Seven Bottles of the Same Oil

A lab bought seven black seed oils and measured what was actually inside them. The results were not close. This is why nobody caught it, and why nobody had to.

By Antonio · Black Forest Supplements

COREWhat it has to say: Two bottles that look identical can differ by 96% inside, and you cannot see it.
Alt text: Two identical backlit amber bottles, one dense with gold oil and one nearly clear

Two people buy black seed oil on the same afternoon in different cities. The bottles make the same promise on the front. They sit at close to the same price.

One of them takes home 77.5 milligrams of the active compound per serving. The other takes home 2.7 milligrams. That is 96% less, out of a bottle making the same claim.

Both of those numbers are real, and a lab published them in January 2025. Neither shopper will ever learn which bottle they carried home. The label does not print the number, the store cannot look it up, and no rule anywhere required a single person in that supply chain to check.

What the lab actually measured

COREWhat it has to say: Somebody finally measured seven of them, and the spread was enormous.
Alt text: Seven sample vials in a row grading from deep amber to almost colorless

In January 2025, the independent testing service ConsumerLab bought seven black seed oil products the way a shopper would and measured the thymoquinone in each one.

Thymoquinone is the part of the seed that the research is about. When a study reports something interesting about black seed, thymoquinone is almost always the compound doing the work. It is also the part that is easy to lose. It sits in the oil in tiny amounts, it breaks down when it meets heat and light, and it cannot be seen or tasted by the person holding the bottle.

Here is what seven bottles of the same product looked like from the inside:

• The strongest product carried 77.5 mg of thymoquinone in a serving (ConsumerLab, January 2025).
• The weakest carried 2.7 mg, which is 96% less than the strongest.
• Two of the seven held less than their own labels claimed. One of them delivered 41.8% of what it promised, so a shopper following the label got about 42% of what they paid for.

Nothing in that list is illegal. That is the part worth sitting with.

It was not one unlucky test

If this were a single bad sample, it would be a story about one company. It is not.

In 2022 a research group published a screening study in the journal Nutrients that did the same exercise on a larger scale, measuring thymoquinone across eleven commercial black seed products: six bottled oils and five capsule products.

• Thymoquinone content ran from 3.08 to 809.4 mg per 100 g of product, so the weakest product held 99.6% less than the strongest (Nutrients, 2022;14(17):3501).
• Even the strongest of the eleven was only 0.81% thymoquinone by weight, which is the whole problem in one number. The compound the research is built on is under 1% of what is in the bottle, so small losses in handling erase most of it.

The authors did not soften their conclusion. They wrote that black seed products "should be regulated regarding TQ content to enable consumers to buy black seed food supplements of known content."

That is a group of researchers, in a peer-reviewed journal, asking for the exact thing a shopper assumes already exists.

Why this oil, of all oils

SECONDARYWhat it has to say: The cheapest way to press is the fastest way to destroy the compound people are buying it for.
Alt text: Hot oil running from an industrial press beside scorched black seeds

Follow one bottle backward and you can see where the number goes missing.

It starts in a field, where the amount of thymoquinone in the seed depends on the variety planted, the soil, the weather that year, and when it was harvested. Two honest farms can hand over two different seeds.

Then the seed gets pressed. Press it fast and hot and you get more oil per ton, which is what a buyer paying by volume wants. Heat is also the thing thymoquinone survives least well, so the cheapest way to press is the fastest way to destroy the reason anyone wanted the oil.

Then it sits. In a drum, in a warehouse, in a truck, in a bottle, in a store, in a cabinet. Every week of that is a week of exposure.

And at every one of those steps, a cheaper liquid waits that looks identical. This is where the economics turn ugly, because the oils used to stretch black seed oil cost only about 3% to 10% of what the real thing costs. A clear, faintly dark, oily liquid is the easiest product in the world to quietly dilute.

The fraud is documented, not theoretical

SECONDARYWhat it has to say: Filler oils cost a fraction of the real thing, so the dilution pays for itself.
Alt text: Pale filler oil poured into dark oil, the boundary still visible

I am not guessing about the dilution. In September 2022 the Botanical Adulterants Prevention Program, a joint effort of the American Botanical Council, the American Herbal Pharmacopoeia and the University of Mississippi's National Center for Natural Products Research, published a bulletin devoted to this one crop.

It names the oils used to cut black seed oil: palm, corn, sunflower, soybean and canola. It reports that whole black seed gets padded with the seed of a different plant, Nigella damascena, which is close enough in size and color to pass a glance. And it says plainly that some products on sale contain no black seed content whatsoever.

• Those filler oils cost roughly 3% to 10% of what real black seed oil costs, which the bulletin names outright as the financial motivation for the fraud (BAPP bulletin, Orhan, September 2022).

To be fair to the bulletin, it does not claim to know how widespread this is, and neither do I. Nobody is counting. Nobody is counting, and the fact that nobody is counting is part of the problem.

Even an honest bottle fades

SECONDARYWhat it has to say: The number measured at bottling is not the number in the bottle you open months later.
Alt text: Four identical bottles receding on a dusty shelf, the oil paling with distance

Suppose the farm was careful, the press was cold, and nobody diluted anything. The number still moves.

A 2023 study in Plants followed cold-pressed black cumin oil through four months of storage and tracked what happened to it. The oil's acidity climbed from 10.26% at extraction to 16.96% after four months, and measurable changes had appeared in its peroxide levels and even its smell (Plants, 2023;12(6):1351).

That test was run at 4 degrees Celsius. The oil was refrigerated the entire time, and it still drifted. Your bottle was not refrigerated on the truck.

So the number printed at bottling, if it was ever measured, is not the number in the bottle you open in month nine. Any test that means anything has to happen on the finished, filled bottle rather than on a drum of raw oil that has not yet had its hard months.

The part that changed how I saw it

COREWhat it has to say: Nobody is breaking a rule, because nobody was ever required to check. The absence is the argument.
Alt text: An empty stool at a dust-covered inspection bench, the instrument powered down Retry note: Hardest concept in the set and the most likely to need retries. If Gemini populates the frame with a person, add: absolutely no people, no figures, no hands, no silhouettes anywhere in the image.

I went into this assuming somebody was breaking a rule. Some corner being cut, some inspection being dodged, some line being crossed by people who knew better.

I was wrong, and the truth is worse than the version I had in my head.

Under the law that governs this entire category, the Dietary Supplement Health and Education Act of 1994, no supplement needs approval before it goes on sale. There is no agency reading the file and signing off. A company can formulate a product on Monday and sell it on Friday, and the first time any regulator looks closely is usually after somebody has already been hurt.

Manufacturing rules do exist, and they require a company to set specifications and confirm it hit them. Read that sentence carefully, because everything lives in it. The company sets its own specification. Nothing obligates that specification to include thymoquinone at all. A brand can declare "1,000 mg black seed oil" on the panel, verify that there is a gram of oil in there, and be entirely in compliance while having never once measured the compound the customer is buying the oil for.

And if a company does measure it, nothing requires them to show you. A Certificate of Analysis is a document you have to know to ask for.

So the honest description of this category is not that the rules are being broken. It is that the law makes each company its own examiner, never requires the exam to cover the thing that matters, and never requires anyone to publish the grade.

It is not a conspiracy. It is worse than one, because a conspiracy needs people to cooperate. This needs nobody to do anything at all.

This is bigger than one oil

If you think a gap this size would surely get caught by somebody, the record does not support the optimism.

• In 1977 the first federal dietary goals were softened after industry pressure, and in the decades that followed obesity and type-2 diabetes both doubled.
• Artificial trans fats were linked to an estimated 250,000 heart attacks and 50,000 deaths a year in the United States, and were not removed from the food supply until 2018, more than 25 years after the evidence was solid. The removal is projected to prevent roughly 90,000 deaths a year.
• When researchers went back and bought supplements the FDA had already recalled for containing banned pharmaceuticals, two thirds of the ones still for sale six months later were still adulterated (Cohen et al., JAMA, October 2014, 27 products tested).
• In 2015 the New York Attorney General had store-brand herbal products from four national retailers DNA tested. Only 21% of the results confirmed the plant named on the label. At one retailer, 4% did.

Two honest notes on that last one, because I would want them if I were reading this. The DNA method used has real limits on heavily processed extracts, and the industry said so loudly at the time. And Cohen's team tested 27 products, not thousands. Neither finding is the whole picture. Both tell you the same thing about how long a problem can sit in plain view before anyone with authority moves.

What you can actually do about it

COREWhat it has to say: One question does the work: show me the result for the finished bottle.
Alt text: One hand offering a single sheet of paper across a dark counter to another

This is the part I would want handed to me, so here it is with no product attached.

Stop reading the front of the bottle. The front is marketing and it is the least regulated surface on the package. Turn it around and read the panel, and notice whether the compound you are buying the product for appears there as a number at all. For most black seed oils, it does not.

Then ask the company one question: can I see a Certificate of Analysis for the finished bottle, not the raw batch? That single sentence does more work than any label claim. A company that tests and publishes will send it without hesitating. A company that does not test will change the subject to how premium their sourcing is. You will learn what you need to know from which reply you get.

Ask it of us too. That is the only version of this that is worth anything.

What we owe you

I am not going to use an article about verification to sell you something unverified, so this section is deliberately the shortest one here.

We decided to hold ourselves to the standard this article argues for: whole seed rather than mystery oil, a cold press to protect the compound instead of a hot one to maximize yield, identity confirmed on the seed we actually buy, and thymoquinone measured and declared as a number a customer can read. Tested on the finished bottle, because that is the only test the storage data respects. And published, because you should not have to take our word for the number.

There is nothing to buy today. Nothing is named and nothing is priced. The door opens next week, and when it does the people on our founding list go first, and that list closes the same day it opens.

You should be able to know what is in the bottle. That should be the floor of this industry rather than something a brand gets to advertise as a virtue. Until the law agrees, the only protection you have is asking the question, and the only thing we can do is answer it in writing.

One more thing before you go. Everything above is about measuring what is already in the bottle, and a measurement is only worth something if somebody acts on the result. On Friday I will show you what we built with these numbers in hand. Until then, the question in the section above works on any bottle you already own.

Sources

1. ConsumerLab, black seed oil product review, January 2025. Thymoquinone 2.7 to 77.5 mg per serving across seven products; two of seven under-labeled; one at 41.8% of claim.
2. Screening of Thymoquinone Content in Commercial Nigella sativa Products. Nutrients, 2022;14(17):3501. Eleven products; 3.08 to 809.4 mg per 100 g.
3. Orhan N. Adulteration of Nigella (Nigella sativa) Seed and Seed Oil. Botanical Adulterants Prevention Bulletin, ABC-AHP-NCNPR Botanical Adulterants Prevention Program, September 2022.
4. Quality Changes of Cold-Pressed Black Cumin, Safflower and Milk Thistle Seed Oils during Storage. Plants, 2023;12(6):1351. Acidity 10.26% to 16.96% over four months at 4 °C.
5. Cohen PA, Maller G, DeSouza R, Neal-Kababick J. Presence of Banned Drugs in Dietary Supplements Following FDA Recalls. JAMA, 22 October 2014. 27 products; 66.7% still adulterated.
6. Office of the New York State Attorney General, press release, 3 February 2015. DNA testing of store-brand herbal supplements at four national retailers; 21% of results verified the labeled plant.
7. Dietary Supplement Health and Education Act of 1994; FDA current good manufacturing practice regulations for dietary supplements, 21 CFR Part 111.
8. US Food and Drug Administration, final determination on partially hydrogenated oils, 2015, compliance date 2018.

These statements have not been evaluated by the Food and Drug Administration. This article is about product quality and labeling, and no product mentioned is intended to diagnose, treat, cure or prevent any disease. It is not medical advice.