Collagen Types Compared: I vs II vs III, Marine vs Bovine
For skin and bones, buy collagen peptides, which are types I and III. For knees, the studied product is undenatured type II (UC-II), at 40 mg a day. The type numbers on most labels matter less than which of these two you buy. Our pick: BulkSupplements Hydrolyzed Bovine Collagen, $0.56 per 10 g.
The powder price is the brand’s, per 10 g (October 24, 2026); the UC-II price is Amazon’s (November 2, 2026).
What to buy
BulkSupplements is plain collagen peptides from cows, which hold types I and III. It is on the NSF Certified for Sport testing list.
BulkSupplements Hydrolyzed Bovine Collagen
$0.56 per 10 g · from cows
Buying for your knees? UC-II is a different product, taken as one small capsule a day.
Healthy Origins UC-II
$0.27 a day on Amazon · 40 mg
Why one collagen is taken in grams and the other in milligrams
The word “collagen” covers two products that work in different ways. Collagen peptides are a food protein: your gut breaks most of a scoop down, and some small pieces reach your blood. So they are dosed in grams, 2.5 to 15 g a day. Undenatured type II is kept whole. It is thought to work as a signal to the immune system in your gut, not as a building block, so the trials used just 40 mg a day (Lugo 2016). More is not better: no trial tested a higher dose.
Every collagen type on a label, compared
| Type | Made from | What trials tested | Buy it? |
|---|---|---|---|
| Type I | Cow hide; fish skin and scales | The skin and bone trials. 2.5 to 5 g a day for 8 weeks in the skin trials; 5 g a day for a year in the bone trial. | Yes: this is what collagen peptides are |
| Type III | Cow hide, always with type I | Never tested on its own. It comes along with type I in every cow-hide powder. | Comes free with type I |
| Type II, undenatured (UC-II) | Chicken breastbone cartilage, kept whole | 40 mg a day eased knee arthritis more than a placebo over 180 days in one trial paid for by the maker. | Yes, for knees: 40 mg a day |
| Type II, hydrolyzed | Chicken cartilage, broken down | No trial of its own. The gram-dose joint trials used type I and III powder. | Buy plain peptides instead |
| Types V and X | Eggshell membrane, cartilage | No trial as a supplement. They show up in “multi-collagen” blends. | No reason to pay for them |
Cow, fish, chicken or eggshell: what the source changes
The source changes the price and which types you get, not what the trials found. Cow (bovine) powders give types I and III and cost the least. Fish (marine) powders give mostly type I and suit people who avoid beef; see best marine collagen. Chicken cartilage gives type II.
The claim that fish collagen absorbs better rests on one study of 5 men, which measured collagen pieces in blood, not skin or joints (Ohara 2007). Eggshell membrane is a different supplement: two small trials with no placebo used 500 mg a day for joint pain (Ruff 2009).
What 746 collagen labels say about type
Most collagen products do not say which type they are. We read 746 collagen labels filed with NIH’s label database on September 14, 2026. Only 43.2% name a type at all. Of those, most say type I and type III.
| Item | Value (%) |
|---|---|
| Type I | 86.3% |
| Type III | 77.3% |
| Type II | 44.7% |
| Type V | 18% |
| Type X | 17.1% |
Type II labels: 40 mg or 2,000 mg
We also searched NIH’s database for type II on its own. Across both searches, 247 labels name type II. Products sold as undenatured type II tell you to take 40 mg a day, the trial dose. Products sold as hydrolyzed “type II” tell you to take 2,000 mg, 50 times more, and have no trial of their own. Check for the word “undenatured” or “UC-II” if knees are your reason.
Which type II product to buy, with 8 checked for dose, testing and cost: best type II collagen.
Multi-collagen blends
92 labels, 12.3% of the shelf, claim three or more types. By weight they are mostly cow and fish peptides, and none is the undenatured type II from the knee trials.
Questions
Is type I or type III collagen better?
You do not have to choose. Cow hide holds both, so a “type I and III” powder and a “type I” cow powder are the same thing. No trial has tested type III on its own. Pick by the grams a scoop, not the type numbers.
Are “5 types of collagen” better than one?
No trial shows it. Types V and X have never been tested as supplements, and by weight the blends are mostly type I and III from cows and fish. On the 746 labels we read, 12.3% claim three or more types.
More collagen we would buy is in the best collagen. How much to take for skin, joints or muscle: the dosage guide. For skin: collagen for skin. What collagen does, and whether it is safe: the collagen guide.
Sources
- Proksch E, et al. Oral supplementation of specific collagen peptides has beneficial effects on human skin physiology. Skin Pharmacol Physiol. 2014. PubMed 23949208
- König D, et al. Specific collagen peptides improve bone mineral density and bone markers in postmenopausal women. Nutrients. 2018. PubMed 29337906
- Lugo JP, et al. Efficacy and tolerability of an undenatured type II collagen supplement in modulating knee osteoarthritis symptoms. Nutr J. 2016. Paid for by the maker. PubMed 26822714
- Clark KL, et al. 24-week study on the use of collagen hydrolysate as a dietary supplement in athletes with activity-related joint pain. Curr Med Res Opin. 2008. PubMed 18416885
- Ohara H, et al. Comparison of quantity and structures of hydroxyproline-containing peptides in human blood after oral ingestion of gelatin hydrolysates from different sources. J Agric Food Chem. 2007. PubMed 17253720
- Ruff KJ, et al. Eggshell membrane: a possible new natural therapeutic for joint and connective tissue disorders. Clin Interv Aging. 2009. PubMed 19554094
- NSF Certified for Sport listing 1796567, BulkSupplements “Bovine Collagen”, read October 24, 2026. nsfsport.com
- Labels: NIH Dietary Supplement Label Database (dsld.od.nih.gov), 746 collagen labels, read September 14, 2026. Download the label data: JSON file.