What chelated minerals are — and why bisglycinate zinc and iron are gentle on the stomach

Labels that say "Zinc Bisglycinate" or "Ferrous Bisglycinate" rather than "Zinc Sulfate" are telling you the mineral is chelated — a small detail with a real effect on daily use.

What a chelate is

From the Greek chele, "claw": a molecule that grips a mineral ion at more than one point. In a bisglycinate, one zinc or iron ion is bound by two glycine molecules in a stable ring [1]. The mineral is not floating free in the stomach, so it reacts less with food and with the gut lining.

Absorption

In healthy volunteers, zinc bisglycinate produced higher blood zinc than zinc gluconate at the same elemental dose [2], while zinc oxide — the cheap, common form — is absorbed clearly less well than other forms [3]. For iron, a randomised trial in pregnant women found 25 mg of iron as bisglycinate was not inferior to 50 mg as sulfate for preventing iron deficiency and anaemia [4], and a 2023 systematic review of 17 randomised trials found slightly higher haemoglobin with bisglycinate in pregnant women and no difference in children [5].

Always read the label as elemental amount: Zinc Bisglycinate 75 mg provides 15 mg zinc; the rest is glycine [6].

Stomach comfort

Nausea, constipation and stomach pain are why many people stop taking iron. In Milman's trial, the low-dose bisglycinate group reported significantly fewer gastrointestinal complaints than the sulfate group [4], and the 2023 review found about two-thirds fewer reported GI events with bisglycinate [5]. High-dose zinc salts are likewise a well-known cause of nausea [6]. A chelated form at a sensible dose makes "every day" realistic.

Safety

EFSA evaluated ferrous bisglycinate as a source of iron in foods and supplements and found no safety concern at intakes within the recommended levels for iron [1]. The glycine released is an ordinary amino acid the body already uses.

In short

• Chelate = mineral bound to an amino acid, not a free mineral salt
• Bisglycinates absorb well and are gentler than sulfate or oxide at equivalent doses
• Compare elemental amounts
• The right dose beats a high dose — more than 40 mg zinc a day long-term can interfere with copper absorption [6]

The zinc, iron and selenium in U-TURN are glycinates. Biotin, zinc and selenium contribute to the maintenance of normal hair, for people who do not get enough from food each day. One capsule a day with the first meal of the day, or whichever meal suits you · Dietary supplement; not intended to prevent or treat any disease.