Iron Deficiency and Oral Treatments: Limitations, Pharmacokinetics, and the Role of Iron Protein Succinylate in Clinical Practice.

Iron deficiency (ID) is the most prevalent nutritional disorder worldwide, affecting diverse populations including children, women of reproductive age, older adults and patients with chronic conditions. Oral iron supplementation remains the cornerstone of treatment, together with management of the underlying causes. However, conventional ferrous and ferric salts are often associated with gastrointestinal side effects, poor adherence and limited efficacy, especially in inflammatory settings due to hepcidin-mediated absorption blockade. This review summarizes iron absorption physiology, limitations of traditional oral therapies, and the potential benefits of iron protein succinylate (IPS), a ferric complex bound to succinylated casein. IPS provides pH-dependent release and contains succinic acid, which may enhance absorption while reducing gastrointestinal adverse events. Clinical studies indicate that IPS achieves hematologic outcomes comparable or superior to standard oral salts, fewer gastrointestinal effects and better tolerability. These properties make IPS suitable for patients who do not tolerate or respond adequately to conventional therapy. Special attention is given to chronic inflammation, pregnancy, cancer, or gastrointestinal disorders, where oral iron often fails due to impaired absorption or poorer tolerance. Practical recommendations are included to optimize supplementation through dosing strategies and tailored approaches. Overall, IPS offers an effective, better-tolerated alternative to conventional oral iron therapy.