Omega-3

Fish oil sits in an awkward place. The general health evidence is enormous and mostly about cardiovascular outcomes over decades. The sports performance evidence is much thinner and mostly about recovery.

Neither of those is the reason most lifters buy it, which is usually a vague sense that it is good for joints.

What the evidence actually supports

Three claims survive reasonable scrutiny.

Delayed-onset muscle soreness is modestly reduced. Pooled analyses of supplementation before unaccustomed or damaging exercise find small but consistent reductions in soreness and in circulating markers of muscle damage. Small is the operative word — you will not stop being sore.

Markers of inflammation come down. This is well established. Whether that translates into training you can measure is less clear, and there is a live argument about whether blunting the inflammatory response to training could blunt adaptation alongside it. Current evidence does not show that happening at normal doses.

Baseline cardiovascular and metabolic health is where the strongest long-term case sits, and it is the reason worth taking it that has nothing to do with the gym.

What is not well supported: meaningful direct gains in strength or hypertrophy in people who already eat adequate protein.

The dose, and the label problem

One to three grams of combined EPA and DHA daily.

This is where almost everyone gets it wrong, because the number on the front of the bottle is the weight of the oil, not the weight of the omega-3 in it. A typical “1,000 mg fish oil” capsule contains around 180 mg of EPA and 120 mg of DHA — 300 mg of what you are actually paying for.

Reaching 2 g of EPA plus DHA from that product means roughly seven capsules a day. Concentrated products get you there in one or two.

Turn the bottle over and add the EPA and DHA lines together. That is your dose. Everything else on the label is oil.

EPA, DHA and where to buy them

EPA is the one most associated with inflammatory signalling and with mood. DHA is structural — it is heavily concentrated in brain and retinal tissue.

For a lifter interested in recovery and joints, an EPA-weighted product is a defensible preference, but the effect of the ratio is far smaller than the effect of the total dose, and most people should not pay a premium for it.

Vegetarians and vegans should use algal oil. Fish do not manufacture omega-3; they accumulate it from algae, and going to the source works. ALA from flax and chia is not a substitute — the conversion rate to EPA is poor and to DHA is close to negligible.

Oxidation is the real quality issue

Long-chain polyunsaturated fats oxidise readily, and independent testing has repeatedly found products on shelves already rancid at the point of sale.

Oxidised fish oil is the likeliest explanation for the fishy repeat that people assume is normal. It is not normal. It means the product has degraded, and degraded oil is not doing what you bought it for.

Buy from a brand that publishes a peroxide value or a total oxidation number, check the manufacture date rather than just the expiry, and keep the bottle in the fridge. If capsules repeat on you, freezing them helps — but treat it as a signal to change product.

Why we grade it B

The evidence for general health is strong. The evidence for training outcomes specifically is real but modest, and the effect sizes for soreness are the kind you detect in a study rather than in your week.

That is a B: worth taking if your diet is short on oily fish, not worth expecting much from if it already is.

Side effects and who should skip it

• Fishy aftertaste and reflux, largely a sign of an oxidised product. Freeze the capsules or switch brands rather than pushing through it.
• Mild blood-thinning at high doses. Tell your surgeon before any procedure, and check with your physician if you already take an anticoagulant.
• Oxidised fish oil is common on shelves and is the one genuine quality risk here. Look for a third-party peroxide value or a recent manufacture date.