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What's the difference between elemental iron, ferrous sulfate, and dried ferrous sulfate?

I'm still trying to figure out iron supplements. 

Slow Fe (what I'm supposed to be taking) lists ferrous sulfate as the main ingredient, but the box also says it as 45mg of elemental iron, and that 45mg of elemental iron is equal to 142mg of ferrous sulfate. 

I had to purchase a store brand again because they were out of Slow Fe, and I started getting tired again, so I double checked the label. The store brand also claims to be 45mg of iron, and lists ferrous sulfate as the main ingredient, but it says nothing about elemental iron. I contacted the company that made it to see if one pill is really an exact match for Slow Fe and they won't tell me how the two compare. 

To further confuse things, I found a third empty bottle from a different brand in my stash- one I don't remember having an issue with- and it also says it's 45mg, but mentions specifically that it's dried ferrous sulfate, which supposedly makes it more potent. 

How are these different products all able to market themselves as being 45mg iron supplements when they're all made differently and may well have different levels of potency? Gah!

Posted - December 22, 2017
Tags : None

Responses


  • 3191
    Elemental iron content is what is important, all contain it.  Regular ferrous sulfate is about 20% elemental, while dried is around 30%.  Additionally, Slow Fe is a sustained-release tablet.  Here's a link, but your best bet is to double check with your doctor and/or pharmacist.

    https://theironmaiden.ca/supplementation-options-for-adults/
      December 22, 2017 12:41 PM MST
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  • 7938
    Thanks. Only SlowFe mentions elemental iron, so no guess as to how much the others really contain, and the manufacturer couldn't or wouldn't tell me anything beyond "read the bottle," which didn't tell me squat. They intentionally marketed it as a Slow Fe replacement, but it didn't specify it was dry ferrous sulfate, so either it's not or they just aren't mentioning it, which means I really could have been getting the exact same thing or not. Bah. Great resource, though- thank you!
      December 22, 2017 4:06 PM MST
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  • 3191
    For standard ferrous sulfate, multiply by 20%.  So 325 mg ferrous sulfate = 65 mg elemental iron.  Dried is ~ 30%.  I did see an article in a pharmaceutical pub that said this unclear labeling on iron supplements is a problem.  
      December 22, 2017 4:29 PM MST
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  • 7280
    That's a great question for a pharmacist. 

    If I recall correctly, the uptake of iron is synergized by certain foods and minimized by others.

    And dosage equivalency is their forte 

    They love to assist you  with stuff like that.
      December 22, 2017 1:43 PM MST
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  • 7938
    The pharmacist can only help me if the manufacturer provides the data, and in this case, even a message to the company that made the supplement didn't clear it up.  
      December 22, 2017 4:08 PM MST
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  • 7280
    Is that what the pharmacist said to you when you asked?
      December 22, 2017 4:55 PM MST
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  • 7280
    If a non-prescription compound is sold in his pharmacy, I can't believe the pharmacist doesn't know what it contains.
      December 22, 2017 5:11 PM MST
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  • 7938
    It was a grocery store and I was told to take it as directed on the bottle and not to compare the two. To be blunt, I don't think his English was great.
      December 22, 2017 5:46 PM MST
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  • 6988
    Well, you could always suck on a clean nail for several hours every day.  Same results.
      December 22, 2017 2:08 PM MST
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  • 44519
    Why clean...she licks doorknobs for fun.
      December 22, 2017 2:18 PM MST
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  • 7938
    Exactly. And, I eat nails for breakfast. 
      December 22, 2017 4:08 PM MST
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  • 22891
    not sure, never heard of it, you could try goggling it
      December 22, 2017 3:39 PM MST
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  • 5835
    Iron(II) sulfate (British English: iron(II) sulphate) or ferrous sulfate denotes a range of salts with the formula FeSO4·xH2O. These compounds exist most commonly as the heptahydrate (x = 7) but are known for several values of x. ~ Wikipedia.org

    All the iron(II) sulfates dissolve in water to give the same aquo complex [Fe(H2O)6]2+ so it is pointless to weigh the amount of chemical. What you care about is the amount of iron in a dose, so that is the number they put on the label. That is called "elemental iron".
      December 22, 2017 4:11 PM MST
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  • 7938
    Hmmm I see what you're saying. I wish the bottles were labeled in a more uniform way because they all read like different products. 
      December 22, 2017 4:41 PM MST
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  • 7280
    The iron in your body is called "elemental iron."

    Oral iron supplements contain different amounts of elemental iron. When you choose a supplement, be sure to check the label to see how much elemental iron it contains; a greater amount means that more iron will be absorbed by your body.

    How much iron supplementation do I need?

    Your doctor will tell you how much iron you need to take every day. Typically, adults need to get between 60 and 120 mg of iron a day. The best way to take the supplement so that you absorb the greatest amount of iron is to take it in two or more doses during the day.

    Please note the following:

    Although the supplements work best on an empty stomach, you may want to take them with food so that they don't upset your stomach.
    You shouldn't take iron supplements with milk, caffeine, antacids, or calcium supplements. These can decrease the amount of iron that is absorbed.
    Try to take your iron supplement with vitamin C (for example, a glass of orange juice) to increase absorption.
    When you should start to feel better depends on your particular situation. Normally, it may take from a week to a month (after you start your iron supplement) before you start to feel better. Continue to watch your symptoms and take note of side effects that might be caused by the supplements. If you have any questions or concerns, talk to your health care provider.

    https://my.clevelandclinic.org/health/articles/14568-oral-iron-supplementation
      December 22, 2017 5:17 PM MST
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  • 7280
    Bozette gave you 2 formula:  Ferrous sulfate in pill / tablet form contains 20% of its weight as elemental iron.  So multiply the milligrams of ferrous sulfate by .2 to get the amount of elemental iron in the pills.   .2 x 325mg = 65 milligrams of elemental iron.

    Ferrous sulfate in dried form (powder, I'm guessing) contains 30% elemental iron---so multiply the milligrams of ferrous sulfate in whatever dosage of powder you might take by .3 to get the milligrams of elemental iron in the dried ferrous sulfate dosage.

    Dosage Forms & Strengths  (For Slow Fe from the website below)

    oral solution

    • 220mg (44mg Fe)/5mL
    • 300mg (60mg Fe)/5mL
    • 15 mg elemental Fe/mL

    oral liquid drops

    • 75mg (15mg Fe)/mL

    tablet

    • 45mg elemental Fe
    • 200mg (65mg Fe)
    • 300mg (60mg Fe)
    • 325mg (65mg Fe)

    tablet, delayed release

    • 325mg (65mg Fe)

    tablet, extended release

    • 160mg (50mg Fe)
    • 142mg (45 mg Fe)
    • 140mg (45 mg Fe)
    https://reference.medscape.com/drug/slow-fe-fer-in-sol-ferrous-sulfate-342161

    Your generic "Slow Fe"  may well have less elemental iron than the original. 

    That's what the generic label will tell you (or allow you to calculate using the 20% equation.)

    (Edit of format failed---not edited) This post was edited by tom jackson at December 22, 2017 5:50 PM MST
      December 22, 2017 5:41 PM MST
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  • 7938
    Thank you!
      December 22, 2017 5:50 PM MST
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  • Best to check with a doctor, preferably one with a specialty in conditions caused or affected by nutrition.
    Excessive iron can cause poisoning.
    Lower levels of excess can prevent the absorption of calcium.
    Some medical conditions can make iron dangerous.
    Many alternatives believe chelated minerals (i.e. bound into organic substances) are easier to absorb and metabolise.

      December 22, 2017 6:22 PM MST
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  • 7938
    My doctor specifically told me to take Slow Fe, which is why I always try to get that one by name. Unfortunately, it's out of stock at lot at multiple grocery stores, so I sometimes substitute for an off brand. If I spoke to her about this, she'd give me the eye and tell me to go find what she told me to have in the first place. lol But, I hate shopping, and I certainly don't want to be dragging my kids from store to store this time of year looking for it, so I hoped the wonderful people of aM would know more than I do on the topic. I do well on what I normally take. It's just when I switch brands that I have an issue. Maybe I should start buying in bulk. :o
      December 22, 2017 9:01 PM MST
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  • 5835
    Doctors have no training in nutrition. Some doctors have confronted me on that point, claiming to be "registered dietitians." They don't even know the difference between a nutritionist and a dietitian. There are some nutritionist MDs, but you are unlikely to get an appointment with one. 
      December 24, 2017 7:56 PM MST
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  • Would it be possible to order Slow Fe online?
      December 22, 2017 11:04 PM MST
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  • 7938
    Yes, which is what I'll probably start doing or I'll keep at least an extra month on hand at home. This was just a fluke and by the time I realized I wasn't getting what I needed, I had already been on the other supplement for close to two weeks, and it takes a full two weeks to rebuild your iron stores. So, the sooner I could start rebuilding my stores, the better, and if I could do so safely with what I had on hand, that would make life easier. When you know you've got two weeks of feeling crappy ahead of you, waiting for a delivery on top of it stinks. So, yeah... the obvious answer here is to not run out of what my doctor recommended, and to keep extra on hand, order online, or whatever so I don't run out again. In the here-and-now, with the hand I have, I was just trying to understand the differences better. I had already self-adjusted my dose to what I thought was the right level, but I couldn't find some of the resources others linked here to verify it, and neither the pharmacist nor manufacturer were helpful, so I thought perhaps the Muggers might be. Indeed, they were. 
      December 23, 2017 12:42 PM MST
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  • 6988
    Do you like the band 'Iron Maiden'?
      December 23, 2017 6:53 AM MST
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  • 7938
      December 23, 2017 12:46 PM MST
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