Vitamin K2 is one of the fat‑soluble vitamins, along with vitamins A, D and E. It plays a key role in the body:
- it contributes to normal blood clotting
- it helps to maintain normal bone structure, notably thanks to its role in calcium regulation
It is now of interest in the fields of sports nutrition and aging. Some researchers are wondering whether its effects could go beyond the skeleton, particularly on muscle function.
The team led by Hannah Lithgow at Heriot‑Watt University in Edinburgh sought to find out whether vitamin K2 supplementation could influence muscle recovery after intense exercise. Let’s break down this study together, published in April 2026.
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How was the study conducted?
The scientists carried out a randomized, double‑blind, controlled trial, considered one of the most robust designs when it comes to scientific studies.
The study included at least 71 participants, divided into two groups, taking age and sex into account:
- a group receiving vitamin K2, menaquinone-7, MK-7 (240 µg/day)
- a placebo group
The study was conducted both in young adults (18 to 40 years) and in older adults (65 years and over), which makes it possible to observe any age-related differences.
The protocol took place in three phases:
- a series of initial physical tests
- 12 weeks of supplementation
- the same tests repeated after the intervention
To concretely assess recovery, the participants followed a strength training protocol, intended to create muscle micro-injuries resulting in soreness. To do this, they had to perform several long sets of leg extensions and bench presses (weightlifting exercises), carried out at 70% of their one-repetition maximum.
After this exercise, recovery was monitored precisely, with repeated measurements 3, 24, 48, and 72 hours after the effort:
- muscle strength
- muscle soreness
- muscle function
- as well as blood markers related to muscle damage
With the aim of comparing the progression between the group supplemented with vitamin K2 and the placebo group, to see whether the vitamin helped limit damage or speed up recovery.
And the results?
First important point: the supplementation worked well. After 12 weeks, vitamin K2 (MK-7) concentrations increased markedly in the supplemented participants, both in the young and in the older adults. In other words, the dose used is well absorbed and effective in improving vitamin K status.
However, vitamin K2 supplementation did not show any significant effect on muscle recovery, whether in young adults or in older participants.
Specifically:
- the loss of strength after exercise was similar between the two groups
- performance recovery followed the same curve
- the biological markers of muscle damage did not differ significantly
In other words, under the conditions of this study, vitamin K2 does not appear to influence recovery after an intense strength training session.
What needs to be qualified
This study does not show that vitamin K2 is “useless,” but rather that it did not have a clear effect in this specific context.
First point: the participants were healthy and had no particular deficiency in vitamin K2.
Next, the intensity of the induced muscle damage was relatively low, which reduces the ability to detect a possible effect.
Finally, even in the absence of a main effect, signals appear in older people, such as the improvement of certain neuromuscular parameters. This could suggest that certain categories of people might benefit from K2 supplementation, but this still needs to be confirmed.
In summary
In the end, this study mainly suggests that vitamin K2 is not a powerful “booster” of muscle recovery. It reminds us that we sometimes need to take a step back from the miracle promises we may occasionally read.
Scientific reference
Lithgow H, Johnston L, Ho F, Dunning E, Nakada S, Celis-Morales C, Hunter AM, Lees JS, Mark PB, Quinn TJ, Gray SR. (2026) The Effects of Vitamin K2 on Recovery from Muscle-Damaging Resistance Exercise in Young and Older Adults: The TAKEOVER Randomized Controlled Trial. https://pubmed.ncbi.nlm.nih.gov/41843412/
