The supplement industry has a transparency problem. Walk into any health shop or browse any online store and you’ll find hundreds of products making bold claims on the front of the label. Turn them around and the picture changes: proprietary blends, artificial fillers, cheap ingredient forms with poor absorption, and additives that have no business being in a health product.
The term “clean supplement” has no legal definition in the UK or EU. There’s no certification body that governs it. That means any brand can call their product “clean” regardless of what’s inside. So the responsibility falls on the consumer to know what to look for and what to avoid.
This guide covers both.
What “Clean” Should Actually Mean
A genuinely clean supplement should meet a few non-negotiable standards. It should contain the active ingredient in a well-absorbed form, at a dose that matches what the research supports, with nothing unnecessary added. That means:
- No artificial colours, flavours, or sweeteners
- No unnecessary fillers or flow agents used purely for manufacturing convenience
- No proprietary blends that hide individual ingredient amounts
- Full transparency on the label: every ingredient listed, every amount disclosed
- Active ingredients in bioavailable forms, not the cheapest version available
This sounds basic, but the majority of supplements on the UK market fail at least one of these criteria.
Ingredients to Avoid in Supplements
Not every additive in a supplement is harmful. Some are necessary for capsule integrity or shelf stability. But many are included purely to reduce manufacturing costs, and several have raised legitimate health concerns.
Artificial Colours
Titanium dioxide (E171) was banned as a food additive in the EU in 2022 following an EFSA safety assessment that concluded it could no longer be considered safe, citing concerns around genotoxicity. Despite this, it still appears in supplements sold outside the EU, and some UK products manufactured before the ban may still be in circulation. Other synthetic colours (tartrazine, sunset yellow, allura red) have been linked to hyperactivity in children and allergic reactions in sensitive individuals.
Artificial Sweeteners
Aspartame, acesulfame-K, sucralose, and saccharin are commonly found in chewable tablets, gummies, and flavoured powders. They offer no nutritional value. While regulatory bodies consider them safe at approved doses, emerging research on their effects on gut microbiome composition has raised questions. If a supplement needs sweetening to be palatable, that itself is worth questioning.
Bulking Agents and Fillers
Maltodextrin, microcrystalline cellulose, and silicon dioxide are commonly used as bulking agents or anti-caking agents. They make manufacturing easier and cheaper but add nothing for the consumer. In some cases they take up capsule space that could be used for the active ingredient. A capsule full of filler delivering a token amount of the nutrient you’re paying for is not a supplement worth taking.
Hydrogenated Oils
Some softgel supplements use partially hydrogenated oils as a carrier. These contain trans fats, which are strongly linked to cardiovascular disease. The WHO has called for the global elimination of industrially produced trans fats. There is no reason for them to be in a health product.
“Other Ingredients” You Can’t Identify
If a supplement label lists ingredients you need a chemistry degree to decode, that’s a red flag. Clean products have short, recognisable ingredient lists. The fewer the non-active ingredients, the better.
How to Read a Supplement Label
The front of a supplement bottle is marketing. The back is where the facts are. Here’s what to check:
The Ingredient Form
This is the single most important detail most people overlook. The same nutrient can come in forms that range from highly bioavailable to nearly useless. For example:
- Magnesium oxide has an absorption rate as low as 4%. Magnesium glycinate absorbs significantly better and is gentler on the digestive system. Both can legally be labelled “magnesium supplement.”
- Vitamin D2 (ergocalciferol) is less effective at raising blood levels than vitamin D3 (cholecalciferol). A product listing “vitamin D” without specifying D3 is likely using the cheaper form.
- Cyanocobalamin (vitamin B12) requires conversion in the body. Methylcobalamin is the active, bioavailable form.
A clean supplement uses the form that the evidence supports, not the form that costs the least to manufacture.
Elemental vs Total Weight
This is where many consumers get misled. A capsule might contain 500mg of magnesium glycinate, but only 55mg of that is elemental magnesium (the amount your body can actually use). Both numbers are technically correct, but they mean very different things.
Some brands exploit this by using cheap, poorly absorbed forms (like magnesium oxide) that show a high elemental figure on the label. The number looks impressive, but if only 4% is absorbed, you’re getting very little. A lower elemental number from a well-absorbed form will deliver more magnesium to your cells than a high number from a cheap form. Always check the form alongside the dose.
Buffered vs Unbuffered
This is the detail almost nobody talks about, and it makes a significant difference to what you actually absorb.
Many supplements labelled “magnesium glycinate” are actually buffered: the glycinate is blended with a cheaper form, usually magnesium oxide, to inflate the elemental magnesium number on the label. A buffered capsule might list 100 to 120mg elemental magnesium, but a meaningful portion of that comes from the oxide component, which absorbs poorly.
A pure, unbuffered product contains only the chelated form. The elemental number per capsule will be lower (around 55mg for magnesium glycinate), but the proportion that actually reaches your system is higher. If the label doesn’t specify “unbuffered” or “pure chelated,” assume it’s buffered.
Proprietary Blends
A “proprietary blend” is a list of ingredients where only the total combined weight is disclosed, not the amount of each individual ingredient. This is legal in the UK, and it’s one of the biggest transparency failures in the supplement industry.
It allows a manufacturer to list an impressive-sounding ingredient at the top of the blend (where ingredients are listed by weight) while including only a token amount. You have no way of knowing whether you’re getting an effective dose of anything in the blend. A clean supplement lists every ingredient with its exact amount. No exceptions.
Third-Party Testing and GMP
GMP (Good Manufacturing Practice) certification means the product was manufactured under controlled, standardised conditions. It doesn’t guarantee the product is effective, but it does mean basic quality control was followed. Third-party testing by an independent lab adds another layer of assurance that the product contains what it says it does, at the doses stated, and is free from contaminants like heavy metals.
What to Look for in a Magnesium Supplement
Magnesium is one of the most commonly supplemented minerals and also one of the most commonly done badly. Here’s what a clean magnesium supplement looks like:
- Form: Pure, unbuffered magnesium glycinate (chelated to the amino acid glycine for superior absorption and digestive tolerance)
- Filler-free: No magnesium oxide blended in, no artificial colours, no unnecessary bulking agents
- Transparent dosing: Clear statement of both the total magnesium glycinate weight and the elemental magnesium per capsule
- Third-party tested: Independent verification of purity and potency
Our Magnesium Glycinate meets all of these: 500mg pure unbuffered magnesium glycinate per capsule, 55mg elemental, no artificial fillers, fully vegan, and GMP manufactured. For a detailed comparison of magnesium forms, see our guide to magnesium glycinate vs citrate.
What to Look for in a Vitamin D Supplement
Vitamin D is one of the most commonly supplemented nutrients in the UK, and one of the areas where cheap formulation choices matter most. Because D3 is used in microgram quantities, there’s a lot of capsule space left to fill — and a lot of opportunity for unnecessary additives and poor carrier choices to creep in.
Here’s what separates a clean D3 supplement from a cheap one:
Form: D3, not D2
Vitamin D3 (cholecalciferol) is the form your body produces naturally in response to sunlight. It’s significantly more effective than D2 (ergocalciferol) at raising and maintaining serum 25-hydroxyvitamin D levels. If a label says only “vitamin D” without specifying D3, assume it’s D2 — and consider switching.
Paired with K2 as MK-7
D3 on its own increases calcium absorption but doesn’t direct where that calcium goes. Vitamin K2 (specifically the MK-7 form, not MK-4) activates osteocalcin and Matrix Gla Protein, the two proteins that route calcium into bone and away from arteries. For year-round D3 supplementation, particularly at doses above 1,000 IU, pairing with K2 MK-7 is the evidence-supported approach.
Carrier oil, not filler
Vitamin D is fat-soluble. Many cheap D3 supplements are dry-filled capsules with no fat source, which makes absorption unpredictable — particularly in older adults whose gut fat absorption declines naturally with age. Softgels that use soybean or sunflower oil as a carrier are a step up, but these oils oxidise over shelf life and can contribute to a heavily processed ingredient profile. MCT oil (medium-chain triglycerides from coconut) is the cleaner option: stable, bioavailable, and pairs well with fat-soluble vitamins.
Transparent dosing in µg and IU
UK vitamin D labelling uses micrograms (µg) while most research and international labels use International Units (IU). A clean supplement shows both — so 100 µg is clearly labelled as 4,000 IU, not buried in fine print. If a label shows only one unit, it may be to make a low dose look higher (25 µg sounds bigger than 1,000 IU to some readers) or vice versa.
No titanium dioxide, no unnecessary fillers
Titanium dioxide (E171) was banned as a food additive in the EU in 2022, but may still appear in older stock or non-EU-manufactured D3 softgels. Other common fillers — maltodextrin, artificial colours, sugar — add nothing to a supplement delivering a microgram-scale nutrient. A clean D3K2 product has a short, recognisable ingredient list: D3, K2 MK-7, a carrier oil, and a capsule shell.
Third-party tested for potency and contaminants
D3 content can degrade over shelf life, particularly in products using oxidation-prone oils. Independent third-party testing confirms that the stated dose is what’s actually in the capsule at the point of sale — and that the product is free from heavy metals, which can concentrate in low-quality raw materials.
Our Vitamin D3 K2 meets all of these: 100 µg (4,000 IU) D3 with 100 µg K2 MK-7, in an MCT oil base, with added zinc and boron, no artificial fillers, no titanium dioxide, fully vegan capsule shell, third-party tested, and GMP manufactured. Both µg and IU are declared on the label.
Our Approach
Epsilon Life was built around a simple principle: every ingredient should be there for a reason, in a form that works, at a dose that matters, with nothing else added.
In practice, that means:
- Bioavailable forms only. We use pure unbuffered magnesium glycinate, not oxide. Vitamin D3 with K2 as MK-7, not D2 alone. NAC at a researched dose, not a token amount in a proprietary blend.
- No artificial fillers. No titanium dioxide, no artificial sweeteners, no hydrogenated oils, no unnecessary bulking agents. If an ingredient doesn’t serve your health, it doesn’t go in the product.
- Full label transparency. Every ingredient listed. Every amount disclosed. No proprietary blends. No hiding behind vague terms.
- Third-party tested. Independent lab verification for purity, potency, and contaminant screening.
- Vegan and allergen-conscious. Our supplements use plant-based capsule shells and are free from common allergens.
We don’t think this should be unusual. It should be the baseline. But in an industry where it isn’t, we think it’s worth being explicit about.
Browse our full range: Epsilon Life supplements.
FAQ
Q: What does “clean supplement” mean?
A: There’s no regulated definition. It should mean a supplement made with bioavailable ingredient forms, transparent labelling, no artificial fillers or colours, and no proprietary blends. Because anyone can use the term, the only way to verify it is to read the label yourself.
Q: What ingredients should I avoid in supplements?
A: The main ones to watch for are artificial colours (especially titanium dioxide), artificial sweeteners (aspartame, sucralose, acesulfame-K), unnecessary fillers (maltodextrin, excess silicon dioxide), hydrogenated oils, and proprietary blends that hide individual ingredient amounts.
Q: What is a proprietary blend?
A: A proprietary blend lists several ingredients but only discloses their combined total weight, not the amount of each ingredient individually. This makes it impossible to know whether you’re getting an effective dose of any single ingredient in the blend. Avoid products that use them.
Q: What does “buffered” mean on a magnesium supplement?
A: Buffered means the magnesium glycinate has been blended with a cheaper form, usually magnesium oxide, to increase the elemental magnesium number on the label. The result is a higher-looking dose that actually absorbs worse. Pure unbuffered glycinate has a lower elemental figure but delivers more usable magnesium.
Q: How can I tell if a supplement is high quality?
A: Check the ingredient form (not just the nutrient name), look for full dosage transparency (no proprietary blends), check for unnecessary additives, and confirm GMP manufacturing and third-party testing. A short, recognisable ingredient list is usually a good sign.
Q: Are supplements without fillers better?
A: Generally, yes. Fillers take up space in the capsule, add nothing nutritionally, and in some cases may affect absorption. A filler-free supplement means you’re getting more active ingredient per capsule and nothing your body doesn’t need.
Q: What should I look for in a magnesium supplement?
A: Look for pure, unbuffered magnesium glycinate. Check that the label shows both the total weight and elemental magnesium per capsule. Avoid magnesium oxide (very poor absorption) and buffered products that blend glycinate with cheaper forms. Check for artificial fillers and confirm third-party testing.
Q: What should I look for in a vitamin D supplement?
A: Choose D3 (cholecalciferol), not D2. Pair it with K2 as MK-7, which directs calcium to bones rather than arteries. Look for an MCT oil carrier rather than dry-filled capsules or oxidation-prone seed oils — this matters for absorption. Check that both µg and IU are declared on the label. Avoid titanium dioxide, artificial colours, and unnecessary fillers. Confirm third-party testing for potency and contaminants.
References
- EFSA. (2021). Safety assessment of titanium dioxide (E171) as a food additive. EFSA Journal, 19(5), e06585.
- WHO. (2023). Trans fat: Fact sheet.
- Firoz M, Graber M. (2001). Bioavailability of US commercial magnesium preparations. Magnesium Research, 14(4), 257-262.
- Tripkovic L, et al. (2012). Comparison of vitamin D2 and vitamin D3 supplementation in raising serum 25-hydroxyvitamin D status: a systematic review and meta-analysis. American Journal of Clinical Nutrition, 95(6), 1357-1364.
- Food Standards Agency. Food supplements: guidance for businesses.
This article is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional before starting any supplement.
