How to Read a Supplement Label: Certificates of Analysis, Standardised Extracts, and Red Flags to Avoid

31 August 2026 6 min read

If you've read the other guides in this series — on oregano oil, black seed oil, garlic, turmeric/curcumin, and black pepper extract — you'll have noticed the same theme repeat: the ingredient name on the front of the label tells you almost nothing on its own. This guide pulls that theme together into one practical checklist for reading any supplement label, botanical or otherwise, and spotting the marketing red flags worth avoiding.

This article is educational, not medical advice. It's intended to help you evaluate supplement labels and marketing claims, not to diagnose, treat, or advise on any health condition. Speak to a pharmacist or GP about any supplement you're considering, especially if you're pregnant, breastfeeding, on medication, or have a health condition.

Why the ingredient name isn't enough

Across oregano oil, black seed oil, garlic, turmeric, and black pepper, one pattern holds true: the active compound researchers actually study (carvacrol, thymoquinone, allicin, curcumin, piperine) can vary enormously in concentration between two products with the exact same ingredient name on the label. A bottle that just says "oregano oil" or "turmeric" without any further detail could contain a well-standardised, tested extract — or a weak, inconsistent one. There's no way to tell from the name alone.

That's the gap a certificate of analysis and standardisation are meant to close.

What is a certificate of analysis (CoA)?

A certificate of analysis is a document, usually from an independent (third-party) lab, confirming what's actually in a specific batch of a product — potency of key compounds, purity, and often screening for contaminants like heavy metals, pesticides, or microbial contamination. It's the difference between a company's marketing claim and an outside party's verification.

What to look for:

Is it from an independent, accredited lab — not just the manufacturer's own in-house testing?
Does it match the specific batch you're buying, or is it a generic document used for every batch regardless of actual test results?
Is it available to you — either published on the product page or provided on request? A company confident in its product usually makes this easy to find.

A product that doesn't offer any form of testing documentation isn't necessarily poor quality, but it does mean you're taking the label on trust alone.

What does "standardised extract" actually mean?

"Standardised" means a manufacturer has processed an ingredient so that a specific active compound is guaranteed to be present at a consistent, stated level in every batch — for example, "92% carvacrol" or "95% curcuminoids." This matters because raw plant material varies naturally: two batches of the same plant, grown in different conditions or harvested at different times, can have meaningfully different compound levels.

Standardisation is what allows:

Consistent dosing — you get roughly the same amount of the active compound every time, not a random amount depending on the batch.
Meaningful comparison between products — a stated percentage lets you compare two "oregano oil" products directly, where an unstandardised one gives you nothing to compare.
A CoA to actually mean something — testing only makes sense in reference to a stated standard.

Marketing red flags worth knowing

Having looked at five botanical ingredients in this series, some consistent red flags stand out:

Claims that a supplement "boosts immunity," "fights infection," "cures," "treats," or "prevents" any illness. Under UK and EU law (the GB Nutrition and Health Claims Register), these are not authorised claims for the botanical ingredients covered in this series. A company making them is not following the rules that apply to every legitimate supplement seller — treat it as a compliance red flag, not a selling point.
No stated potency or standardisation — just an ingredient name with no percentage, dose, or specification.
No testing information available, and no willingness to provide it on request.
Proprietary blends that hide individual ingredient amounts. If a "blend" lists several ingredients under one combined weight with no individual breakdown, you can't tell how much of any single ingredient you're actually getting.
Urgency-driven sales tactics (fake countdown timers, "doctors don't want you to know this") that are more common in low-quality supplement marketing than in companies focused on product transparency.

What honest, compliant marketing looks like instead

A supplement seller following the rules will typically:

State what the ingredient traditionally has been used for, without implying it treats or prevents disease.
Reference the traditional/culinary history of an ingredient as historical context, not as proof of effect.
Be specific about standardisation (percentages, milligram doses) and back it up with testing.
Include a clear disclaimer that the product is a food supplement, not a medical treatment.
Point you toward talking to a pharmacist or GP, particularly around interactions with medication.

This is a deliberately less exciting way to market a supplement than the red flags above — but it's the version that's actually compliant with UK/EU regulations, and arguably a better signal of a company that will still be standing behind its product a year from now.

A quick checklist before you buy

Does the label state a specific compound and percentage/dose (not just an ingredient name)?
Is there a certificate of analysis available, from an independent lab, matching the batch?
Does the marketing avoid disease-treatment or "boosts immunity" language?
Is the format and dosage clearly explained, with a sensible serving size?
Is there a clear disclaimer and guidance to speak to a healthcare professional?

If a product ticks most of these boxes, you're looking at a company that's treating its label as a technical document, not just a sales pitch.

The bottom line

Across every ingredient in this series, the pattern is the same: the name on the label is the least useful piece of information on it. Standardisation, third-party testing, and compliant, non-exaggerated marketing tell you far more about what you're actually buying than the plant name on the front of the box.

ImmuneShield Complex is formulated with 92% carvacrol oregano oil, black seed oil, garlic, turmeric, and black pepper (piperine) in a single softgel, tested for potency. View the product details and full ingredient breakdown →

FAQ

Is a certificate of analysis the same as FDA or MHRA approval?

No — a CoA is a lab's confirmation of what's in a specific batch. Food supplements aren't approved by regulators the way medicines are; a CoA is a transparency and quality measure, not a regulatory approval.

Why can't supplement companies say their product "boosts immunity"?

Under the GB Nutrition and Health Claims Register, only specific, scientifically authorised claims can be made about food ingredients. General immune-boosting or disease-related claims haven't been authorised for the botanical ingredients covered in this series, so making them is a compliance breach, not a legitimate marketing choice.

Does a higher price mean a better-tested product?

Not necessarily — price alone isn't a reliable signal. Checking for standardisation and available testing documentation is a more direct way to judge quality than price.

Should I always ask a pharmacist before starting a new supplement?

It's good practice, particularly if you take any regular medication, are pregnant or breastfeeding, or manage a health condition — several of the ingredients discussed in this series can interact with common medications.