9 Best Collagen Peptides Supplements (2024), According to R.D.s and Nutrition Coaches

Collagen is a protein — but it’s not just any protein. Found in bone broth and eggshell membranes, it’s the most abundant protein in the human body, and it plays a major role in maintaining the health and structure of various connective tissues. (1) It’s known for its importance in maintaining skin elasticity, which is why it has such broad applications in the anti-aging industry. But collagen also has applications supporting hair health, joint health, and cardiovascular health. 

At BarBend, we know you want the best: The best whey protein powder, the best creatine, and the best, well, everything. If you’re looking to add collagen to your supplement stack, you’ll be pleased to know that we also have the best collagen peptides supplements. And we know where to point you — we’ve tested nearly 40 collagen supps and have gotten expert input from registered dietitian Chelsea Rae Bourgeois, M.S., RDN, LD.  And from hydrolyzed collagen to marine collagen, our product testers rated nearly a dozen options against criteria like solubility, flavor, and collagen per serving.

The 9 Best Collagen Supplements of 2024

• Best Collagen Supplement Overall: Transparent Labs Collagen Hydrolysate
• Best Collagen Supplement for Women: Gainful Collagen
• Best Budget Collagen Supplement: Nutricost Collagen
• Best Organic Collagen Supplement: Sports Research Organic Collagen
• Best Collagen Supplement for Hair: Pro Health Longevity Collagen
• Best Liquid Collagen Supplement: Momentous Collagen Shot
• Best Collagen Supplement for Skin: Bulletproof Collagen
• Best Collagen Supplement for Athletes: BUBS Naturals Collagen
• Best Collagen Capsules: HUM Collagen Love

Editor’s note: The content on BarBend is meant to be informative in nature, but it should not be taken as medical advice. The opinions and articles on this site are not intended for use as diagnosis, prevention, and/or treatment of health problems. It’s always a good idea to talk to your doctor before beginning a new fitness, nutritional, and/or supplement routine. Individual needs for vitamins and minerals will vary.

How We Tested and Chose the Best Collagen Peptide Supplements

At BarBend, we take supplement testing seriously. We know how confusing it can be to look at dozens of products lined up on shelves, let alone navigate the hundreds of products available online. Our team consists of registered dietitians, certified specialists in sport dietetics, sports nutrition coaches, healthcare professionals, and fitness professionals. 

For this guide to collagen peptide supplements, we tested a dozens of products and researched many more. Our team performed hands-on tests — meaning, we bought, mixed, and consumed the supplements — and a registered dietitian analyzed the formulas for these products. In our testing, we looked at the following factors:

• Collagen source: Is it marine collagen, bovine collagen, or vegan collagen (yes, it exists!)? 
• Collagen type: Does it contain just one type of collagen, or a blend of collagens type I, II, III, IV, and/or V? 
• Collagen per serving: How many grams of collagen are in one serving, and how many grams is the scoop or capsule?
• Other ingredients: Does the supplement also contain related ingredients, like keratin or biotin? 
• Supplement form: Is it a powder, capsule, caplet, gummy, or liquid?
• Third-party testing: Is the supplement backed by independent testing for particulates, such as metals, and/or allergens and banned substances?
• Price per serving: How much are you paying for a serving of collagen peptides?
• Available flavors: Is it available unflavored and/or in additional flavor options?
• Taste: Does it actually taste alright?
• Solubility: If a powder, does it dissolve completely, or are there chunks? If a pill, how easy (or hard) is it to get down?
• Side effects: Did our testers or any customers (based on reviews) experience unwanted side effects after consuming the product?

Best Collagen Supplement Overall: Transparent Labs Collagen Hydrolysate

Transparent Labs gets high marks all around for its commitment to ingredient and labeling transparency. The Collagen Hydrolysate, for example, has been tested for various heavy metals, bacteria, and yeast, and found to meet health standards in all areas. 

Lab testing aside, the supplement facts label on Transparent Labs’ Collagen Hydrolysate is pleasing to any nutrition professional’s eyes. The list is as short as can be, with hydrolyzed collagen alone on the unflavored version. Health-conscious folks who opt for the chocolate flavor, like I did, will be pleased to know that cocoa powder — not “natural flavors” — is used to create the rich chocolate taste. It is sweetened with stevia, which may be a dealbreaker for those who don’t like the taste of stevia or find it to interrupt digestion.  

Our product tester tried the chocolate flavor and noted, “It’s not my favorite when mixed with water, but if you mix it with a milk product, the taste is a lot better,” rating it with 4 out of 5 possible points. Even a dairy-free beverage, like almond or oat milk, significantly improves the taste, in my opinion. As far as solubility, our tester awarded the Collagen Hydrolysate with the maximum of 5 out of 5 points, saying it dissolved completely, even in plain water.

From a sport nutrition coach’s perspective, I’m a big fan of the simple formula in this collagen peptides powder. It doesn’t have the highest amount of collagen per serving — some formulas have 20 grams per serving — but for the price and the fact that the collagen is hydrolyzed for enhanced absorption, I’m satisfied. Besides, research shows that dosages from 2.5 to 15 grams of collagen can be effective; for its simplicity, natural ingredients, and effective dose, I give the formula 4 out of 5 points. (2) 

[Read More: Transparent Labs Whey Protein Review]

Best Collagen Supplement for Women: Gainful Collagen

This simple blend of collagen, calcium, and vitamin C is an excellent choice for women and people of any gender who want to enhance their body’s natural synthesis of collagen and support their bone health. 

Kate Meier, BarBend editorial team member and certified personal trainer, has been taking collagen for years. She tested Gainful Collagen, noting that she likes the formula. “I love the collagen content as well as added vitamins and minerals,” she says.

The 10 grams of collagen supports the strengthening of connective tissues, including tendons, ligaments, and cartilage. With 50 milligrams of vitamin C — more than 50 percent of the daily recommended value — per serving, this blend also contributes to your body’s endogenous (internal) synthesis of collagen. 

Gainful Collagen also includes a small amount of calcium. At 50 milligrams (4% of the daily recommended value), it’s not a ton of calcium, but every bit matters for people who may be facing osteoporosis or age-related bone mineral density loss. 

Vitamin C may play a role in bone health, too: A 2007 case-control study associated lower serum vitamin C levels with a greater risk of osteoporosis-related fractures. (10) Other research has found a positive association between vitamin C supplementation and bone mineral density. (11)(12)

In terms of taste, Meier gives this a 5 out of 5. “The best part of collagen in your coffee is not knowing there is collagen in your coffee, and Gainful is truly unflavored and unnoticeable,” she says. 

This straightforward formula is free from artificial sweeteners, preservatives, dyes, and flavor agents. It’s collagen, plain and simple, with the bonus of containing small amounts of essential vitamins and minerals. Though it doesn’t have the highest amount of collagen per serving, I think this formula earns a solid 4 out of 5 points for its no-frills nature. 

Meier warns that the solubility isn’t perfect. “While it dissolved completely in my coffee, I noticed that if I mixed it with water, there were still pieces of it even minutes after allowing the cup to settle,” she says, rating solubility an overall 4 out of 5.

Best Budget Collagen Supplement: Nutricost Collagen

Cost-conscious shoppers will be fond of Nutricost Collagen, a grass-fed, hydrolyzed collagen peptide powder that costs less than 75 cents per serving. Just be sure to purchase the larger tub of 31 servings, rather than the smaller tub of 10 servings — the small tub is twice the price from a cost-per-serving standpoint. 

In addition to being budget-friendly upfront, Nutricost offers a 60-day money-back guarantee. You can return the product for a 100% refund of the list price you paid (not including shipping and handling). But wait! There’s more! If you sign up for the subscribe-and-save option, you can bring the cost per serving down to a very impressive 59 cents. 

Kate Meier, certified personal trainer and BarBend editorial member, says after testing that Nutricost may be one of her favorite collagen supplements. “I have been using collagen for years, and Nutricost may be my favorite because of how affordable it is and that it’s a quality formulation.”

Despite the lower cost, you won’t miss out on anything by choosing Nutricost over similar competing products. Nutricost Collagen includes 11 grams of collagen — a blend of type I and type III — that’s hydrolyzed for optimal absorption. 

There aren’t any funky unnecessary ingredients, either: just collagen in the unflavored version, and sweeteners and flavoring agents in the chocolate, vanilla, and salted caramel powders. Nutricost did opt to use “natural flavors” in its flavored options, which is no big deal but something to be aware of for those who prefer whole-food ingredients. The flavored collagen powders are also sweetened with stevia, which some people find to have an icky aftertaste or cause an upset stomach.

All things considered, I think the formula deserves 4 out of 5 points for providing an ample serving of collagen and containing no unnecessary ingredients. 

Solubility-wise, Kate raves, “This is probably the best, fastest-dissolving collagen I’ve ever used, and I’ve used probably 20-plus collagen supplements.” She gives it a 5 out of 5 for both solubility and taste. “Even in plain water, after stirring for just 15 seconds, there were no floaters, and you can’t taste anything.”

Best Organic Collagen Supplement: Sports Research Organic Collagen

Supplement seekers looking for an ultra-simple, organic collagen peptide supplement will love the Sports Research Organic Collagen. The label on the tub lists just one thing: organic hydrolyzed bovine collagen.

Chelsea Rae Bourgeois, RDN, is also a fan of this product, saying, “When it comes to supplements, I love when simplicity gets the job done. Sports Research Collagen uses one ingredient and provides an impressive amino acid profile to support healthy skin, hair, joints, and nails, along with muscle recovery.”

It provides an impressive amino acid profile, though with 10 grams of collagen per serving, “you might look for a more nutrient-dense option” if you want more than that, Bourgeois says. Still, as noted in the aforementioned study, collagen dosages as low as 2.5 grams may be effective, so this product is worthy of a 4-out-of-5-point rating in the formula category. (2) 

Other bonuses, according to Bourgeois, are that hydrolyzed peptides are said to be easier to digest and utilize and the product is third-party tested, unlike many other collagen products available.

After taste-testing Sports Research Collagen, it earned high remarks for taste and texture, too. “I like this collagen supplement compared to the others I’ve taken in the past,” our tester says. “There isn’t a strong smell or taste—it’s unnoticeable. I tried the unflavored collagen, and I did not taste anything when trying it in water and coffee, so I give it a 5 out of 5 for taste.”

“It’s also easy to mix the powder with water at room temperature,” our tester says, noting that the collagen did not stick to the sides of the cup or float on the top. It mixes well with hot coffee, too, our tester finds, but undissolved chunks persisted in cold coffee. Our tester was able to remedy the cold coffee issue by using a shaker bottle, and ultimately awarded the product a score of 5 out of 5 points for solubility.

Best Collagen Supplement for Hair: Pro Health Longevity Collagen

Part of what makes Pro Health Longevity Collagen an excellent choice for those with hair troubles is that it includes marine-based collagen, which is the type that has been most extensively studied for its effects on hair health.

Though more research is needed to support the use of collagen for hair health, some evidence does show promise. (3) For example, increases in total hair count, hair density, and hair regrowth have all been noted after supplementation with marine-based hydrolyzed collagen. (4)(5)

Registered dietitian Chelsea Rae Bourgeois rates this collagen’s formula with 4.5 out of 5 points, stating that her “main hiccup” is that the manufacturer doesn’t disclose how much of each type of collagen is in the blend. “Those who prefer to know how much of each source is included in the blend may be turned off by the mystery of it all,” she says.

The blend includes an impressive 20 grams of collagen per serving and a hefty dose of hyaluronic acid, biotin, vitamin C, and zinc. The 250-milligram dose of hyaluronic acid is “on the upper end of what research has shown to be effective for skin health and significantly more than competing collagen powders,” Bourgeois says. (6)(7)

The biotin in this blend could also help strengthen your locks. Biotin is vitamin B7; individuals with a B7 deficiency may experience brittle, weak hair and/or hair loss (though biotin deficiency is rare). (8)(9) 

All of these benefits come with a cost: This is the most expensive collagen peptide powder in our guide, at nearly $2 per serving.

Our product testers awarded Pro Health Longevity Collagen 4 out of 5 points for taste and 5 out of 5 points for solubility. “I couldn’t detect it at all in my coffee, but I could pick up a little taste in plain water,” our tester says. They note that the collagen mixes excellently in both water and coffee, though it does produce a lot of foam if you blend it. No big deal if you like frothy smoothies.

Best Liquid Collagen Supplement: Momentous Collagen Shot

If you’re looking for an on-the-go collagen supplement that doesn’t require mixing, consider Momentous Collagen Shots. This liquid collagen formula is much like a running gel: Tear off the top and squeeze it into your mouth. With no stirring or shaking needed, it’s a great option for people who travel often or take their supplements on the way to or from work and the gym. 

“If you’ve taken running gels, then this should be a breeze to take,” our tester said. “Even if you haven’t used gels before, I think it’s pretty easy to take.” They rated the shot with 4 out of 5 points for “swallowability.”

The Momentous Collagen Shot earned 3 out of 5 points for taste because it has a slight aftertaste, although “if you do it like a shot, that aftertaste isn’t nearly as strong,” our tester said. Otherwise, it tastes slightly sweet with hints of orange, according to our tester.

Those watching their sugar intake should know that the shot contains 3 grams of sugar, 2 of which are added sugar. It’s not much, but worth noting.  

As far as the formula, it’s pretty standard, with 10 grams of hydrolyzed bovine collagen per serving. It also includes 35 milligrams of vitamin C to encourage enhanced collagen synthesis in the body. For its simplicity and effective dosing, Momentous collagen earns 4 out of 5 points in the formula category. 

Individuals on a tight budget may want to look elsewhere: Momentous Collagen Shots cost about $2.80 per serving, compared to the typical $1-$2 per serving range.

[Read More: Best Creatine Gummies]

Best Collagen Supplement for Skin: Bulletproof Collagen

Bulletproof may be known for its MCT-enhanced Bulletproof Coffee, but the brand manufactures a number of other supplements, too, collagen being one of them. Bulletproof Collagen is available unflavored or in vanilla and chocolate flavors. There are also caffeinated and probiotic-enhanced versions available. 

Bulletproof Collagen contains collagens type I and type III. Type I is the most common collagen in the body and is critical for providing structure to the skin. Type III is found in many tissues in association with type I, and may play a role in the size regulation of type I collagen. (13)(14)

The regular unflavored, chocolate, or vanilla powders pack 20 grams of collagen per serving, which is on the high end across collagen supplements. The unflavored version boasts an incredibly simple ingredients list, which includes just one ingredient: hydrolyzed bovine collagen.

The chocolate and vanilla versions, on the other hand, come with a list of other ingredients you may or may not want in your collagen supplement: MCT oil, coconut creamer powder, maltodextrin, stevia, and erythritol, to name a few. None of these are inherently bad, but if you prefer a simpler formula, the unflavored option is your better bet. 

I rate the unflavored version with 5 out of 5 points for its simplicity and high dose of collagen, and the flavored versions with 3 out of 5 points due to the extra and, frankly, unnecessary ingredients; the overall score averages out of 4 out of 5 points for the formula. 

Our testers rated Bulletproof Collagen with 5 out of 5 points for both taste and solubility, saying, “The flavor really is unflavored. I couldn’t detect it at all in my coffee and not much in water, either; I mixed it with a spoon in a cold drink, and in my hot coffee with a spoon, and in both instances, it dissolved almost entirely with minimal effort.”

[Related: Should Strength Athletes Be Drinking Bulletproof Coffee?]

Best Collagen Supplement for Athletes: BUBS Naturals Collagen

Competitive athletes must take special care when choosing supplements to ensure they are free from performance-enhancing drugs or any other substances banned in their sport. BUBS Natural Collagen is an excellent choice for athletes because it’s an NSF Informed Sport product, meaning it has undergone extensive testing to ensure it’s free from banned substances. 

Our product tester, a competitive weightlifter, confidently used BUBS Natural Collagen for months and had positive things to say overall. They awarded it 5 out of 5 points for taste (or lack thereof): “Not even a hint of taste in my coffee,” our tester said. 

BUBS didn’t score quite as high in the solubility department, but still earned a very respectable 4 out of 5 points. Our tester said, “There were still some small pieces floating in my coffee, but it’s not enough to deter me from drinking it.” 

In addition to its solid taste and texture, this collagen peptide powder has a straightforward formula: It’s just collagen, and 20 grams of it per serving at that. The sports nutrition coach in me is thrilled with this — it’s simple and effectively dosed — and I give it 5 out of 5 points for formula.

This isn’t the least nor most expensive collagen powder available, with the price per serving falling at around $1.70 for the larger tub (28 servings). Our tester opted to try the travel packs, which have a higher cost per serving ($1.85) but are more convenient. “I love the single-serve travel packs, which were an easy way for me to keep up my collagen intake while I was on the road for work,” our tester said.

[Read More: Best Muscle Recovery Supplements]

Best Collagen Capsules: HUM Collagen Love

Prefer a pill over a powder? HUM Collagen Love might be the right collagen peptide supplement for you. “These capsules are pretty small, definitely smaller than a fish oil pill, for instance,” our expert tester says. “Personally, I don’t have any issues taking them. “They don’t have any taste or aftertaste at all, which is great.”

This third-party tested capsule contains hydrolyzed, grass-fed bovine collagen, vitamin C, hyaluronic acid, and antioxidants. Vitamin C is important for natural collagen synthesis in the body, and hyaluronic acid has been shown to reduce wrinkles and increase skin hydration. (15) (16) “I like that the formula has some vitamin C in it,” one of our testers said. “That way, you probably don’t have to take an additional vitamin C supplement.”

The formula also contains other ingredients with potential skin health benefits. Chondroitin sulfate, a compound that provides structure to the skin, may have anti-aging properties, and grape-seed extract may reduce UV-related oxidative stress in the skin. (17) (18)

Still, one serving contains just 6 grams of collagen, leading me to rate the formula with 3.5 out of 5 points. If a lot of collagen is what you’re after, you may want to try another option with 10 to 20 grams per serving.

At $1.33 per serving, HUM Collagen Love is reasonably priced. Our tester didn’t have any issues with the taste — the capsules are flavorless — and said that the capsules are small enough to swallow easily. HUM Collagen Love earned 5 out of 5 points for both taste and “swallowability.” That said, one of our testers noted: “You have to take three per dose, which can be a bit much, especially if you’re taking other supplements.”

Benefits of Collagen

Collagen is well-known for its supporting a youthful appearance. It does, after all, play a huge role in providing structure to the skin. However, that’s not the only reason to take collagen. As it’s such an abundant protein in the body, it makes sense that it has a number of other potential benefits, too. 

• Supports healthy skin: According to a 2022 review of randomized controlled trials in Dermatology Practical and Conceptual, oral collagen supplementation “can contribute to reducing or delaying skin aging.” (19) And in 2019, a systematic review in the Journal of Drugs in Dermatology found that supplementing with 3 to 10 grams of collagen daily improves skin hydration and elasticity. (20)
• Supports healthy joints: Reduced levels of type II collagen have been associated with the development of osteoarthritis, a degenerative joint disease, according to 2017 research in Mechanisms of Ageing and Development. (21) Collagen supplementation can reduce osteoarthritis symptoms, say researchers in a 2019 meta-analysis in International Orthopaedics. (22) In 2020, authors of a systematic review in Rheumatology and Therapy concluded that collagen supplementation could be a potential therapeutic for osteoarthritis and associated symptoms, like joint pain. (23)
• May improve hair and nail health: If nail and hair growth are priorities for you, collagen might help. There is less research in this area, but what we do have is promising. A 2022 animal study in the International Journal of Molecular Science concluded that six weeks of fish collagen supplementation resulted in “hair-growth-promoting effects.” (24) A 2017 trial in the Journal of Cosmetology found that 24 weeks of collagen supplementation resulted in fewer broken nails and a 12% increase in nail growth rate. (25)
• May support cardiovascular health: Some types of collagen are found in the arteries; the protein provides structure and flexibility to these blood vessels. According to research in Vascular Health and Risk Management, low levels of collagen can increase arterial stiffness, which in turn increases the risk of atherosclerosis. (26) (27) A 2017 trial in the Journal of Atherosclerosis and Thrombosis found that six weeks of collagen supplementation can improve biomarkers related to atherosclerosis; note that there was no placebo control for this trial. (28)
• May play a role in muscle mass: Collagen is found in muscle tissue; specifically, it may account for up to 10% of muscle mass dry weight, according to research in Muscle & Nerve. (29) In older cis men with sarcopenia (age-related muscle loss), taking collagen supplements and doing strength training results in greater muscle gain than strength training alone, according to a study in the British Journal of Nutrition. (30) Just remember: While collagen is high in some amino acids, including glycine, it lacks the essential amino acid tryptophan. It shouldn’t be a replacement for a complete protein powder.
• May support bone health: Collagen is also found in bone tissue, so scientists have proposed that it may be able to reduce bone mineral density loss and delay the development of osteoporosis. Research is less profound in this area, but some research, including a 2016 systematic review that looked at 10 years of studies, has found that collagen can positively impact bone mineral density. (31)

How Much Do Collagen Supplements Cost

You can expect to pay around $40 for a month’s worth of collagen, on average. As usual, some brands offer less expensive collagen peptide powders and some offer more expensive options. The price differences account for how high-quality the collagen is; what type(s) of collagen are in the powder; additional ingredients; and third-party testing, among other things.If you’re committed to your collagen supplement, you can save some cash by signing up for recurring purchases. 

Best Collagen Supplement Overall	Transparent Labs Collagen Hydrolysate	$34.99 (30 servings)
Best Collagen Supplement for Hair	Pro Health Longevity Collagen	$59.95 (30 servings)
Best Budget Collagen Supplement	Nutricost Collagen	$14.95 (10 servings); $22.95 (31 servings)
Best Organic Collagen Supplement	Sports Research Collagen	$14.95 (10 servings); $36.95 (41 servings)
Best Collagen Supplement for Women	Gainful Collagen	$22 (14 servings); $44 (28 servings); $66 (42 servings)
Best Liquid Collagen Supplement	Momentous Collagen Shot	$41.95 (15 servings)
Best Collagen Supplement for Skin	Bulletproof Collagen	$43.95 (25 servings); $85.54 (60 servings)
Best Collagen Supplement for Athletes	BUBS Natural Collagen	$47 (28 servings)
Best Collagen Capsules	HUM Collagen Love	$40 (30 servings)

What to Consider Before Buying Collagen

Like most supplements, there’s a lot that goes into making an effective collagen peptide powder. Factor these considerations into your search when shopping for collagen. 

Collagen Type 

You’ll find five types of collagen in supplements, generally. They are (32): 

• Type I collagen: The most abundant type; found in skin, joint tissues (tendons and ligaments), and bone tissue
• Type II collagen: Found in elastic cartilages; important for joint health
• Type III collagen: Found in muscle tissue, organ tissues, and arteries
• Type IV collagen: Found in the skin; responsible for providing structure to the skin
• Type V collagen: Found in some layers of the skin; also found in corneas and hair

Because type I collagen is the most abundant type, making up about 90% of all collagen found in the body according to Cleveland Clinic, the formula for most supplements is mainly type I. However, some formulas contain blends based on specific desired outcomes; for example, a skin health formula may contain mostly type I with type IV as well.

Collagen Source

Those with dietary concerns or preferences will want to look at the source of the collagen. The most common sources are bovine and marine. You may want to look for bovine collagen from sources that are grass-fed or pasture-raised, or from marine sources that are not farmed. Vegan collagen exists, too, and it is created in labs from modified yeast, bacteria, human genes, and enzymes. (33) 

Other Ingredients

Some collagen supplements contain additional ingredients for other health benefits, including probiotics, keratin, biotin, vitamins, minerals, and antioxidants. Sweeteners, including regular sugar and alternative or artificial sweeteners, may be present, too. Study the supplement facts label to make sure the ingredients align with your dietary preferences, whether you need something that’s paleo-friendly, non-GMO, keto, gluten-free, or something else. 

Grams Per Serving and Cost

A cost per serving between $0.70 and $2 is considered reasonable for collagen peptide supplements. Anything higher is on the expensive side, and should come with some special benefit (like additional ingredients or extensive lab testing) to justify the cost. For anything less expensive than $0.70 per serving, research the product to find out if it contains unnecessary filler ingredients and/or has poor manufacturing processes.

Third-Party Testing

Independent lab testing, also called third-party testing, refers to a process that manufacturers can pursue to certify their products. By going through this process, manufacturers can prove that their supplements are free from heavy metals, bacteria, allergens, and substances that are banned in sport. Athletes in particular should look for NSF certified supplements to ensure they are free from performance-enhancing drugs.

The Best Collagen Peptides Supplements FAQs

References

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2. Paul C, Leser S, Oesser S. Significant Amounts of Functional Collagen Peptides Can Be Incorporated in the Diet While Maintaining Indispensable Amino Acid Balance. Nutrients. 2019;11(5):1079. https://pubmed.ncbi.nlm.nih.gov/31096622/  
3. Rustad AM, Nickles MA, McKenney JE, Bilimoria SN, Lio PA. Myths and media in oral collagen supplementation for the skin, nails, and hair: A review. J Cosmet Dermatol. 2022;21(2):438-443. https://onlinelibrary.wiley.com/doi/10.1111/jocd.14567 
4. Ablon G. A 6-month, randomized, double-blind, placebo-controlled study evaluating the ability of a marine complex supplement to promote hair growth in men with thinning hair. J Cosmet Dermatol. https://onlinelibrary.wiley.com/doi/10.1111/jocd.12265 
5. Milani M, Colombo F; GFM-O-Trial Investigators Group: Chiara Baraldo (Padova), Mauro Barbareschi (Milano), Paolo Chieco (Ruvo di Puglia), Laura Colonna (Roma), Mandel Victor Desmond (Modena), Maria Cristina Fiorucci (Genova). Efficacy and tolerability of an oral supplement containing amino acids, iron, selenium, and marine hydrolyzed collagen in subjects with hair loss (androgenetic alopecia, AGA or FAGA or telogen effluvium). A prospective, randomized, 3-month, controlled, assessor-blinded study. Skin Res Technol. 2023;29(6):e13381. https://onlinelibrary.wiley.com/doi/10.1111/srt.13381  
6. Hsu TF, Su ZR, Hsieh YH, et al. Oral Hyaluronan Relieves Wrinkles and Improves Dry Skin: A 12-Week Double-Blinded, Placebo-Controlled Study. Nutrients. 2021;13(7):2220. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8308347/ 
7. Gao YR, Wang RP, Zhang L, et al. Oral administration of hyaluronic acid to improve skin conditions via a randomized double-blind clinical test. Skin Res Technol. 2023;29(11):e13531. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10661223/ 
8. Office of Dietary Supplements. National Institute of Health. Biotin: Health Professional Fact Sheet. https://ods.od.nih.gov/factsheets/Biotin-HealthProfessional/ 
9. Bistas KG, Tadi P. Biotin. [Updated 2023 Jul 3]. In: StatPearls [Internet]. https://www.ncbi.nlm.nih.gov/books/NBK554493/ 
10. Martínez-Ramírez MJ, Palma Pérez S, Delgado-Martínez AD, Martínez-González MA, De la Fuente Arrillaga C, Delgado-Rodríguez M. Vitamin C, vitamin B12, folate and the risk of osteoporotic fractures. A case-control study. Int J Vitam Nutr Res. 2007;77(6):359-368. https://pubmed.ncbi.nlm.nih.gov/18622945/ 
11. Rondanelli M, Peroni G, Fossari F, et al. Evidence of a Positive Link between Consumption and Supplementation of Ascorbic Acid and Bone Mineral Density. Nutrients. 2021;13(3):1012. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8003869/ 
12. Stevens, Christopher & Bhusal, Kamal & Levine, Steven & Dhawan, Richa & Jain, Sushil. (2023). The association of vitamin C and vitamin D status on bone mineral density and VCAM-1 levels in female diabetic subjects: Is combined supplementation with vitamin C and vitamin D potentially more successful in improving bone health than supplementation with vitamin D alone?. Human Nutrition & Metabolism. 34. 200221. https://www.sciencedirect.com/science/article/pii/S2666149723000385 
13. Kuivaniemi H, Tromp G. Type III collagen (COL3A1): Gene and protein structure, tissue distribution, and associated diseases. Gene. 2019;707:151-171. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6579750/ 
14. Liu X, Wu H, Byrne M, Krane S, Jaenisch R. Type III collagen is crucial for collagen I fibrillogenesis and for normal cardiovascular development. Proc Natl Acad Sci U S A. 1997;94(5):1852-1856. https://www.pnas.org/doi/full/10.1073/pnas.94.5.1852 
15.  Pullar JM, Carr AC, Vissers MCM. The Roles of Vitamin C in Skin Health. Nutrients. 2017;9(8):866. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5579659/ 
16. Hsu TF, Su ZR, Hsieh YH, et al. Oral Hyaluronan Relieves Wrinkles and Improves Dry Skin: A 12-Week Double-Blinded, Placebo-Controlled Study. Nutrients. 2021;13(7):2220.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8308347/ 
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