted from the whole body of oily fish and contains minimal vitamin D and vitamin A. Cod liver oil, as the name implies, comes specifically from the liver of cod, where fat-soluble vitamins concentrate. This means a single teaspoon of cod liver oil delivers meaningful doses of vitamin A (as retinol) and vitamin D alongside the omega-3s EPA and DHA.1The Journal of the American Board of Family Practice. Fish Oil versus Cod Liver Oil: Is Vitamin D a Reason to Go Back to the Future For skin, this matters because each of those nutrients influences skin biology through distinct mechanisms. It also means cod liver oil carries unique risks that pure fish oil does not, particularly around vitamin A intake, which we will get to later.
How Vitamin A in Cod Liver Oil Affects Skin
Vitamin A is arguably the most well-established skin nutrient in dermatology. Prescription retinoids (synthetic relatives of vitamin A) have been used for acne and photoaging for decades. The vitamin A in cod liver oil is preformed retinol, which the body converts into retinoic acid, the active form that interacts directly with skin cells. Retinoic acid regulates how quickly skin cells turn over, influences wound healing, and affects melanocyte activity in a dose-dependent way.2PubMed Central. Vitamin A in Skin and Hair: An Update In practical terms, adequate vitamin A supports your skin’s ability to repair itself, maintain an even tone, and shed dead cells at a healthy pace.
That said, the retinol in a standard serving of cod liver oil is far less concentrated than what you’d get from a prescription retinoid cream. You’re not going to replicate the effects of tretinoin by swallowing a teaspoon of cod liver oil. Where dietary retinol matters most is in preventing deficiency, which causes rough, dry skin and impaired healing. For people whose diets are low in vitamin A, the retinol in cod liver oil can fill a genuine nutritional gap.
Vitamin D and the Skin’s Immune Defense
Vitamin D’s role in skin goes beyond bone health. Your skin is actually one of the few organs that can synthesize vitamin D on its own when exposed to sunlight, and it also uses vitamin D to regulate its immune defenses. One of the better-understood pathways involves cathelicidin, an antimicrobial peptide that helps the skin fight off bacterial and viral invaders. The gene responsible for producing cathelicidin contains a vitamin D response element, meaning vitamin D directly switches on this line of defense.3PubMed Central. Vitamin d, the cutaneous barrier, antimicrobial peptides and allergies: is there a link? Researchers have identified the vitamin D pathway as a potential target for managing both infectious and inflammatory skin conditions.4PubMed Central. The vitamin D pathway: a new target for control of the skin’s immune response?
Low vitamin D status is common in northern latitudes, in people who wear extensive sun protection, and in those with darker skin. If you fall into any of those categories, the vitamin D in cod liver oil may meaningfully support your skin’s barrier function and its ability to fight infection. A systematic review found that oil-based vehicles produced the greatest rate of increase in blood vitamin D levels compared to other delivery forms, which suggests the fat in cod liver oil itself helps your body absorb the vitamin D it contains.5PubMed Central. Evaluation of vehicle substances on vitamin D bioavailability: A systematic review
Omega-3s and Skin Inflammation
The omega-3 fatty acids EPA and DHA are the workhorses behind most of cod liver oil’s anti-inflammatory effects on skin. In a mouse model of psoriasis-like skin inflammation, diets enriched with DHA increased levels of specialized pro-resolving mediators in the skin, molecules that actively help shut down inflammation rather than just blocking it. EPA-treated animals also showed lower levels of prostaglandin E2 in the skin, a compound that drives redness, swelling, and pain.6PubMed. Comparison of the dietary omega-3 fatty acids impact on murine psoriasis-like skin inflammation and associated lipid dysfunction This matters because chronic low-grade inflammation underlies many common skin problems, from acne to eczema to premature aging. By shifting the balance away from inflammatory signaling, omega-3s may address the root biology rather than just masking symptoms.
What the Evidence Says About Acne
Acne is one of the conditions most frequently discussed alongside fish oil and cod liver oil supplements, and the evidence here is interesting but messy. A pilot study of 13 people taking fish oil for 12 weeks found no statistically significant change in acne overall, but the individual responses varied wildly: eight people improved, four got worse, and one stayed the same. The people who improved tended to have moderate-to-severe acne at baseline, while three of the four who worsened had mild acne to begin with.7PubMed Central. Effects of fish oil supplementation on inflammatory acne An earlier case series of five people taking EPA with antioxidant nutrients reported improvements in inflammatory lesions and general well-being, but with only five participants and no control group, that barely qualifies as preliminary.8PubMed Central. Acne vulgaris, mental health and omega-3 fatty acids: a report of cases
The strongest acne data comes from a randomized, double-blind, controlled trial that tested both omega-3 fatty acids and gamma-linolenic acid supplements over 10 weeks. Both groups saw significant decreases in inflammatory and non-inflammatory acne lesions, along with reduced levels of the inflammatory marker interleukin-8 in skin biopsies. No serious side effects were reported.9PubMed. Effect of dietary supplementation with omega-3 fatty acid and gamma-linolenic acid on acne vulgaris: a randomised, double-blind, controlled trial That trial’s authors described omega-3s as a potential adjuvant treatment for acne, meaning something you’d use alongside conventional therapies, not as a standalone replacement.
If you have moderate-to-severe inflammatory acne, there is reasonable evidence that omega-3 supplementation could help. If your acne is mild or primarily non-inflammatory (blackheads and whiteheads without much redness), the benefit is less clear and, going by the pilot study data, could theoretically go either way.
Psoriasis and Omega-3 Supplementation
Psoriasis has a larger body of evidence behind fish oil supplementation than acne does. A review across 15 trials found moderate evidence of benefit, with 12 trials showing clinical improvement and 3 showing none.10PubMed Central. Diet and Psoriasis: Part 3. Role of Nutritional Supplements – Section: Fish Oil The studies varied in design and outcomes measured, but the overall trend favored supplementation. One controlled study found that patients taking an omega-3 supplement alongside topical treatment saw roughly double the improvement in a standardized psoriasis severity score compared to those using topical treatment alone. The supplement group also showed better outcomes for scalp lesions, itching, redness, and scaling.11PubMed Central. Study on the use of omega-3 fatty acids as a therapeutic supplement in treatment of psoriasis
Cod liver oil, specifically, has a potential additional edge over plain fish oil here because of its vitamin D content. Low vitamin D levels are common in psoriasis patients, and vitamin D analogs are already used as prescription topical treatments for the condition. Whether the amount of vitamin D in cod liver oil is enough to move the needle on top of topical therapy is uncertain, but the combination of omega-3s and vitamin D in a single supplement makes cod liver oil a logical choice for people managing psoriasis who want to explore supplementation.
Eczema and Early-Life Fish Intake
Eczema, or atopic dermatitis, is another inflammatory skin condition that may respond to omega-3 intake, though the most compelling data relates to prevention rather than treatment. A large observational study found that children who consumed fish at one year of age had a lower prevalence of eczema at age six. Among children who took cod liver oil more than four times per week at age one, the odds of having current eczema at six were about 30% lower compared to those who did not, even after adjusting for maternal diet, breastfeeding, and other factors.12PubMed Central. Fish Consumption at One Year of Age Reduces the Risk of Eczema, Asthma and Wheeze at Six Years of Age – Section: 3. Results
For adults already dealing with eczema, the evidence for fish oil or cod liver oil as a treatment is less clear-cut. The relationship between omega-3 intake and eczema seems to be more about immune system programming during early development than about calming existing flares. That does not mean supplementation is useless for adult eczema sufferers, but expectations should be tempered. If you are a parent wondering whether to give your young child cod liver oil, the eczema prevention data is one of the more encouraging reasons to consider it.
UV Protection and Skin Aging
One of the more surprising benefits of omega-3 fatty acids is their ability to raise the skin’s resistance to sunburn. A study in which participants took fish oil rich in omega-3s for three months found that the dose of UVB radiation needed to produce redness nearly doubled, rising from about 20 to about 34 units. The researchers attributed this partly to lower levels of prostaglandin E2 in the skin, an inflammatory mediator that drives the sunburn response.13PubMed. Dietary fish oil reduces basal and ultraviolet B-generated PGE2 levels in skin and increases the threshold to provocation of polymorphic light eruption A review of the broader literature concluded that omega-3s show potential to protect skin from both acute UV injury and chronic UV overexposure through multiple mechanisms.14PubMed. Omega-3 polyunsaturated fatty acids: photoprotective macronutrients
Animal research reinforces this picture. Mice deficient in omega-3 fatty acids developed significantly more skin barrier damage after repeated UV exposure than mice with adequate omega-3 status, including disrupted epidermal structure, a coarser outer skin layer, and abnormal cell turnover patterns.15PubMed. Omega-3 fatty acids mitigate skin damage caused by ultraviolet-B radiation Since cumulative UV damage is the primary driver of wrinkles, dark spots, and loss of elasticity, anything that raises your skin’s UV tolerance is, by extension, an anti-aging intervention.
To be clear, omega-3 supplementation does not replace sunscreen. The effect is modest compared to a good SPF product. But as a complement to external sun protection, the photoprotective effect of dietary omega-3s is genuinely supported by data.
Wound Healing
The use of cod liver oil for wound care goes back centuries, and modern research has at least partially validated the tradition. In a mouse study, wounds treated with a 25% cod liver oil ointment healed their surface layer in an average of about 9 days, compared to about 14 days for control wounds. New blood vessel growth, essential for supplying healing tissue with oxygen and nutrients, also appeared significantly faster in the cod liver oil group. When the researchers tested vitamin A alone at equivalent doses, it matched the healing speed of the full cod liver oil, suggesting that retinol is the primary active ingredient driving wound repair.16PubMed. Topical application of cod liver oil ointment accelerates wound healing: an experimental study in wounds in the ears of hairless mice
This is one area where topical application has stronger evidence than oral supplementation. Swallowing cod liver oil and applying it directly to a wound are fundamentally different delivery methods, and the wound healing data comes from the topical route. That said, adequate systemic levels of vitamin A and omega-3s also support healing from the inside, so oral supplementation is not irrelevant, just less directly studied for this purpose.
Skin Hydration and the Barrier
Your skin’s outermost layer functions as a waterproof barrier, and when it is compromised you lose moisture, feel dryness, and become more vulnerable to irritants. Omega-3 fatty acids are structural components of cell membranes throughout the skin, and there is reason to think supplementation can improve the barrier’s integrity. Two randomized, double-blind, placebo-controlled pilot studies of krill oil (another marine omega-3 source) found that supplementation significantly reduced transepidermal water loss while increasing skin hydration and elasticity compared to placebo.17PubMed Central. Krill oil supplementation improves transepidermal water loss, hydration and elasticity of the skin in healthy adults – Section: Results Though this specific trial used krill oil rather than cod liver oil, the active agents (EPA and DHA) are the same, so similar barrier-supporting effects are biologically plausible with cod liver oil.
People who notice their skin feeling drier or less resilient during winter months, or who live in arid climates, may find that an omega-3-rich supplement like cod liver oil provides a noticeable improvement in skin texture over weeks. This will not replace a good moisturizer, but it works from a different angle, building healthier cell membranes rather than coating the surface.
Topical Cod Liver Oil as an Antibacterial Agent
Beyond oral supplementation, researchers have explored topical formulations made from cod liver oil’s fatty acid extracts. Laboratory testing found that a 20% concentration of the fatty acid extract from cod liver oil showed good activity against several common skin-relevant bacteria, including Staphylococcus aureus, which is frequently involved in skin infections, wound infections, and eczema flares.18PubMed Central. Topical Formulation Comprising Fatty Acid Extract from Cod Liver Oil: Development, Evaluation and Stability Studies This is still in the early stages of development, but it points toward potential applications for cod liver oil derivatives as natural topical antibacterials, which could be useful for people looking to avoid antibiotic resistance issues with conventional topical treatments.
The Gut-Skin Connection
An emerging area of research links the gut microbiome to skin health, and omega-3 fatty acids appear to influence this relationship. Omega-3 supplementation has been associated with shifts in gut bacteria, particularly increases in butyrate-producing species and changes in the balance between major bacterial groups. These bacterial shifts are the opposite of the patterns seen in inflammatory bowel conditions, and they lead to greater production of short-chain fatty acids, compounds that help maintain the intestinal lining and regulate immune responses throughout the body.19PubMed Central. Impact of Omega-3 Fatty Acids on the Gut Microbiota Since systemic inflammation originating in the gut can manifest on the skin (a connection well-documented in conditions like rosacea and psoriasis), supporting a healthier gut environment through omega-3 intake may indirectly benefit skin as well. This pathway is harder to quantify than the direct effects on skin cells, but it adds another layer to why omega-3-rich supplements like cod liver oil seem to help inflammatory skin conditions.
Safety and the Vitamin A Question
The same feature that makes cod liver oil special for skin, its high vitamin A content, is also its most important safety concern. Vitamin A is fat-soluble, meaning excess amounts are stored in the body rather than flushed out. Chronic intake above the tolerable upper limit (about 10,000 IU per day for adults) can cause toxicity symptoms including dry, peeling skin, which is ironic given that people take it to improve their skin. More seriously, excessive vitamin A during pregnancy is linked to birth defects, so pregnant women need to be especially careful about dosing.
Different brands of cod liver oil vary enormously in their vitamin A content. Some deliver around 1,000 IU per teaspoon; others pack more than 4,000 IU. If you are already eating liver, taking a multivitamin, or using retinoid skincare products, you could push your total intake uncomfortably high without realizing it. Always check the label for the retinol (preformed vitamin A) content, and keep your total daily intake from all sources well below the upper limit.
Contaminant concerns also apply. As with any fish-derived product, cod liver oil can contain trace amounts of heavy metals and persistent organic pollutants, though reputable manufacturers test for and filter out these contaminants. Products that carry third-party purity certifications are a safer bet. Rancidity is another practical issue: omega-3 fatty acids oxidize easily, and oxidized fish oil may do more harm than good. Store your cod liver oil in a dark, cool place, and discard it if it smells strongly fishy or bitter.
A Long History in Dermatology
The idea of using cod liver oil for skin problems is far from new. As far back as 1849, a physician named Emery reportedly treated patients with lupus vulgaris, a form of skin tuberculosis, by giving them enormous doses of cod liver oil and claimed to have cured 74 patients.20JAMA. CALCIFEROL IN LUPUS VULGARIS By modern standards those claims are impossible to verify, and the doses described (about a liter per day) are not something anyone should attempt. But the historical record is a reminder that the dermatological use of cod liver oil predates modern nutrition science by over a century, and that physicians have been observing real skin responses to it for a very long time. What has changed is not the basic observation that cod liver oil helps skin, but our ability to identify which components are responsible and in what conditions they are most likely to work.