Comprehensive medication guide to Slow-Fe XR including estimated pricing, availability information, side effects, and how to find it in stock at your local pharmacy.
Estimated Insurance Pricing
Slow-Fe XR is an OTC supplement not covered by standard prescription insurance. FSA/HSA pre-tax dollars may be used for reimbursement. Medicaid patients may get prescription ferrous sulfate 325 mg tablets covered at $0–$3 copay.
Estimated Cash Pricing
$8–$15 retail for a 30-count bottle; $14–$20 for 60-count at major pharmacies and grocery stores. Generic extended-release ferrous sulfate available for as low as $4–$8 at Walmart, Target, and Costco.
Medfinder Findability Score
82/100
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Slow-Fe XR is a brand-name extended-release iron supplement containing ferrous sulfate — the form of oral iron most frequently recommended by doctors. Each tablet provides 45 mg of elemental iron (equivalent to 142 mg of ferrous sulfate) using a controlled-release hydrogel matrix that gradually releases iron over several hours, reducing the stomach irritation common with standard iron tablets.
Slow-Fe XR is classified as an over-the-counter (OTC) dietary supplement and does not require a prescription. It is available at major chain pharmacies, grocery stores, mass merchandisers, and online retailers across the United States. The product is manufactured by Alcon and holds the #1 doctor-recommended status among OTC iron-only supplement brands.
Iron deficiency affects approximately 12% of women aged 12–49 in the United States, making iron supplements one of the most commonly recommended OTC health products. Slow-Fe XR is particularly well-suited for patients who require long-term iron supplementation and have experienced nausea, constipation, or stomach cramping with immediate-release ferrous sulfate tablets.
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Slow-Fe XR delivers iron using a hydrogel matrix tablet that absorbs moisture in the stomach and gradually expands, releasing ferrous sulfate slowly over several hours. This controlled delivery prevents the sudden iron spike that causes nausea and stomach cramping with standard iron tablets, while still releasing iron primarily in the duodenum and upper jejunum where absorption is most efficient.
Once absorbed through the intestinal lining, iron binds to transferrin — the body's iron transport protein — which carries it to the bone marrow. There, iron is incorporated into hemoglobin inside developing red blood cells. Adequate hemoglobin allows red blood cells to carry oxygen efficiently throughout the body. Iron is also stored as ferritin in the liver and spleen for future use.
Clinical research confirms that slow-release iron technology reduces the incidence of abdominal pain and nausea by approximately 30% compared to standard ferrous sulfate tablets, making Slow-Fe XR a preferred option for patients who prioritize GI tolerability. A hormone called hepcidin regulates iron absorption — when iron stores are low, absorption increases; when replete, it decreases — making iron supplementation self-regulating in healthy adults.
45 mg elemental iron (142 mg ferrous sulfate) — extended-release tablet
Standard adult dose: 1 tablet daily
45 mg elemental iron (137 mg ferrous sulfate) — extended-release tablet
Alternate formulation; equivalent elemental iron dose
Slow-Fe XR receives a findability score of 82/100 — generally available nationally, but with intermittent gaps at individual pharmacies. There is no active FDA shortage as of 2026. However, the extended-release formulation is a specialty item not stocked by every pharmacy, and individual stores may experience stockouts due to high demand, limited shelf allocation, or irregular reorder cycles.
Patients who struggle to find Slow-Fe XR in stock should call ahead before visiting a pharmacy, or use medfinder to have multiple pharmacies checked at once. medfinder calls pharmacies near you to find out which ones have Slow-Fe XR in stock and texts you the results, eliminating the need for multiple phone calls.
Online ordering through Amazon, CVS.com, and Walgreens.com offers more consistent availability than in-store stock. When Slow-Fe XR is unavailable locally, asking your pharmacy to place a special order typically results in availability within 2–3 business days.
Slow-Fe XR is an OTC supplement that does not require a prescription. However, iron deficiency and iron deficiency anemia are medical conditions best managed with professional guidance. The following providers routinely diagnose iron deficiency and recommend or prescribe iron supplementation:
Primary care physicians (PCPs) and family medicine doctors
OBGYNs (especially for pregnancy and menstrual-related iron deficiency)
Hematologists (for complex or refractory iron deficiency anemia)
Gastroenterologists (for IDA secondary to IBD, celiac disease, or GI bleeding)
Nephrologists (for anemia in chronic kidney disease)
Nurse practitioners (NPs) and physician assistants (PAs)
Telehealth providers can evaluate iron deficiency symptoms and review lab results virtually, making Slow-Fe XR accessible through telehealth platforms. Since no prescription is required, a telehealth visit is a convenient option for patients seeking professional guidance without waiting for an in-person appointment.
No. Slow-Fe XR is not a controlled substance and is not scheduled under the DEA Controlled Substances Act. It is classified as an over-the-counter (OTC) dietary supplement and can be purchased without a prescription at any pharmacy, grocery store, or online retailer.
There are no special prescription requirements, refill restrictions, or prescription monitoring program (PDMP) considerations associated with Slow-Fe XR. Any adult can purchase it over the counter without provider involvement, though a physician evaluation is recommended before starting iron supplementation to confirm iron deficiency and rule out underlying causes.
Common side effects (expected and generally not dangerous):
Dark or black stools (universal and harmless)
Constipation
Nausea (significantly reduced compared to immediate-release iron)
Stomach cramping or epigastric discomfort
Diarrhea (less common)
Serious side effects (seek medical attention):
Signs of allergic reaction: hives, difficulty breathing, swelling of face/lips/tongue/throat
Bright red blood in stool (different from normal dark black stools)
Iron overdose in children — call Poison Control (1-800-222-1222) immediately
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Ferrous Gluconate (Fergon)
OTC alternative with 37 mg elemental iron per 300 mg tablet; marginally gentler on the stomach; widely available at most pharmacies.
Ferrous Fumarate (Ferro-Sequels)
Higher elemental iron content (106 mg per 322 mg tablet); some formulations include a stool softener; appropriate for more severe IDA requiring faster repletion.
Ferric Maltol (Accrufer)
FDA-approved prescription iron supplement (30 mg elemental iron per capsule) with excellent GI tolerability; for patients who cannot tolerate ferrous iron supplements.
Iron Polysaccharide Complex (Niferex)
Non-ionic OTC/Rx iron supplement available in 60–150 mg elemental iron doses; some patients find it easier on the stomach; available as tablets or liquid.
Prefer Slow-Fe XR? We can find it.
Levothyroxine (Synthroid)
majorIron significantly reduces levothyroxine absorption. Separate doses by at least 4 hours.
Tetracycline antibiotics (doxycycline, minocycline)
majorIron chelates tetracyclines, reducing antibiotic absorption. Separate by 2–4 hours.
Fluoroquinolone antibiotics (ciprofloxacin, levofloxacin)
majorIron chelation significantly reduces fluoroquinolone blood levels. Separate by 2 hours before or 6 hours after iron.
Eltrombopag (Promacta)
majorContraindicated concurrent use; iron reduces eltrombopag levels. Separate by at least 4 hours.
Antacids / calcium supplements
moderateAntacids reduce iron absorption by raising gastric pH. Calcium competes with iron for absorption. Separate by 2 hours.
Proton pump inhibitors (omeprazole, pantoprazole)
moderatePPIs reduce gastric acid and may modestly reduce iron absorption.
Levodopa/carbidopa (Sinemet)
moderateIron chelates levodopa and carbidopa, reducing absorption. Separate by at least 2 hours.
Slow-Fe XR is a proven, high-quality iron supplement that delivers 45 mg of elemental iron per tablet in a format specifically engineered to minimize the GI side effects that cause many patients to abandon iron therapy. For patients who have struggled with nausea, constipation, or stomach pain on standard ferrous sulfate tablets, the extended-release format represents a meaningful clinical improvement in tolerability.
The key challenges with Slow-Fe XR are availability and cost. As an OTC supplement, it is not covered by most insurance plans, and the branded product can cost $10–$20 per month. Switching to a generic extended-release ferrous sulfate equivalent and purchasing through the most affordable retailer can significantly reduce this expense. Additionally, individual pharmacy availability can be inconsistent, so patients should be prepared to check multiple locations.
If you're having difficulty finding Slow-Fe XR in stock at your local pharmacy, medfinder can help — it calls pharmacies near you to find which ones have it available and texts you the results, so you can spend less time searching and more time focusing on your health.
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Our medication guides are researched and written to help patients make informed decisions. All content is reviewed for accuracy and updated regularly. Learn more about our standards
Real-time availability
Medfinder is actively checking pharmacy inventory for Slow-Fe XR. We don't publish a number until we have enough verified pharmacy checks to be accurate — start a search and our team confirms current availability near you, usually within 24 hours.
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