Verified
“65 mg elemental ferrous sulfate is effective for repletion”
Ferrous sulfate is the long-standing reference iron for correcting deficiency; 65 mg elemental is a standard effective repletion dose.
Reviewed
Verified by SAC team
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Best Budget
Nature Made
Nature Made Iron 65 mg (Ferrous Sulfate) Review
6.6/10SAC Product Score™
It works and it is dirt cheap, which is exactly the trap. Ferrous sulfate at 65 mg is the classic reference iron and it will replete you — but it also causes the most GI complaints of anything here (Tolkien 2015), and gentler chelates match its efficacy at lower doses (Milman 2014). Buy it only if you tolerate it and cost is decisive.
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Read the complete Iron guide →How we built the SAC Product Score™ — 6.6/10
Form & Bioavailability30%6/10
Ferrous sulfate is the classic reference iron — effective and well-absorbed, but not optimized for tolerance, and gentler chelates match its efficacy at lower doses (Milman 2014).
Dose Appropriateness20%7/10
65 mg elemental is an effective repletion dose, but the high dose compounds the tolerability problem inherent to ferrous sulfate.
GI Tolerance & Safety20%4/10
The weakest score in the set: ferrous sulfate drives the highest rate of nausea and constipation of any form, roughly doubling GI side-effect risk versus placebo (Tolkien 2015).
Third-Party Testing & Purity20%8/10
USP Verified (brand-stated) and free of artificial dyes and gluten — a genuine product-level verification and the strongest testing credential among the budget picks.
Value per Serving10%10/10
At ~$0.05 per tablet across a 180-day supply, it is the cheapest pick by a wide margin.
The product at a glance
- Form
- Ferrous sulfate (325 mg salt)
- Elemental iron
- 65 mg per tablet
- Size
- 180 tablets (180-day supply)
- Testing
- USP Verified (brand-stated)
- Free-from
- Artificial dyes, gluten
- Serving
- 1 tablet daily
- Price (approx.)
- ~$9.50
- Cost / serving
- ~$0.05
Marketing claims vs. reality
Verified
“USP Verified for identity and potency”
USP Verified is a genuine product-level verification of identity, potency and manufacturing quality; it is stated for this product, making it the strongest testing credential among the cheapest picks.
Verified
“Cheapest per serving of any pick”
At ~$0.05 per tablet across 180 tablets, it is the lowest cost-per-serving in the set by a clear margin.
Partial
“An effective and well-tolerated everyday iron”
Effective, yes; well-tolerated, no — ferrous sulfate causes the most GI side effects of any form (OR 2.32 vs placebo; Tolkien 2015, PMID 25700159), and chelates match its efficacy at lower doses with fewer complaints (Milman 2014, PMID 24152889).
Partial
“A #1 pharmacist-recommended brand”
This is a brand-level marketing distinction, not a product-specific or independently audited claim about this iron's tolerability or efficacy.
What our test actually found
01It genuinely works
Ferrous sulfate is the reference iron for a reason — it reliably replaces iron stores, and at 65 mg elemental this is a full repletion dose. On raw efficacy for a confirmed deficiency, it is not the problem.
02Tolerance is the catch, not price
The reason it ranks last is not cost — it is the gut. A meta-analysis of 6,831 people found ferrous sulfate roughly doubled GI side-effect risk versus placebo, with no relationship to dose (Tolkien 2015). Many people simply cannot stay on it.
03Chelates match it for less discomfort
A randomized trial showed 25 mg bisglycinate matched 50 mg ferrous sulfate for preventing deficiency, with fewer GI complaints (Milman 2014). So you can get the same result at a lower dose and a gentler experience — for about a dollar more.
04The one credential it wins on
USP Verified is a real product-level check on identity and potency, and this product states it — a genuine advantage over the untested budget options. On a nickel-a-tablet iron, that is a meaningful reassurance.
Pros & cons, no sugar-coating
Pros
- 65 mg elemental from the classic reference iron — effective for repletion
- Cheapest per-serving pick by a wide margin (~$0.05)
- USP Verified; a mainstream pharmacist-recommended brand
- 180-tablet supply
- Free of artificial dyes and gluten
Cons
- Ferrous sulfate drives the highest rate of nausea and constipation of any form
- 65 mg high dose compounds the tolerability problem
- Cheap, but tolerability — not price — is the reason it ranks low
The budget baseline — and the tolerance trap
It works and it is dirt cheap, which is exactly the trap. Ferrous sulfate at 65 mg causes the most GI complaints of anything here (Tolkien 2015), and gentler chelates match its efficacy at lower doses (Milman 2014). Buy it only if you tolerate it and cost is decisive — otherwise the extra dollar for a chelate is the best money you will spend. Take only with confirmed deficiency.
Check Nature Made on AmazonIf this doesn’t fit — try these
Thorne Iron Bisglycinate 25 mg
9.2/10The gentle, certified chelate worth the extra dollar for most people.
See it on the list →Nutricost Iron Bisglycinate 25 mg
8.8/10A gentle chelate at nearly budget pricing — the smart upgrade from ferrous sulfate.
See it on the list →Vitron-C High Potency Iron + Vitamin C
6.8/10A high-dose alternative in a safer carbonyl form with added vitamin C.
See it on the list →Sources & further reading
- Tolkien Z, et al. PLoS One. 2015;10(2):e0117383.Tolkien Z, Stecher L, Mander AP, Pereira DIA, Powell JJ · 2015 · PLoS One · PMID 25700159
Ferrous sulfate supplementation causes significant gastrointestinal side-effects in adults: a systematic review and meta-analysis
Across 43 trials and 6,831 participants, ferrous sulfate roughly doubled GI side-effect risk versus placebo (OR 2.32), with no relationship to dose.
- Milman N, et al. J Perinat Med. 2014;42(2):197-206.Milman N, Jønsson L, Dyre P, Pedersen PL, Larsen LG · 2014 · Journal of Perinatal Medicine · PMID 24152889
Ferrous bisglycinate 25 mg iron is as effective as ferrous sulfate 50 mg iron in the prophylaxis of iron deficiency and anemia during pregnancy in a randomized trial
A 25 mg chelate matched a 50 mg ferrous sulfate dose for preventing deficiency, with fewer GI complaints — showing gentler forms match efficacy at lower doses.
- Stoffel NU, et al. Lancet Haematol. 2017;4(11):e524-e533.Stoffel NU, Cercamondi CI, Brittenham G, et al. · 2017 · The Lancet Haematology · PMID 29032957
Iron absorption from oral iron supplements given on consecutive versus alternate days and as single morning doses versus twice-daily split dosing in iron-depleted women
Alternate-day dosing improved fractional absorption and can reduce the GI exposure of high daily iron doses.