Last updated 4/3/2024
Does fish oil actually work?
Omega-3s from fish oil work better for depression than a placebo. The difference in improvement between fish oil and placebo isn’t very big, but it isn’t for antidepressants either — because placebos work pretty well. As long has you’ve got good hope and some confidence that what you’re taking is going to help, it’s got a good chance to do so. Fish oil pills are better than that. They work for anxiety too.
So, should you try omega-3s from fish oil before an antidepressant like bupropion/Wellbutrin or fluoxetine/Prozac? You could get several different answers depending on who you ask. The answer probably depends on your interpretation of risks, more than benefits, which may not be very different.
Omega-3s or an antidepressant? It’s about risks.
If potential for improvement is about the same, or close, then choosing between fish oil pills and prescription antidepressant pills is based on comparing their short-term and long-term risks. I’ve presented my version of antidepressant risks, which is relatively “conservative” (presenting the risks rather strongly).
More information about antidepressant risks? At one end of a spectrum of opinions, you’ll find sites that don’t say much or anything about withdrawal and sexual side effects, e.g. this one from the Mayo Clinic. At the other end of the spectrum, very firm “anti-antidepressant” views can found in essays on the Mad in America site. Here’s a responsibly written example. The truth is probably somewhere in the middle between these rather opposite presentations of antidepressant safety. Guidelines for the British National Health Service describing the process of getting off antidepressants present a balanced look at this problem.
Fish oil side effects and risks
“Fish burps” are the most common side effect. Combat these by keeping your pills in the refrigerator between doses. If that doesn’t work, put them in the freezer.
Risks? Nearly zero. That’s the key point about fish oil. Nearly zero risk. (There is a single case report of fish oil causing hypomania but since I can’t find even one more case report I think this concern should be dismissed.)
Got it? Okay, a few details. Fish oil does not increase the risk of bleeding, including having a bleeding-related stroke. You’ll find other sites saying bleeding is a risk. That’s because fish oil “decreases platelet aggregation”: the clot-making blood fragments, platelets, are a little less likely to stick together. This is a laboratory finding, yes. But there are no studies showing an increased incidence of bleeding-related stroke in people taking fish oil supplements. In other words, this is not a “clinically demonstrated risk”.
A 30-minute literature search just now (1/19/2024) for other risks turned up no other clear concerns. You see what I mean about “nearly zero”? Unless there’s a reason to hurry (which for severe depression there might be), why not start with a treatment that has basically no risk? If it doesn’t work, then you can move on.
What dose? What kind?
Some researchers have concluded that certain versions of fish oil work better than others. Following their recommendations makes choosing a fish oil brand more complicated. But you might say “hey, if’ I’m going to do it, might as well use the version most likely to help.” If so, here’s the recommendation: find a fish oil that has twice as much EPA as DHA (those initials explained in a moment), and take at least 750 mg per day of EPA (the DHA part doesn’t count toward this 750 mg).
What are EPA and DHA?
EPA is an abbreviation of eicosapentaenoic acid, one of the two main types of omega-3 fatty acids. The other is DHA, docosahexaenoic acid. These are not “acids” except in the chemical sense. They are simply two forms of the healthy fats one finds in various foods and in our own bodies.
For some reason (unknown, as far as I can tell) EPA seems to have more of an effect on mood than DHA. This has been found in most studies of fish oil (not quite all).
Further detail if you’re interested: here’s an example. Treating hepatitis C infection with interferon commonly causes depression (an interesting story itself). But when people were given EPA for two weeks before interferon began, only 10% became depressed, versus 30% who received placebo pills. DHA didn’t work (28% became depressed).
How long does it take to work?
Same as antidepressants: it can start to show some benefit in as little as a week, but for most people, it can take several weeks to really show improvement on fish oil. And, just like antidepressants, to really give it a fair trial takes at least 4 weeks. Preferably 6 weeks, and best 8 weeks if you can wait that long while taking something you are increasingly sure is not working.
Okay, I’m interested. Give me the details.
Dose: least 750-1000 mg per day of EPA. Your goal is to find that amount in a fish oil that has twice as much EPA as DHA. In two pills per day. At a fairly low cost.
Choosing a fish oil
Here are the steps. Then I’ll provide some examples.
- Look at the back of the bottle. How much DHA? Double that amount. Is that total less than the amount of EPA? If yes, then that fish oil is a candidate. (This math means that the ratio of EPA to DHA is 2-to-1 or more — good)
- Next step: how many pills per day? Look at the top of the label. Most often the amount of EPA and DHA is shown for two pills per day. If the amount of EPA is over 750 mg with the two pills, fine. If it’s less, move on. Your goal is two pills per day.
- Cost per day? Here’s the math. Divide the cost of one bottle by the number of pills in the bottle. Then multiply by two.
Examples
I put “fish oil” in Google. The first product listed, GNC Triple Strength, has 730 mg of EPA at two pills per day. Not quite 750 mg as recommended. So move on.
Next up, Viva Naturals, has 1400 mg of EPA and 480 mg of DHA (that’s in 2 pills/day). Doubling the DHA would be 960 mg, which is less than the 1400 of EPA, so this is a candidate. Now, cost: $55/bottle divided by 180 pills/bottle times 2 pills per day, or 55/180 x 2 = $.61/day. Sixty-one cents/day.
Thorne Super EPA has 1300 mg of EPA and 320 mg of DHA. Doubling DHA would be 640 mg, which is less than the 1300 mg of EPA, so this is also a candidate. Now, cost: $91/bottle divided by 60 pills/bottle times 2 pills per day, or 91/60 x 2 = $3/day. Wow, what a difference.
Nordic Naturals: Nope, EPA 650, DHA 450. Doubling the DHA would be 900, which is more than the 650 of EPA, so this is not a candidate.
California Gold, how quaint. Nope: EPA 300, DHA 240. Live Conscious, charming. Nope: EPA 800, DHA 600. Sports Research: nope, can’t even read the numbers. Dr. Tobias: nope, EPA 1300, DHA 860. Nature’s Blend: nope, they don’t break down EPA and DHA values.
Ah, here’s one, OceanBlue Professional: EPA 1300, DHA 600. Cost: $45/180 pills times 2 pills per day equals $.50. Fifty cents a day.
When you read this, the numbers will have changed. Or you’ll find other fish oil versions in your local market. Remember the math. You can do it standing right there in the grocery, yes you can.
Does fish oil go bad?
If you start down this rabbit hole, you’ll find videos and essays saying that fish oil can go “rancid” (ick, awful term, sounds terrible doesn’t it? Oxidation is the more neutral term). They suggest you check the bottle labels for expiration dates, and that the bottle should be dark colored to prevent oxidation. Okay, wait a minute, show me some evidence.
There’s a 2015 study that says 80% of products on the shelf are oxidized. But this study was followed by a series of others (example) that found basically the opposite: fish oil oxidizes at about the same rate as other oils you have in your cupboard. Don’t believe everything you read or see on the internet, right? (including from me. When I mention something controversial, I’ll link research data where possible).