Cold outdoor air and forced-air heat dry out your face all winter, and that scalding shower adds to it. Water leaves the outer layer of skin faster, so it tightens and flakes, and some men break out on top of that. That layer is built from what you eat, and in one recent study two kiwifruit a day raised the vitamin C inside skin within eight weeks. More than a dozen other foods and diets have human skin data too, each with a very specific amount attached.
The outer skin layer holds water with natural moisturizing factor and slows its exit with barrier lipids. Cold air and low indoor humidity raise the rate of water loss through skin.[9]
Stratum corneum hydration, transepidermal water loss (TEWL), skin vitamin C and acne lesion counts.
Measured changes in skin vitamin C and winter hydration over 6 to 12 weeks, plus fewer acne lesions at 20 weeks, at the amounts each trial tested.[1,2,3]
Educational Disclaimer. This article is for informational purposes only and offers no medical advice. The food amounts below come from research protocols and menu planning, and none is a validated treatment for dry skin. Talk to a physician or registered dietitian before changing your diet if you have food allergies or take blood thinners, and see a dermatologist for persistent flaking or cracking.
Executive summary
- Winter dryness comes down to water leaving skin. Cold air and low humidity are linked to weaker barrier function and higher transepidermal water loss, or TEWL[9].
- Two kiwis a day put more vitamin C into skin. Eight weeks of two SunGold kiwifruit, about 250 mg of vitamin C daily, raised whole-skin vitamin C from 99 to 150 nmol per gram in 12 adults with low vitamin C. The pilot had no control group[1].
- A fiber powder improved skin through a winter. In 70 adults, 5 g a day of partially hydrolyzed guar gum (PHGG) lowered TEWL and improved elasticity against placebo by week 6. Nine of the 70 were men[2].
- Almonds reduced acne in young adults. Eating 60 g of whole almonds a day for 20 weeks cut total lesions 22.2%, with a 9.8% drop in controls, in 74 people aged 18 to 35[3].
- Fatty fish has a mechanism and no tested skin dose. The closest acne study combined a Mediterranean diet with algae omega-3 capsules and had no control group[4,7].
- The list goes well past kiwi and almonds. Controlled trials tied tomato paste, high-flavanol cocoa, green tea and avocado to measured changes in UV redness, hydration or elasticity[11,12,13,14].
- Plan for a full winter. Study timelines spanned 8 to 20 weeks, and nobody has tested the combined food list as one regimen[1,2,3].
Your winter skin plan includes daily topical care. GOA's Essentials Set brings together the Purifying Face Cleanser, Collagen + Control Facial Serum, and Regenerative Face Cream in a three-step routine. RFC provides the moisturizing step, with glycerin, sodium PCA, squalane, and oils in its published formula[10]. Make cleansing, treatment, and moisturizing part of your at-home facial longevity system.
Why winter skin dries out
The outermost layer of your skin, the stratum corneum, is a thin wall of flattened dead cells set in fat. The cells hold water-binding compounds called natural moisturizing factor. The fats between them, mostly ceramides, cholesterol and free fatty acids, slow water on its way out. When either part drops, the surface tightens and flakes.
Dermatologists track two numbers. Skin hydration measures how much water sits in that outer layer. Transepidermal water loss, or TEWL, measures how fast water moves outward through the epidermis and into the air. They are separate measurements, and a diet or a cream can shift one while the other holds steady.
In cold, dry weather, both numbers get worse. A review of humidity and temperature research linked low humidity and cold to weaker barrier function and higher TEWL. The same conditions were tied to dermatitis flares[9]. Forced-air heat dries indoor air further, and long, hot showers strip barrier lipids on top of that. How hard this hits you depends on your climate and your heating.
Diet supplies the raw materials. Skin cells use vitamin C to build collagen[1]. Essential fatty acids form part of every cell membrane, and a deficiency causes rough, scaly skin[7]. Vitamin A supports normal cell growth and differentiation[8]. Fiber feeds gut bacteria that make short-chain fatty acids, a pathway researchers propose as a gut-to-skin link[2].
Hydration and water loss are two separate readings. A good skin study reports both.
GOA Magazine · Skin ScienceA dozen foods, diets and supplements now have human skin data, and every trial used a fixed dose for a fixed number of weeks. The full table of the best foods for dry winter skin, with tested amounts and results, is in the research section.
What the new research shows
Three recent studies measured skin directly after a food or fiber change. A fourth tested diet plus omega-3 capsules on acne. They enrolled different people and measured different outcomes.
Vitamin C in skin
A University of Otago team conducted a two-site pilot. Each site enrolled 12 healthy adults with low blood vitamin C, who ate two SunGold kiwifruit a day for 8 weeks, about 250 mg of vitamin C daily[1].
At the New Zealand site, whole-skin vitamin C rose in every participant, from 99 to 150 nmol per gram of tissue[1]. At the German site, ultrasound skin density rose from 0.154 to 0.228 scanner units, and Ki-67, a marker of epidermal cell renewal, climbed from 21.1 to 27.4 units[1]. Two kiwis a day measurably raised vitamin C inside human skin.
The same study found no change in UVA protection or in procollagen type I, a direct collagen-building marker, and elasticity dipped about 7%[1]. Ultrasound density reflects structural proteins in the dermis. It does not convert into a percentage collagen gain, and no wrinkle result exists.
A separate analysis of skin from 38 surgical patients showed skin vitamin C tracks blood levels, with epidermal levels about double dermal levels per gram of tissue[1]. Zespri International, the kiwifruit company, helped fund the work[1].
Fiber and winter dryness
This is the one trial here built around winter. Researchers randomized 70 healthy adults, 61 women and 9 men with a mean age of 45.5, to 5 g a day of partially hydrolyzed guar gum or a placebo for 12 weeks during the winter season[2]. PHGG is a processed fiber powder made from guar beans.
By week 6, the fiber group showed lower TEWL and better elasticity scores than placebo. Hydration improved across the winter as well, and no adverse events were reported[2].
The proposed mechanism goes through the gut. Bacteria ferment the fiber into short-chain fatty acids, which may influence inflammation and skin. The trial did not prove that pathway[2]. Five of the six authors work for Taiyo Kagaku, the company that makes the fiber, and the paper appeared online in June 2024 ahead of its January 2025 issue[2].
That result belongs to the PHGG powder. Lentils and oats carry their own fiber mixes, and no trial has set a skin dose for either.
Food and blemishes
In Mumbai, 74 adults aged 18 to 35 with mild to moderate acne ate either 60 g of whole, unsalted, skin-on almonds a day or a snack with matched calories, for 20 weeks[3]. The dermatologist counting lesions did not know who ate what.
Total lesions fell 22.2% in the almond group and 9.8% in controls. Inflammatory lesions dropped 8.3% with almonds and rose 12% in controls[3]. Skin microbial diversity also climbed, with the Shannon index moving from 2.6 to 3.4[3]. The Almond Board of California funded the trial[3].
The omega-3 evidence comes with asterisks. A 2024 Munich study put 60 acne patients on a Mediterranean diet plus algae-derived capsules: 600 mg DHA and 300 mg EPA daily for weeks 1 to 8, then 800 mg DHA and 400 mg EPA for weeks 9 to 16[4]. Nearly all of them, 98.3%, started with low omega-3 levels, and the mean omega-3 index rose from 4.9% to 8.3%[4]. Inflammatory and non-inflammatory lesions both improved. With no control group and two changes at once, nobody can say which part did the work[4]. Treat the dose as a research detail.
More foods with skin trials
Two foods showed measurable sun protection from the inside. In a randomized trial of 20 women, 55 g of tomato paste with olive oil daily for 12 weeks raised the UV dose needed to redden skin to 36.6 mJ/cm², against 23 in the olive-oil group, and increased procollagen I[11]. A cocoa drink with 326 mg of flavanols a day cut UV redness 25% and raised skin hydration 28% over 12 weeks in 24 women, and a low-flavanol drink produced no change[12]. The protection is modest, so keep the SPF, and Mars supplied the cocoa[12].
Green tea did similar work in older skin. Sixty women aged 40 to 65 drank a beverage with 1,402 mg of green tea catechins a day for 12 weeks and showed less UV redness, with better elasticity, roughness and density than a control group[13].
Avocado and almonds have firmness and wrinkle data in women. One avocado a day for 8 weeks increased forehead elasticity and firmness in 39 women[14]. Almonds at 20% of daily calories, about 340 kcal, cut wrinkle severity 16% at 24 weeks in 49 postmenopausal women[15].
Mango comes with a dose warning. Half a cup of Ataulfo mango four times a week reduced deep wrinkles 23% at two months in postmenopausal women[16]. The group eating 1½ cups saw more wrinkles, and the researchers suspect the extra sugar[16].
Only one of these trials enrolled men alone. Forty-three males aged 15 to 25 on a low-glycemic-load diet, 25% protein and 45% low-glycemic carbohydrates, had fewer acne lesions after 12 weeks than men on a usual diet, and they lost more weight[17].
Extra water has thin data. Women who drank about 2 extra liters a day for 30 days showed higher surface and deep skin hydration with no change in TEWL, in a study without randomization[18]. Collagen powders lose their effect under scrutiny. A 2025 meta-analysis of 23 trials and 1,474 people found benefits only in industry-funded and lower-quality trials, and high-quality trials showed no effect on hydration, elasticity or wrinkles[19].
Pistachios have a recent eye study and no skin data. In a Tufts University trial of 36 middle-aged and older adults with low macular pigment, 57 g of pistachio kernels a day (2 oz) for 12 weeks raised macular pigment optical density, a marker of lutein in the retina, by week 6[6]. The study measured no skin outcomes and did not test eye-disease prevention. The American Pistachio Growers and the NIH funded it[6].
| Food or diet | Tested amount | Measured skin result | Evidence |
|---|---|---|---|
| SunGold kiwifruit | 2 a day, 8 weeks | Skin vitamin C up from 99 to 150 nmol/g; skin density and epidermal renewal up | Pilot, no control, 24 adults [1] |
| PHGG fiber powder | 5 g a day, 12 weeks, winter | Lower TEWL and better elasticity than placebo by week 6 | Randomized, double-blind, 70 adults [2] |
| Whole almonds, acne | 60 g a day, 20 weeks | Total acne lesions down 22.2%, against 9.8% in controls | Randomized, 74 adults aged 18 to 35 [3] |
| Whole almonds, wrinkles | 20% of calories, about 340 kcal, 24 weeks | Wrinkle severity down 15% at 16 weeks and 16% at 24 weeks | Randomized, 49 postmenopausal women [15] |
| Tomato paste + olive oil | 55 g a day (16 mg lycopene), 12 weeks | Higher UV dose needed to redden skin; more procollagen I; less UV-driven MMP-1 | Randomized, 20 women [11] |
| High-flavanol cocoa | 326 mg flavanols a day, 12 weeks | UV redness down 25%; hydration up 28%; skin density up 16% | Controlled against low-flavanol cocoa, 24 women [12] |
| Green tea catechins | 1,402 mg a day in a beverage, 12 weeks | Less UV redness; better elasticity, roughness and density | Randomized, 60 women aged 40 to 65 [13] |
| Avocado | 1 a day, 8 weeks | Higher forehead elasticity and firmness | Controlled pilot, 39 women [14] |
| Ataulfo mango | ½ cup, 4 times a week, 16 weeks | Deep wrinkles down 23% at 2 months; the 1½-cup group saw more wrinkles | Randomized pilot, 28 postmenopausal women [16] |
| Low-glycemic-load diet | 25% protein, 45% low-GI carbs, 12 weeks | Fewer acne lesions than a usual diet; more weight lost | Randomized, 43 males aged 15 to 25 [17] |
| Mediterranean diet + algae omega-3 | 600 mg DHA + 300 mg EPA, then 800 + 400, 16 weeks | Fewer inflammatory and non-inflammatory acne lesions | No control group, 60 patients [4] |
| Extra water | About 2 L a day extra, 30 days | Surface and deep hydration up; TEWL unchanged | No randomization, 49 women [18] |
| Collagen peptide powders | Varied by trial | No effect on hydration, elasticity or wrinkles in high-quality trials | Meta-analysis, 23 trials, 1,474 people [19] |
| Pistachios | 57 g a day, 12 weeks | Eye pigment up by week 6; skin never measured | Randomized, 36 adults, eye endpoint only [6] |
| Carrots or sweet potato | Short-term intake changes | Blood carotenoids rose; skin carotenoid scores unchanged | Randomized, 16 people, no visible endpoint [5] |
| Salmon or sardines | No tested skin dose | No skin trial of the fish serving itself | Nutrient data only [7] |
| Everyday yogurt | No tested skin dose | Probiotic results belong to the specific strains tested | No food-level skin trial |
Where the evidence gets thin
Each study above has limits that matter for a man in his 40s or 50s.
Most of these trials enrolled women, and the winter fiber trial had 9 men among 70[2]. The all-male acne diet trial capped age at 25[17]. Kiwi participants who started with saturated blood vitamin C showed no measurable rise, so a man who already eats plenty of fruit may see little change[1].
The kiwi pilot and the omega-3 acne study had no control arm[1,4]. Seasonal shifts and placebo effects can account for part of any before-and-after change.
Zespri helped fund the kiwi work, and the Almond Board of California funded the almond trial[1,3]. Five of six PHGG authors work for the fiber's manufacturer, and Mars supplied the cocoa[2,12]. The National Mango Board funded the mango pilot[16]. Independent replication would settle these results.
Hydration, TEWL, acne counts, ultrasound density and macular pigment are five separate measurements[1,2,3,6]. A result on one tells you nothing about the others. None of these studies measured wrinkles.
The winter hydration result came from a 5 g fiber powder[2]. The omega-3 acne result came from capsules plus a diet overhaul[4]. Moving either onto a dinner plate adds a step no trial has tested.
The dose gap
Each study fed a precise amount for a precise number of weeks. The table lists those protocols next to practical menu portions and flags foods with no tested skin amount at all. Fit any of it around your allergies and calorie needs.
| Food | Tested protocol and menu portion |
|---|---|
| SunGold kiwifruit | Tested: 2 fruits daily, 8 weeks, about 250 mg vitamin C. Menu: the same 2 fruits at breakfast |
| Whole almonds, skin on | Tested: 60 g (2.1 oz) daily, 20 weeks, about 350 kcal. A standard 1 oz serving is 28 g |
| Tomato paste | Tested: 55 g daily with olive oil, 12 weeks. Menu: about 3½ tablespoons cooked into a sauce |
| Ataulfo mango | Tested: ½ cup, 4 times a week. The 1½-cup group saw more wrinkles |
| Cocoa | Tested: 326 mg flavanols daily from a specially processed drink. Store cocoa and dark chocolate rarely list flavanol content |
| Pistachios | Tested: 57 g (2 oz) edible kernels daily, 12 weeks, for eye pigment |
| PHGG fiber | Tested: 5 g powder daily, 12 weeks. No whole-food equivalent defined |
| Algae omega-3 capsules | Tested: 600 mg DHA + 300 mg EPA, then 800 mg + 400 mg, with a diet change, 16 weeks |
| Salmon or sardines | No tested skin dose. Menu: 3 to 4 oz cooked, twice a week |
| Lentils or beans | No tested skin dose. Menu: ½ to 1 cup cooked with a meal |
| Carrots or sweet potato | No tested skin dose. Menu: ½ cup carrots or 1 medium sweet potato |
Three ounces of cooked farmed salmon carries 1.24 g of DHA and 0.59 g of EPA, and the same portion of sardines in tomato sauce carries 0.74 g and 0.45 g[7]. Two salmon dinners a week average out to roughly 0.5 g of EPA plus DHA a day. The acne protocol delivered 0.9 to 1.2 g every day from capsules[4].
Half a cup of raw carrots supplies 459 mcg RAE, and one baked sweet potato supplies 1,403 mcg, against an adult male target of 900 mcg a day[8]. That covers nutritional adequacy. No trial has tested either food as a winter barrier treatment.
What the research flags
The trial's 60 g almond dose carries roughly 350 kcal, the energy matched in its control snack[3]. Add it on top of your current diet and you take in about 2,450 extra kcal a week. Swap it in for another snack.
Tree nuts are a major food allergen, and kiwifruit allergy is well documented. The almond and kiwi trials both excluded people with those allergies[1,3], so they offer no safety data for allergic readers.
Fish oil may raise clotting times in people on warfarin, and the FDA says supplement labels should not recommend more than 2 g of EPA plus DHA a day[7]. High-dose beta-carotene pills raised lung cancer risk in smokers in two large trials[8].
Low humidity and cold are linked to dermatitis flares[9]. Flaking that persists despite steady moisturizer use needs a dermatologist, and so does skin that cracks or bleeds. Eczema and seborrheic dermatitis both show up as winter flaking.
Where the science is headed
The plan with the firmest footing pairs daily topical care with food changes judged over weeks. Indoor humidity and shorter, cooler showers help the barrier hold its water[9].
What a moisturizer adds
Moisturizers work two ways. Humectants such as glycerin and sodium PCA draw water into the outer layer. Emollients and occlusives such as squalane and plant oils fill the gaps between cells and slow evaporation. RFC's published formula lists glycerin, sodium PCA, squalane and several oils, including safflower, jojoba and avocado[10]. Those ingredient functions are well established. GOA has published no TEWL test of the finished cream.
If your skin is cracked or stinging, pause the serum, which contains retinol and salicylic acid, and keep the cleanser and cream going until the skin settles[10].
Timing
Each result comes from a set study length: kiwi 8 weeks, PHGG and pistachios 12, almonds 20[1,2,3,6]. In a 2025 randomized trial of 16 people, blood carotenoids responded to short-term intake changes. Skin carotenoid scores showed no significant change, and the study measured no visible skin endpoint[5]. No study here supports a seven-day result. Judge a food change across a full winter.
What the next trials need
The next useful trial would enroll men aged 35 to 60 and keep them on whole foods through a real winter. It would measure facial hydration and TEWL against a control group, and a topical arm would test food and moisturizer together.
Protocol System
These are menu suggestions built from the studies above. Nobody has tested the combined plan as a skin regimen.
Porridge with two sliced SunGold kiwifruit. The kiwi study used two fruits daily for 8 weeks[1].
Lentil soup with carrots, using ½ to 1 cup of cooked lentils. Half a cup of raw carrots supplies about half the daily vitamin A target for men[8].
A 3 to 4 oz portion of salmon or sardines with cooked vegetables. Three ounces of farmed salmon carries 1.24 g DHA and 0.59 g EPA[7].
Cook with tomato paste and olive oil several times a week; the UV trial used 55 g a day[11]. Add green tea to the day. The skin trial used a beverage with 1,402 mg of catechins daily[13].
A measured nut portion. The acne trial used 60 g of almonds a day, about 2.1 oz, split into a midmorning and an evening serving[3]. A loose handful lands closer to 1 oz, under half the trial amount.
Cleanse with the Purifying Face Cleanser, then apply one pump of Collagen + Control Facial Serum and half a pump of Regenerative Face Cream[10]. Keep showers short and lukewarm.
Portion nuts and batch-cook a pot of lentils on Sunday. Put two fish dinners on the calendar.
Use a bedroom humidifier if your home has forced-air heat. Low humidity is linked to higher TEWL[9].
Keep Reading
FAQs
Which foods have recent human skin studies, and how much was used?
Two SunGold kiwifruit a day for 8 weeks raised skin vitamin C[1]. Whole almonds at 60 g a day for 20 weeks reduced acne lesions in adults aged 18 to 35[3]. A fiber supplement, PHGG, at 5 g a day for 12 weeks improved winter hydration and TEWL[2]. Tomato paste, high-flavanol cocoa, green tea, avocado and mango also have controlled skin trials, listed with their amounts in the table above[11,12,13,14,16].
Does ordinary yogurt reproduce probiotic-trial results?
Probiotic trials test defined bacterial strains in set preparations and doses. Those effects belong to the strains tested and cannot be assigned to every yogurt or fermented food. Plain yogurt is a fine food with no proven winter-skin dose.
How does nutrition fit with moisturizer?
Food changes in these studies took 8 to 20 weeks to register[1,2,3]. A moisturizer adds humectants that draw water into the outer layer and oils that slow its loss. A winter plan uses both every day. The Essentials Set covers the topical side in three steps.
When should persistent flaking or irritation get a clinical assessment?
See a dermatologist if flaking persists despite steady moisturizer use, if skin cracks or bleeds, if itching disturbs sleep, or if a rash spreads. Low humidity and cold are linked to dermatitis flares, which need their own diagnosis and treatment[9].
- Pullar JM, Bozonet SM, Segger D, von Seebach A, Vlasiuk E, Morrin HR, Pearson JF, Simcock J, Vissers MCM. Improved Human Skin Vitamin C Levels and Skin Function after Dietary Intake of Kiwifruit: A High-Vitamin-C Food. Journal of Investigative Dermatology. Online 28 October 2025; print 2026;146(5):1408-1411.e7. https://doi.org/10.1016/j.jid.2025.10.587
- Kapoor MP, Abe A, Morishima S, Nakajima A, Ozeki M, Sato N. Dietary intervention of prebiotic partially hydrolyzed guar gum improves skin viscoelasticity, stratum corneum hydration, and reduction of trans-epidermal water loss: a randomized, double-blind, and placebo-controlled clinical study in healthy humans. Journal of Clinical Biochemistry and Nutrition 2025;76(1):96-115. Online June 2024. https://doi.org/10.3164/jcbn.24-69
- Moitra P, Madan J, Shah K, Mandavkar P, Joshi R, Kalita S, Udipi SA. Almond Supplementation Improves Acne Lesions and Skin Microbial Diversity in Adults with Mild to Moderate Acne Vulgaris. Nutrients 2026;18(4):625. https://doi.org/10.3390/nu18040625
- Guertler A, Neu K, Lill D, Clanner-Engelshofen B, French LE, Reinholz M. Exploring the potential of omega-3 fatty acids in acne patients: A prospective intervention study. Journal of Cosmetic Dermatology 2024;23(10):3295-3304. https://pubmed.ncbi.nlm.nih.gov/38982829/
- Mak IEK, et al. Plasma carotenoids and skin carotenoid status response following short-term changes in carotenoid intakes: a randomised clinical trial. European Journal of Nutrition 2025;64:302. https://link.springer.com/article/10.1007/s00394-025-03824-5
- Scott TM, Ogunbodede O, McKay D, Johnson EJ. Pistachio Consumption Increases Macular Pigment Optical Density in Healthy Adults: A Randomized Controlled Trial. Journal of Nutrition 2025;155:168-174. Online October 2024. https://doi.org/10.1016/j.tjnut.2024.10.022
- NIH Office of Dietary Supplements. Omega-3 Fatty Acids: Fact Sheet for Health Professionals. https://ods.od.nih.gov/factsheets/Omega3FattyAcids-HealthProfessional/
- NIH Office of Dietary Supplements. Vitamin A and Carotenoids: Fact Sheet for Health Professionals. Updated March 2025. https://ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/
- Engebretsen KA, Johansen JD, Kezic S, Linneberg A, Thyssen JP. The effect of environmental humidity and temperature on skin barrier function and dermatitis. Journal of the European Academy of Dermatology and Venereology 2016;30(2):223-249.
- GOA Skincare. Essentials Set and Regenerative Face Cream product pages and ingredient lists. 2026. https://goaskincare.com/products/essentials-set and https://goaskincare.com/products/regenerative-face-cream
- Rizwan M, Rodriguez-Blanco I, Harbottle A, Birch-Machin MA, Watson REB, Rhodes LE. Tomato paste rich in lycopene protects against cutaneous photodamage in humans in vivo: a randomized controlled trial. British Journal of Dermatology 2011;164(1):154-162. https://pubmed.ncbi.nlm.nih.gov/20854436/
- Heinrich U, Neukam K, Tronnier H, Sies H, Stahl W. Long-term ingestion of high flavanol cocoa provides photoprotection against UV-induced erythema and improves skin condition in women. Journal of Nutrition 2006;136(6):1565-1569.
- Heinrich U, Moore CE, De Spirt S, Tronnier H, Stahl W. Green tea polyphenols provide photoprotection, increase microcirculation, and modulate skin properties of women. Journal of Nutrition 2011;141(6):1202-1208.
- Henning SM, et al., Li Z. Avocado consumption increased skin elasticity and firmness in women: a pilot study. Journal of Cosmetic Dermatology 2022. https://pmc.ncbi.nlm.nih.gov/articles/PMC9786235/
- Rybak I, Carrington AE, Dhaliwal S, Hasan A, Wu H, Burney W, Maloh J, Sivamani RK. Prospective Randomized Controlled Trial on the Effects of Almonds on Facial Wrinkles and Pigmentation. Nutrients 2021;13(3):785. https://doi.org/10.3390/nu13030785
- Fam VW, Holt RR, Keen CL, Sivamani RK, Hackman RM. Mango fruit intake and facial wrinkles in postmenopausal women: a randomized clinical pilot study. Nutrients 2020. https://pmc.ncbi.nlm.nih.gov/articles/PMC7694217/
- Smith RN, Mann NJ, Braue A, Mäkeläinen H, Varigos GA. A low-glycemic-load diet improves symptoms in acne vulgaris patients: a randomized controlled trial. American Journal of Clinical Nutrition 2007;86(1):107-115. https://pubmed.ncbi.nlm.nih.gov/17616769/
- Palma L, Marques LT, Bujan J, Rodrigues LM. Dietary water affects human skin hydration and biomechanics. Clinical, Cosmetic and Investigational Dermatology 2015;8:413-421. https://doi.org/10.2147/CCID.S86822
- Myung SK, Park Y. Meta-analysis of 23 randomized controlled trials of oral collagen supplements and skin aging. The American Journal of Medicine 2025. Summary: NutraIngredients, 26 August 2025
