The short answer: magnesium glycinate, citrate and chloride do different jobs. Glycinate is the gentlest oral form and has the most direct sleep evidence. Citrate is the best-absorbed oral form and is mildly laxative. Chloride is the form used on skin, in balms, oils and bath flakes. Pick by the job, not by a ranking.
By Dr. Doug Strobel, MD, a board-certified neurologist who formulated Dr. Doug's balms.
Why the form of magnesium matters at all
The form matters because magnesium always arrives bound to a partner, and that partner decides how well it absorbs and how your gut reacts. You never take magnesium on its own. It comes as glycinate, citrate, chloride, oxide and so on, and those differences show up clearly in trials, not just on labels.
Magnesium oxide: start by knowing what to avoid
Magnesium oxide is the cheapest and most common form on the shelf, and in a randomized trial it performed no better than placebo on absorption. I am putting this first because it is the most useful thing on this page for most readers.
Walker and colleagues ran a randomized, double-blind, placebo-controlled trial in 46 healthy adults taking 300 mg of elemental magnesium a day for 60 days, comparing an amino-acid chelate (the family glycinate belongs to), citrate and oxide. The organic forms absorbed significantly better than oxide at 60 days (P = 0.033), and the authors reported that oxide "resulted in no differences compared to placebo." [1]
Werner and colleagues found the same pattern in 2019 with a different design: 14 healthy men, a single 400 mg dose of citrate or oxide. Citrate significantly raised 24-hour urinary magnesium; oxide did not. Plasma magnesium was significantly higher with citrate at 4 and 8 hours. [2]
Two studies, two designs, one answer. If your bottle says oxide, you may be getting very little magnesium for your money.
Magnesium citrate: the best-absorbed oral form
Citrate is the best-absorbed oral form in head-to-head testing, and its catch is a laxative effect at higher doses. In Walker's trial it produced the highest mean serum magnesium of any form tested, after a single dose (P = 0.026) and after 60 days (P = 0.006). [1]
The same property that helps it absorb, pulling water into the bowel, is why it is used as a laxative. For general daytime intake with a steady stomach, citrate is a defensible choice. If you are taking it in the evening hoping to sleep better, a laxative effect is not what you want at 2am.
Magnesium glycinate: the gentlest, and the one with the sleep data
Glycinate is the best-evidenced form for sleep, and the effect is real but small. It is magnesium bound to glycine, an amino acid, it is easy on the stomach, and it is the form most people choose for the evening.
Schuster and colleagues published a randomized, double-blind, placebo-controlled trial in 2025: 155 adults with self-reported poor sleep took 250 mg of elemental magnesium as bisglycinate or a placebo. By week 4, Insomnia Severity Index scores fell further with magnesium than with placebo, -3.9 versus -2.3 (p = 0.049). [3]
Now the part a supplement ad would leave out. The effect size was small (Cohen's d = 0.2), which the authors call "a modest benefit," and no other psychological outcome differed. The most interesting signal was exploratory: people who ate less magnesium to begin with improved more. If someone tells you glycinate transforms sleep, they have not read the trial.
Magnesium chloride: the form that goes on skin
Chloride is the form used in topical products, because it dissolves easily and spreads well in a balm, oil or bath. This is where my own work sits, so here is the disclosure up front: I make a magnesium chloride balm.
Here is the honest framing, and it is narrower than most topical brands will give you. Whether meaningful amounts of magnesium reach your bloodstream through intact skin is still argued about by researchers, and I will not tell you a balm raises your magnesium level. The reason to use a chloride balm is local. It works right where you put it: the calf you are working it into, the sore shoulder, the few unhurried minutes at the end of the day. It is not a replacement for oral magnesium if your intake is genuinely low.
And because it is the thing that separates a physician from a brand: if your goal is sleep and nothing else, the better-evidenced choice is oral glycinate, not my balm. Many people use both, for different reasons, and that is reasonable.
Magnesium glycinate vs citrate vs chloride vs oxide: the comparison table
| Glycinate | Citrate | Chloride | Oxide | |
|---|---|---|---|---|
| Bound to | Glycine | Citric acid | Chloride | Oxygen |
| How it is used | Oral | Oral | Topical (balms, oils, flakes) | Oral |
| Absorption | Good, gentle | Best oral form tested | Through skin: still debated | No better than placebo in a trial |
| Gut effect | Minimal | Laxative at higher doses | None, it is not swallowed | Not the issue: it barely absorbs |
| Best for | Evening use, sensitive stomachs | General intake, regularity | Massaging into tired muscles, a wind-down routine | Little, honestly |
| Key evidence | 155-adult trial: modest sleep benefit, d = 0.2 [3] | Highest serum magnesium of forms tested [1] | Local, sensory use | No difference vs placebo [1] |
So which magnesium should you buy?
Buy the form that matches your goal:
- You want help sleeping. Oral glycinate, in the evening. Expect a modest effect, and more of one if your diet is low in magnesium.
- You want general intake and your stomach is fine. Citrate. Start low, because the laxative effect depends on dose.
- You want something for tired legs, a sore shoulder, or a wind-down routine you can feel. A magnesium chloride balm, massaged right where you feel it.
- You want the cheapest bottle on the shelf. Read the label first. If it says oxide, the trials say you may be buying very little.
- You are treating a diagnosed deficiency. That is a conversation with your own physician, and the form and dose should be theirs to choose.
What Dr. Doug's makes
Dr. Doug's Magnesium Balm is magnesium chloride in organic olive and coconut oils, beeswax and organic shea butter, with peppermint and lavender essential oils. It is dermatologist-tested and formulated by a board-certified neurologist. The 2.5 oz twist-up stick is $42, and it also comes as an 8 oz jar and a 0.5 oz mini.
Chloride, on skin, at the end of the day. That is the whole claim, and I am comfortable that it is the right size.
New to magnesium balm? Start with What Is Magnesium Balm and How Does It Work? If restless legs are why you are here, read Best Magnesium for Restless Legs.
Frequently asked questions
Is magnesium glycinate or citrate better?
They do different jobs. Glycinate is gentler and has a direct sleep trial behind it. Citrate absorbs better and is mildly laxative. For evening use, most people do better with glycinate; for general daytime intake, citrate is a solid choice.
Which magnesium is best for sleep?
Oral magnesium glycinate has the most direct evidence. A 2025 randomized trial in 155 adults with poor sleep found a small but statistically significant improvement in insomnia severity, with a bigger effect in people whose diets were low in magnesium.
Which magnesium is best absorbed through skin?
Magnesium chloride is the form used in skin products, because it dissolves easily. Whether any form raises your body's magnesium through intact skin is still debated by researchers, so I would not count on a topical for that. Use a chloride balm for what it does right where you put it.
Is magnesium better absorbed through skin or orally?
Orally. Oral absorption is well measured in trials, and citrate and amino-acid forms absorb well. Absorption through skin is not well established. If your goal is to raise your magnesium intake, take an oral form; use a balm for local comfort and routine.
Is magnesium oxide bad?
It is not harmful, it is just poorly absorbed. In a randomized trial of 46 adults over 60 days, magnesium oxide produced no difference from placebo on absorption measures. It is common because it is cheap.
Is magnesium glycinate better than citrate for leg cramps?
Neither has strong evidence for cramps. A 2020 Cochrane review concluded that magnesium supplements are unlikely to give older adults clinically meaningful protection from muscle cramps. Adequate magnesium intake is worth having, but it is not a reliable cramp treatment, whichever form you choose.
Can you use a magnesium balm and take magnesium at the same time?
Yes, many people do, for different reasons: an oral form for intake and a balm massaged into tired muscles. If you have kidney disease or take medication that affects magnesium, ask your own doctor before taking oral magnesium.
Sources
- Walker AF, Marakis G, Christie S, Byng M. Mg citrate found more bioavailable than other Mg preparations in a randomised, double-blind study. Magnes Res. 2003;16(3):183-91. PMID 14596323
- Werner T, Kolisek M, Vormann J, et al. Assessment of bioavailability of Mg from Mg citrate and Mg oxide by measuring urinary excretion in Mg-saturated subjects. Magnes Res. 2019;32(3):63-71. PMID 32162607
- Schuster J, Cycelskij I, Lopresti A, Hahn A. Magnesium Bisglycinate Supplementation in Healthy Adults Reporting Poor Sleep: A Randomized, Placebo-Controlled Trial. Nat Sci Sleep. 2025;17:2027-2040. PMID 40918053
- Garrison SR, Korownyk CS, Kolber MR, et al. Magnesium for skeletal muscle cramps. Cochrane Database Syst Rev. 2020;9:CD009402. PMID 32956536
This article is educational and is not medical advice. Dr. Doug's products are cosmetic and are not intended to diagnose, treat, cure or prevent any disease. The sleep and absorption evidence above describes oral magnesium supplements, not our topical product.