Puerarin is a truly distinctive isoflavone. Renowned for its properties, it is extracted from the root of Pueraria lobata, also known as Kudzu. This Asian climbing plant has attracted the attention of the scientific and cosmeceutical communities for its cellular protective activities.
Its benefits extend remarkably successfully to the field of skincare. This result is due to the distinctive chemical structure of the isoflavone, which, thanks to its phenolic groups, demonstrates the ability to neutralize free radicals, thereby protecting the skin from oxidative stress and environmental damage.
To fully understand their importance, it is useful to remember that free radicals are unstable and reactive molecules that can cause cellular damage, accelerating the aging process. Acting as a shield, puerarin helps protect skin cells.
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What are isoflavones?
Isoflavones are phytoestrogens, polyphenolic compounds found in leguminous plants. Their chemical structure is similar to that of endogenous estrogens, giving them the ability to interact with certain receptors in the human body.
From a cosmeceutical perspective, this is highly significant in counteracting the biological processes underlying premature skin aging. One of the main attributes of isoflavones is their recognized antioxidant activity: they act by stabilizing molecules that could otherwise cause cellular damage.
Recent research also suggests a protective effect against UV-induced damage, one of the main factors in premature skin aging: through their antioxidant action, isoflavones can neutralize some of the free radicals generated by sun exposure. However, they remain a supplement rather than a substitute for sun protection.
Isoflavones and menopause: the benefits of genistein
During menopause, there is a natural decline in hormones that is also reflected in the skin: tissues become thinner and hydration levels decrease. The skin loses density and firmness, cell turnover slows, and the complexion appears duller.
Phytoestrogens are used in cosmetics specifically to support these changes. Soy is rich in them, as is Kudzu, which contains isoflavones such as puerarin and genistein.
Genistein is an interesting isoflavone in cosmetics because its chemical structure is similar to that of estradiol. In vitro studies show that it can bind to type beta estrogen receptors (ERβ) found in skin fibroblasts.
Several studies report positive effects of the topical application of isoflavones such as genistein on the skin, including support for the presence of hyaluronic acid and the synthesis of collagen.
Genistein also interferes with the tyrosine kinase protein, which is involved in the signaling cascade that leads to the degradation of collagen and elastin. This helps maintain the structure of the dermis.
One clarification is worth making: when applied to the skin, phytoestrogens act locally and do not alter the body's hormonal balance. They in no way replace hormone replacement therapy, which is a medically supervised treatment. Anyone taking hormone therapies or with a history of hormone-sensitive conditions should discuss even topical use with their doctor or gynecologist.
The benefits of puerarin for the skin
Puerarin is an isoflavone with important protective effects for the skin. Its molecules act by capturing free radicals and helping to maintain the structural integrity of cells.
This isoflavone provides protective action against oxidative stress induced by agents such as wind and pollution, as well as protective action on cellular lipids.
The lipids present in cell membranes are in fact susceptible to oxidation, and this oxidation damages their structure and function. Thanks to its antioxidant properties, puerarin protects lipids from lipid peroxidation, helping to maintain membrane integrity.
It also acts on the extracellular matrix of the papillary dermis, and its effect extends to the microcirculation, with positive effects on the skin’s radiance and elasticity.
The most interesting aspect is not its antioxidant action
There is one finding worth highlighting because it changes how this active ingredient is understood. In a 2021 study on senescent human fibroblasts—cells that were still alive but had stopped producing matrix—puerarin reduced the proportion of cells in that state. In the same study, however, free radicals did not decrease: its effect on senescence therefore occurs through a pathway different from the antioxidant one.
This is why Kudzu deserves its own section: its appeal in an anti-aging formula lies not only in protecting, but also in acting on cells that have stopped producing.
The benefits of Kudzu isoflavones
Kudzu, also known as Pueraria lobata, is a climbing plant native to Japan, China, and Korea, belonging to the Fabaceae family and now cultivated worldwide. In traditional medicine, it has been used for centuries for its antioxidant properties.
The name Pueraria derives from the Swiss botanist Marc Nicolas Puerari; however, its assonance with “puer” has fueled the idea of a plant “linked to youth,” a suggestion that fits well with its antioxidant profile.
Kudzu extract is rich in isoflavones, including:
- puerarin
- genistein
- daidzein
- tectorigenin
It also contains other polyphenols with antioxidant action, including quercetin, which belongs to the class of flavonols rather than isoflavones.
They are all compounds capable of counteracting inflammatory processes and protecting the skin from oxidative stress. This extract promotes an even complexion, supports hydration, and can soothe sensitive skin.
Isoflavones in skincare: the ideal products
Our job is to harness the benefits of active ingredients in skincare products: that is why we have included the benefits of isoflavones in the Collagenetic Serum and the Hyaluronic Advance anti-ageing face cream.
COLLAGENETIC SERUM Collagen Stimulating Serum - Firming Stimulates collagen synthesis for firmer skin. Improves skin tone and elasticit... Discover COLLAGENETIC SERUM
HYALURONIC ADVANCE Anti-Aging Elasticizing Face Cream - Ultra Fill Filler like action Stimulates the production of Endogenous Hyaluroni... Discover HYALURONIC ADVANCE
Both products, designed for mature skin that needs hydration and protection, act on the extracellular matrix and help to:
- give the face a radiant appearance;
- reduce the appearance of wrinkles;
- maintain and increase hydration;
- support the skin's elasticity.
Face serum and cream are the essential steps in a skincare routine, and it is their combination that allows antioxidant active ingredients to perform at their best.
You can also find LeLang products at partner pharmacies throughout Italy.
Frequently asked questions about isoflavones
Are phytoestrogens in creams safe?
At cosmetic concentrations, yes: they act locally and do not alter the body's hormone levels. However, anyone with a history of hormone-sensitive tumors should discuss using them with their oncologist or gynecologist beforehand, even for topical use.
What is the difference between puerarin and genistein?
They are two isoflavones found in the same extract but with different profiles. Puerarin is mainly focused on antioxidant protection, microcirculation, and fibroblast senescence; genistein has a structure more similar to estradiol and is the one on which studies of cutaneous beta receptors focus.
Does puerarin lighten dark spots?
No, and this is an area of confusion. Regarding tyrosinase—the key enzyme in melanin synthesis—puerarin has a twofold effect: it inhibits one of the enzyme's two activities and activates the other. It is therefore not a dark-spot treatment, and molecules specifically studied for that purpose are needed to address that concern. The full explanation can be found in the Kudzu overview.
Are isoflavones only useful during menopause?
No. The antioxidant component is useful at any age. The part related to phytoestrogens simply has a stronger rationale when hormonal decline begins to affect the skin.
Are supplements or cosmetics better?
These are two different and non-interchangeable approaches. Isoflavone-based supplements act throughout the body and should be evaluated with a doctor; cosmetics act where they are applied and improve the appearance of the skin.
Is cosmetic Kudzu the same as the one used in herbal medicine?
The plant is the same, but the cosmetic extract is standardized and formulated for topical use. Extracts intended for oral use have different concentrations and purposes.
Can they be used together with retinol?
Yes, there are no known incompatibilities. As always, when skin is adjusting to retinoids, it is best to introduce one active at a time.
Sources for this article
01 Study on senescent human dermal fibroblasts treated with puerarin, showing a reduction in the proportion of senescent cells without a decrease in free radicals — PLOS ONE, 2021.
02 Qu L. et al. — study on the effect of puerarin on the two activities of tyrosinase (monophenolase inhibition, diphenolase activation), Molecules, vol. 25 no. 2, 2020.
03 Regulation (EC) No 1223/2009 of the European Parliament and of the Council on cosmetic products.
04 Commission Regulation (EU) No 655/2013, common criteria for the justification of claims relating to cosmetic products.
On the website: Kudzu · elastin · skin and menopause · sensitive skin.
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