25 plant-based, mineral and naturally derived ingredients. For each one: what it is, what the research actually shows, how people use it, and the cautions that marketing leaves out. "Natural" is not a safety guarantee, so every entry includes who should avoid it.
Traditional West African soap from plantain-skin and cocoa-pod ash with palm or shea oils
African black soap is a true soap made from plant ash and palm or shea oils. It cleans thoroughly and is popular for oily skin and acne, but it has never been tested as an acne treatment: the evidence is one user survey and laboratory bacteria tests, and its alkalinity makes it drying and irritating when overused.
Aloe barbadensis leaf juice / inner leaf gel
Aloe vera gel is a light, cooling moisturiser with mild anti-inflammatory activity. The best evidence is for minor burns and for making acne medicines easier to tolerate; on its own it does little for established acne or dark spots.
Alpha-arbutin (4-hydroxyphenyl alpha-D-glucopyranoside); natural beta-arbutin from bearberry, Arctostaphylos uva-ursi
Arbutin is a sugar-bound form of hydroquinone found in bearberry leaves; alpha-arbutin is a more stable version made by fermentation. It slows the pigment enzyme tyrosinase and has a few small trials behind it for melasma, with a fraction of hydroquinone's irritation.
Nonanedioic acid, a naturally occurring dicarboxylic acid
Azelaic acid is a gentle multitasker: it unclogs pores, reduces acne bacteria, calms inflammation and slows pigment production. Prescription 15 to 20% products are well proven for acne and rosacea; over-the-counter 10% is milder and slower.
Centella asiatica (gotu kola) extract; madecassoside, asiaticoside
Centella asiatica is a gentle, well-tolerated soothing ingredient whose triterpenes encourage collagen production in the lab. Small human trials support faster recovery of irritated or freshly treated skin; claims about fading old scars are not proven.
Matricaria chamomilla (German) and Chamaemelum nobile (Roman); bisabolol
Chamomile extracts and bisabolol are reasonable calming ingredients for mildly irritated or dry skin, backed by small and mostly older studies. People allergic to ragweed and other daisies can react badly, and chamomile should stay away from the eyes.
Cocos nucifera oil
Virgin coconut oil is a rich, lauric-acid-heavy oil with two reasonable trials behind it for atopic eczema. It is a good body moisturiser for many people, a poor choice for acne-prone faces, and no substitute for sunscreen.
Avena sativa kernel flour
Colloidal oatmeal is finely milled whole oat that forms a soothing film on the skin. It is one of the few natural ingredients recognised by the FDA as a skin protectant, and small trials show 1% creams ease mild to moderate eczema.
Camellia sinensis leaf extract (EGCG)
The polyphenols in green tea, especially EGCG, reduce oil, inflammation and acne bacteria. Several small trials of 1 to 5% topical products show fewer spots and less shine; the evidence for sun protection and redness is thinner.
Honey from Apis mellifera; manuka honey from Leptospermum scoparium nectar
Honey is antibacterial, moisturising and soothing, and sterilised medical-grade honey speeds the healing of minor burns in good trials. As an acne treatment the evidence is disappointing, so think of a honey mask as comfort rather than therapy.
Simmondsia chinensis seed oil
Jojoba is a light, stable liquid wax that behaves more like skin's own sebum than like a true oil. It is a sensible moisturiser and carrier oil for most skin types, but the acne evidence amounts to a single uncontrolled study.
Kaolinite (china clay) and smectite-rich bentonite
Kaolin and bentonite clays absorb oil and leave skin matte for a few hours, which is pleasant but is not acne treatment. Used once or twice a week with moisturiser afterwards they are low risk; used daily they dry and irritate, and unregulated clays can carry lead.
5-hydroxy-2-(hydroxymethyl)-4-pyrone, a fungal fermentation product
Kojic acid is a tyrosinase inhibitor produced by fungi during fermentation. Small trials show it lightens melasma, usually at 1 to 2% in combination with other agents and more slowly than hydroquinone. It sensitises more often than most brightening ingredients.
Glycyrrhiza glabra root extract (glabridin, liquiritin)
Licorice root contains glabridin, which slows pigment production and calms inflammation, and liquiritin, which appears to help disperse existing pigment. A few small trials suggest benefit for melasma and dark marks; none is large or long enough to call it proven.
Niacinamide (nicotinamide), a form of vitamin B3
Niacinamide is a water-soluble form of vitamin B3 that calms inflammation, slows pigment transfer, reduces oil and helps skin make its own barrier lipids. It is one of the best-studied gentle actives, with a sweet spot of 2 to 5%.
Rosa canina / Rosa rubiginosa seed oil
Rosehip seed oil is a thin, linoleic-rich oil with a reputation for fading scars and marks. Two small studies of fresh surgical scars are encouraging; for acne marks, old scars and dark spots there is no direct evidence.
2-hydroxybenzoic acid; originally from Salix alba (willow) bark
Salicylic acid is an oil-soluble beta hydroxy acid that loosens the plugs of dead cells blocking pores. At the 0.5 to 2% strengths sold without prescription it is a sensible first step for blackheads, whiteheads and mild spots, used gently and consistently.
Vitellaria paradoxa (Butyrospermum parkii) seed butter
Shea butter is the fat pressed from the nuts of a West African tree. It is an occlusive, softening emollient with anti-inflammatory compounds, used for generations on dry skin and eczema, though the modern trial evidence is thin.
Elemental sulfur (precipitated or colloidal), 3 to 10%
Sulfur loosens blocked pores, inhibits bacteria and yeast, and dries oily skin, with a long record of use in acne, rosacea and seborrhoeic dermatitis. The best modern trials are of prescription sulfur combined with sodium sulfacetamide.
Helianthus annuus seed oil
High-linoleic sunflower seed oil is one of the few plant oils shown in a small controlled study to support the skin barrier rather than weaken it. It is a reasonable, low-cost emollient for dry and eczema-prone skin, with real caveats for newborns.
Melaleuca alternifolia leaf oil
Tea tree oil is an antibacterial, anti-inflammatory essential oil with two randomised trials behind a 5% gel for mild to moderate acne. It must always be diluted, it is a well-known cause of allergic contact dermatitis, and it is poisonous if swallowed.
Curcuma longa rhizome; curcumin
Turmeric's active compound curcumin is a genuine anti-inflammatory in the laboratory, and a handful of small human studies are encouraging. None is strong enough to call it a treatment, it stains skin yellow, and it can cause allergic reactions.
L-ascorbic acid; ascorbyl glucoside; magnesium ascorbyl phosphate; tetrahexyldecyl ascorbate
Vitamin C is an antioxidant that helps skin make collagen, blunts UV damage and slows pigment formation. L-ascorbic acid at 10 to 20% is the best-studied form but it is unstable and can sting; gentler derivatives trade some potency for stability.
Hamamelis virginiana leaf and bark extract
Witch hazel can take the edge off mild redness, but the effect is modest and the alcohol in most drugstore distillates dries and irritates skin. Alcohol-free forms, used sparingly, suit oily skin; people with rosacea should skip astringents altogether.
Zinc oxide (ZnO), mineral UV filter and skin protectant
Zinc oxide is one of the best-supported ingredients in skin care: a regulator-approved broad-spectrum sunscreen filter and skin protectant with a long safety record. The practical issues are white cast on deeper skin tones and the nano debate, which the evidence largely settles.
Strong means several good-quality human trials or a major guideline agree. Moderate means a few decent human trials. Limited means small, short or poorly controlled studies. Lab-only means it has been tested on cells or bacteria in a dish, not on people. Our full method is in the editorial policy.
An ingredient with limited evidence is not useless; it is simply unproven. We tell you so you can decide with open eyes.
One short, evidence-based lesson a day for five days, then one practical tip a week. Free, from a nonprofit; unsubscribe any time.