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.
The form of vitamin B12 you choose probably matters less in the long run than how much you take and how you take it. At a low dose of around 2 micrograms, your body absorbs an average of 46%; at a high single dose of around 18 micrograms, that drops to just 8%. Small, spread-out doses are therefore more efficient if your gut is working normally.
If you want to correct a deficiency, the amount is what counts. Older adults respond poorly to daily oral doses below 500 micrograms, even without a classic absorption disorder. The recommended amount is 1000 micrograms per day for at least one month, followed by long-term maintenance. On the label you are looking for 'Vitamin B12 1000 µg'. Whether you then choose cyanocobalamin, methylcobalamin or hydroxocobalamin makes little difference to the end result: all three ultimately deliver comparable amounts of active substance to your cells. The finding that hydroxocobalamin is taken up by cells more quickly than cyanocobalamin has been demonstrated in cells in the laboratory, not in people; do not draw hard conclusions from it. If you have a deficiency or take medication, always discuss supplementation with your doctor.
After a total gastrectomy you can no longer absorb vitamin B12 normally. In that case, people in research received 1500 micrograms of mecobalamin (a form of methylcobalamin) per day orally, or 1000 micrograms of cyanocobalamin by injection, for at least 3 months, presumably lifelong. On the label you are looking for 'Vitamin B12 1500 µg (mecobalamin)'. Discuss this with your doctor: in the case of an absorption disorder, an injection may be necessary.
For cognitive decline, cellular ageing or compensating for smoking, vitamin B12 has been too little studied to recommend. In smokers it has been shown that the active form in the blood is significantly lower than in non-smokers, while the total B12 result appears normal. A standard blood test therefore does not fully rule out a functional deficiency in smokers, but whether supplementation corrects that has not been studied.
The cell studies on absorption speed are laboratory research (HeLa cells), not human clinical research. The conclusions about dosing and injections in malabsorption are based on reviews and one clinical trial. The strength of evidence varies by sub-question: moderate for dosing and injection in malabsorption, limited for the comparison of B12 forms at the cellular level.
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 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.
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.
When is the best time to take fisetin?
There is no human research identifying an optimal time to take fisetin. What the available animal research makes clear is that formulation matters far more than timing: plain fisetin is poorly absorbed, and improved forms have so far only been tested in mice.
How much CoQ10 do you need per day?
There is no established daily dose of CoQ10 for healthy people. The form on the label determines how much your body absorbs: a soft-gel capsule works considerably better than a standard tablet.
Does liposomal vitamin C work better than regular vitamin C?
Liposomal vitamin C reaches higher blood levels than regular vitamin C, but whether that translates into real health benefits has not been proven. The higher price cannot yet be justified for most people.