Last time I said testosterone sets the floor and something else builds the house. I promised you maca. Here it is, and I am starting with a confession.
I have tried maca before and got nothing from it. I now know that was my fault rather than the root’s. I gave it days rather than weeks. And at one point I gave it a heaped tablespoon of raw powder on my muesli, several times what any trial has ever used, and spent the rest of that day regretting it. That is not an experiment. It is a purchase followed by a mistake.
So this is the post I should have read first. What maca does to lust in men, and for women. Why the hormone story on the tub is wrong in an interesting way, and what might be doing the work instead. The one job it has proper trial data for. And the safety questions nobody prints on the label. Every claim is linked.
What you are actually buying
Maca is a root from the Peruvian Andes, grown at around 4,000 metres where almost nothing else will. It is a cousin of broccoli and mustard, and the people who have eaten it for centuries cook it first.7 It comes in yellow, red and black, and the colours differ in their chemistry. You can buy it as raw flour, as gelatinised powder (heated to strip out the starch, which also tames the bitterness) or as an extract.
Nearly every human trial used about 3 grams a day of gelatinised powder or the equivalent in extract.1 So the evidence is for 3 grams of cooked maca. A spoonful of raw flour in a smoothie is a different substance at a different dose. I have the receipts.
What it does to lust in men
The trial everyone quotes is from 2002, in Lima (Gonzales).2 Men aged 21 to 56 took 1.5 or 3 grams a day or a placebo for 12 weeks. Desire rose in the maca groups from week eight. Not week one. It was not a mood effect, because the researchers measured mood too. Nor was it hormones. Testosterone and oestradiol stayed exactly where they were.
The same team later gave the honest number. Desire improved in 42% of the men.7 Fewer than half, after two months. Say that out loud before you buy a tub.
An Italian trial in 2009 (Zenico) gave 50 men with mild difficulty getting or keeping an erection 2,400 mg of extract a day for 12 weeks.3 Erection scores rose in both groups, because placebo is a real drug in this field. They rose more on maca, 1.6 points against 0.5, and only the maca group felt better physically and socially. The authors called the effect “small but significant”. That is the right size of claim. Maca is not a treatment for erections.
A Korean trial in 2023 (Shin) picked an interesting group: 80 men with the symptoms of low testosterone but normal blood levels.5 Three grams a day for 12 weeks improved their symptom scores, erection scores and prostate symptom scores against placebo, with no safety signal. Men with the complaint but not the hormone problem. Hold on to that.
The largest trial came in 2016, again from Peru (Gonzales-Arimborgo).7 175 adults took red or black maca extract, 3 grams a day, for 12 weeks. About half of those on red reported more desire by week 12, but placebo did nearly as well, and red maca only beat it clearly in the group living at high altitude where the root is grown. Red beat black. Mood and energy improved in more than eight out of ten.
So here is the honest expectation. A modest lift in lust in roughly half of men after two months. A more reliable lift in mood and energy. Nothing worth buying it for on erections.
The hormones do not move. That is the point.
The 2003 paper (Gonzales) is the hormone half of the 2002 trial.6 LH, FSH, prolactin, testosterone and oestradiol were measured at 2, 4, 8 and 12 weeks. Nothing changed, at either dose, at any point. In 2008 an Australian team (Brooks) gave 14 postmenopausal women 3.5 grams a day for six weeks.8 Oestradiol, FSH, LH and SHBG did not budge. When they tested the root itself in the lab it showed no oestrogen-like or testosterone-like activity at all. The women’s psychological and sexual scores still improved against placebo.
The 2026 review (Bloomer) sums it up in five words: favourable effects “without negatively altering hormone levels”.1
Which is the floor-and-house argument from the last post with a plant attached. Whatever maca does, it does not do it through testosterone, and every tub that says otherwise is guessing. The floor is untouched. Something in the house moved.
So what is doing it?
Nobody knows for certain. The best guess is a family of compounds found only in maca called macamides. In 2014 a Swiss and Hungarian team (Hajdu, with Gertsch’s lab in Bern) found that one macamide binds the same brain receptor that cannabis acts on.9 It also slows the enzyme that breaks down anandamide and strongly blocks anandamide from being mopped back up.
Anandamide is the body’s own cannabis-like chemical, named after the Sanskrit word for bliss. It was on the map in the last post as one of the chemicals that sit on the accelerator and the brake. If macamides keep more of it around, that would explain why mood and energy respond more reliably than lust. Red maca also carries more GABA, a calming brain chemical, and the 2016 team think that is why red did better on mood.7
A bench result, not a human one. Nobody has measured anandamide in a person taking maca. But it is a better story than the hormone one, because it at least agrees with the evidence. Chemistry of the house, not the floor.
The one job it has real data for
Antidepressants. A 2001 Spanish study (Montejo) followed 1,022 people starting them.10 Between 58% and 73% of those on SSRIs or venlafaxine developed sexual problems, and desire and orgasm were both hit. Two Harvard trials (Dording) tried maca on exactly that. The 2008 pilot, 20 people, found 3 grams a day improved both sexual function scales and 1.5 grams did not.11 The 2015 trial gave 45 women 3 grams or placebo for 12 weeks. Remission was higher on maca but the numbers are small, 9.5% against 4.8% on one scale.12 Most of the benefit was in postmenopausal women.
So if your lust went the week your prescription started, maca at 3 grams is one of the few things with any trial data at all. Thin data, and three caveats that matter more than the data. Never stop or cut an antidepressant to try a root. Talk to the doctor who prescribes it first. And no serotonin problem has ever been reported with maca, which has no known action on serotonin, but the interaction file is thin because almost nobody has looked.
Women
Mixed, and I would rather say so than sell it. The 2026 review’s verdict is consistent positives in men, positives in mixed groups and mixed results in women-only trials, most of them in postmenopausal women.1 The Australian crossover was positive but had 14 women in it.8 The Harvard result was modest.12 The 2016 trial found no clear gain in desire over placebo in its low-altitude group.7 A woman reading this should expect less certainty than a man, and more effect on mood than on lust.
The safety questions the label leaves out
At 3 grams a day for 12 weeks maca has one of the cleanest safety records in the supplement literature. It also has one of the thinnest. Nobody has run a trial longer than 12 weeks and almost nobody has looked for drug interactions. Both halves of that sentence are true.
Blood pressure. Three human signals, mostly reassuring. The 2016 trial found no change against placebo, and its authors point out maca is high in potassium and low in sodium, so a fall is more plausible than a rise.7 A 2015 Hong Kong trial (Stojanovska) gave 29 postmenopausal women 3.3 grams a day and diastolic pressure fell, while thyroid hormone, cholesterol and blood sugar did not move.15 The one signal the other way is a 2008 Czech study (Valentova) in people with metabolic syndrome. There 0.6 grams a day for 90 days produced a moderate rise in diastolic pressure and in a liver enzyme called AST, an effect that vanished when maca was combined with silymarin.16 If you take blood pressure medication, measure at home for the first month. Expect nothing or a small drop, and stop if it climbs.
Liver. That Czech AST rise is one signal.16 A 2017 Chinese case report of liver injury is another, but from a maca “medicinal liquor”, an alcohol-steeped preparation rather than the powder.17 Every 12-week trial reported clean safety bloods.5 7 Not a liver-toxic plant on the evidence. Anyone with liver disease mentions it to their doctor anyway.
Drug interactions. A 2019 study at Auburn University screened maca against CYP3A4, the liver enzyme that handles roughly 60% of prescribed drugs.18 It found no meaningful effect. A 2023 Polish review of 1,816 adverse event reports found exactly one maca case, restless legs in a patient on the antidepressant mianserin.19 Its authors state there were no previous interaction reports for maca at all. The file is nearly empty. That is reassuring and it is also a sign nobody has looked hard. If you are on a drug with a narrow safety margin, warfarin, anti-epileptics, transplant drugs, ask before you add anything.
Serotonin. No reports, and no mechanism: maca’s active compounds work on the cannabis-like system, not the serotonin one.9 The strongest human reassurance is that 65 people in the Harvard trials took up to 3 grams a day alongside SSRIs and SNRIs for 12 weeks and the trials reported it well tolerated.11 12 One 2023 mouse study found that particles extracted from maca raised serotonin production through the gut.20 A laboratory preparation, not the powder, but it is why I say “no known risk” rather than “no risk”.
Thyroid. Raw crucifers carry glucosinolates, the compounds behind the old worry about raw cabbage and the thyroid. Cooking and gelatinising reduce them. In the one trial that measured it, thyroid stimulating hormone did not change on 3.3 grams a day.15 Anyone with a thyroid condition uses gelatinised or extract, never raw flour, and tells their doctor.
Hormone-sensitive conditions. The hormone data are reassuring, in men and in the lab.6 8 One caution: a 2022 Brazilian study found a maca extract made triple-negative breast cancer cells in a dish more mobile and sharply raised a gene linked to spread.21 A dish is not a person. But anyone with a breast cancer history talks to their oncologist before taking it. On the prostate, the Korean trial found symptom scores improved rather than worsened.5
Joints. No evidence it makes arthritis worse and one trial pointing the other way. A 2007 Indian trial (Mehta) compared glucosamine with a product combining 1,500 mg of maca with cat’s claw in 95 people with knee osteoarthritis.22 Both worked, the maca combination needed less paracetamol, and safety bloods were unchanged. An industry product and a combination, so maca alone is unproven. No sign of harm, a hint of help.
Sleep. A 2024 review raised the question of whether maca’s effect on energy disturbs sleep, and nobody has measured it.23 Take it in the morning. Pregnancy and breastfeeding: no human data, so avoid it.
The raw root. A 2024 Belgian analysis notes that regulators in Belgium, Germany and the United States have raised questions about alkaloids in raw maca.14 It measured a tenfold variation between products and recommends a maximum level rather than a ban. Buy gelatinised powder or extract from a brand that publishes its testing. Not raw flour. Not by the tablespoon.
What this means in practice
The bottom line. Three grams a day of gelatinised maca or extract, red if you can get it, in the morning with food. Give it eight to twelve weeks and score lust, mood and energy separately, because they do not move together. Expect lust up a notch in about half of men, mood and energy up two notches in most people, and your hormones to do nothing at all. If nothing has moved by twelve weeks, stop. If your blood pressure climbs, stop sooner.
If you are on prescription medication, have liver, thyroid or hormone-sensitive disease, or are pregnant, that is a conversation with a doctor before the first spoonful. The reassurance in the trials is real and the data behind it are thin. Both are worth knowing.
As for me, I will begin self experimentation soon. Three grams a day. Twelve weeks. No tablespoons.
Maca will not raise your testosterone and was never going to. What it may do, for about half the men who take it, is lift lust a notch and mood two notches, through chemistry that has nothing to do with the hormone on the label. That is a smaller promise than the tub makes. It is also a more interesting one.
Citations
1. Bloomer RJ. Effects of Maca (Lepidium meyenii) on Sexual Health and Libido, A Review. J Diet Suppl. 2026;23(5):582–601. https://pubmed.ncbi.nlm.nih.gov/42680584/
2. Gonzales GF, Córdova A, Vega K, et al. Effect of Lepidium meyenii (MACA) on sexual desire and its absent relationship with serum testosterone levels in adult healthy men. Andrologia. 2002;34(6):367–372. https://pubmed.ncbi.nlm.nih.gov/12472620/
3. Zenico T, Cicero AF, Valmorri L, Mercuriali M, Bercovich E. Subjective effects of Lepidium meyenii (Maca) extract on well-being and sexual performances in patients with mild erectile dysfunction: a randomised, double-blind clinical trial. Andrologia. 2009;41(2):95–99. https://pubmed.ncbi.nlm.nih.gov/19260845/
4. Stone M, Ibarra A, Roller M, Zangara A, Stevenson E. A pilot investigation into the effect of maca supplementation on physical activity and sexual desire in sportsmen. J Ethnopharmacol. 2009;126(3):574–576. https://pubmed.ncbi.nlm.nih.gov/19781622/
5. Shin D, Jeon SH, Piao J, et al. Efficacy and Safety of Maca (Lepidium meyenii) in Patients with Symptoms of Late-Onset Hypogonadism: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial. World J Mens Health. 2023;41(3):692–700. https://pubmed.ncbi.nlm.nih.gov/36593713/
6. Gonzales GF, Córdova A, Vega K, Chung A, Villena A, Góñez C. Effect of Lepidium meyenii (Maca), a root with aphrodisiac and fertility-enhancing properties, on serum reproductive hormone levels in adult healthy men. J Endocrinol. 2003;176(1):163–168. https://pubmed.ncbi.nlm.nih.gov/12525260/
7. Gonzales-Arimborgo C, Yupanqui I, Montero E, et al. Acceptability, Safety, and Efficacy of Oral Administration of Extracts of Black or Red Maca (Lepidium meyenii) in Adult Human Subjects: A Randomized, Double-Blind, Placebo-Controlled Study. Pharmaceuticals. 2016;9(3):49. https://pmc.ncbi.nlm.nih.gov/articles/PMC5039502/
8. Brooks NA, Wilcox G, Walker KZ, Ashton JF, Cox MB, Stojanovska L. Beneficial effects of Lepidium meyenii (Maca) on psychological symptoms and measures of sexual dysfunction in postmenopausal women are not related to estrogen or androgen content. Menopause. 2008;15(6):1157–1162. https://pubmed.ncbi.nlm.nih.gov/18784609/
9. Hajdu Z, Nicolussi S, Rau M, et al. Identification of endocannabinoid system-modulating N-alkylamides from Heliopsis helianthoides var. scabra and Lepidium meyenii. J Nat Prod. 2014;77(7):1663–1669. https://pubmed.ncbi.nlm.nih.gov/24972328/
10. Montejo AL, Llorca G, Izquierdo JA, Rico-Villademoros F. Incidence of sexual dysfunction associated with antidepressant agents: a prospective multicenter study of 1022 outpatients. J Clin Psychiatry. 2001;62 Suppl 3:10–21. https://pubmed.ncbi.nlm.nih.gov/11229449/
11. Dording CM, Fisher L, Papakostas G, et al. A double-blind, randomized, pilot dose-finding study of maca root (L. meyenii) for the management of SSRI-induced sexual dysfunction. CNS Neurosci Ther. 2008;14(3):182–191. https://pmc.ncbi.nlm.nih.gov/articles/PMC6494062/
12. Dording CM, Schettler PJ, Dalton ED, et al. A double-blind placebo-controlled trial of maca root as treatment for antidepressant-induced sexual dysfunction in women. Evid Based Complement Alternat Med. 2015;2015:949036. https://pmc.ncbi.nlm.nih.gov/articles/PMC4411442/
13. Shin BC, Lee MS, Yang EJ, Lim HS, Ernst E. Maca (L. meyenii) for improving sexual function: a systematic review. BMC Complement Altern Med. 2010;10:44. https://pmc.ncbi.nlm.nih.gov/articles/PMC2928177/
14. Le NTH, Foubert K, Theunis M, et al. UPLC-TQD-MS/MS Method Validation for Quality Control of Alkaloid Content in Lepidium meyenii (Maca)-Containing Food and Dietary Supplements. ACS Omega. 2024;9(14):15971–15981. https://pmc.ncbi.nlm.nih.gov/articles/PMC11007719/
15. Stojanovska L, Law C, Lai B, et al. Maca reduces blood pressure and depression, in a pilot study in postmenopausal women. Climacteric. 2015;18(1):69–78. https://pubmed.ncbi.nlm.nih.gov/24931003/
16. Valentová K, Stejskal D, Bartek J, et al. Maca (Lepidium meyenii) and yacon (Smallanthus sonchifolius) in combination with silymarin as food supplements: in vivo safety assessment. Food Chem Toxicol. 2008;46(3):1006–1013. https://pubmed.ncbi.nlm.nih.gov/18054420/
17. Drug-induced Liver Injury Due to Lepidium meyenii (Maca) Medicinal Liquor. Chin Med J. 2017 (case report). https://pubmed.ncbi.nlm.nih.gov/29237937/
18. Zhang Y, Rants’o TA, Jung D, et al. Screening for CYP3A4 inhibition and induction coupled to parallel artificial membrane permeability assay (PAMPA) for prediction of botanical-drug interactions: The case of açaí and maca. Phytomedicine. 2019;59:152915. https://pubmed.ncbi.nlm.nih.gov/30981185/
19. Siwek M, Woroń J, Wrzosek A, Gupało J, Chrobak AA. Harder, better, faster, stronger? Retrospective chart review of adverse events of interactions between adaptogens and antidepressant drugs. Front Pharmacol. 2023;14:1271776. https://pmc.ncbi.nlm.nih.gov/articles/PMC10565488/
20. Lepidium meyenii Walp (Maca)-derived extracellular vesicles ameliorate depression by promoting 5-HT synthesis via the modulation of gut-brain axis. iMeta. 2023. https://pubmed.ncbi.nlm.nih.gov/38867934/
21. Bizinelli D, Flores Navarro F, Lima Costa Faldoni F. Maca Root (Lepidium meyenii) Extract Increases the Expression of MMP-1 and Stimulates Migration of Triple-Negative Breast Cancer Cells. Nutr Cancer. 2022;74(1):346–356. https://pubmed.ncbi.nlm.nih.gov/33560149/
22. Mehta K, Gala J, Bhasale S, et al. Comparison of glucosamine sulfate and a polyherbal supplement for the relief of osteoarthritis of the knee: a randomized controlled trial. BMC Complement Altern Med. 2007;7:34. https://pmc.ncbi.nlm.nih.gov/articles/PMC2131759/
23. The increasing popularity of Peruvian maca (Lepidium meyenii) and its potential impacts on sleep and quality of life. Clinics (Sao Paulo). 2024;79:100398. https://pmc.ncbi.nlm.nih.gov/articles/PMC11214369/
The content on this site is for informational purposes only and does not constitute medical advice. Always consult a qualified doctor before starting any supplement, particularly if you are taking prescription medication.