Collagen Supplements After 40: What the Evidence Does and Doesn't Show

Collagen has become one of the best-selling supplements in America, especially among women in midlife. The promises are appealing: firmer skin, fewer wrinkles, stronger hair and nails, a "younger glow."

So what does the science actually say? The honest answer is: more than nothing, less than the marketing suggests, and with some important caveats. This guide walks through the evidence so you can decide whether a collagen supplement is worth it for you.

What collagen is and why it declines

Collagen is the most abundant protein in your body. In the skin, it forms a supportive network that gives skin strength and firmness, working alongside elastin, which gives skin its bounce.

Your body makes collagen continually, but production slows with age. Sun damage and smoking break it down faster. Menopause adds another factor: the American Academy of Dermatology notes that skin can lose a significant amount of collagen in the first years after menopause, which contributes to dryness, thinning and sagging.

How collagen supplements are supposed to work

Most collagen supplements contain hydrolyzed collagen, also called collagen peptides, made from the skin, bones or scales of cows, pigs, chickens or fish. "Hydrolyzed" means the protein has been broken into smaller pieces that are easier to digest.

For years, a common objection was that collagen is simply digested into amino acids like any other protein, so it cannot specifically help skin. Research suggests the picture may be more nuanced: some small collagen fragments (peptides) appear in the blood after you take collagen, and laboratory studies suggest they might act as signals that stimulate the cells that make collagen. But how much this matters in real life is still being studied.

What the studies show

Randomized trials

A number of randomized, placebo-controlled trials have tested collagen supplements for skin. One frequently cited 2014 study gave women aged 35 to 55 a specific collagen peptide or a placebo for eight weeks. The researchers reported improvements in skin elasticity in the collagen group, particularly in older women, compared with placebo.

A meta-analysis

A 2021 systematic review and meta-analysis published in the International Journal of Dermatology pooled 19 randomized controlled trials with about 1,125 participants, most of them women aged 20 to 70. It found that hydrolyzed collagen supplementation was associated with improvements in skin hydration, elasticity and wrinkles compared with placebo, with studies typically lasting around 90 days.

The caveats

Before you rush to buy, it is worth knowing the limitations, which Harvard's Nutrition Source also highlights:

Industry funding. Many collagen studies are funded by companies that make collagen products, which can introduce bias.
Small studies. Many trials have fewer than 100 participants and last only a few months.
Different products. Studies used different types, doses and formulations of collagen, often combined with other ingredients, so results from one product cannot be assumed to apply to another.
Modest effects. Improvements are generally measured with instruments and may be subtle to the eye.
Long-term data is limited. We know little about effects beyond a few months.

So a fair summary is: there is some evidence of modest benefits for skin hydration and elasticity, but it is not conclusive, and collagen will not reverse aging.

The role of vitamin C and protein

Your body cannot make collagen without vitamin C. The NIH Office of Dietary Supplements notes that vitamin C is needed to make collagen. Women need 75 mg of vitamin C a day, which is easy to get from food: a medium orange, a cup of strawberries or half a cup of red bell pepper each provides a good amount.

Collagen is also made from amino acids that come from the protein you eat. Getting enough overall protein from a variety of foods supports your body's own collagen production. See Harvard's guide to protein and our article on protein needs after 40.

Is collagen safe?

Collagen supplements are generally well tolerated. Some people report mild digestive symptoms or a feeling of fullness. A few practical points:

Allergies. Collagen can come from fish, shellfish, eggs or other animal sources. Check the source if you have allergies.
Diet. Collagen is an animal product, so it is not suitable for vegans or vegetarians.
Quality. As the FDA explains, supplements are not approved for safety or effectiveness before they are sold. Look for products verified by independent testing organizations.
Added ingredients. Gummies often contain sugar, and some products include herbs or high doses of vitamins. Read the full label and check for interactions.
Not a treatment. Collagen supplements are not approved to treat or prevent any disease.

The NIH Office of Dietary Supplements' guide, Dietary Supplements: What You Need to Know, is a helpful primer on choosing any supplement.

How to choose a collagen supplement if you want to try one

Look for hydrolyzed collagen or collagen peptides, the form used in most studies.
Check for third-party testing, such as NSF or USP seals, which verify that the product contains what it claims.
Read the whole label, including sugar content and any added herbs or high-dose vitamins.
Be realistic about dose and time. Studies typically used daily doses for at least eight to twelve weeks.
Avoid products with miracle claims, such as reversing years of aging, before-and-after promises or celebrity endorsements.
Talk to your clinician if you are pregnant, breastfeeding, have kidney disease, take medications or have allergies.

What works better than any supplement

If your goal is healthier-looking skin, these steps have stronger evidence than collagen:

Daily broad-spectrum sunscreen, SPF 30 or higher. See our sunscreen guide.
A topical retinoid, which has decades of research behind it for fine lines.
Not smoking.
Moisturizing to support the skin barrier.
A diet with plenty of fruits, vegetables and protein.

Collagen, if you choose to try it, is best thought of as a possible extra, not a foundation.

The bottom line

Collagen supplements are not a scam, but they are not a miracle either. Some trials and a meta-analysis suggest modest improvements in skin hydration and elasticity over a few months, though many studies are small and industry-funded. If you want to try one, choose a third-party-tested hydrolyzed collagen, give it a fair trial and keep your expectations realistic. And keep doing the things with the strongest evidence: sunscreen, a retinoid and a healthy diet.

Frequently asked questions

How long does it take for collagen supplements to work?

Most studies that found benefits lasted around eight to twelve weeks. Effects, when present, were generally modest.

Is marine collagen better than bovine collagen?

There is no strong evidence that one source is clearly better for skin. Choose based on dietary preferences, allergies and product quality.

Do collagen supplements help hair and nails?

Evidence for hair and nails is much more limited than for skin. Hair thinning in midlife has many possible causes worth discussing with a clinician.

Can I get collagen from food?

Bone broth and gelatin contain collagen, but how much reaches your skin is unclear. Eating enough protein and vitamin C supports your body's own collagen production.