Is it your iron? Two minutes will tell you more than the forum thread did.

Most tablets use iron salts like ferrous sulfate. Ferrous bisglycinate is iron bound to an amino acid. In a double-blind crossover trial, 38 women took both at the same 50 mg dose, two weeks each. Significantly more preferred the chelated form, and the researchers put that down to fewer side effects: bloating, constipation and nausea were all lower on it.

In a University of California, Davis study, iron from ferrous bisglycinate added to a maize porridge was taken up about four times as well as iron from ferrous sulfate: 6.0% against 1.7%.

Coplin et al., Clinical Therapeutics 1991⁵ · Bovell-Benjamin et al., American Journal of Clinical Nutrition 2000⁶

At ETH Zurich, forty young women with low iron stores took the same iron either every day or every other day. On alternate days they absorbed a larger share of it: 21.8% against 16.3%. The researchers put it down to hepcidin, the hormone that decides how much iron the gut lets through. It rises after each dose and takes about a day to settle.

That trial used doses far larger than a food sachet, in women with low iron stores, so we don't claim its numbers for bloodflo². We built the routine around it.

Stoffel et al., The Lancet Haematology 2017⁷

Vitamin C "contributes to iron absorption from food", in the words the Food Standards Code allows. Acerola, a small red cherry from South America and the Caribbean, holds around 50 times the vitamin C of an orange by weight: published figures run from 1,000 to 4,500 mg per 100 g, against about 50 mg for a peeled orange. We sourced it ourselves and put it in the same sachet.

FSANZ Schedule 4⁴ · Review of Natural Products⁸

Two university trials looked at women with periods, not anaemic, nothing a doctor would flag, who were tired without an obvious reason. In the BMJ trial, 144 women aged 18 to 55 took iron or a placebo for four weeks: fatigue scores fell 29% on iron and 13% on placebo. In the larger CMAJ trial from the University of Lausanne and the University of Geneva, 198 women took iron or placebo for 12 weeks: fatigue fell 47.7% on iron against 28.8% on placebo.

Both used prescription-strength doses, under a doctor. bloodflo² is a food, not a treatment, and this page can't tell you what your iron is doing. It's why the Food Standards Code lets a food with enough iron say that iron "contributes to the reduction of tiredness and fatigue".

Verdon et al., BMJ 2003⁹ · Vaucher et al., CMAJ 2012¹⁰ · FSANZ Schedule 4⁴

Exercise raises a hormone that makes the gut take in less iron for a few hours after a session, and hard training uses more of it. An Australian review by researchers at Edith Cowan University, the University of Western Australia and the WA Institute of Sport found "up to 35 percent of female athletes are iron deficient", against about 5 percent of the general population.

Sim et al., European Journal of Applied Physiology 2019¹¹

Researchers at the Florey Institute in Melbourne describe iron as vital for making the brain's chemical messengers, for the insulation around nerve cells and for the energy supply inside them. In the Code's words, iron "contributes to normal cognitive function".

Hare et al., Frontiers in Aging Neuroscience 2013¹² · FSANZ Schedule 4⁴

Two minutes now, and we do the remembering. One email the day bloodflo² is released, and The Blocker List to read in the meantime.

bloodflo² is a food, not a medicine, and we won't promise how you'll feel. What we can show you is what's in it, where it's made, and the research behind every decision, which is all on this page. The quiz costs two minutes and nothing else. There's nothing to buy yet.

Vanessa built it for herself first. Then 900 women took the quiz, aged 18 to 50 plus, and the answers barely moved with age. About four in ten take iron tablets, in every bracket. About one in five signed up because supplements upset their stomach, in every bracket. Whatever box you tick, you won't be the only one in it.