Maca Powder

Maca is well tolerated, and the evidence is still thin. These are the questions our naturopaths ask in store, which are mostly about choosing the right form and knowing what to expect.

A good fit if

• Libido is what you're after, and you'll give it a couple of months
• You want mood and energy support and you know it's based on one solid trial
• You'd prefer a non-hormonal option, which is what the hormone tests suggest maca is
• You'll take a gelatinised or extract form rather than raw powder

Check with us first if

• You take blood pressure medicine. Maca lowered diastolic pressure in one trial and blocks renin and ACE in lab tests.
• You take diabetes medicine. Black maca lowered blood glucose in a trial.
• You take an antidepressant. There's an individual case report of a problem with mianserin.
• You're pregnant, breastfeeding or buying for a child. We have no evidence in any of these groups.
• You have a thyroid condition, so we can talk through the glucosinolate question properly.
• The product says Lepidium peruvianum. That's not a name an Australian listed medicine can use.

• Yellow maca. Best known for: The default in maca powder when no colour is named. Absorption: Not measured separately in the trials. Typical use: General use. The one trial that named yellow maca found no effect on what it measured.
• Red maca. Best known for: Mood and energy. Absorption: GABA was the main compound in the red spray-dried extract. Typical use: In the 175-person trial, mood, energy and health scores improved more with red.
• Black maca. Best known for: The variety men usually choose. Absorption: More fatty acids and macamides than red in the same trial. Typical use: Lowered blood glucose in that trial. The memory and sperm claims linked to black maca come from animal studies in a narrative review.
• Gelatinised maca. Best known for: The form with the best human evidence. Absorption: Processed with heat and pressure to remove the starch. Typical use: The form used in the sexual desire trial (1,500 to 3,000 mg) and the trial on symptoms of low testosterone, or hypogonadism (3 g a day).
• Dry extract. Best known for: Concentrated capsules. Absorption: Not measured. Typical use: 2,400 mg a day in one trial of 50 men.
• Spray-dried extract. Best known for: The form used in the largest trial. Absorption: Chemically tested for macamides, fatty acids and GABA. Typical use: 3 g a day for 12 weeks.
• Raw powder, nibs, chocolate, blends. Best known for: Food use. Absorption: None of the trials in our sources used raw powder. Typical use: Fine in a smoothie. It can't be matched to any trial dose, and as a food it carries no therapeutic claim at all.

Reference values. There's no Nutrient Reference Value for maca. It's a root vegetable and a herb, not a nutrient.

Typical supplemental range. Human trials used 1,500 mg to 3.3 g a day, for 12 to 16 weeks. The sexual desire trial used 1,500 mg or 3,000 mg of gelatinised maca, and the mood and energy trial used 3 g of spray-dried extract.

Upper level. In a listed medicine, the maximum recommended daily dose can't provide more than 3.5 g of dried root or the extract equivalent. An extract has to be worked back to its dried-root amount, so a 10:1 extract at 350 mg is already at the limit. Maca sold as a food doesn't have that limit. But no human trial we've reviewed went above 3.3 g a day either, so 3.5 g is the top of the evidence as well as the top of the rules.

Worth knowing. The longest human trials ran for 12 to 16 weeks, so there's no long-term safety data. Give it eight weeks before you judge it, because that's when the desire effect appeared. What you need depends on your age, diet and health, so talk to one of our naturopaths in store.

Food first, where the diet allows it.

• Maca root, as eaten in Peru: A traditional food crop of the high Andes, usually cooked or processed rather than raw
• Maca powder in food formats: maca content per serve is usually not declared as a dried-tuber equivalent, so it can't be matched to a trial dose

If any of these sound like you, talk to one of our naturopaths or your doctor before you start.

• You take blood pressure medicines. Maca lowered diastolic pressure in a 29-person crossover trial, and lab studies show it blocks renin and ACE. The effects could plausibly add up, so this is one for your prescriber.
• You take diabetes medicines. Black maca lowered blood glucose in a 175-person trial. For the same reason, talk to whoever manages your medicine.
• You take antidepressants. A review of 1,816 side-effect reports linked maca taken with mianserin to restless legs syndrome. Adaptogens as a group made up 9% of side effects reported with antidepressants.
• Pregnancy and breastfeeding. Our sources have no evidence either way, and Schedule 1 carries no warning. No warning does not mean it is safe.
• Children. Every human trial we hold was in adults, so there is nothing to base advice on.
• Thyroid. Maca is in the cabbage family (Brassicaceae) and contains glucosinolates. The most recent review of 123 studies found these plants do not affect the thyroid in people who get enough iodine, and the one trial that measured TSH found no change. Still worth a conversation if you are being treated.
• Unstandardised products and self-dosing. Mild to severe side effects have been reported with taking too much, or with unstandardised products.
• Long-term use. The longest human trials ran for 16 weeks. Nobody has studied taking it for years.