Introduction
Collagen is the most abundant protein in your body. It provides structure and strength to your skin, bones, tendons, and ligaments. However, as you get older, your natural collagen production slows down. That’s why you may start noticing wrinkles, looser skin, and achy joints (1). These changes have spurred the popularity of collagen supplements, which many people take to support skin health, joint comfort, and overall connective tissue wellness. But how exactly is collagen absorbed by your body, and which collagen products work best? Read on to learn about collagen digestion and absorption, the types of collagen (including hydrolyzed and marine), and tips for picking the best one for beauty and health benefits.
Collagen Digestion and Absorption: From Protein to Peptides
Collagen in its natural state is a big, complex protein that has to be broken down before your body can use it. You can’t absorb it in its whole form. Instead, your stomach and intestines break it down into small amino acid chains (called peptides) or single amino acids that can pass through the gut lining (1).
When you eat collagen-rich foods - like bone broth or animal skin - or take a collagen supplement, digestive enzymes split the collagen into smaller fragments so your body can absorb it. Most collagen supplements are already “pre-broken” into these smaller pieces (hydrolyzed collagen peptides) because these smaller particles are much easier for your body to take in.
Research shows a significant amount of these collagen peptides make it into your bloodstream intact. After ingesting hydrolyzed collagen, blood tests show a surge in special collagen-related peptides (like hydroxyproline-containing dipeptides) (2). In one study, more than 60% of collagen peptides stayed in their peptide form after digestion (3). These peptides can then travel to places like your skin and joints, where they may trigger cells (fibroblasts, chondrocytes) to produce fresh collagen. Scientists have found these collagen fragments in skin and cartilage, indicating they don’t just break down - they also go where they’re needed.
Even the fragments that do get broken down into individual amino acids still help build new collagen wherever your body needs it. This mix of intact peptides and amino acids is a big reason why ingestible collagen can be effective. It’s also why simply applying collagen on your skin (via creams) can’t match the deeper impact of collagen supplements, as topically applied collagen is too large to penetrate past the skin’s surface.
Hydrolyzed vs. Native Collagen: Why Form Matters for Bioavailability
Because whole collagen is tough to absorb, most supplements rely on hydrolyzed collagen (collagen peptides). Hydrolysis is a process where enzymes break collagen into shorter peptide chains (often around 2,000 - 5,000 Daltons in size). These small peptides dissolve easily in water and are absorbed efficiently in your digestive tract. Research shows that whether these hydrolyzed peptides come from fish (marine), cows (bovine), or pigs (porcine), the body can absorb them just as well (4). A recent clinical trial found that all three sources produced similar levels of essential collagen fragments (hydroxyproline peptides) in the blood (4). That means if you’re using hydrolyzed collagen, absorption is likely to be good, regardless of the source.
Gelatin (like the type used in cooking) is partially broken-down collagen, so it isn’t absorbed quite as well as fully hydrolyzed collagen peptides. Raw collagen (like what’s in animal tendons or skin) has even lower bioavailability because your body has more work to do to break it down. That’s why most collagen supplements use the hydrolyzed form - your body can more readily take it in.
Studies show a high absorption rate for hydrolyzed collagen peptides. Some indicate over 90% of bovine-sourced collagen peptides can be absorbed within a few hours. Marine collagen may be absorbed about 1.5 times more efficiently than some other sources, but both marine and bovine forms still have excellent bioavailability. So while there may be slight differences, the main takeaway is that any hydrolyzed collagen source can be well-absorbed.
Collagen Types and Sources: Which Is Best for Skin, Joints, and More?
Collagen isn’t one single type - there are at least 28 kinds. The most common in your body are Types I, II, and III. Different supplement sources provide different collagen types, and that can matter if you have specific goals.
- Type I: This type is the most common in skin, bones, and tendons. It’s key for skin elasticity and firmness. Marine collagen (fish-derived) is rich in Type I, which is why many people consider it the “best collagen for skin.” Bovine hide collagen also has plenty of Type I (plus Type III), making it another popular pick for skin and hair. If your goal is smoother skin or stronger nails, a supplement high in Type I collagen (from marine or bovine sources) is a good choice.
- Type II: This type is found mostly in cartilage. It’s important for healthy joints (like your knees). Chicken collagen (often labeled “UC-II” or undenatured collagen) contains a lot of Type II. Marine collagen can have some Type II, but not as much as chicken collagen. If you have osteoarthritis or want to protect your joints from wear and tear, Type II collagen may be ideal.
- Type III: This type often appears along with Type I in skin and blood vessels, supporting skin structure and elasticity. Bovine collagen contains both Type I and Type III, so it’s another great option for skin and for gut health.
In short, if you’re after beauty and skin benefits, Type I (and III) from marine or bovine collagen is often recommended. If your focus is on joints, Type II from chicken collagen may be a better fit. Some supplements contain multiple types (I, II, III, and sometimes V and X) to cover more bases.
Choosing the Right Collagen Supplement Form
Collagen supplements come in many forms: powders, liquids, capsules, gummies, and shots. It can be confusing to know which one is best. The good news is they generally contain the same hydrolyzed collagen peptides, so absorption mainly depends on the peptide size and the amount you take - not on whether it’s a powder or a drink.
- Collagen Powder: This can be plain or flavored. You add it to drinks like smoothies, coffee, or water. Powders often let you measure out larger servings (10–20 grams), making them cost-effective for higher daily doses. If you don’t mind mixing it every day, powders are a great choice.
- Liquid Collagen (Collagen Drinks): These are sold as ready-to-drink or as liquid packets you can mix with water. They’re often flavored and may include extra nutrients like vitamins. Despite marketing claims, there’s no solid proof that liquid collagen is absorbed faster than a powder that you mix into a drink. The main advantage is convenience—no scooping or stirring. Just be mindful of added sugars, preservatives, or fillers in some formulas. Some brands, like Lemon & Co., focus on creating a “clean” liquid collagen product to address these concerns.
- Capsules or Tablets: These contain collagen powder inside a pill shell. They’re handy for traveling or if you dislike the taste of collagen, but you may need several pills to get a decent dose. Each capsule might only have half a gram of collagen, so you’d need four to six pills (or more) for a typical serving. Once the pill dissolves in your stomach, the collagen peptides are absorbed just like powder.
- Gummies: These taste good and are easy to chew, but typically offer lower collagen amounts and include added sugars. To reach an effective collagen dose, you might need to eat multiple gummies, which increases sugar intake. They can be a fun extra but may not provide a strong therapeutic dose.
- Topical Collagen Creams: While not an ingestible supplement, it’s worth mentioning that collagen applied to your skin mostly stays on the surface. The collagen molecules are too large to deeply penetrate. They can help moisturize the top layers, but don’t significantly boost collagen levels in deeper layers (5).
Key tip: Whichever form you choose, buy from a reputable brand that tests for purity. Animal-based products can sometimes be contaminated with heavy metals, so quality testing is crucial. If you have dietary preferences or allergies (e.g., a fish allergy), choose your collagen source accordingly. Some of the best collagen products for skin also include vitamin C or biotin, which help the body make and maintain collagen fibers.
Maximizing Benefits for Skin, Beauty, and Health
Once absorbed, how does collagen help you? Early studies show that consistent collagen supplementation can improve skin elasticity and hydration, as well as support healthy joints (6). For example, several controlled studies found that taking collagen peptides every day for 8 - 12 weeks reduced wrinkles and boosted skin moisture compared to a placebo (7). Other research links collagen to reduced joint pain in athletes and people with osteoarthritis (7).
It’s important to note that collagen works over time. You won’t see major changes after a day or two. Rather, you need consistent use over at least 2-3 months to notice improvements in skin or joint comfort (7). Pairing collagen with healthy habits - like a balanced diet, regular exercise, and nutrients like vitamin C - can amplify its effects. (We’ll cover this in the article “Optimizing Your Collagen Routine: Timing, Vitamin C, and Lifestyle Factors.”)
By understanding how collagen is absorbed and picking a supplement form and type that fits your goals, you can get the most out of your collagen routine. In the next article, we’ll look at the best times to take collagen (morning vs. night, post-workout), why vitamin C matters, and lifestyle choices that help your body produce and use collagen effectively.
Disclaimer: 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. If you are pregnant, nursing, or have a known medical condition, consult your health care provider before use.
