21st Century Slow Release Iron Tablets — 60 Count

Slow and Steady Wins the Race

Standard iron tablets release everything at once — which is part of why they cause constipation and nausea for so many people. 21st Century Slow Release Iron works differently. The tablet is designed to dissolve gradually, releasing iron steadily over several hours rather than all at once. The result is more consistent absorption and significantly less digestive disruption.

Why Slow Release Matters

When iron floods the gut all at once, the excess that isn't immediately absorbed sits in the intestine and causes irritation. Slow release solves this by spacing out delivery so your body absorbs what it needs as it moves through the digestive tract — reducing the unabsorbed iron that causes side effects.

• Gentler on the stomach — less nausea and cramping than immediate-release iron
• Less constipation — the most common reason people stop taking iron
• High potency formula — effective for replenishing low iron stores
• Gluten free — suitable for those with gluten sensitivity

The Best-Selling Choice

With over 14,500 reviews at 4.6 stars and Amazon's Overall Pick badge, this is the most purchased iron supplement on this page by a significant margin. The price point — starting under $5 for a 60-count bottle — makes it accessible for anyone who wants to address iron deficiency without a large upfront cost.

Good to Know

At one tablet per day, the 60-count bottle is a 2-month supply. A pack of 2 and pack of 3 are available for better value. If you are new to iron supplementation and want to test how your body responds before committing to a premium formula, this is an ideal starting point.