Which type of collagen is best to take?
For the skin, hydrolysed collagen peptides (2.5 to 5 grams per day for at least 8 to 12 weeks) are the best-supported option. For knee pain, you can try UC-II (40 mg per day) or hydrolysed collagen (10 grams per day) for six months, but the only independent study found no effect.
Which type of collagen you choose depends on your goal. For the skin, choose hydrolysed collagen: the label will say 'collagen peptides', 'gehydrolyseerd collageen' or 'hydrolyzed collagen'. Whether it comes from fish, beef or pork makes no difference. Take 2.5 to 5 grams per day for at least 8 to 12 weeks. Multiple studies comparing it against a placebo show improvements in hydration, wrinkles and elasticity. This is the best-supported application.
For knee pain caused by osteoarthritis, you can try two forms. Unprocessed type II collagen, labelled 'UC-II' or 'undenatured type II collagen', is taken as a capsule: 40 mg per day for 6 months. Hydrolysed collagen is taken as a powder: 10 grams per day for 6 months. Worth noting: the positive UC-II study involving 191 participants was conducted by employees of the manufacturer. The only independent study, with 68 participants, found no difference compared with the placebo after 12 weeks. If you want to try it, bear in mind that the outcome is uncertain.
If you are an active athlete with joint pain but without osteoarthritis, you can also try hydrolysed collagen: 10 grams per day for 6 months. If you exercise less, it is probably not worth your money. For bone density after menopause, you can try specific collagen peptides: 5 grams per day for 12 months. This is based on a single study with 131 women, so the level of certainty is limited.
For tendons and injury prevention, collagen has been too little studied to recommend: the only study included 8 men and lasted 3 days. For muscle mass, other protein works better. For hair, nails and heart health, there is no evidence. Do not buy collagen for those purposes, however tempting the packaging may be. One final observation about this whole topic: many positive studies have been funded by or conducted at manufacturers. The only fully independent study on osteoarthritis found no effect at all. That calls for modest expectations.
Based on multiple RCTs (n=32 to n=191), one small crossover study (n=8), and two review articles. Important caveat: a considerable portion of the positive evidence comes from (partly) industry-funded research; the only fully independent RCT (PMID 40897777) found no effect.
Which form of magnesium is best to take?
Magnesium citrate has the strongest evidence for absorption into the body. Magnesium oxide, the cheapest option, demonstrably performs the worst and is best avoided.
Which form of vitamin B12 is best to take?
The form of vitamin B12 matters less than the dose: when correcting a deficiency, what counts above all is taking enough. When there is an absorption disorder, injections are the indicated route; discuss that with your doctor.
Which form of zinc is best to take?
Zinc picolinate and zinc histidine have the strongest independent evidence for good absorption, but all comparative studies are small. Avoid large portions of grains around the time of intake, as phytate substantially blocks absorption.
What is best not to combine with creatine?
Combining creatine with caffeine powder adds nothing to your performance and increases the risk of gastrointestinal complaints; ready-made pre-workout blends with many ingredients carry additional risks due to possible contamination and unknown long-term effects.
How much collagen per day is worthwhile?
For the skin, 2.5 to 5 grams of hydrolysed collagen per day demonstrably works after at least 8 to 12 weeks: pay attention to the active peptide content, not just the grams on the label. For knee complaints, a completely different product has been studied, so look carefully at which form you buy.
Does collagen help your joints and your skin?
For joint pain due to knee osteoarthritis and for active athletes, collagen is worth trying: 10 grams of collagen peptides per day for 6 months, preferably in combination with exercise. For the skin, 2.5 to 5 grams per day is recommended, but some of the research comes from manufacturers.