How long does it take for supplements to work? We ask the experts
A friend of mine recently started taking B vitamins. After months of feeling really run down, she turned to a B-complex supplement to boost her mood and energy (vitamin B6 and B12 together are known to boost energy by forming red blood cells and converting fat and protein into energy). Within a week, she was like a different person.
She’d come into the office fizzing with renewed vigour. She was meal prepping, talking about getting into running – things she probably didn’t have the energy to do beforehand. Seeing how quickly she seemed to benefit from them, I wanted to know how it takes for vitamin supplements to work and whether she was benefiting from a placebo effect or genuinely experiencing a B vitamin power drive.
“This differs slightly for everyone, but generally, vitamins are absorbed in a matter of hours,” says Melissa Snover, registered nutritionist and founder of 3D-printed personalised vitamin brand Nourished. “For people who are significantly lacking in a certain vitamin or nutrient, it may take longer to recover from the deficiency and restore your nutrients back to an optimal level.”
The time it takes for a supplement to be absorbed, however, may depend on the type of supplement you’re taking (tablet, liquid or gummy, for example). Snover highlights the fact that a recent study looked to establish whether vitamin D supplements are best absorbed when taken as a pill or gummy, and the findings suggested that “gummies allow for increased absorption of the vitamin D”.
HOW LONG DOES IT TAKE TO NOTICE A DIFFERENCE?
My pal may have noticed a difference immediately, but I’ve been taking B vitamins for a while too (I’m vegan, I need that sweet B12) and to be honest, I’m no different to before. As ever, Snover stresses that we’re all different so how long it takes to notice vitamins working – and indeed what “working” looks like – is going to be different for each of us.
Snover recommends allowing up to 12 weeks to notice a change in energy (if that’s what you’re looking to improve). “Like anything, you need to be consistent and remember to take them daily.”

Daniel O’Shaughnessy, director of nutrition and certified functional medicine practitioner at The Naked Nutritionist, tells Stylist that you’ve got to bear in mind the dose and type of supplement you’re taking. “For something to correct a deficiency such as vitamin D, it can take up to three months to work. Others, such as a digestive enzyme, can work immediately by improving the digestion of food.”
HOW TO GET THE MAXIMUM BENEFIT FROM YOUR SUPPLEMENTS
The key, as that vitamin D study suggests, is how you take your vitamins. You want to make sure that they’re as bioavailable and open to absorption as possible. Some vitamins, for example, are best taken with meals.
SUPPLEMENTS TO EAT WITH MEALS
Fat-soluble vitamins like A, D, E and K require fat for your body to absorb them, so you’re best off taking them alongside a fatty breakfast (yoghurt and fruit, avocado on toast, eggs, protein shake bowls). “Sometimes probiotics are also better with food to help reach the gut alive and not be destroyed by stomach acid,” O’Shaughnessy says.
SUPPLEMENTS TO TAKE WITHOUT FOOD
But others are best off taken on an empty stomach. “Usually it can depend on the supplement being better absorbed if taken on an empty stomach or with food. An example would be glutathione (which helps with tissue repair), which is better on an empty stomach.” Read More...