Epsilon Life Magnesium Glycinate contains one active ingredient: magnesium bisglycinate chelate. No magnesium oxide blended in, no bulking agents, no artificial fillers. Just the chelated mineral, a small amount of brown rice flour for capsule flow, and an HPMC shell.
This article explains why we chose this specific form, why it’s unbuffered, how the dosage works, and what sets this magnesium glycinate supplement apart from the hundreds of alternatives on the UK market. If you’re comparing magnesium glycinate products and trying to work out which one is worth buying, the details below should help.
Why magnesium glycinate
Magnesium supplements come in many forms: oxide, citrate, glycinate, threonate, taurate, malate. The form matters because it determines how much of the magnesium your body actually absorbs and whether you experience side effects.
We chose magnesium glycinate (also known as magnesium bisglycinate) for three reasons.
First, absorption. Magnesium glycinate is a chelated form: each magnesium ion is bonded to two molecules of the amino acid glycine. This chelation protects the magnesium from binding to other compounds in the gut, allowing it to pass through the intestinal wall more efficiently.
A study in Magnesium Research (2001) found that magnesium oxide had a bioavailability of just 4%, while organic and chelated forms performed significantly better. More recent research in Biological Trace Element Research (2019) confirmed that magnesium bisglycinate chelate produced higher plasma magnesium levels than oxide at equivalent doses.
Second, tolerability. Magnesium oxide and magnesium citrate are known to cause loose stools and GI discomfort, particularly at higher doses. This is because poorly absorbed magnesium draws water into the intestine through osmosis. Glycinate is one of the best-tolerated forms precisely because more of it is absorbed before reaching the lower GI tract. For anyone who has tried magnesium before and experienced stomach issues, the form was likely the problem, not the mineral itself. Our articles on magnesium side effects and which forms cause diarrhoea cover this in more detail.
Third, glycine itself. The amino acid used in chelation is not inert. Glycine has independent calming effects, particularly for sleep. Research in Sleep and Biological Rhythms (2007) showed that glycine before bed improved subjective sleep quality, confirmed by polysomnography. A follow-up study in Neuropsychopharmacology (2015) identified the mechanism: glycine activates NMDA receptors in the suprachiasmatic nucleus (the brain’s master clock), promoting a drop in core body temperature that signals the body to sleep.
When you take magnesium glycinate, you get both the magnesium and the glycine. This is why it has become the go-to form for magnesium glycinate for sleep and why many people now prefer it to melatonin.
What unbuffered means and why it matters
This is probably the most important section of this article, and it addresses something most supplement brands would prefer you didn’t know about.
“Buffered” magnesium glycinate is a product that blends magnesium bisglycinate chelate with magnesium oxide. Brands do this because oxide contains about 60% elemental magnesium by weight, compared to about 14% for glycinate. By mixing in oxide, they can print a much larger elemental number on the label.
The problem: magnesium oxide has roughly 4% bioavailability. You see an impressive number on the label, but much of it passes straight through you.
Our product is unbuffered. The 55mg of elemental magnesium per capsule comes entirely from the chelated form, so the proportion that actually reaches your bloodstream is substantially higher than what you would get from a buffered product claiming three or four times the elemental content.
How to spot a buffered product:
- Check the ingredients list (not just the front label)
- If “magnesium oxide” appears alongside “magnesium glycinate,” it is buffered
- Vague terms like “magnesium complex” or unlisted proportions are red flags
- If the elemental magnesium per serving seems unusually high for the amount of glycinate listed, it almost certainly contains oxide
The dose: 500mg per capsule, 55mg elemental
Each capsule contains 500mg total fill (magnesium bisglycinate chelate plus a small amount of brown rice flour). The elemental magnesium content is 55mg per capsule, confirmed by independent testing at Campden BRI.
Because the product is unbuffered, you are getting 55mg of highly bioavailable elemental magnesium rather than a large number that is mostly unabsorbed. This is why most people find 1 to 2 capsules per day is all they need:
- 1 capsule (55mg elemental) suits people topping up alongside a magnesium-rich diet, or those new to supplementation who want to start low.
- 2 capsules (110mg elemental) is what many of our customers settle on for sleep support, muscle recovery, or general wellbeing.
The bottle contains 120 capsules, so that is a four-month supply at one per day or two months at two per day. There is no fixed serving size because the right dose depends on your diet, your existing levels, and what you are using the supplement for. The UK Expert Group on Vitamins and Minerals sets the supplemental guidance level at 400mg elemental per day, so even at two capsules you are well within safe limits. Our guide to magnesium glycinate dosage for sleep covers timing in more detail.
Why magnesium matters in the first place
Magnesium is involved in over 300 enzymatic reactions in the body. It is required for energy production, protein synthesis, muscle and nerve function, blood glucose regulation, and blood pressure control. It is also essential for the activation of vitamin D; without adequate magnesium, vitamin D remains in its inactive storage form. Our article on vitamin D with zinc and magnesium explains this relationship in detail. For a full overview of vitamin D deficiency symptoms and how to confirm whether you’re affected, see our dedicated guide.
Despite its importance, magnesium deficiency is widespread in the UK. Data from the National Diet and Nutrition Survey shows that around 12% of women and 15% of men have intakes below the Lower Reference Nutrient Intake (the threshold below which deficiency is likely). When measured against the full RNI of 270mg for women and 300mg for men, roughly 60% of UK adults fall short.
The reasons are straightforward: modern diets rely heavily on processed foods that have lost magnesium during refining, and soil mineral depletion means even whole foods contain less than they did decades ago. For more on dietary sources, see our guide to magnesium-rich foods.
What is not in it
The full ingredient list: magnesium bisglycinate chelate, brown rice flour, HPMC capsule shell. That is everything. Here is what you will not find:
- No magnesium oxide (the cheap buffer used to inflate elemental numbers)
- No magnesium stearate
- No artificial colours
- No artificial flavours
- No sweeteners
- No preservatives
- No bulking agents or unnecessary excipients
The brown rice flour is a natural flow agent that prevents the powder from clumping during encapsulation. Without it, capsules cannot be filled consistently at scale. It contributes no active ingredients and is standard practice in clean-label supplement manufacturing.
The HPMC (hydroxypropyl methylcellulose) capsule shell is plant-derived, making the entire product suitable for vegans. This is certified, not simply claimed.
Testing and quality
Manufactured in the UK to GMP and BRCGS standards. BRCGS is a GFSI-benchmarked certification covering food safety, HACCP, quality systems, and facility standards. It is the standard that major UK retailers require of their food suppliers.
We also sent this product to Campden BRI for independent potency testing. Campden BRI is one of the world’s largest independent food and drink research organisations, based in Chipping Campden, Gloucestershire. Their testing confirmed that the elemental magnesium content matches our label claim. Most UK supplement brands do not do this; they rely solely on manufacturer-provided certificates of analysis.
The product is vegan-certified: an independent certifying body has verified the entire supply chain, from raw materials to finished capsule.
How to take it
Take one or two capsules daily, preferably in the evening. For sleep support, take your dose 30 to 60 minutes before bed. It works best when taken consistently rather than as an occasional sleep aid. For more on the timing, see our article on how magnesium helps you sleep.
If you are also taking our Vitamin D3 + K2 supplement, take the D3K2 in the morning and the magnesium in the evening. This avoids competition between zinc and magnesium for absorption transporters and aligns each supplement with its optimal time of day.
Magnesium glycinate can be taken with or without food. Unlike some forms, it does not typically cause stomach discomfort on an empty stomach.
Who is this supplement for
This product is designed for adults in the UK looking for a pure, high-quality magnesium glycinate supplement without fillers or buffering agents. It is particularly relevant for:
- People who want to improve their sleep quality (the glycine component adds a distinct advantage here)
- Anyone experiencing muscle cramps, tension, or poor recovery after exercise (our magnesium for muscle recovery article covers this in depth)
- Women approaching or going through menopause, when magnesium needs increase and sleep quality often declines
- Anyone who has tried other magnesium forms and experienced GI side effects
It is also suitable for people who are already taking magnesium but want to switch to a verified, unbuffered product where the label accurately reflects what is inside the capsule.
If you have kidney disease or take medications that affect magnesium excretion, consult your GP before supplementing. Magnesium can also interact with certain antibiotics and bisphosphonates; take them at least two hours apart.
Frequently asked questions
Is magnesium glycinate the same as magnesium bisglycinate?
Yes, they are the same compound. Magnesium bisglycinate is the precise chemical name (indicating two glycine molecules bonded to one magnesium ion), while magnesium glycinate is the more commonly used consumer-facing term. If you see either name on a supplement label, they refer to the same chelated form. Our product uses the fully reacted bisglycinate chelate.
What does unbuffered magnesium glycinate mean?
Unbuffered means the product contains only magnesium bisglycinate chelate, with no magnesium oxide or other cheap forms blended in. Many brands “buffer” their glycinate with oxide to inflate the elemental magnesium number on the label. The problem is that magnesium oxide has roughly 4% bioavailability, so much of that advertised elemental content is not absorbed. Our product is 100% unbuffered chelate.
Why is the elemental magnesium only 55mg per capsule?
Because the product is unbuffered. Magnesium bisglycinate chelate contains about 14% elemental magnesium by molecular weight. Products advertising 200mg or 300mg of elemental magnesium from “glycinate” are almost always buffered with magnesium oxide. Our 55mg comes entirely from the chelated form, which is absorbed significantly more efficiently. Two capsules provide 110mg of highly bioavailable elemental magnesium.
How much magnesium glycinate should I take for sleep?
Most clinical research on glycine and sleep used 3g of glycine before bed. Two capsules of our product provide 110mg of elemental magnesium along with glycine released from the chelated complex (the clinical sleep studies used 3g of standalone glycine, so the glycine here is a contributing factor rather than the full clinical dose). Many of our customers find one to two capsules taken 30 to 60 minutes before bed effective for sleep support. The UK supplemental guidance level is 400mg elemental magnesium per day, so even at two capsules you are well within safe limits. See our full dosage guide for sleep for more detail.
What is the best magnesium glycinate supplement in the UK?
When evaluating magnesium glycinate supplements in the UK, check for three things: whether the product is unbuffered (contains no magnesium oxide), whether the elemental magnesium content is independently verified by a third party, and whether the brand is transparent about what is and is not in the capsule. Many UK products use buffered blends, rely solely on manufacturer certificates rather than independent testing, or include unnecessary fillers. We designed this product to meet all three criteria, with Campden BRI verification, no buffering, and a clean three-ingredient formula.
Can I take magnesium glycinate with vitamin D?
Yes, and there is a good reason to. Magnesium is required for the enzymatic conversion of vitamin D from its storage form (25-hydroxyvitamin D) to its active form (1,25-dihydroxyvitamin D). Without adequate magnesium, supplementing vitamin D may be less effective. We recommend taking our Vitamin D3 + K2 in the morning and magnesium in the evening for optimal absorption and to support your natural sleep cycle.
Is this supplement suitable for vegans?
Yes. The product is vegan-certified. The capsule shell is HPMC (plant-derived), the flow agent is brown rice flour, and the magnesium bisglycinate chelate contains no animal-derived components. Our NAC+ supplement is also vegan-certified.
What does Campden BRI testing mean?
Campden BRI is one of the world’s largest independent food and drink research organisations, headquartered in the UK. We sent our product to Campden BRI for independent testing to verify that the elemental magnesium content matches our label claim and that the product meets safety standards. This is a higher level of verification than the manufacturer-provided certificates of analysis that most supplement brands rely on.
References
- Firoz M, Graber M. Bioavailability of US commercial magnesium preparations. Magnesium Research. 2001;14(4):257-262. PubMed
- Ates M, Kizildag S, Yuksel O, et al. Dose-Dependent Absorption Profile of Different Magnesium Compounds. Biological Trace Element Research. 2019;192(2):244-251. doi:10.1007/s12011-019-01663-0
- Yamadera W, Inagawa K, Chiba S, Bannai M, Takahashi M, Nakayama K. Glycine ingestion improves subjective sleep quality in human volunteers, correlating with polysomnographic changes. Sleep and Biological Rhythms. 2007;5(2):126-131. doi:10.1111/j.1479-8425.2007.00262.x
- Kawai N, Sakai N, Okuro M, et al. The sleep-promoting and hypothermic effects of glycine are mediated by NMDA receptors in the suprachiasmatic nucleus. Neuropsychopharmacology. 2015;40(6):1405-1416. doi:10.1038/npp.2014.326
- Public Health England. National Diet and Nutrition Survey: Results from Years 9 to 11. 2020.
- Expert Group on Vitamins and Minerals. Safe Upper Levels for Vitamins and Minerals. Food Standards Agency. 2003.
- Uwitonze AM, Razzaque MS. Role of Magnesium in Vitamin D Activation and Function. The Journal of the American Osteopathic Association. 2018;118(3):181-189. doi:10.7556/jaoa.2018.037
- Siebrecht S. Magnesium Bisglycinate as safe form for mineral supplementation in human nutrition. 2013. Semantic Scholar
This article is for informational purposes only and does not constitute medical advice. If you suspect a magnesium deficiency or have a medical condition, speak with your GP or a qualified healthcare practitioner before starting supplementation.
View our Magnesium Glycinate: 100% Pure Chelated Vegan Capsules – unbuffered magnesium bisglycinate chelate, 500mg per capsule, 120 capsules per bottle. No magnesium oxide, no artificial fillers. Vegan-certified, Campden BRI tested, made in the UK to GMP and BRCGS standards.
