Nature Made Iron 65 mg (325 mg Ferrous Sulfate)

Our assessment

The evidence shows that Nature Made Iron 65 mg (325 mg Ferrous Sulfate) is a standard dose supplement used to address iron deficiency. However, you should be aware that this product contains only iron, and data on calcium is provided for context. The FDA has received a total of 592,059 adverse event reports across all supplements, but specific report counts for this exact product are not available in the provided data [FDA data].

How it works

Iron is essential for making hemoglobin, the protein in red blood cells that carries oxygen to your tissues. When you take this supplement, the ferrous sulfate form is absorbed in your small intestine to help restore healthy iron levels. For comparison, calcium supports bone mineralization and neuromuscular relaxation, but this product does not contain calcium [NIH ODS].

Safety profile

Data not available for specific side effects of this iron product from the provided FDA data. However, general safety information for calcium — a different mineral — notes that high levels can cause constipation, nausea, weight loss, extreme tiredness, and abnormal heart rhythms [NIH ODS]. Calcium can also reduce absorption of medications like bisphosphonates, tetracycline antibiotics, and levothyroxine [NIH ODS]. These findings do not apply directly to iron supplements.

Our recommendation

Start by having your healthcare provider check your iron levels before supplementing. Take this product on an empty stomach for best absorption, but with food if you experience stomach upset. Avoid taking it within two hours of calcium-rich foods or medications, as calcium can interfere with iron absorption. Do not exceed the recommended dose without medical supervision [NIH ODS] [FDA data].

Supplement labels contain several key sections regulated by the FDA:

• Serving Size — The recommended amount per dose. Always check this — some products require multiple capsules per serving.
• Amount Per Serving — Shows the quantity of each nutrient in the product, typically in IU (International Units), mg (milligrams), or mcg (micrograms).
• % Daily Value (%DV) — Indicates how much a nutrient in a serving contributes to a daily diet. 5% DV or less is low; 20% DV or more is high.
• Other Ingredients — Lists inactive ingredients like fillers, binders, and capsule materials (e.g., gelatin, cellulose, magnesium stearate).
• Suggested Use — The manufacturer's recommended directions for taking the supplement, including timing and dosage.

Source: FDA Dietary Supplement Labeling Guide