Many greens products are marketed to athletes, so why do they include this proven testosterone-zapping ingredient?
Go grab your greens powder or superfoods supplement and look at the ingredients. If you use one of those kitchen-sink products with 75 ingredients, this may take a minute. Got it? Okay, now look for licorice or licorice root extract or powder. Does your supplement contain it? If so, you might want to toss it out.
The Problem with Licorice Root
Licorice root (Glycyrrhiza glabra) can lower testosterone levels, primarily through its effects on hormone metabolism and enzyme activity.
Licorice contains glycyrrhizin, a compound that inhibits the enzyme 11β-HSD which normally converts cortisol into its inactive form, cortisone. By inhibiting 11β-HSD, licorice increases cortisol levels in certain tissues. (Cortisol builds up because it isn't converted to cortisone.) Elevated cortisol suppresses the HPG axis, which regulates testosterone production, leading to reduced testosterone synthesis in the testes.
Additionally, glycyrrhizin and its metabolite, glycyrrhetinic acid, may interfere with 17,20-lyase, another enzyme involved in testosterone biosynthesis. Studies show that licorice can reduce serum testosterone levels.
One study from the New England Journal of Medicine found that men consuming 7 grams of licorice extract daily (about 500 mg of glycyrrhizin) for 4 days experienced a significant drop in total testosterone levels, from an average of 740 ng/dL to 413 ng/dL. Animal studies have similarly shown decreased testosterone with licorice root exposure, often linked to altered steroidogenesis.
Also, licorice's cortisol-boosting action might indirectly lower testosterone by increasing stress on the body. It can even raise blood pressure and lower potassium levels, which might compound hormonal disruptions in sensitive individuals.
So Why Do Greens Powders Contain It?
Licorice root is classified as an adaptogen, meaning it's believed to help the body resist stress and maintain balance. Does it? Well, studies are mixed. At high dosages, it may work, but there's far more evidence supporting other adaptogens like ashwagandha and rhodiola.
At higher doses (>100 mg glycyrrhizin/day), licorice causes mineralocorticoid excess – raised blood pressure and potassium loss. This toxicity clashes with the "safe at normal doses" adaptogen requirement. Even in small amounts, chronic use could accumulate effects, undermining its safety profile.
So why do popular greens supplements contain it? Partly due to tradition: licorice root has been part of these formulations since the 1970s and many consumers just expect it to be in there. It may also soothe stomach issues caused by other grassy ingredients in the products.
But it's also added as a sweetener. Licorice root is up to 50 times sweeter than sugar, thanks to glycyrrhizin. Greens powders often contain bitter or earthy ingredients like spirulina or wheatgrass, making them unpalatable. Adding licorice root masks bitterness (but at a cost).
Do These Supps Contain Enough to Do Harm?
It's hard to say because most greens powders use proprietary formulas: they don't say how much of each ingredient is included. Based on the number of grams a serving contains and the number of total ingredients in the product, there's probably not enough licorice root to do severe harm. But why risk it? The testosterone-lowering effect is dose-dependent, but daily use could have a cumulative effect.
This also brings up another issue. If a greens product doesn't contain enough licorice to do major harm, that also means it doesn't contain enough to reap any of licorice's potential (but questionable) benefits. The more ingredients the product contains, the less of each ingredient is included (unless the scoop size is gigantic). That could mean the supplement doesn't contain enough healthy ingredients to have a positive effect. That's one of the many problems with green products that contain 30, 50, or 75-plus ingredients.
A Better Choice
Not every greens powder contains licorice, so find one that doesn't. You might also want to avoid the common allergens that some companies like to toss in as filler (wheatgrass, barley grass, alfalfa, and dandelion).
That's tough to find, which is why we made our own: Superfood ➔ Buy at Biotest. We excluded any testosterone-lowering ingredients like licorice and any potential allergens. There are no sweeteners or artificial colors.
We also focused on more than greens and included the most potent "reds" and "blues." We included inflammation-tamping polyphenols, metabolism-boosting EGCG, and estrogen-fighting indoles, among other things. It only has 18 ingredients, because that's all it needs.