Firstly, many sweet black licorice sticks on the market contain very little real licorice; they often use anise seed oil as a near identical substitute.
Secondly, licorice is more than candy; there are no licorice mines or trees instantly producing the candy you know and love. The flavour comes from the licorice root, or Glycyrrhiza, which is native to the Mediterranean.
The plant was consumed in a liquid form for thousands of years before the long black candy was invented. Licorice root has a long medicinal history. Today, women like to use it for keeping PCOS symptoms down, whereas Ancient Greek soldiers marched into battle with licorice root in their pockets to quench their thirst in the sun. It’s riddled with controversy too, since too much can lead to high blood pressure or even heart attacks.
Whether licorice root is a positive or negative for health overall is a mystery. What’s beyond doubt is that this herb is a very powerful substance…
…and one of the conditions licorice root has the biggest impact upon is our arch enemy acne vulgaris.
Licorice root – the cure for oily skin?
Over 400 different active medicinal compounds have been identified in the licorice root, including glabridin, isoliquiritigenin and the unique licochalcone.
However, one specific compound is responsible for the distinctive taste that spawned a whole industry. Glycyrrhizic acid, or glycyrrhiza, which also tastes approximately 50 times sweeter than sugar without rotting your teeth.
It’s a very potent compound for acne as well. Why? Glycyrrhizic acid can lower testosterone and massively inhibit androgen stimulation of the sebaceous glands, with the result being less oily skin and clogged pores. That’s the licorice root’s main power for acne by far.
The reductions are very significant. First we have this 1988 in vitro study which applied glycyrrhizic acid to rat cells and tested the hormonal effects. Significant reductions in testosterone occurred, due to the inhibition of an enzyme called 17β-HSD, which is a vital catalyst for production. This occurred with a very modest dosage of the compound.
Of course, a study on rat testicular cells isn’t much use to a living, breathing human being with acne. So fast forward eleven years and we have an in vivo human study which conducted a very similar experiment. 7 healthy men were given 7 grams of a commercially sold licorice candy which contained 0.5 grams of glycyrrhizic acid.
After just four days their total testosterone levels decreased by nearly 45%, from 740 ng/dL to 414 ng/dL. On day 7 testosterone increased, going back up to 484 ng/dl, but the levels were still suppressed.
Removing the licorice rapidly restored testosterone levels to 704 ng/dl. Back in 2004 licorice root was tested on women as well; 9 women aged 22-26 years old were given 3.5 grams of licorice daily consisting of 7% glycyrrhizic acid. As you can see, the study was almost identical to the 1999 one on men.
After one month, their total serum testosterone levels declined from 27.8ng/dL to 19.0ng/dL. After another month, levels fell to 17.5ng/dL. Once again, this reduction was rapidly reversed when women stopped taking the licorice.
What we have is a rapid initial reduction in testosterone followed slowly but surely by a further reduction.
Finally, several of the active compounds in licorice root are famed for their estrogenic properties, which counteract testosterone. According to this animal study, glabridin and glabrene increased the activity of estrogen. According to this study, a whole licorice extract led to increases in a biomarker of estrogen called creatine kinase.
How licorice root affects acne
So it’s pretty clear that licorice root is one of the most potent anti-androgenic compounds on Earth. This common candy ingredient ranks up there with saw palmetto and green tea for slashing testosterone and DHT.
Furthermore, it works extremely quickly, slashing testosterone counts in just 4 days. If testosterone fell by 45% in that time, then in 2 days there could have been a good 20% fall.
Those Ancient Greek soldiers were extremely foolish. Maybe their liquorice tonic would have rehydrated them, but during each battle they probably wondered where their aggression and urge to fight went. Every single time, the Ancient Egyptian armies probably thought “excellent, these idiots are using liquorice root again!”, and couldn’t help but chuckle to themselves.
For acne, taking licorice will therefore decrease the activity of your sebaceous glands, make your skin less oily and put an end to constant clogged pores. If licorice has ever erased your acne or your best friend’s acne, whether in a black stick or brewed into tea, inhibited androgens is probably why.
Why you should never supplement with licorice
Despite that, I still wholeheartedly advise you to avoid this remedy. You can enjoy licorice as candy, but you should never supplement with enough to kick-start the anti-androgen train.
Why? For men, there’s the crippled sex drive, the lack of focus, the decreased muscle mass, and reduced physical energy that comes with low DHT and testosterone. I don’t recommend lowering androgens internally for men; you can read about why it’s not worth it for acne here. Such hormones make you a man and fuel your existence.
For women, there’s no threat there. Potentially, there’s a bonus benefit because licorice is proven to minimise the side effects from spironolactone, the king of PCOS drugs, which triggers acne in addition to fatigue.
32 women were fed either spironolactone or licorice and spironolactone in this study. Those taking the licorice and spironolactone experienced significantly less fatigue. Many women are excited about licorice root for protecting against spironolactone acne and it might be effective.
However, licorice is such a powerful herb that it causes increased blood pressure and can trigger heart attacks. The standard advice from doctors is to take licorice supplements for only one week.
Furthermore, there’s a hormonal side effect which affects both genders – licorice root is proven to increase the stress hormone cortisol. This study found that licorice root raises cortisol levels in men. This study found that licorice root increased the activity of cortisol across many bodily tissues.
Licorice root works by inhibiting the 11 beta-dehydrogenase enzyme, which normally converts the highly active cortisol into the inactive cortisone. According to this study, glycyrrhizic acid produces a metabolite which is responsible for this inhibition.
If you supplement with licorice root then here’s what will happen. Your skin will become less oily and your pores will gradually unclog. Your acne will fade away. However, your skin will become exceedingly dull and lifeless looking due to elevated stress hormones.
Finally, the one week safety limit makes licorice less effective than saw palmetto, even though the latter takes weeks to reduce DHT. Licorice root might slash testosterone in two days, but it takes pores weeks to free themselves from sebum and dead skin cells.
Hence, you need weeks of suppressed androgens for licorice to work. Saw palmetto wins for that purpose.
Overall, licorice looks terrific as an anti-androgen supplement, food, or beverage on paper, but in practise it is flawed, catastrophically so.
Topical licorice is the best
Licorice has anti-androgenic properties when you apply it to human skin, in addition to eating it. This study tested several plants, and among all the herbal extracts tested, licorice extract was the most potent at inhibiting the 5-alpha reductase enzyme on the skin’s surface.
5-AR is the enzyme which converts testosterone to DHT. More 5-AR equals less DHT equals less oily skin, because DHT is more powerful at stimulating sebaceous glands than testosterone.
It’s believed that licochalcone is behind the 5-AR inhibition; that’s different to the glycyrrhizic acid which disrupts testosterone formation inside the body. A different mechanism, but the same result. Most importantly, applying licorice topically produces no increased cortisol, no sluggish sex drive and no low mood.
If you want to take advantage of licorice, place an extract in aloe vera gel, grapeseed oil or jojoba oil and apply it directly. The study also confirmed the reduced sebum production, and additionally, weakened androgen receptor activity. That means that the androgens you do have will be less damaging.
Licorice reduces oily skin from multiple angles. This study also revealed a bonus benefit – protection from UV radiation. 22 women had licochalcone extract applied to their arms. After two weeks of the licorice lotion there was a significant reduction in free radicals generated by the skin in response to UVA radiation exposure.
Essentially, licorice keeps your skin healthy in the face of sunlight, and gets rid of some of the biggest culprits behind acne. This was in comparison to a group with no licorice applied to their skin.
If true, that’s great news. Topical licorice can clear acne, and replace your chemical-rich sunscreen. Benefits were observed with small levels of licorice, whereas higher concentrations inhibited the free radicals from sunlight almost completely.
Our last study is more mixed, but 75% promising. Scientists developed a new skincare formulation containing licochalcone, l-carnitine, and 1,2-decanediol. They tested it on 60 volunteers with mild to moderate acne aged between 14 and 40.
A variety of acne factors were tested including p.acnes bacteria, sebum levels, total lesion counts, and stratum corneum hydration to assess its moisturising ability.
The formulation improved every one of those measurements. Sebum production, p.acnes colonisation and acne lesions fell, while skin hydration went up, compared to the control patients.
Why is the study a mixed bag then? Because of the presence of the l-carnitine and 1,2-decanediol. We cannot confirm that the licorice was the miracle acne substance.
However, neither are famous skincare ingredients, nor ones with any brilliant studies (apart from this one obviously). L-carnitine is a protein compound derived from the amino acid lysine, whereas 1,2-decanediol is a research chemical.
Therefore I’d judge that the licorice extract was responsible. What’s more, we have confirmation that the oily skin powers work in practise.
An acne-friendly hyperpigmentation remedy
Last but not least, licorice root extract is one of the handful of plants found in nature which have been discovered to have skin whitening properties. You might have heard claims like this: “licorice root has depigmenting properties 75 times more effective than ascorbic acid and equally effective as kojic acid”.
None of those claims are confirmed, but the phytonutrient glabridin is a known tyrosinase inhibitor on the skin’s surface. Tyrosinase is an enzyme which is used to manufacture melanin, through conversion from the non-essential amino acid tyrosine. This pigments your skin white, olive, black, or whatever your genetics determine, but in people with hyperpigmentation, tyrosinase is out of control.
This study found that two types of glabridin extracted from licorice root could inhibit melanin synthesis. They functioned by inhibiting both T1 and T3 tyrosinase. A 0.5% glabridin cream was tested on guinea pig skin; it successfully inhibited UVB radiation-induced hyperpigmentation. As a bonus, the glabridin lowered inflammation levels effectively too.
Then we have this interesting study. Scientists tested a whole licorice extract, and were shocked to find that it had more potent skin-whitening properties than the detected concentrations of glabridin would suggest.
So they discovered two new compounds, glabrene and isoliquiritigenin, which also had dose dependent anti-tyrosinase activity. The activity correlated closely to the compounds’ ability to inhibit melanin formation. The two compounds “may serve as candidates for skin-lightening agents”; licorice root contains them.
Licorice root also contains liquiritin, which has zero effect on tyrosinase but does act directly on melanin to disperse and remove it. A liquiritin cream was tested on 20 Egyptian women and was found to be safe and effective in treating melasma, which is any tanning bed addict’s nightmare, a grey and dull tan instead of a brown and healthy one.
Here we have yet more evidence that applying licorice topically is the way forward, not supplementing with it, whether your goal is acne reduction or an even skin tone.
Licorice has one of the strongest arsenals of unique compounds in any acne plant. The glabridin, the glycyrrhizic acid, and the licochalcone are found nowhere else. They have a ton of interesting properties.
Licorice is one of the most fascinating plants for acne overall. To recap, its main power is inhibiting DHT and testosterone and oily skin, followed by curing hyperpigmentation without the chemicals. With the unique compounds, there may be acne powers to be discovered still.
But there’s little debate on your strategy – use licorice topically, and if you’re eating liquorice, let it be in some tasty candy or tea only.
Thanks for reading!