Molasses: iron tonic, trial syrup, still a sugar

Molasses has a reputation as a sugar that is secretly a supplement. The trials behind that reputation mostly did not test the jar in your kitchen. One gave constipated children 1 mL/kg/day of a 40% blackstrap molasses syrup, one gave infants grape molasses as an iron treatment, and one stirred a filtered sugarcane concentrate into breakfast. Keep that in mind for everything below. Iron is the best-known claim, and it came out weaker than a plain iron supplement. In infants with iron deficiency anaemia, grape molasses raised blood iron by 27.0 micrograms/dL against 60.6 for ferrous sulfate. In infants who were not anaemic the two were level, at 23.0 and 23.8. In 92 children aged 4 to 12, a month of 1 mL/kg/day of a 40% blackstrap molasses syrup relieved constipation as well as polyethylene glycol (PEG), a standard laxative, and neither group reported side effects. The syrup was compared with PEG, and there was no placebo group. That is the only trial we have on it, and until a larger one repeats it, the result is promising and unsettled.

The numbers, per 100 g

How much is actually in it

• The 40% blackstrap molasses syrup used in the trial, given at 1 mL/kg/day, held 12430 micrograms of potassium, 3320 of calcium, 80 of iron and 960 of polyphenols per mL. — 92 children aged 4-12 with functional constipation, 1 mL/kg/day of a 40% syrup for 1 month (n = 92) Evidence D source
  K 12430, Ca 3320, Fe 80, polyphenols 960 microg/mL

What a real portion looks like

• Among Brazilian babies aged 6 to 12 months, 23.8% were already eating sugar foods such as honey, molasses and unrefined cane sugar. — 218 children aged 6-24 months, primary care, Macae, Brazil (n = 218) Evidence C source
  23.8% at 6-12 months, 31% at 12-18, 33.9% at 18-24

What your body absorbs

• In infants with iron deficiency anaemia, iron from grape molasses (pekmez, not cane molasses) raised serum iron by 27.0 micrograms/dL versus 60.6 for ferrous sulfate. — 56 children aged 6-36 months, 30 with iron deficiency anaemia and 26 without (n = 56) Evidence B source
  Serum iron rise 27.0 +/- 13.4 vs 60.6 +/- 17.0 microg/dL, p < 0.05
• In non-anaemic infants, grape molasses (pekmez, not cane molasses) and ferrous sulfate raised serum iron by a similar 23.0 and 23.8 micrograms/dL. — 56 children aged 6-36 months, 30 with iron deficiency anaemia and 26 without (n = 56) Evidence B source
  23.0 +/- 4.3 vs 23.8 +/- 10.0 microg/dL, p > 0.05

What it does to your health

• In 92 constipated children, 1 mL/kg/day of a 40% blackstrap molasses syrup for a month worked as well as polyethylene glycol syrup. — 92 children aged 4-12 with functional constipation, 1 mL/kg/day of a 40% syrup for 1 month (n = 92) Evidence B source
  No significant difference between groups, both improved
• Adding increasing doses of a filtered sugarcane molasses concentrate to a breakfast lowered insulin responses dose by dose in healthy adults, while glucose curves did not change across the 5 test meals. — healthy adults, standard breakfast with placebo syrup or 4 rising doses of molasses concentrate (n = not reported in abstract) Evidence B source
  Insulin lowered dose-dependently, glucose similar; size not reported in abstract; extract, not table molasses

Safety, limits and interactions

• No side effects were seen in 92 children given 1 mL/kg/day of a 40% blackstrap molasses syrup or PEG for one month. — 92 children aged 4-12 with functional constipation, 1 mL/kg/day of a 40% syrup for 1 month (n = 92) Evidence B source
  No adverse effects
• In records of 196 hospitalised adults given a milk and molasses enema by nursing staff, no serious enema-related harm was documented. — 196 hospitalised adults given a milk and molasses enema by nursing staff (n = 196) Evidence C source
  No serious adverse events recorded

What people believe that the data does not support

• In US labelling rules, the word light in light molasses describes colour or taste and is not a claim of fewer calories or less sugar. — US food labelling (n = -) Evidence E source
  Light molasses exempt from light nutrient claim rules

Who this works differently for

• Among 50 children, those with black tooth stain ate significantly more molasses, an iron-rich food, than those without. — 23 children aged 6-13 with black tooth stain and 27 without (n = 50) Evidence C source
  Higher molasses intake in black stain group, p <= 0.05

The bottom line

If you like the taste, use molasses the way you would use any other sweetener. The infant iron trial does not support using it in place of an iron supplement. When the anaemia was real, ferrous sulfate did more than twice the work. The breakfast finding sounds better than it is. Rising doses of the sugarcane concentrate lowered the insulin response step by step, while blood sugar curves stayed the same across all five meals. That was an extract in healthy adults, and it tells you nothing about pouring syrup on porridge if you have diabetes. The word light on a jar is also easy to misread. Under US labelling rules, light molasses means lighter in colour or flavour. It makes no promise of fewer calories or less sugar. For children, two things. A Brazilian study counted molasses among the sugar foods, alongside honey and cane sugar, and found 23.8 percent of babies aged 6 to 12 months already eating them. And in a small comparison of 50 children, those with black stain on their teeth ate more molasses than those without. That study shows the two go together. It cannot show that molasses causes the stain. The constipation trial gave 1 mL/kg/day of a 40% blackstrap molasses syrup, a diluted product dosed by the child's weight under supervision, so if your child is constipated, the dose belongs with your paediatrician and not with this page. The enema record in the safety section comes from 196 hospitalised adults treated by nursing staff, so it says nothing about eating molasses or about home use, and it did not test whether the enema worked. What we could not find matters too. No card here looks at molasses and blood sugar in people with diabetes, at kidney disease and its potassium, or at an upper limit for adults. On those questions the honest answer is that we do not know yet.

Sources

1. mols-b1-05 · lab analysis
   The BSM naturally contained polyphenols (960 μg/mL), potassium (12430 μg/mL), iron (80 μg/mL) and calcium (3320 μg/mL).
   J Ethnopharmacol, 2019 · checked 2026-09-23
2. mols-b1-09 · cross-sectional
   In contrast, 23.8% were already consuming sugar-based food sources (honey, molasses, simple sugar, and unrefined cane sugar), 34.7% industrialized juice, and 17.8% soft drinks.
   Cien Saude Colet, 2016 · checked 2026-09-23
3. mols-b1-01 · RCT
   The mean increase of serum iron in GM-given infants with IDA was 27.0 +/- 13.4 micrograms/ dl and in FS-given infants, 60.6 +/- 17.0 micrograms/dl (p < 0.05).
   Turk J Pediatr, 1997 · checked 2026-09-23
4. mols-b1-02 · RCT
   In the non-anemic group, the mean increase of serum iron of GM-given infants was 23.0 +/- 4.3 micrograms/dl, and that of FS-given infants, 23.8 +/- 10.0 micrograms/dl (p > 0.05).
   Turk J Pediatr, 1997 · checked 2026-09-23
5. mols-b1-03 · RCT
   Ninety-two patients were randomly divided in two groups of BSM or PEG syrups (40%) with a dose of 1 mL/kg body weight/day for 1 month... Treatment was successful with both interventions with no significant difference between the groups.
   J Ethnopharmacol, 2019 · checked 2026-09-23
6. mols-b1-06 · RCT
   The plasma glucose concentration curves were similar for the five test meals. Plasma insulin curves were lowered in a dose-dependent manner.
   Eur J Nutr, 2016 · checked 2026-09-23
7. mols-b1-04 · RCT
   No side -effects were observed.
   J Ethnopharmacol, 2019 · checked 2026-09-23
8. mols-b1-07 · retrospective cohort
   No cases of nontraumatic abdominal compartment syndrome or other serious adverse enema-related events were documented in the EHR.
   Am J Nurs, 2019 · checked 2026-09-23
9. mols-b1-10 · regulation
   (f) If a manufacturer can demonstrate that the word “light” has been associated, through common use, with a particular food to reflect a physical or organoleptic attribute (e.g., light brown sugar, light corn syrup, or light molasses) to the point where it has become part of the statement of identity, such use of the term “light” shall not be considered a nutrient content claim subject to the requirements in this part.
   21 CFR 101.56, Nutrient content claims for light or lite · checked 2026-09-23
10. mols-b1-08 · cross-sectional
    In the BS group, the mean intake of molasses, a food rich in iron, was significantly higher (p ≤ 0.05).
    BMC Oral Health, 2026 · checked 2026-09-23