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The evening after a hard day: a late game under the lights, a double session at the pool, a long ride in the heat. You stretch, you foam roll, you try to get to bed on time, and somewhere in that wind-down routine a lot of athletes now reach for magnesium. Finding the best magnesium supplement comes down to three things: the form (glycinate, citrate, threonate), how much magnesium a serving really gives, and whether it’s tested for sport. Here are the magnesium supplements worth a look in 2026, what each form is, which are certified, and how to choose.
Prices change often. The prices below are what we saw at the maker or a major retailer in October 2026; check the current price before you buy.
This guide compares products; it isn’t medical advice. Talk to a doctor or registered dietitian before you take magnesium, especially if you have kidney problems, take prescription medication (magnesium can interact with some antibiotics and other drugs) or are pregnant, and take it as the label says.
Our top picks
Thorne Magnesium Bisglycinate
- 200 mg per scoop, powder
- 60 servings
- NSF Certified for Sport
Klean Athlete Klean Magnesium
- 120 mg per capsule, glycinate
- 90 capsules
- NSF Certified for Sport
Designs for Sport Magnesium Bisglycinate
- 300 mg per 2 capsules
- 60 servings
- NSF Certified for Sport
Momentous Magnesium L-Threonate
- 145 mg from 2 g Magtein
- 30 servings, 3 capsules
- NSF Certified for Sport
Natural Vitality Calm
- 325 mg per serving, citrate
- 16 oz, about 113 servings
- Not certified for sport
Doctor's Best High Absorption Magnesium
- 200 mg per 2 tablets
- 240 tablets, 120 servings
- Not certified for sport
Magnesium supplements compared
| Product | Form | Magnesium per serving | Certification | About (Oct 2026) | Per serving |
|---|---|---|---|---|---|
| Thorne Magnesium Bisglycinate | Bisglycinate powder | 200 mg (1 scoop) | NSF Certified for Sport | $52 (60 servings) | about $0.87 |
| Klean Athlete Klean Magnesium | Glycinate capsules | 120 mg (1 capsule) | NSF Certified for Sport | $25–$28 (90 capsules) | about $0.29 |
| Designs for Sport Magnesium Bisglycinate | Bisglycinate capsules | 300 mg (2 capsules) | NSF Certified for Sport | $36–$39 (60 servings) | about $0.60–$0.66 |
| Momentous Magnesium L-Threonate | L-threonate (Magtein) capsules | 145 mg (3 capsules) | NSF Certified for Sport | $50 ($37.50 subscribed) | about $1.25–$1.67 |
| Natural Vitality Calm | Citrate drink powder | 325 mg (about 2 tsp) | Not third-party certified for sport | $29–$36 (16 oz) | about $0.26–$0.32 |
| Doctor’s Best High Absorption Magnesium | Glycinate lysinate chelate tablets | 200 mg (2 tablets) | Not third-party certified for sport | $24 (120 servings) | about $0.20 |
Glycinate, citrate or threonate?
Magnesium in a supplement is always bound to something else, and that partner gives the form its name. Glycinate (or bisglycinate) is magnesium bound to the amino acid glycine; makers describe it as well absorbed and gentle on the stomach, which is why it’s the most common pick for evening routines. Citrate is bound to citric acid, dissolves easily in water and is used in drink powders; in larger amounts it’s known for loosening the bowels. L-threonate (sold as Magtein) is a newer, pricier form; makers market it for the brain and sleep, and it gives less magnesium per capsule. You’ll also see oxide in cheap tablets: lots of magnesium on the label, but makers of other forms point to better absorption. Whatever the form, check the “magnesium” line on the label, which shows the actual (elemental) magnesium, not the weight of the whole compound: 2 g of Magtein gives 145 mg of magnesium.
The best magnesium supplements for athletes
1. Thorne Magnesium Bisglycinate: best overall
A lightly sweetened powder you stir into water: one 4 g scoop gives 200 mg of magnesium as bisglycinate, 60 scoops a tub. The only other ingredients are citric acid and monk fruit concentrate. It’s NSF Certified for Sport and free of gluten, dairy and soy. Thorne suggests it as part of an evening routine, and many athletes make it their post-training or bedtime drink.
- Good: certified; short ingredient list; a powder is easy to split into smaller amounts.
- Watch out: the priciest bisglycinate here per serving.
- Best for: anyone who’d rather drink it than swallow pills.
Check the Thorne Magnesium Bisglycinate price on Amazon
2. Klean Athlete Klean Magnesium: best value certified
One small vegetarian capsule with 120 mg of magnesium as magnesium glycinate, 90 capsules a bottle. Like everything Klean Athlete makes, it’s NSF Certified for Sport, and it’s gluten-free. The label says to take 1 capsule 1 to 4 times a day as directed by a healthcare professional, so you and your doctor can set the amount.
- Good: lowest certified price per capsule; flexible small dose.
- Watch out: 120 mg per capsule is a modest amount, so the cost goes up if your doctor suggests more.
- Best for: tested athletes who want a simple capsule.
Check the Klean Magnesium price on Amazon
3. Designs for Sport Magnesium Bisglycinate: highest dose certified
Designs for Sport is the sport line of Designs for Health. Two capsules give 300 mg of magnesium as bisglycinate; the bottle holds 120 capsules, so 60 servings. It’s NSF Certified for Sport, vegan, and free of gluten, dairy and soy. Note that 300 mg is close to the 350 mg a day from supplements that U.S. health authorities set as the upper limit for adults, so count any other magnesium you take.
- Good: the most magnesium per serving among the certified picks.
- Watch out: easy to go over the upper limit if you also take a multivitamin or electrolyte mix with magnesium.
- Best for: athletes whose doctor has suggested a higher amount.
Check the Designs for Sport Magnesium price on Amazon
4. Momentous Magnesium L-Threonate: best threonate
Three capsules give 2 g of Magtein magnesium L-threonate, which is 145 mg of magnesium; 90 capsules make 30 servings. The other ingredients are rice flour, the capsule, magnesium stearate and silica. It’s NSF Certified for Sport, vegan and gluten-free, and Momentous suggests taking it 30 to 60 minutes before bed. You pay for the form: it’s the most expensive per milligram of magnesium in this guide.
- Good: the threonate form, certified for sport; built for a bedtime routine.
- Watch out: three capsules for 145 mg; high price per serving.
- Best for: people who specifically want threonate and don’t mind paying for it.
Check the Momentous Magnesium L-Threonate price on Amazon
5. Natural Vitality Calm: best citrate drink
The fizzy orange drink a lot of people know from the grocery aisle. About 2 teaspoons (4 g) give 325 mg of magnesium as magnesium citrate, sweetened with organic stevia, and a 16 oz tub lasts about 113 servings. It’s Non-GMO Project Verified and vegan, but not third-party certified for sport. The label amount is close to the 350 mg upper limit for supplements, and citrate in larger amounts can loosen the bowels, so many people start with less; follow the label and your doctor.
- Good: cheap per serving; a warm or cold drink fits an evening routine.
- Watch out: not certified for sport; a full serving is a lot of citrate for some stomachs.
- Best for: untested recreational athletes who like a drink at night.
Check the Natural Vitality Calm price on Amazon
6. Doctor’s Best High Absorption Magnesium: budget pick
A long-time bestseller: two tablets give 200 mg of magnesium as a glycinate lysinate chelate (Albion’s TRAACS), and a 240-tablet bottle lasts 120 servings at about $0.20 each. It’s vegan, but not third-party certified for sport, so it isn’t screened for banned substances.
- Good: the lowest price per serving here for a chelated form.
- Watch out: not certified for sport; two tablets per serving.
- Best for: weekend warriors who aren’t drug tested.
Check the Doctor's Best Magnesium price on Amazon
How to choose a magnesium supplement
- Add up all your magnesium. Multivitamins, electrolyte mixes and some sleep products contain it too. U.S. health authorities set 350 mg a day from supplements as the upper limit for adults (food doesn’t count toward it).
- Pick the form for your routine. Capsules of glycinate for simplicity, a citrate or bisglycinate drink if you like a nightly mug, threonate if you want that form specifically.
- Read the elemental amount. Compare the “magnesium” line, not the compound weight.
- Drug tested? Look it up. Search nsfsport.com or the Informed Sport database for the exact product.
- Food first. Nuts, seeds, beans, whole grains and leafy greens all carry magnesium. A dietitian can tell you if you need a supplement at all.
Building a better wind-down? Browse recovery and sleep supplements and hydration and electrolytes, read our guides to the best multivitamin for athletes and the best creatine, and pair your routine with gear from best recovery tools for athletes or a massage gun.
Magnesium questions
Which form of magnesium do athletes use most?
Glycinate (bisglycinate) is the most common in sport-certified products, including the picks from Thorne, Klean Athlete and Designs for Sport. Citrate is popular in drink powders, and threonate is a newer, pricier option.
Can you take too much magnesium?
Yes, from supplements. The adult upper limit is 350 mg a day from supplements, and too much can cause diarrhea, nausea and cramping. People with kidney disease need to be especially careful, so check with a doctor.
When should I take magnesium?
Follow your label. Many people take it in the evening as part of a wind-down routine; Momentous suggests 30 to 60 minutes before bed for its threonate.
Is magnesium in my multivitamin enough?
Multivitamins usually carry only 20 to 30 mg, because magnesium takes up a lot of room in a capsule. Whether you need more depends on your diet; a dietitian or doctor can help you decide.
Does magnesium interact with medicines?
It can, including with some antibiotics and osteoporosis drugs, and some medicines change how much magnesium your body keeps. If you take any prescription medication, ask your doctor or pharmacist before you start.