Cod liver oil

Why it matters

Cod liver oil is one of the oldest supplements in the Western world — spooned out to generations of children through dark winters — and unusually, the old wisdom lines up with current science. Its value for hormones rests almost entirely on vitamin D, which behaves less like a vitamin and more like a hormone in its own right. The cells that manufacture testosterone carry vitamin D receptors, and across population studies low vitamin D status tracks closely with low testosterone. In a country where the sun is too weak to make vitamin D in the skin for half the year, most people run low for months at a time — and cod liver oil is one of the few foods that delivers a genuinely meaningful dose in a single spoonful, with a large helping of omega-3 alongside it. That combination is precisely why it earns a place here.

What's inside

The three active components are unusually concentrated. Vitamin D — around 1,360 IU (34 µg) per tablespoon — is the co-factor your body needs to build testosterone and to keep bones, mood and immunity steady. Omega-3 fatty acids (roughly 2.5–3 g of EPA and DHA per tablespoon) lower the chronic, low-grade inflammation that muddies hormone signalling and support healthy blood flow. And vitamin A (retinol, ~4,080 µg RAE) supports vision, skin and immune function and plays a role in reproductive tissue — but it is also the reason cod liver oil must be used with a light hand, since vitamin A is fat-soluble and accumulates. This is a food where the dose is the whole story: one modest daily serving is a gift; several is a liability.

For men

For men, the appeal is the clean vitamin D–testosterone link. Where a genuine deficiency exists — extremely common in northern winters — restoring vitamin D is associated with healthier testosterone, and cod liver oil is among the most efficient dietary ways to do it. The omega-3s are a second, quieter win, linked to better sperm quality and motility and to lower inflammation. None of this is a drug-like surge; it is foundational support that lets your own production work as it should, particularly through the months when sunlight can't help you.

For women

For women, cod liver oil supports the whole hormonal picture rather than any single hormone. Vitamin D underpins bone strength, fertility, mood and immune balance — all areas that come under pressure through perimenopause and menopause — while the omega-3s are among the best-studied nutrients for easing period pain and steadying mood across the cycle. The one firm exception is pregnancy: because of its high vitamin A (retinol) content, cod liver oil is not recommended during pregnancy, where a pregnancy-specific omega-3 or vitamin D supplement is the safer route. Outside pregnancy, a modest daily dose is a sensible winter ally.

How to eat it

This is a supplement-style food, so treat it like one: one tablespoon of liquid oil, or the equivalent in capsules, once a day — ideally with a meal containing some fat, which improves absorption. A lemon or orange-flavoured oil masks the fishiness that puts people off. Take it consistently through the darker months, when your skin makes little or no vitamin D of its own. There is no benefit to doubling up, and real downside if you do.

Worth knowing

The vitamin A content is the single most important caveat on this page. Do not stack cod liver oil on top of a multivitamin or other retinol supplements without checking the combined total, and do not exceed the label dose — chronically high vitamin A can harm the liver and bones and is dangerous in pregnancy. If your main goal is simply omega-3 without the vitamin A load, a standard fish-oil or algae-oil supplement is a cleaner choice; if it's vitamin D specifically, a plain vitamin D3 supplement lets you control the dose precisely. Cod liver oil shines when you want a traditional, food-based hit of all three at once — used sensibly, and never during pregnancy.

Bottom line

Cod liver oil packs vitamin D, omega-3 and vitamin A into a single traditional spoonful — a genuinely useful winter ally for your hormones, provided you respect the dose and skip it in pregnancy.