Popeye's superhuman strength from spinach is attributed to the plant steroid ecdysterone. The document reviews various studies showing ecdysterone's anabolic effects on muscle mass and strength in animals and humans. It discusses ecdysterone's biological mechanisms, metabolism, safety and regulatory status. While promising for fitness and bodybuilding, almost all commercial ecdysterone supplements are underdosed and its use in athletes may be banned in the future.

1. POPEYE’S SUPERHUMAN STRENGTH
IS DUE TO
ECDYSTERONE IN SPINACH
By
Kevin KF Ng, MD, PhD.
Former Associate Professor of Medicine
Division of Clinical Pharmacology
University of Miami, Miami, FL., USA
Email: kevinng68@gmail.com
A slide presentation for HealthCare Providers June 2021 https://giphy.com/explore/spinach

2. • Popeye is a cartoon sailor who possesses
superhuman strength after ingesting a can
of spinach.
• Popeye was created by Elzie Crisler Segar,
who on January 17, 1929 introduced the
character into his existing newspaper
cartoon strip, Thimble Theatre.
January 17, 1929
Popeye the Sailor Man
https://en.wikipedia.org/wiki/Popeye

3. What is Spinach?
▪ Spinach is a green leafy flowering plant native to
central and western Asia.
▪ It is of the order Caryophyllales, family Amaranthaceae,
species spinacia
▪ Its leaves are a common edible vegetable consumed
either fresh, or after storage using preservation
techniques by canning, freezing, or dehydration.
▪ In the 1980s, ecdysterone (beta-ecdysone, a “Russian
secret”), was suspected to be used by Russian Olympic
athletes.
https://www.medicinenet.com/is_eating_spinach_every_day_good_for_you/article.htm

4. World's Leading Spinach Producing Countries
https://www.atlasbig.com/en-au/countries-by-spinach-production

5. Scientific classification of Spinach
©DRKEVINKFNG

6. Number of publications “Spinach” in PubMed from
1925 to 2020
https://pubmed.ncbi.nlm.nih.gov/?term=Spinach

7. NUTRIENTS IN SPINACH

8. Nutrient composition of raw spinach per100 grams
https://fdc.nal.usda.gov/fdc-app.html#/food-details/1103136/nutrients

9. Phytochemicals in Spinach
20E (ecdysterone) is the most frequently encountered phytoecdysteroid
and very frequently is the major phytoecdysteroid present in the plant.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8146789/

10. ECDYSTEROIDS

11. What are ecdysteroids ?
▪ Ecdysteroids are insect molting hormones
(ecdysone and its homologues).
▪ Ecdysteroids in plants are called phytoecdysteroids.
▪ Ecdysteroids are not found in humans.
▪ Ecdybase now contains 527 ecdysteroids.
▪ The bioactive ecdysteroid is ecdysterone (20-E)
which is soluble in water, and 100% ethanol
http://ecdybase.org/
Molecular wt.. 480.6

12. WHAT OTHER NAMES IS ECDYSTERONE KNOWN BY?
▪ 20-Hydroxy-Ecdysterone
▪ 20-Hydroxyecdysone,
▪ 20-Hydroxy-Beta-Ecdysterone
▪ Alfa-ecdysone
▪ Beta-ecdysone
▪ Beta Ecdysterone
▪ Commisterone
▪ Ecdisten
▪ Ecdysone
▪ Ecdystérone,
▪ Ecdysterona
▪ Hydroxyecdysterone,
▪ Isoinokosterone
▪ Suma.
https://www.rxlist.com/ecdysterone/supplements.htm

13. Structure of steroid skeleton, cholesterol and ecdysterone (20E)
https://saylordotorg.github.io/text_the-basics-of-general-organic-and-biological-chemistry/s20-04-steroids.html
(c) ecdysterone (20E)

14. Biosynthesis of 20E (20-hydroxyecdysone) in plants
Anna Petryk et al. PNAS 2003;100:24:13773-13778
©2003 by National Academy of Sciences

15. Chemical structure of ecdysterone and other anabolic agents
https://www.researchgate.net/publication/275209205_Ecdysteroids_A_novel_class_of_anabolic_agents
ecdysterone selective androgen receptor modulator (SARM)
anabolic androgenic steroid dihydrotestosterone estradienedione

16. Structure of ecdysterone, testosterone & estrone
ecdysterone testosterone estrone
©DRKEVINKFNG

17. Ecdysone receptor:
20-hydroxyecdysone (20E) acts through the ecdysone receptor
Crystallographic structure of the ligand binding
domain of the ecdysone receptor (rainbow color,
N-terminus = blue, C-terminus = red) from Heliothis
virescens complexed with ponasterone A (space-
filling model, carbon = white, oxygen = red)
https://en.wikipedia.org/wiki/Ecdysone_receptor
In humans, it is hypothesized to bind to the estrogen receptor
beta (ERβ) protein-coding gene

18. Proposed mode of action of 20E (20-hydroxyecdysone) in the regulation
of protein synthesis in C2C12 muscle cells in vitro (2021)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8146789/

19. BIOLOGICAL FUNCTIONS OF ECDYSTEROIDS

20. Conversion of inactive Ecdysone to active Ecdysterone
©DRKEVINKFNG

21. Biological Functions of Ecdysterone
Ecdysterone
©DRKEVINKFNG

22. SCIENTIFIC STUDIES IN ANIMALS

23. Effect of ecdysterone on Protein Synthesis In Vitro (2021)
Leucine incorporation Myotube diameter
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8146789/

24. Effects of DHT, IGF-1, and ecdysterone (Ecdy) on the
diameter of C2C12 myotubes.
Determination of diameters of 47 myotubes per group. (2015)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4447764/
10−6 M) 10−6 M
10 ng · mL−1

25. Anabolic effect of ecdysterone (Ecdy) expressed as
fiber size of soleus muscle in intact rats. (2015)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4447764/

26. Anti-Obesity Effect of ecdysterone (20E) in mice (2021)
Effect of 20E on mice fed a high-fat diet (HF), when
compared to mice fed a low-fat diet (LF). The
animals received either pure 20E (50 mg/kg/day) or
the same amount of 20E as a quinoa extract (Q).
Panel (A) shows the impact on the mass of
epididymal adipose tissue (*** p < 0.01 when
compared to LF; ## p < 0.01 and ### p < 0.001
when compared to HF) and panel (B) shows the
effect on adipocyte diameter
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC814678
9/

27. SCIENTIFIC STUDIES IN HUMANS

28. Ecdysteroids as non-conventional anabolic agent:
performance enhancement by ecdysterone supplementation in 40 humans (2019)
https://www.researchgate.net/figure/Serum-concentrations-of-ecdysterone-
ng-mL-of-serum-grouped-boxpots-in-the-different_fig1_333322619

29. Serum concentrations of ecdysterone ([ng/mL of serum], grouped boxpots)
in the different treatment groups at
t1, thalf, and t2, one outlier (Co group) eliminated (2019)
https://link.springer.com/article/10.1007/s00204-019-02490-x

30. Ecdysteroids as non-conventional anabolic agent:
performance enhancement by ecdysterone supplementation in humans (2019)
https://link.springer.com/article/10.1007/s00204-019-02490-x

31. METABOLISM OF ECDYSTEROIDS

32. Pharmacokinetics of 20E (20-hydroxyecdysone) in young and elderly
humans given a single dose of 1400 mg. (20E was quantified by HPLC-MS (2021)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8146789/
20-Hydroxyecdysone (20E)

33. Cumulative urinary excretion of ecdysterone and metabolites following
single dose of 50 mg ecdysterone in 12 subjects (2021)
Adapted from
https://www.researchgate.net/publication/351399386_Urinary_Elimination_of_Ecdys
terone_and_its_Metabolites_following_a_Single-Dose_Administration_in_Humans

34. Time-course of the distribution of radioactivity in the stomach/intestine/feces in
mice after the oral application of [1α,2α-3H2]20E (20-hydroxyecdysone) (2021)
Time-course of the distribution of radioactivity in the
stomach/intestine/feces in mice after the oral
application of [1α,2α-3H2]20E. Note the logarithmic
scale for abscissa. Each value is a mean of 2 animals.
Note the plateau of small intestine content that is best
explained by an entero-hepatic cycle and consistent with
the prolonged concentration of radioactivity in bile.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8146789/

35. POTENTIAL BENEFITS OF ECDYSTEROIDS

36. Summary of the literature concerning 20E’s pharmacological
effects in mammals (2021)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8146789/

37. Experimental and Clinical Studies with ecdysteroids:
Beneficial effects (2021)
Early experimental studies and clinical trials on humans have indicated that
20E or plant extracts containing significant amounts of ecdysteroids produced
the following effects:
• Prevent sleep disorders
• Improve nerve functioning in the CNS
• Improve sexual function
• Improve hepatic function in hepatitis
• Improve learning and memory
• Improve cardio-vascular function
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8146789/

38. SAFETY ISSUES

39. Ecdysteroid Dosage
▪ There is no official recommendation for ecdysteroid dosage.
▪ Spinach is a relatively poor ecdysteroid source: it contains ca. 0.005–0.08%
of ecdysteroids (primarily 20E) per fresh weight depending on the time of
harvest.
▪ Sportsmen (most typically body-builders) take up to several grams of 20E
per day, which dose has never been studied for long-term safety.
▪ In contrast with spinach, Cyanotis arachnoidea, a plant native in China, is
among the richest sources of 20E; depending on the time and area of
harvest, the levels of 20E in the roots can reach as high as 4–5%
▪ There is evidence that some food supplements contain Cyanotis extract
instead of spinach as claimed.
https://www.nature.com/articles/srep37322#:~:text=On%20the%20other%20hand%2C%20spinach,per%20day%20from%20this%20source.

40. Median lethal dose (LD50) in mice
https://link.springer.com/chapter/10.1007/978-3-642-65769-6_27

41. Regulatory status of botanical supplements in different countries
https://refubium.fu-berlin.de/bitstream/handle/fub188/27234/Thesis_Gabriella_Ambrosio.pdf?sequence=4&isAllowed=y

42. Is Ecdysterone banned by WADA (World Anti-Doping Agency) ?
▪ Scientists at the Freie Universität Berlin recommended that ecdysterone should be
added to the World Anti-Doping Authority's (WADA) list of banned substances
because of its potentially steroid-like effects. Jun 26, 2019
▪ In 2020, WADA added ecdysterone to the Monitoring Program. This means they are
now testing for it and considering it for future listing.
▪ Ecdysteroids and its metabolites can now be identified in the urine.
▪ ecdysterone
▪ 14-deoxy ecdysterone
▪ 14-deoxy poststerone
https://pubmed.ncbi.nlm.nih.gov/31123801/

43. Commercial Products
▪ Spinach extract powder
▪ Smoothie Powder
▪ Ecdysterone supplements
▪ 500 mg capsule
▪ 1000 mg capsule
▪ Cyanotis Ecdysterone Extract powder

44. Almost all ecdysterone supplements are underdosed (2021)
https://www.ergo-log.com/almost-all-ecdysterone-supplements-are-underdosed.html

45. Summary
▪ The use of spinach for superhuman strength was created in 1929 by the
cartoon of Popeye the sailor man ingesting a can of spinach.
▪ In the 1980s, ecdysterone (beta-ecdysone, a “Russian secret”), was suspected
to be used by Russian Olympic athletes.
▪ Physical performance enhancement and increase in muscle mass had
recently been demonstrated in animal and human studies.
▪ The anabolic properties of ecdysterone led WADA (World Anti-Dope Agency)
to place ecdysterone on a Monitoring Program with the possibility of banning
its use in athletes.
▪ Almost all ecdysterone supplements are underdosed

46. Other slide presentations available at:
https://www.slideshare.net/ssusera9ba27
https://giphy.com/explore/popeye-and-bluto