Magnesium exists in many forms, each with different tissue affinities and bioavailability. Quatro 900 combines three complementary forms for maximum coverage: magnesium bisglycinate (500mg), a chelated form bound to two glycine molecules with the best oral bioavailability (intestinal absorption above 80%) — glycine is itself a relaxing amino acid that reinforces magnesium’s anti-stress effect, with excellent digestive tolerance and no laxative effect; magnesium glycerophosphate (260mg), an organic form bound to glycerophosphoric acid with very high bioavailability and perfect gastric tolerance, with a particular affinity for the nervous system and brain; and magnesium acetyl taurinate (140mg), a proprietary Be-Life form bound to acetylated taurine, a sulphur-containing amino acid abundant in the heart, brain and muscles, targeting the cardiovascular and nervous systems specifically. Combining three forms means each takes a different intestinal absorption route, avoiding saturation of a single transporter and increasing total absorption.

Quatro 900’s dosage is one of the highest on the market: 356mg of elemental magnesium per 4-capsule dose — 95% of Nutrient Reference Values, close to the optimal daily dose of 375-400mg recommended by micronutrition experts — and 1.4mg of vitamin B6 as pyridoxal-5-phosphate (P5P), the active form of B6, directly usable by the body with no liver conversion needed. B6 is the cofactor for cellular magnesium absorption: without enough B6, magnesium enters cells less efficiently. The “900” in the name refers to the total weight of magnesium salts per dose (900mg of salts), of which 356mg is pure magnesium — a high dose, not a maintenance one.

Magnesium is involved in over 300 enzymatic reactions, essential to the nervous system, muscles, bones, energy metabolism and sleep. Yet French studies (SU.VI.MAX, INCA) show 75% of the population falls short of recommended intake, due to soil depletion (intensive farming has reduced magnesium content in agricultural soils by 30-50% over 50 years), cereal refining (magnesium is concentrated in bran and germ, removed during refining), chronic stress (cortisol increases urinary magnesium loss, and magnesium deficiency in turn increases stress sensitivity — a vicious circle), coffee and alcohol (which increase renal excretion of magnesium), and certain medications (PPIs, diuretics and some antibiotics reduce absorption or increase losses). Common signs of magnesium deficiency include persistent tiredness, cramps, eyelid twitching, irritability, sleep disturbance, muscle tension and headaches.

Dose: 3 to 4 capsules a day, split into 2 doses (morning and evening) — the evening dose supports relaxation and sleep. 90 capsules cover 22 to 30 days. A course of at least 2-3 months is recommended, as magnesium is not stored by the body and needs a regular supply; one course per season is a good habit. Magnesium pairs well with vitamin D3 (magnesium is a cofactor for its activation), zinc bisglycinate, ashwagandha KSM-66 for stress, or sleep supplements taken in the evening.

Not recommended in cases of severe kidney impairment. High-dose magnesium can have a mild laxative effect — this is normal and not dangerous (reduce the dose if needed). Compatible with pregnancy (consult a doctor for dosage). Food supplement. Not a substitute for a varied, balanced diet and a healthy lifestyle. Do not exceed the recommended daily dose. Keep out of reach of children.

How long before I feel the effects?

The first effects (fewer cramps, better sleep, less tiredness) appear within 1 to 2 weeks. The full effect requires 2 to 3 months of regular supplementation.

Can magnesium be taken continuously?

Yes, magnesium is not stored by the body. Continuous supplementation is possible, with a 1-2 week break every 3 months.

Herba Barona is an independent specialist supplement shop in the heart of Paris — established in 2006. What you order is genuinely on our shelves: we ship from our own stock, with no dropshipping and no long waits.

Visit us at 10 rue Théophile Roussel, Paris 12 — or use Click & Collect and pick up your order in-store. We also deliver across France and Europe. Friendly, expert advice in English from our team.

Where is the shop?

Herba Barona is at 10 rue Théophile Roussel, 75012 Paris — a two-minute walk from Ledru-Rollin (line 8), close to Bastille. Open Tuesday to Saturday, 9:30 am–6:30 pm.

Can I order online or collect in store?

Yes. We ship across France and Europe under the same conditions as our French store, or choose Click & Collect to pick up your order for free at our Paris shop.