Supplements for Skin Health, Graded

Quick answer

Four graded entries qualify for skin, all moderate. Three describe what the body needs vitamin C, zinc and vitamin A for, which is about getting enough. The fourth is hydrolyzed collagen, studied at 2.5 to 10 g a day for 8 to 12 weeks, and its result depends on who funded the trial.^1,2

Key facts

Vitamin C is required to make collagen, and normal skin holds high levels of it.^3,4
A 2023 meta-analysis of 26 trials with 1,721 people found better skin hydration and elasticity with hydrolyzed collagen, but only one trial used bovine collagen.¹
A 2025 meta-analysis of 23 trials found the collagen benefit only in company-funded trials.²
How well vitamin C applied to the skin works, compared with getting enough in the diet, is poorly understood.⁴
Regular high intakes of preformed vitamin A can dry the skin, and retinoid creams are different products that these statements do not cover.^5,6

What the evidence shows

Four graded entries qualify. Three are nutrient functions: vitamin C, zinc and vitamin A each have a role in normal skin, and the entries say these describe getting enough. The collagen entry is different because it comes from supplement trials, and it carries a caution about funding.

Contributes to normal collagen formation for the normal function of skin, gums, teeth, bones, cartilage and blood vessels*^3,4,7

Moderate evidence

A well-established nutrient function. NIH states that vitamin C is required to make collagen, an essential part of connective tissue, and EU regulators permit this wording, as six separate statements, for foods that are at least a source of vitamin C. Normal skin holds high levels of vitamin C. The claim describes what the body needs vitamin C for. It does not show that extra vitamin C changes how skin looks in someone who already gets enough, and how creams and serums compare with getting enough in the diet is poorly understood.

Amount studied: Recommended intake: 75 mg a day for women and 90 mg for men, from food and supplements

Contributes to the maintenance of normal skin, hair and nails*^8,9

Moderate evidence

A well-established nutrient function. EU regulators permit these three statements, after EFSA review, for foods that are at least a source of zinc, and NIH lists skin among the tissues affected when zinc runs short. The claim describes what the body needs zinc for. It does not show that extra zinc changes skin, hair or nails in someone who already gets enough.

Amount studied: Recommended intake: 11 mg a day for men and 8 mg for women, from food and supplements

Contributes to the maintenance of normal skin and mucous membranes*^5,6

Moderate evidence

Both are on the EU list of permitted nutrient-function statements for vitamin A, after EFSA review, and NIH describes vitamin A's role in normal cell growth and specialization. They are about getting enough. They are not evidence that extra vitamin A from supplements changes how skin looks, and regular high intakes of preformed vitamin A can dry the skin. Retinoid creams and prescription retinoids are different products and are not covered by these statements.

Amount studied: The recommended intake: 900 mcg RAE a day for men and 700 mcg RAE for women, from food and supplements together

May support skin hydration and elasticity*^1,2

Moderate evidence

A 2023 meta-analysis of 26 randomized trials (1,721 people, mostly women) found better skin hydration and elasticity with hydrolyzed collagen, usually 2.5 to 10 g a day for 8 to 12 weeks, though only one trial used bovine collagen like this product. A 2025 meta-analysis of 23 trials (1,474 people) found the benefit only in company-funded trials; trials without company funding, and higher-quality trials, showed no effect.

Amount studied: 2.5 to 10 g a day for 8 to 12 weeks

How much the studies and the guidelines use

Skin trials mostly used 2.5 to 10 g of hydrolyzed collagen a day for 8 to 12 weeks. Across 26 trials the amounts ranged from under 1 g to 12 g a day.¹

Recommended daily amounts for adults, from food and supplements together^3,5,9
Nutrient	Recommended per day
Vitamin C	90 mg for men, 75 mg for women
Zinc	11 mg for men, 8 mg for women
Vitamin A	900 mcg RAE for men, 700 mcg RAE for women

The three nutrient entries are about reaching these amounts. The collagen amount is the range the trials used, and it is not a recommended intake.

Food first

Vitamin C is required to make collagen, so the foods below matter whether or not you take a collagen powder.³

Fruits and vegetables are the best sources, especially citrus fruits, red and green peppers, kiwifruit, broccoli, strawberries, Brussels sprouts and cantaloupe. Some breakfast cereals have vitamin C added.³

Oysters have more zinc per serving than any other food. Meat, fish and other seafood are the richest sources, eggs and dairy products add some, and fortified breakfast cereals are a major source in the US diet.⁹

Beta-carotene and other provitamin A carotenoids come from green leafy vegetables, orange and yellow vegetables such as sweet potatoes, carrots and winter squash, tomato products, and fruits such as cantaloupe, mangos and apricots.^5,10

Preformed vitamin A is found in beef liver and other organ meats, fish such as herring and salmon, eggs, and dairy products such as milk and cheese.^5,10

Bone broth made to a standard recipe held much less glycine, proline and hydroxyproline than a 20 g dose of a collagen supplement, and broths made to other recipes varied widely, so it is not a reliable source.¹¹

Upper limits and who should ask first

The upper limit for adults is 2,000 mg a day from food and supplements combined, including during pregnancy and breastfeeding. It is 1,800 mg for teens aged 14 to 18 and lower for children. It does not apply to people given vitamin C as medical treatment by a doctor.^3,12

The upper limit for adults is 40 mg of zinc a day from all sources: food, drinks, supplements and medicines, including during pregnancy and breastfeeding. It is 34 mg for teens aged 14 to 18 and lower for children. It is set to protect copper status and does not apply to people given zinc as medical treatment by a doctor.^9,13

The upper limit for preformed vitamin A is 3,000 mcg a day for adults 19 and older, including in pregnancy and while breastfeeding, and 2,800 mcg for teens 14 to 18. It counts food, drinks and supplements, and it is lower for children: 600 mcg up to age 3, 900 mcg at 4 to 8 and 1,700 mcg at 9 to 13. The limits do not apply to people taking vitamin A under a doctor's care. No upper limit is set for beta-carotene, but the Food and Nutrition Board advises against beta-carotene supplements for the general population except as a source of vitamin A.^5,10

No tolerable upper intake level has been set for collagen. Most trials used 2.5 to 15 g a day for up to 12 months, and a review of 15 trials found no adverse effects reported, including in short studies at 60 g a day.^14,15

You are allergic to fish, beef, pork or gelatin, or have alpha-gal syndrome. Check the source of any collagen.
You are pregnant, could become pregnant or are breastfeeding. Ask before taking any vitamin A supplement.
You take orlistat, acitretin, bexarotene or another retinoid medicine. Ask before taking vitamin A.
You have kidney disease or have had kidney stones. Ask before taking collagen or vitamin C in large amounts.
You take a quinolone or tetracycline antibiotic, penicillamine or a thiazide diuretic. Zinc can interact with them.

Questions people ask

Does collagen work for skin?

A 2023 meta-analysis found better skin hydration and elasticity, but a 2025 analysis found the benefit only in company-funded trials. The entry is graded moderate with that caution.^1,2

Is vitamin C in a serum the same as vitamin C I swallow?

How well vitamin C applied to the skin works, compared with getting enough in the diet, is poorly understood. The entry on this page is about the vitamin C the body takes in.⁴

Is bone broth a good source of collagen?

A broth made to a standard recipe held much less glycine, proline and hydroxyproline than a 20 g dose of a collagen supplement, and broths made to other recipes varied widely.¹¹

Can too much vitamin A affect the skin?

Regular high intakes of preformed vitamin A can dry the skin and cause fatigue and abnormal liver test results. The adult upper limit is 3,000 mcg a day from food, drinks and supplements together.^5,10

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Sources

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.