By Jia, Certified Nutritionist since 2018 | Last reviewed: 13 October 2026
TL;DR: A supplement label tells you what a brand says is inside. It can’t tell you whether that’s true. In many markets, including Singapore, supplements aren’t independently checked against their labels before they’re sold. That’s why, when scientists test supplements against their labels, they keep finding products with far less, far more, or none of what’s claimed. Use the label for a quick check that the form and dose make sense. Then verify quality through third-party testing of the finished product, for both active ingredient content and contaminants such as heavy metals, microbes, and yeast and mould, and look closely at the manufacturer behind it.
Key takeaways
- A label is a claim made by the brand. No one independently verifies it before the product reaches you.
- Independent tests of NMN, melatonin, vitamin D and fish oil have all found many products that don’t match their labels.
- A label can’t tell you whether the ingredient is in the right form, whether the dose is actually in your capsule, what contaminants are present, or whether it was manufactured under the right conditions.
- “Clean” labels can mislead. Some ingredients that sound scary are there to keep the dose accurate in every capsule and protect the active ingredient, and a short ingredient list may simply mean the inactive ingredients weren’t declared.
- The label is still useful for checking form, elemental dose and serving size on paper. Verification has to come from testing.
In 2024, researchers from NUS Medicine and Temasek Polytechnic tested 18 NMN supplements sold in Singapore. 3 contained no NMN at all, 12 contained less than their label claimed, and only 3 contained the labelled amount or more.
In November 2025, Singapore’s Health Sciences Authority (HSA) warned the public about a herbal product sold as a traditional supplement. It was marketed as steroid-free, genuine and premium quality, yet HSA’s tests found two potent steroids and an anti-inflammatory painkiller inside.
Every word on that label was reassuring. None of it was true.
One case is a quality failure and the other is outright fraud, but in both, the label gave no warning. The same principle applies to every supplement you buy, including ours. I run a supplements factory in Ang Mo Kio, and the question I’m asked most is some version of “which one is better?”, usually while someone holds two bottles side by side and compares the labels. Here’s why that’s the wrong comparison, and what to look at instead.
A label is a promise, not proof
Everything printed on a supplement bottle, from the ingredient and dose to words like “pure” and “premium”, is written by the brand selling it. It tells you what the company intends you to get. It doesn’t tell you what’s actually inside, because printing a label doesn’t require anyone else to have checked the contents.
Who checks the label before you buy?
In many countries, including Singapore, the answer is no one. Here, health supplements don’t require approval and aren’t evaluated before they go on sale. The brand is responsible for the safety and quality of its own products, and the regulator steps in when it detects a problem. Before a product reaches the shelf, though, no one independently confirms that what’s inside matches the label.
HSA itself recognises how hard this is for consumers. In one alert it noted that you can almost never tell from the packaging whether a product has been adulterated.
What happens when scientists test supplements against their labels?
The NMN study above isn’t a one-off. Every time researchers check, they find the same pattern, across countries and ingredients:
- Melatonin gummies, US (2023): In a study published in JAMA, only 3 of 25 products were within 10% of their label. Actual melatonin content ranged from 74% to 347% of the stated amount.
- Melatonin, Canada (2017): Across 16 products, actual doses ranged from 17% to 478% of the label.
- Vitamin D, US (2013): Researchers tested 55 bottles from 12 manufacturers. Content ranged from 9% to 146% of the label, and pills from the same bottle varied from 52% to 135%.
- Fish oil, New Zealand (2015): Only 3 of 32 products contained at least the EPA and DHA stated on the label. Most exceeded recommended oxidation limits.
- Omega-3, North America (2015): Of 171 products tested, half exceeded voluntary recommended limits for oxidation.
Different countries, different ingredients, same conclusion: the label alone isn’t a reliable guide to what you’re getting.
One nuance worth knowing: a result above the label isn’t automatically a red flag. Many ingredients slowly degrade over time, especially in heat and humidity, so manufacturers often add a small, deliberate overage as a buffer against that loss. The real warning signs are large misses in either direction, and inconsistency from one capsule to the next.
Storage matters too. Keep supplements somewhere cool and dry, away from direct sunlight, and out of humid spots like the bathroom.
Four things a supplement label can’t tell you
1. Whether it’s the right ingredient, in the right form
The same ingredient name can hide very different things. Some products sold as magnesium glycinate are “buffered”, meaning part of the magnesium comes from a cheaper form such as magnesium oxide. In the worst cases, a product contains something that isn’t on the label at all. Ingredient identity can only be confirmed by testing, which is why we fingerprint our raw materials before they’re allowed into production.
2. Whether the dose is actually in your capsule
A raw material can be 99% pure and the finished capsule can still be wrong. Manufacturing decides how much ends up in each capsule: how evenly powders are blended, how accurately capsules are filled, and how well sensitive ingredients are protected during production. That’s how vitamin D pills from a single bottle can differ by more than double.
A supplier’s certificate for the raw powder tells you about the powder. Only a test on the finished product tells you about what you swallow.
3. What shouldn’t be in it
A label lists only what’s meant to be inside. It will never list heavy metals, microbial contamination, yeast and mould, pesticide residues or undeclared drug ingredients. These only show up when someone tests for them.
4. Whether it was manufactured under the right conditions
Many ingredients are sensitive to moisture, heat and air. NMN, for example, absorbs moisture and degrades quickly when exposed, which is why encapsulation has to be fast and done by machine. Whether a product was made in a clean, controlled environment, with proper processes and trained people, shapes its quality as much as the raw material does. None of that appears on a label. Look at the factory behind the product, and the certifications it holds.
The clean-label trap
Because labels are what people compare, labels have become marketing. Brands compete to look “clean” with claims like “no fillers”, “no additives”, “100% pure” and “natural”. Some of this is meaningful. A lot of it is designed to make you afraid of ingredients you don’t recognise, even when they’re there for a good reason.
Take flow agents like magnesium stearate and silicon dioxide. They’re used in tiny amounts so powder flows evenly into every capsule, which is part of how each capsule ends up with the same dose. Other ingredients, such as natural antioxidants added to oils, are there to protect the active ingredient from breaking down. Strip these out and the product can end up inconsistent, or degrade faster. “No fillers” can be a marketing win and a quality loss.
There’s another catch. Not every market requires inactive ingredients to be listed in full. So a short, clean-looking ingredient list doesn’t necessarily mean there’s nothing else inside. It may just mean the rest isn’t declared. And as the steroid case shows, ingredients can also be declared wrongly, or the label can be outright false. A clean-looking label is not the same as a clean product.
Fear-mongering works the same way. A recent example is the claim that NMN products are full of useless alpha NMN. It’s half true, because alpha NMN isn’t useful to us, but modern NMN production is designed to make beta NMN. Meanwhile, the problem independent testing actually keeps finding is products with too little NMN, or none at all.
“Natural” isn’t a guarantee either. HSA advises caution with products that market themselves as natural, and the steroid product above was sold as a traditional herbal remedy.
To be fair, some clean-label concerns are legitimate. Titanium dioxide, once common in coatings and capsules, was banned as a food additive in the EU in 2022. So the better question isn’t “does this ingredient sound scary?” It’s “why is it here, and does it need to be?”
So is reading the label pointless?
No. Use the label to shortlist, then use testing to verify. A label is genuinely useful for a quick check of:
- Form: magnesium glycinate vs oxide, vitamin D3 vs D2, ubiquinol vs ubiquinone.
- Elemental amount: for minerals, the weight of the compound isn’t the weight of the mineral. Our Calcium Glycinate lists 250mg of elemental calcium per serving, because that’s the number that counts.
- Serving size: check whether the stated dose is per capsule or per serving of several capsules.
- Proprietary blends: a single total weight for a “blend” hides how much of each ingredient you’re actually getting.
- Dose vs evidence: compare the dose with what was used in human studies.
What to ask a brand instead
- Is there a third-party test on the finished product, not just the raw material?
- Who does the third-party testing? Is it a credible lab, and is it truly independent?
- Does testing cover content (is the dose there?) and contaminants (heavy metals, microbes, yeast and mould)?
- How recent are the results, and which batch do they cover?
- Who makes it, and what certifications does the factory hold? Remember that GMP certifies the manufacturing system, not the contents of each bottle.
- Are reports published in full, or only “available on request”?
- Are you buying from the official store? A counterfeit can carry a perfect copy of the real label.
How we test at Estalife
We hold ourselves to the same questions. Here’s exactly what we test, and how often:
- Every raw material lot: identity confirmed in-house by FTIR fingerprinting on our Agilent system before release to production.
- New and high-risk raw materials: purity tested by an independent third-party lab (usually SGS or Eurofins) on the first lot, which becomes the reference fingerprint for every lot after.
- Every finished batch: third-party testing for heavy metals and microbial contamination.
- Finished-product content: third-party testing on representative batches once or twice a year, to confirm the dose on the label is in the capsule.
- Transparency: all reports are published unredacted on our website.
Our products are made in our family factory in Ang Mo Kio, Singapore’s largest NSF GMP-certified supplements factory. It’s also SOCOTEC cGMP certified, with an ISO Class 7 certified cleanroom. We sell only direct from the factory, with no resellers or distributors, so if you see Estalife sold anywhere else, it isn’t from us.
Frequently asked questions
Are supplement labels accurate?
Not reliably. Independent studies of NMN, melatonin, vitamin D and fish oil have found many products with substantially less or more than their labels state, and some with none of the stated ingredient at all.
Does anyone check supplements before they’re sold?
In Singapore and many other markets, supplements aren’t independently checked against their labels before sale. Brands are responsible for the safety and quality of their own products.
What is a certificate of analysis (COA)?
It’s a lab document showing test results for a specific batch of material. Check whether it covers the raw material or the finished product, which batch it relates to, and which lab did the testing.
Is a supplement with “no fillers” better?
Not necessarily. Some excipients help keep the dose consistent from capsule to capsule or protect the active ingredient. A short ingredient list may also simply mean inactive ingredients weren’t declared. Judge each ingredient by its purpose, not its name.
Is it bad if a supplement contains more than its label says?
Small overages are normal and intentional. They act as a buffer against natural degradation over time. Very large overages, or big variation between capsules, are a concern.
How can I tell if my supplement contains what it says?
Ask for third-party test results on the finished product, check that they’re from a credible third-party lab, and buy only from the brand’s official store.
Are natural supplements safer?
“Natural” isn’t a safety guarantee. HSA has repeatedly found undeclared drug ingredients in products marketed as herbal or natural.
References
- Health Sciences Authority. How health supplements are regulated by HSA. hsa.gov.sg
- Health Sciences Authority. HSA alerts public to adulterated health products purchased overseas that have caused serious adverse reactions. hsa.gov.sg
- Health Sciences Authority. Consumer alert on an adulterated herbal product, November 2025.
- NUS Yong Loo Lin School of Medicine. Label claim analysis of NMN and urolithin A supplements sold in Singapore. 2024.
- Cohen PA, et al. Quantity of melatonin and CBD in melatonin gummies sold in the US. JAMA. 2023;329(16):1401-1402. doi:10.1001/jama.2023.2296
- Erland LAE, Saxena PK. Melatonin natural health products and supplements: presence of serotonin and significant variability of melatonin content. J Clin Sleep Med. 2017;13(2):275-281.
- LeBlanc ES, et al. Over-the-counter and compounded vitamin D: is potency what we expect? JAMA Intern Med. 2013. doi:10.1001/jamainternmed.2013.3812
- Albert BB, et al. Fish oil supplements in New Zealand are highly oxidised and do not meet label content of n-3 PUFA. Sci Rep. 2015;5:7928. doi:10.1038/srep07928
- Jackowski SA, et al. Oxidation levels of North American over-the-counter n-3 (omega-3) supplements. J Nutr Sci. 2015. PMID: 26688721
About the author: Jia has been a certified nutritionist since 2018. She runs Singapore PharmaTech, the NSF cGMP-certified manufacturing facility in Ang Mo Kio behind Estalife. She holds an EMBA from Singapore Management University and is completing an MSc in Nutrition and Lifestyle Medicine at the NUS Yong Loo Lin School of Medicine.
This article is for general education and is not medical advice. Estalife products are health supplements and are not intended to diagnose, treat, cure or prevent any disease.
