Peanut flour: a pantry protein that allergy clinics dose by the milligram

A Cochrane review of peanut oral immunotherapy found one small randomized trial, 28 children aged 1 to 16, in which all 16 who completed peanut flour treatment tolerated 5,000 mg of peanut protein. Nine of 19 needed antihistamines for reactions, 2 needed epinephrine, and the reviewers concluded the treatment could not be recommended. That search dates from 2012 and larger trials followed. In 120 people aged 7 to 55, 35 percent on peanut flour passed a 4,000 mg challenge against 4 percent on oat flour placebo (odds ratio 12.7, 95% CI 1.8 to 554.8), and only 13 percent still passed a year after stopping. In 201 children aged 1 to 10, 18 months of defatted peanut flour left 51 percent tolerant against 5 percent on placebo, with treatment-related side effects in 88 percent. All of this is medical treatment under supervision. Palforzia, the approved product, is peanut flour made to drug standards, and a bag from the shop is no substitute.

The numbers, per 3.5 oz (100 g)

How much is actually in it

• USDA lists low fat peanut flour at 33.8 g of protein and 21.9 g of fat per 3.5 oz (100 g), while fully defatted peanut flour carries 52.2 g of protein and only 0.55 g of fat. — USDA SR Legacy records Peanut flour, low fat and Peanut flour, defatted (n = 2 records) Evidence E source
  Low fat: 428 calories, protein 33.8 g, fat 21.9 g, fiber 15.8 g per 3.5 oz (100 g); defatted: 327 calories, protein 52.2 g, fat 0.55 g per 3.5 oz (100 g)

What a real portion looks like

• A cup of peanut flour weighs about 2.1 oz (60 g) by USDA, which gives about 20 g of protein for low fat flour and 31 g for defatted flour. — USDA SR Legacy portion for Peanut flour, low fat and defatted (n = 2 records) Evidence E source
  1 cup = 60 g; protein per cup about 20.3 g (low fat) and 31.3 g (defatted), recalculated from 100 g

What your body absorbs

• In a feeding study of 63 adults, people eating peanut flour lost less fat in their stool than people eating whole peanuts, 3.75% against 5.22% of stool weight. — 63 healthy men and women from Ghana, Brazil and USA, 15 to 16 per group, whole peanut, butter, oil or flour (n = 63) Evidence C source
  Fecal fat 3.75% (flour) vs 5.22% (whole peanuts); fecal energy 18.5 vs 21.4 kJ/g

What cooking and storage change

• In a consumer test of extruded and fried snacks made with 12% fat peanut flour, products with 50% peanut flour scored lowest, about 5.5 on a 9-point liking scale. — consumer panel rating puffed snacks with 30%, 40% or 50% partially defatted peanut flour Evidence B source
  Overall liking 5.5 of 9 at 50% peanut flour; optimum around 42 to 45% peanut flour

What it does to your health

• In an RCT on 39 untrained adults with an average age of 58.6, a daily defatted peanut powder shake with 30 g of protein during 6 to 10 weeks of strength training added thigh muscle thickness but not lean mass. — 39 untrained adults, age 58.6, resistance training twice weekly for 6 or 10 weeks, 75 g peanut powder daily vs no supplement (n = 39) Evidence B source
  Greater vastus lateralis thickness (interaction p = 0.041), no difference in DXA lean mass or fat mass

Safety, limits and interactions

• In a double-blind challenge of 14 adults with peanut allergy given commercial peanut flour, as little as 100 micrograms of peanut protein caused symptoms in some of them. — 14 adults with challenge-proven peanut allergy, doses 10 ug to 50 mg (n = 14) Evidence B source
  One systemic reaction at 5 mg peanut protein, objective reactions at 2 mg and 50 mg, subjective symptoms from 100 ug
• In 27 peanut-sensitized children challenged with peanut flour, 22 reacted and the highest dose with no reaction was 1 mg of flour, about 2 mg of whole peanut. — 27 peanut-sensitized children, representative of 96 eligible, 9 doses from 10 ug to 3 g peanut flour (n = 27) Evidence C source
  81% positive challenge; NOAEL 1 mg peanut flour (2 mg whole peanut)
• A Cochrane review found one small RCT where 16 of 16 children on peanut flour immunotherapy tolerated 5,000 mg of peanut protein, but 47% had reactions needing treatment and it could not be recommended. — 28 children aged 1 to 16 with peanut allergy, one RCT, peanut flour vs oat flour placebo, about one year (n = 28) Evidence A source
  All 16 per-protocol OIT children tolerated 5000 mg vs placebo median 280 mg; 9 of 19 (47%) had adverse events needing antihistamines, 2 needed epinephrine
• In an RCT on 201 children aged 1 to 10 with peanut allergy, 18 months of oral immunotherapy with defatted peanut flour led to sustained tolerance in 51% against 5% on placebo. — 201 children aged 1 to 10 with food-challenge-confirmed peanut allergy, 18 months of treatment, 2000 mg peanut protein maintenance (n = 201) Evidence B source
  Sustained unresponsiveness 42/83 (51%) OIT, 36/79 (46%) probiotic plus OIT, 2/39 (5%) placebo; treatment-related adverse events 88% OIT
• In an RCT on 120 people aged 7 to 55 with peanut allergy, peanut flour immunotherapy let 35% pass a 4,000 mg challenge against 4% on placebo, but tolerance faded after stopping. — 120 participants aged 7 to 55 with peanut allergy, peanut flour built up to 4000 mg protein to week 104 vs oat flour placebo (n = 120) Evidence B source
  Passed 4000 mg at weeks 104 and 117: 35% vs 4% (OR 12.7, 95% CI 1.8 to 554.8); only 13% still passed at week 156 after stopping
• FDA approved Palforzia, a peanut allergen powder, for children aged 1 to 3 in July 2024 after its 2020 approval for ages 4 to 17, and users must still avoid peanuts. — children with confirmed peanut allergy Evidence E source
  Approval of oral immunotherapy product (no effect size)

What people believe that the data does not support

• A case report describes a systemic allergic reaction in a woman who ate about 45 mg of peanut protein from peanut flour hidden in a soup flavoring. — one 33-year-old peanut-sensitive woman (n = 1) Evidence D source
  Systemic reaction after about 45 mg peanut protein, treated in emergency room

Who this works differently for

• In a trial on 336 malnourished toddlers in Sierra Leone, adding a peanut flour based paste to feeding program rations shortened recovery from about 8.2 to 5.5 weeks. — malnourished children, mean age 14 months, feeding program alone vs plus peanut flour, palm oil, milk powder mix (n = 336) Evidence B source
  Best weight-for-height gain in 64% vs 21%; recovery 5.54 vs 8.16 weeks; not recovered 13% vs 25.3%

The bottom line

In the kitchen it is ground peanuts with part of the fat pressed out. USDA lists low fat peanut flour at 33.8 g of protein and 21.9 g of fat per 3.5 oz (100 g), and fully defatted flour at 52.2 g of protein and 0.55 g of fat, from two legacy records with no spread. Commercial flours sit between the two at 12 or 28 percent fat. A cup weighs about 2.1 oz (60 g), which works out to roughly 20 g of protein for low fat flour and 31 g for defatted. Grinding changes how much fat you absorb. In a feeding study of 63 adults from Ghana, Brazil and the USA, stool fat was 3.75 percent of stool weight on peanut flour against 5.22 percent on whole peanuts, so less of the fat left the body unused. In a randomized trial on 39 untrained adults with an average age of 58.6, everyone did 6 to 10 weeks of strength training. A daily 75 g peanut powder shake with 30 g of protein thickened one thigh muscle more than training alone (p = 0.041 in pooled groups). Lean mass on the body scan did not differ, there was no placebo, and the powder maker was involved. In 336 malnourished toddlers in Sierra Leone, a paste of peanut flour, palm oil, milk powder and sugar added to feeding rations cut recovery from about 8.2 to 5.5 weeks, in a poorly reported trial that may have been retrospective. The caution is peanut allergy, and the amounts are tiny. In a double-blind challenge of 14 allergic adults given commercial peanut flour, some had symptoms from 100 micrograms of peanut protein, and one had a systemic reaction at 5 mg. In 27 sensitized children, 22 reacted, and the highest dose with no reaction was 1 mg of flour, in a non-randomized challenge. One case report describes a woman who reacted to about 45 mg of peanut protein from peanut flour hidden in a soup flavoring. FDA extended Palforzia to children aged 1 to 3 in July 2024, and people who take it must still avoid peanuts. We found nothing on peanut flour in pregnancy or kidney disease.

Sources

1. pfl-r2-01 · USDA FoodData Central SR Legacy, dataset
   Peanut flour, low fat (FDC 172435, SR Legacy): energy 428 kcal, protein 33.8 g, fat 21.9 g, fiber 15.8 g per 100 g; Peanut flour, defatted (FDC 174267, SR Legacy): energy 327 kcal, protein 52.2 g, fat 0.55 g per 100 g
   USDA FoodData Central, SR Legacy, FDC 172435 and 174267 · checked 2026-09-29
2. pfl-r2-02 · USDA FoodData Central SR Legacy, dataset
   Peanut flour, low fat (FDC 172435) and Peanut flour, defatted (FDC 174267): portion 1 cup = 60.0 g; protein 33.8 g and 52.2 g per 100 g
   USDA FoodData Central, SR Legacy, FDC 172435 and 174267, portion 1 cup · checked 2026-09-29
3. pfl-r2-03 · controlled feeding study
   Compared to control, the percentage of fat in the feces increased significantly for the P group (5.22+/-0.29%) relative to the other three groups ((PO=3.07+/-0.36%, PB=3.11+/-0.31% (P=0.001), and PF=3.75+/-0.40% (P=0.019)).
   Int J Obes (Lond), 2008 · checked 2026-09-29
4. pfl-r2-04 · sensory trial
   The product extruded with 50% peanut flour at screw speed of 400 rpm and feed rate of 6 kg/h received the lowest score of 5.5 on overall liking in a 9-point hedonic score.
   J Food Sci, 2007 · checked 2026-09-29
5. pfl-r2-12 · RCT
   There was, however, a significant increase in VL thickness in PP versus CTL participants when the 6- and 10-week cohorts were pooled (interaction p = 0.041).
   J Int Soc Sports Nutr, 2020 · checked 2026-09-29
6. pfl-r2-05 · RCT
   As little as 100 microg of peanut protein provokes symptoms in some subjects with peanut allergy.
   J Allergy Clin Immunol, 1997 · checked 2026-09-29
7. pfl-r2-06 · controlled challenge study
   Twenty-two children (81%) had a positive DBPCFC. The NOAEL in this group was 1 mg peanut flour, corresponding to 2 mg whole peanut.
   J Allergy Clin Immunol, 2006 · checked 2026-09-29
8. pfl-r2-08 · Cochrane systematic review
   In view of the risk of adverse events and the lack of evidence of long-term benefits, allergen-specific peanut OIT cannot currently be recommended as a treatment for the management of patients with IgE-mediated peanut allergy.
   Cochrane Database Syst Rev, 2012 · checked 2026-09-29
9. pfl-r2-09 · RCT
   36 (46%) of 79 children in the PPOIT group and 42 (51%) of 83 children in the OIT group achieved sustained unresponsiveness compared with two (5%) of 39 children in the placebo group
   Lancet Child Adolesc Health, 2022 · checked 2026-09-29
10. pfl-r2-10 · RCT
    21 (35%) of peanut-0 group participants and one (4%) placebo group participant passed the 4000 mg challenge at both 104 and 117 weeks (odds ratio [OR] 12·7, 95% CI 1·8-554·8; p=0·0024).
    Lancet, 2019 · checked 2026-09-29
11. pfl-r2-13 · FDA announcement
    Those who take Palforzia must continue to avoid peanuts in their diets.
    US FDA, FDA Roundup July 26, 2024 · checked 2026-09-29
12. pfl-r2-07 · case report
    Investigation of the soup manufacturer revealed that undeclared peanut flour was a component of a flavoring ingredient in the soup. Based on the concentration of peanut flour in the flavoring, we estimated the patient ate approximately 45 mg of peanut protein.
    Ann Allergy Asthma Immunol, 1997 · checked 2026-09-29
13. pfl-r2-11 · RCT
    The children receiving FSP portions plus "Parma pap" recovered faster (5.54 week on average) than those treated with FSP regimen only (8.16 on average).
    Acta Biomed, 2014 · checked 2026-09-29