Honeydew melon: a watery fruit whose health trials tested a capsule

The longest trial on this page did not test the fruit. It tested a 10 mg daily capsule of a patented melon concentrate rich in the enzyme SOD. In 61 adults aged 29 to 60 it lowered perceived stress by 8.8% at day 28 and 7.2% at day 84 against placebo, in a study funded by the maker of the extract. The EU register lists the antioxidant and immune claims for that extract as non-authorized, which is a refusal to approve the wording and says nothing either way about fresh melon. The fruit itself is mostly water with a modest dose of vitamin C. The US food survey gives raw honeydew 18 mg of vitamin C, 228 mg of potassium and 36 calories per 3.5 oz (100 g), and a cup of 5.5 oz (155 g) carries 27.9 mg of vitamin C. That is a single value with no spread between samples, and ripeness and variety are not stated.

The numbers, per 3.5 oz (100 g)

As people eat it, per 3.5 oz (100 g)

How much is actually in it

• Raw honeydew provides about 18 mg vitamin C, 228 mg potassium and 36 calories per 3.5 oz (100 g). — FNDDS food Honeydew melon, raw (63127010) Evidence E source
  Per 100 g: vitamin C 18 mg, potassium 228 mg, energy 36 calories; per 1 cup (155 g): 27.9 mg, 353.4 mg, 55.8 calories

What a real portion looks like

• A cup of honeydew weighs 5.5 oz (155 g) and a medium wedge 125 g, while a whole medium melon is about 2.2 lb (1 kg). — FNDDS portion weights for Honeydew melon, raw Evidence E source
  1 cube or ball 15 g; 1 cup 155 g; small, medium, large wedge 65, 125, 190 g; small, medium, large melon 800, 1000, 1320 g

What your body absorbs

• In 30 people with low-citrate kidney stones, about 13 fl oz (385 mL) of fresh melon juice raised urinary citrate as much as orange juice, and melon and orange juices alone raised urinary potassium, pH and net gut alkali absorption. — 30 hypocitraturic stone-forming patients, 10 per juice, single 13 fl oz (385 mL) serving after overnight fast, urine to 6 hours (n = 30) Evidence B source
  Comparable significant rise in urinary citrate in all groups; urinary potassium, pH and net gastrointestinal alkali absorption rose only after melon and orange juice

What cooking and storage change

• In 4,691 pre-cut fruit samples from Canadian retail, Listeria was found in 0.51%, and melons were among the fresh-cut fruits more likely to be contaminated. — 10,070 pre-packaged ready-to-eat samples, Canadian retail, 2012-2016 (n = 10,070) Evidence C source
  L. monocytogenes in 0.51% (95% CI 0.34-0.76) of fresh-cut fruit; melons and apples more often contaminated
• According to FDA, melons should be scrubbed with a clean produce brush before cutting, since they count as firm produce. — consumers Evidence E source
  Scrub the rind of melons with a clean produce brush

What it does to your health

• In a 12-week trial in 61 adults, a daily 10 mg capsule of SOD-rich melon concentrate lowered perceived stress by 8.8% at day 28 and 7.2% at day 84 versus placebo. — 61 adults aged 29-60 years, 32 active and 29 placebo, 12 weeks (n = 61) Evidence B source
  PSS-14 difference in favor of supplement: -8.8% at day 28, -7.2% at day 84, P<0.05

Safety, limits and interactions

• In a 15-day trial in 53 young adults eating 8.8 oz (250 g) melon a day, red-cell and plasma cholinesterase activity was higher with organic melon than with diazinon-exposed market melon. — 53 healthy young volunteers, Iran, 250 g melon daily for 15 days, organic (22) vs market (31) (n = 53) Evidence B source
  RBC cholinesterase at day 15: 5.86 vs 5.11 IU/mL, P=0.002; plasma cholinesterase 58.7% vs 50.5%, P=0.001
• A 2007 Salmonella Litchfield outbreak of 30 cases at an Atlantic City hotel restaurant was most likely traced to the honeydew in a fruit salad, contaminated by an ill food handler. — 30 confirmed or probable cases from eight states who ate at one hotel restaurant (n = 30) Evidence C source
  Outbreak most likely associated with fruit salad, particularly honeydew
• For honeydew, FDA advises scrubbing firm produce such as melons with a clean produce brush, buying pre-cut produce such as half a watermelon only if refrigerated or surrounded by ice, refrigerating all pre-cut or packaged produce, and storing perishable fruit at 40°F or below. — general public Evidence E source
  Scrub melon rind with produce brush, refrigerate pre-cut produce, store at 40°F or below

What people believe that the data does not support

• The EU register lists antioxidant and immune claims for an SOD-containing melon extract as non-authorized. — — Evidence E source
  Claim for Melon extract (containing SOD) with wheat gliadin, status Non-authorized

Who this works differently for

• Of 53 adults reporting reactions to melon, double-blind food challenges confirmed melon allergy in 19 (36%), mostly oral allergy syndrome, with two life-threatening reactions. — 53 consecutive adult patients reporting adverse reactions to melon (n = 53) Evidence C source
  19 of 53 (36%) confirmed; oral allergy syndrome in 14; 2 life-threatening reactions; skin prick positive predictive value 42%
• Among 222 adults with seasonal hay fever in Ankara, 14% reported pollen-food allergy, and melon was one of the five most common culprit foods. — 222 adults with seasonal allergic rhinitis, Turkey (n = 222) Evidence C source
  31 of 222 (14%) reported pollen-food allergy syndrome; culprits eggplant, walnut, kiwi, peach, melon
• FDA counts pregnant women and their unborn or newborn babies, adults over 65 and people with weakened immune systems as the high-risk groups for serious effects of listeriosis. — pregnant women and their unborn or newborn baby, adults over the age of 65, people with weakened immune systems Evidence E source
  Named as high-risk groups susceptible to the serious and adverse effects of listeriosis
• For honeydew and other melons, CDC Listeria advice says to avoid cut melon left out for more than 2 hours, or 1 hour above 90°F, and cut melon kept in the refrigerator for more than a week, and to choose melon that has just been cut. CDC lists pregnant women, newborns, people 65 or older and people with a weakened immune system as at higher risk. — general public, higher risk: pregnant women, newborns, people 65 or older, weakened immune system Evidence E source
  Avoid cut melon held over 2 hours at room temperature (1 hour above 90°F) or over a week refrigerated

The bottom line

In 30 people who form kidney stones and have low urinary citrate, a single 13 fl oz (385 mL) glass of fresh melon juice raised urinary citrate about as much as orange juice did. Only melon and orange juice also raised urinary potassium and pH. Each juice had 10 people, urine was followed for 6 hours, the melon variety was not named, and nobody counted new stones. The cautions on this page are real ones. Of 53 Spanish adults who said melon gave them reactions, double-blind food challenges confirmed allergy in 19 (36%). Most had an itchy mouth and throat, and two had life-threatening reactions. Among 222 adults with hay fever in Ankara, 14% reported food reactions linked to pollen, and melon was one of the five foods named most often, by self-report. The rind is where the germs sit. In 2007 a Salmonella outbreak of 30 cases at one hotel restaurant was most likely traced to honeydew in a fruit salad, contaminated by a sick food handler. In Canadian shops fresh-cut melon was among the pre-cut fruits more likely to carry Listeria, though the survey does not give a figure for melon alone. FDA counts pregnant women and their unborn or newborn babies, adults over 65 and people with weakened immune systems as the high-risk groups for serious effects of listeriosis. CDC Listeria advice for melon is to avoid cut melon left out for more than 2 hours, or 1 hour above 90°F, and cut melon kept in the refrigerator for more than a week, and to choose melon that has just been cut. FDA advises scrubbing the rind with a clean produce brush before cutting, buying pre-cut melon only if it is refrigerated or surrounded by ice, and keeping cut melon in a refrigerator at 40°F or below. In an open trial in Iran, 53 young adults ate 8.8 oz (250 g) of melon a day for 15 days. Red cell cholinesterase was 5.86 IU/mL with organic melon against 5.11 with market melon sprayed with the pesticide diazinon, and what that means for health was not measured. We found no study of honeydew itself in pregnancy, in children, in kidney disease or with medicines. That gap is not a sign of safety, and in pregnancy the Listeria advice above is the one that applies.

Compared with other foods

Sources

1. hdm-r4-06 · reference dataset
   FNDDS 63127010 Honeydew melon, raw — Vitamin C, total ascorbic acid 18 MG · Potassium, K 228 MG · Energy 36 KCAL per 100 g
   USDA FNDDS 2021-2023 via FoodData Central, fdc_id 2709241 (Honeydew melon, raw, 63127010) · checked 2026-09-29
2. hdm-r4-07 · reference dataset
   FNDDS 63127010 Honeydew melon, raw — 1 cube 15 g · 1 cup 155 g · 1 small wedge/slice 65 g · 1 medium wedge/slice 125 g · 1 large wedge/slice 190 g · 1 medium melon 1000 g
   USDA FNDDS 2021-2023 via FoodData Central, fdc_id 2709241 (Honeydew melon, raw, 63127010) · checked 2026-09-29
3. hdm-r4-01 · randomized acute feeding trial
   Significant and comparable increases of mean urinary citrate were observed in all groups, whereas mean urinary potassium, pH, and NGIA were significantly increased only after consumption of melon and orange juices.
   J Endourol, 2012 · checked 2026-09-29
4. hdm-r4-09 · prevalence survey
   However, contamination by L. monocytogenes can infrequently occur in fresh-cut fruits and vegetables, with certain types of fresh-cut fruits (i.e., melons, apples) and vegetables (i.e., mushrooms, cauliflower) being more likely to be contaminated than others.
   Int J Food Microbiol, 2020 · checked 2026-09-29
5. hdm-r4-10 · agency guidance
   Scrub firm produce, such as melons and cucumbers, with a clean produce brush.
   U.S. Food and Drug Administration, Selecting and Serving Produce Safely, 2024 · checked 2026-09-29
6. hdm-r4-04 · randomized controlled trial
   Results presented on Table 2 and Figure 1 show that the difference between the two groups was in favor of the S group at D28 (−8.8%) and D84 (−7.2%).
   Nutrients, 2014 · checked 2026-09-29
7. hdm-r4-03 · randomized controlled trial
   RBC [5.86 ± 1.27 vs. 5.11 ± 1.2 IU/mL] and plasma cholinesterase activities [58.7 ± 10.0 vs. 50.5 ± 13.0%] significantly increased in organic melon-exposed vs. market melon-exposed participants (p = 0.002 and p = 0.001, respectively).
   Eur Rev Med Pharmacol Sci, 2016 · checked 2026-09-29
8. hdm-r4-08 · outbreak investigation
   Investigators concluded that the outbreak most likely was associated with fruit salad, particularly the honeydew melon component, and that contamination likely resulted from an ill food handler.
   MMWR Morb Mortal Wkly Rep, 2008 · checked 2026-09-29
9. sf-melon-r1-honeydew-2 · agency advice
   When buying pre-cut, bagged or packaged produce — such as half of a watermelon or bagged salad greens — choose only those items that are refrigerated or surrounded by ice...Store perishable fresh fruits and vegetables (like strawberries, lettuce, herbs, and mushrooms) in a clean refrigerator at a temperature of 40° F or below...Scrub firm produce, such as melons and cucumbers, with a clean produce brush...Refrigerate all produce that is purchased pre-cut or packaged.
   FDA, Selecting and Serving Produce Safely · checked 2026-10-08
10. hdm-r4-05 · regulatory register entry
    POL-HC-7577 Melon extract (containing SOD) /Wheat Gliadin - Reinforces the body’s own natural defences. - Promotes the whole natural defences against free radicals in excess - Helps maintain the immune system Non-authorised
    EU Register on nutrition and health claims, claim POL-HC-7577, snapshot 2026-09-21 · checked 2026-09-29
11. hdm-r4-02 · double-blind food challenge study
    Actual clinical reactivity was confirmed in 19 (36%) of 53 patients. The most frequent symptom was oral allergy syndrome (n = 14), but two patients experienced life-threatening reactions, including respiratory symptoms and hypotension.
    J Allergy Clin Immunol, 2000 · checked 2026-09-29
12. hdm-r4-11 · cross-sectional survey
    The most frequently involved foods are eggplant, walnut, kiwi, peach, and melon in Ankara Province.
    Eur Rev Med Pharmacol Sci, 2023 · checked 2026-09-29
13. sf-listeriarisk-honeydew-2 · agency advice
    Pregnant women and their unborn or newborn baby, adults over the age of 65, and those with weakened immune systems, are all considered to be high-risk groups that are susceptible to the serious and adverse effects of listeriosis.
    Listeria (Listeriosis), US Food and Drug Administration, At-Risk Groups · checked 2026-10-08
14. sf-melon-r1-honeydew-1 · agency advice
    You may be at higher risk if you are in one of the following groups: Women who are pregnant Newborns People who are 65 years or older People who have a weakened immune system...Cut melon left out for more than 2 hours (1 hour if it’s exposed to temperatures hotter than 90°F, such as a picnic or hot car) Cut melon in refrigerator for more than a week...Melon that has just been cut
    CDC, Preventing Listeria Infection · checked 2026-10-08