Skin: nootropics and compounds | sci-wiki

Phenylalanine

Phenylalanine is an essential amino acid and the first step in making dopamine and noradrenaline: the body converts it to tyrosine, tyrosine to L-DOPA, and L-DOPA to dopamine. That chain is the entire basis for taking it, and it is also the reason to be measured about it, because supplying more of the first ingredient does not reliably speed up a pathway that is regulated further downstream. The best-supported use is not mood at all; L-phenylalanine combined with light therapy has a real if modest evidence base in vitiligo [9][10]. The critical safety fact is short and absolute: anyone with phenylketonuria must not take it [7].

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Supplement

Biotin

Biotin, also known as vitamin B7 (and historically as vitamin H), is a water-soluble B vitamin that the body needs as a coenzyme for several key metabolic enzymes. It acts as an essential cofactor for carboxylase enzymes involved in the metabolism of fats, carbohydrates, and amino acids [1]. True deficiency is rare because biotin is widespread in foods and is also made by gut bacteria, but it is a popular dietary supplement, most often marketed for hair, skin, and nail health despite limited supporting evidence in people who are not deficient [2]. High-dose biotin can also interfere with common laboratory blood tests [4].

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Retinoid

Isotretinoin

Isotretinoin is an oral retinoid, a derivative of vitamin A also known as 13-cis-retinoic acid, used chiefly for severe or treatment-resistant acne. It is regarded as the single most effective therapy for nodulocystic acne because it acts on every major factor that drives the disease, and a completed course can produce lasting remission rather than only temporary control; it is thought to shrink the sebaceous glands by increasing the transcription factor FOXO1 and reducing mTOR nutrient-sensing signaling, promoting programmed cell death of sebocytes. The same differentiating action underlies its use, at high dose, in the maintenance treatment of high-risk neuroblastoma. Owing to its potent teratogenicity it is tightly regulated in most countries and dispensed by prescription under pregnancy-prevention programs.

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Amino Acid

L-Histidine

L-Histidine is an essential amino acid built around an imidazole ring, which gives it an unusual set of jobs: it is the direct precursor to histamine and (with beta-alanine) to carnosine, it buffers pH near physiological range, and it chelates divalent metals like iron and copper while scavenging singlet oxygen and hydroxyl radicals. It shows up in food protein and is sold as a standalone supplement. Human outcome data is modest but real for skin barrier (atopic dermatitis) and metabolic markers, with most of its antioxidant reputation resting on biochemistry and preclinical work.

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Peptide

MT-1

MT-1, also known as Melanotan-1 or afamelanotide, is a synthetic analog of the body's own alpha-melanocyte-stimulating hormone and the first melanocortin-1 receptor agonist to reach the market. By switching on the skin's natural pigment machinery, it produces protective tanning and shields against light-induced damage. In its pharmaceutical form, afamelanotide, it is an approved medicine backed by rigorous clinical trials and decades of study.

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Supplement

Vitamin B3 (Niacin)

Vitamin B3 is an essential water-soluble nutrient that exists in two main forms, nicotinic acid (niacin) and nicotinamide (niacinamide), both of which the body converts into the coenzymes NAD+ and NADP+ that drive hundreds of redox reactions in energy metabolism. A prolonged dietary lack causes pellagra, the deficiency disease classically remembered by the "three Ds" of dermatitis, diarrhea, and dementia. In pharmacologic doses nicotinic acid favorably shifts blood lipids (raising HDL while lowering LDL, triglycerides, and lipoprotein(a)) and produces the characteristic warm "niacin flush," whereas nicotinamide has neither the flush nor the lipid effects and is used mainly in dermatology. It is distinct from the dedicated NAD-boosting precursors nicotinamide riboside (NR) and NMN, which are covered in their own entries.

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Supplement

Vitamin B5 (Pantothenic Acid)

Pantothenic acid, better known as vitamin B5, is a water-soluble vitamin whose central role is to serve as the building block of coenzyme A, the cofactor that carries acyl groups through energy production and the synthesis and breakdown of fats. Its name derives from the Greek pantothen, meaning "from everywhere," reflecting how widely it is distributed across foods, which makes true dietary deficiency very rare. The vitamin is present in meat, eggs, dairy, legumes, whole grains, avocados, and mushrooms, and gut bacteria contribute some as well. Its stable alcohol derivative, panthenol (dexpanthenol), is widely used in topical skincare and wound-care products as a humectant and barrier-repair agent.

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Supplement

Vitamin E

Vitamin E is the collective name for a group of eight fat-soluble compounds, four tocopherols and four tocotrienols, of which alpha-tocopherol is the form the body preferentially retains and the one with the greatest vitamin activity. Its principal role is as a lipid-soluble antioxidant that protects cell membranes from damage by free radicals. Vitamin E is found in vegetable oils, nuts, seeds, and green vegetables, and dietary deficiency is rare, usually resulting from disorders of fat absorption rather than low intake.

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Mineral

Zinc Bisglycinate

Zinc bisglycinate is elemental zinc chelated to two molecules of the amino acid glycine. The chelate structure is small, stable across stomach pH, and tends to be better absorbed and gentler on the gut than cheaper salts like zinc gluconate or sulfate. Zinc itself is an essential trace mineral and a cofactor for hundreds of enzymes tied to immunity, skin, wound healing, taste and smell, and reproductive hormones.

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Retinoid

Adapalene

Adapalene is a synthetic, third-generation topical retinoid used mainly to treat acne vulgaris. Chemically a stable naphthoic acid derivative, it acts on retinoic acid receptors in the skin to normalize the shedding of skin cells and to calm inflammation. Sold under brand names such as Differin, it was the first retinoid approved for over-the-counter acne treatment in the United States.

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Blend

Adapalene + Benzoyl Peroxide

Adapalene/benzoyl peroxide is a fixed-dose combination medication for acne vulgaris that pairs the topical retinoid adapalene with the antimicrobial and keratolytic agent benzoyl peroxide in a single gel. Marketed under brand names such as Epiduo, it is applied to the skin and brings together two ingredients that act on different causes of acne. Combining them in one product targets several of the factors behind acne at once and can work faster than either ingredient used alone.

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Dermatological

Azelaic Acid

Azelaic acid is a naturally occurring saturated dicarboxylic acid (chemically nonanedioic acid, a nine-carbon molecule) used mainly as a topical treatment in dermatology. It is found in cereal grains such as wheat, rye, and barley and is produced on the skin by Malassezia yeast. Applied to the skin it treats acne, rosacea, and pigmentation problems such as melasma, working through antibacterial, pore-normalizing, anti-inflammatory, and pigment-reducing actions.

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Antibiotic

Azithromycin

Azithromycin is a broad-spectrum antibiotic in the macrolide family, specifically the first of the azalide subclass, sold under brand names such as Zithromax and the Z-Pak. It treats a range of bacterial infections, including respiratory, skin, and sexually transmitted infections. Discovered by scientists at the Croatian company Pliva in the early 1980s, it is known for concentrating heavily in body tissues and having a long half-life, which allows short, simple courses of treatment.

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Blend

Bacitracin Zinc + Neomycin + Polymyxin B

Bacitracin zinc, neomycin, and polymyxin B is a topical antibiotic combination, sold over the counter as triple antibiotic ointment under brand names such as Neosporin. Blended into a petroleum-jelly base, the three antibiotics attack bacteria in complementary ways and together cover a wide range of gram-positive and gram-negative organisms. It is applied to minor cuts, scrapes, and burns to lower the chance of skin infection while a wound heals.

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Antibiotic

Cephalexin

Cephalexin, also spelled cefalexin, is a first-generation cephalosporin antibiotic taken by mouth to treat a variety of common bacterial infections [1][2]. It works by blocking construction of the bacterial cell wall and is used chiefly against gram-positive organisms, in conditions such as skin infections, strep throat, ear infections, and urinary tract infections [1][2]. First marketed in 1969 under the brand name Keflex, it is inexpensive, widely available as a generic, and listed on the World Health Organization Model List of Essential Medicines [1]. It is generally well tolerated, with digestive upset among the more common side effects [1][2].

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Antibiotic

Clindamycin

Clindamycin is a lincosamide antibiotic, a semisynthetic derivative of lincomycin, that inhibits bacterial protein synthesis by binding the 50S ribosomal subunit at the peptidyl transferase center and blocking the nascent peptide exit tunnel. It is active against many Gram-positive cocci and anaerobes and is used for skin and soft-tissue, dental, and bone infections as well as some MRSA disease. A distinctive feature is its ability to suppress translation of bacterial exotoxins independent of bactericidal killing, which makes it a valued adjunctive agent in streptococcal and staphylococcal toxic shock syndrome and necrotizing soft-tissue infection, where it curbs production of superantigens and Panton-Valentine leukocidin. Because it also disables the apicoplast of apicomplexan parasites, clindamycin serves as an antimalarial partner drug and in the treatment of toxoplasmosis and babesiosis. Its principal drawback is a comparatively high risk of Clostridioides difficile colitis.

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Blend

Glutathione + Kojic Acid

Glutathione and kojic acid is a combination of two agents used together in cosmetic skin-lightening and brightening products. Glutathione is a naturally occurring antioxidant tripeptide that can shift melanin production toward lighter pigments, while kojic acid is a fungal-derived compound that inhibits tyrosinase, the key enzyme in melanin synthesis. Marketed in creams, soaps, and oral supplements, the pairing is intended to reduce hyperpigmentation and even out skin tone, although the strength of the clinical evidence varies.

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Dermatological

Glycolic Acid

Glycolic acid is the smallest of the alpha-hydroxy acids, a colorless, odorless, water-soluble crystalline compound found naturally in sugarcane and some fruits. In industry it is used in textiles, adhesives, and as a chemical building block, but it is best known in dermatology, where it is a widely used ingredient in exfoliating skincare products and chemical peels. Its small size allows it to penetrate the skin readily, loosening the bonds between surface cells and promoting exfoliation and renewal.

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Dermatological

Hydroquinone

Hydroquinone is an aromatic organic compound, a benzene-1,4-diol (para-dihydroxybenzene) belonging to the phenol family. In medicine and cosmetics it is the classic topical skin-lightening agent, used to fade melasma, age spots and other hyperpigmentation by curbing the skin's production of melanin. The same molecule also serves industrial roles as a photographic developer, an antioxidant and a polymerization inhibitor.

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Blend

Hydroquinone + Octinoxate + Oxybenzone

Hydroquinone + Octinoxate + Oxybenzone is a combined topical preparation that pairs the skin-lightening agent hydroquinone with two organic ultraviolet filters, octinoxate and oxybenzone. It is used to treat melasma and other facial hyperpigmentation, with hydroquinone fading existing pigment while the sunscreen filters shield the treated skin from the ultraviolet light that darkens it. The formula reflects the standard clinical principle that pigment-lightening therapy works best alongside daily photoprotection.

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Antiviral

Imiquimod

Imiquimod is a topical immune response modifier of the imidazoquinoline class that works as an agonist of toll-like receptor 7 (TLR7). Applied as a skin cream, it is used to treat external genital warts, actinic keratosis, and superficial basal cell carcinoma by prompting the body's own immune system to attack abnormal or virus-infected cells. It was first approved in 1997 and is marketed under the brand name Aldara among others.

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Corticosteroid

Mometasone Furoate

Mometasone furoate is a synthetic corticosteroid (glucocorticoid) with strong anti-inflammatory activity, used for a range of allergic and inflammatory conditions. It is applied to the skin for inflammatory rashes, sprayed into the nose for hay fever and nasal polyps, and inhaled to help control asthma. Patented in 1981 and introduced in the late 1980s, it appears on the World Health Organization's list of essential medicines and is available generically.

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Immunomodulator

Pimecrolimus

Pimecrolimus is a topical calcineurin inhibitor, a non-steroidal anti-inflammatory cream used to treat eczema (atopic dermatitis). Sold under the brand name Elidel, it calms the overactive immune response in the skin by blocking a signaling enzyme inside immune cells, and unlike corticosteroids it does not cause skin thinning, which makes it useful on delicate areas such as the face. It is generally reserved for when standard treatments are unsuitable or ineffective, and it carries a boxed warning about a theoretical cancer risk that later research has not supported.

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Dermatological

Salicylic Acid

Salicylic acid is a beta-hydroxy acid and one of the best known dermatological agents, taking its name from the willow tree (Latin salix) from which its precursor salicin was first isolated. It is used widely on the skin as a keratolytic to treat acne, warts, dandruff, psoriasis, and other conditions in which the outer layer of skin thickens or sheds abnormally. It is also the parent compound of aspirin, and in plants it functions as a signaling hormone.

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Retinoid

Tazarotene

Tazarotene is a topical retinoid, a vitamin-A-derived compound of the third generation, used on the skin to treat acne, plaque psoriasis, and signs of sun-related aging. It is applied as a gel, cream, lotion, or foam and works as a prodrug that the skin converts into its active form, tazarotenic acid. Like other retinoids, it is avoided during pregnancy.

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Antifungal

Terbinafine

Terbinafine is an antifungal drug of the allylamine class, used to treat fungal infections of the skin, hair, and nails, most notably onychomycosis of the nails and dermatophyte infections such as ringworm and athlete's foot. It works by blocking squalene epoxidase, an enzyme fungi need to build their cell membranes, which makes it fungicidal rather than merely slowing growth. Terbinafine is available as oral tablets for deeper or nail infections and as topical creams for superficial skin conditions [2].

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Dermatological

Zinc Oxide (Sunscreen)

Zinc oxide is an inorganic compound widely used as a mineral, or physical, sunscreen active ingredient. Applied to the skin, it provides broad-spectrum protection against both UVA and UVB ultraviolet light, and it is regarded as one of the most photostable and gentle of the sunscreen filters. The same compound is used in barrier creams for diaper rash and in calamine lotion as a skin protectant.

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Dermatological

Crisaborole

Crisaborole (Eucrisa) is a boron-containing, non-steroidal topical PDE4 inhibitor, FDA-approved in December 2016 for mild-to-moderate atopic dermatitis (eczema) in patients aged three months and older. Two pivotal Phase 3 trials showed superior skin clearance and itch relief versus vehicle with a favorable safety profile. Honesty note: this is a skin drug with negligible systemic absorption and no CNS or cognition relevance whatsoever; it is included here only for PDE4-class completeness, not as a nootropic.

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Dermatological

Difamilast

Difamilast (Moizerto) is a selective, PDE4B-preferring topical PDE4 inhibitor and the first PDE4 inhibitor approved in Japan (2021) for atopic dermatitis in patients aged two years and older. Two Phase 3 trials in adults and children showed clear eczema clearance superior to vehicle with a rapid antipruritic effect. Like crisaborole, it is a skin drug with negligible systemic exposure and no CNS or cognition evidence; included here for PDE4-class completeness, not as a nootropic.

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Supplement

GLA

Gamma-linolenic acid, abbreviated GLA, is an omega-6 polyunsaturated fatty acid found in a small number of plant seed oils, notably evening primrose, borage, and blackcurrant seed oils. The body can also make it from the common dietary fat linoleic acid, and it serves as a precursor to compounds with anti-inflammatory activity [1][2]. It is sold as a dietary supplement and has been studied for skin conditions such as eczema and for inflammatory disorders including rheumatoid arthritis [2][3].

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Peptide

Palmitoyl Hexapeptide-12

Palmitoyl Hexapeptide-12 is a synthetic cosmetic peptide; a short six-amino-acid chain with a palmitic acid (a fatty acid) tail attached so it sits better in the skin's lipid layers. It is used topically in anti-aging and conditioning skincare, marketed to support the look of firmness and smoothness. This is a cosmetic ingredient, not a drug, and the systemic (whole-body) evidence for it is limited.

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Peptide

Palmitoyl Tetrapeptide-7

Palmitoyl Tetrapeptide-7, sold under the name Rigin, is a synthetic cosmetic peptide; a four-amino-acid chain (glycine-glutamine-proline-arginine) with a palmitic acid tail to help it settle into the skin. It is used topically as an anti-aging and anti-inflammatory skincare ingredient, marketed on the idea that it dampens a signaling molecule called interleukin-6. It is a cosmetic ingredient, and the strongest data comes from manufacturer testing rather than large independent trials.

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Supplement

Tetrahydrocurcumin

Tetrahydrocurcumin is a colorless compound formed when curcumin, the principal yellow pigment of turmeric, is reduced, and it is one of the main metabolites produced when curcumin is broken down in the body. Chemically it is a hydrogenated curcuminoid; unlike its brightly colored parent it is nearly white, and it tends to be more chemically stable and more readily absorbed [1]. Marketed as a dietary supplement and cosmetic ingredient, tetrahydrocurcumin has been studied mainly for antioxidant and anti-inflammatory activity, though most of the evidence comes from laboratory and animal work rather than large human trials [1].

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Antineoplastic

Vusolimogene oderparepvec

An oncolytic herpes simplex virus given by injection into the tumour, approved by the FDA in August 2026 in combination with nivolumab for advanced cutaneous melanoma that has progressed on a PD-1 blocking antibody. It kills tumour cells directly and turns the tumour into a target the immune system can then see elsewhere in the body.

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